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* [PATCH v4 0/4] PCI EP driver support MSI doorbell from host
@ 2022-08-12 21:52 Frank Li
  2022-08-12 21:52 ` [PATCH v4 1/4] irqchip: allow pass down .pm field at IRQCHIP_PLATFORM_DRIVER_END Frank Li
                   ` (3 more replies)
  0 siblings, 4 replies; 11+ messages in thread
From: Frank Li @ 2022-08-12 21:52 UTC (permalink / raw
  To: maz, tglx, robh+dt, krzysztof.kozlowski+dt, shawnguo, s.hauer, kw,
	bhelgaas
  Cc: kernel, devicetree, linux-arm-kernel, linux-pci, peng.fan,
	aisheng.dong, jdmason, kernel, festevam, linux-imx, kishon,
	lorenzo.pieralisi, ntb, lznuaa


                  ┌───────┐          ┌──────────┐
                  │       │          │          │
┌─────────────┐   │       │          │ PCI Host │
│ MSI         │◄┐ │       │          │          │
│ Controller  │ │ │       │          │          │
└─────────────┘ └─┼───────┼──────────┼─Bar0     │
                  │ PCI   │          │ Bar1     │
                  │ Func  │          │ Bar2     │
                  │       │          │ Bar3     │
                  │       │          │ Bar4     │
                  │       ├─────────►│          │
                  └───────┘          └──────────┘

Many PCI controllers provided Endpoint functions.
Generally PCI endpoint is hardware, which is not running a rich OS,
like linux.

But Linux also supports endpoint functions.  PCI Host write BAR<n> space
like write to memory. The EP side can't know memory changed by the Host
driver. 

PCI Spec has not defined a standard method to do that.  Only define
MSI(x) to let EP notified RC status change. 

The basic idea is to trigger an IRQ when PCI RC writes to a memory
address. That's what MSI controller provided.  EP drivers just need to
request a platform MSI interrupt, struct MSI_msg *msg will pass down a
memory address and data.  EP driver will map such memory address to
one of PCI BAR<n>.  Host just writes such an address to trigger EP side
IRQ.

If system have gic-its, only need update PCI EP side driver. But i.MX
have not chip support gic-its yet. So we have to use MU to simulate a
MSI controller. Although only 4 MSI IRQs are simulated, it matched
vntb(pci-epf-vntb) network requirement.

After enable MSI, ping delay reduce < 1ms from ~8ms

IRQchip: imx mu worked as MSI controller: 
     let imx mu worked as MSI controllers. Although IP is not design
as MSI controller, we still can use it if limited IRQ number to 4.

pcie: endpoint: pci-epf-vntb: add endpoint MSI support
	 Based on ntb-next branch. https://github.com/jonmason/ntb/commits/ntb-next
	 Using MSI as door bell registers
	 This patch is totally independent on previous on. It can be
applied to ntb-next seperately.

i.MX EP function driver is upstreaming by Richard Zhu.
Some dts change missed at this patches. below is reference dts change

--- a/arch/arm64/boot/dts/freescale/imx8-ss-hsio.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8-ss-hsio.dtsi
@@ -160,5 +160,6 @@ pcieb_ep: pcie_ep@5f010000 {
                num-ib-windows = <6>;
                num-ob-windows = <6>;
                status = "disabled";
+               MSI-parent = <&lsio_mu12>;
        };

--- a/arch/arm64/boot/dts/freescale/imx8-ss-lsio.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8-ss-lsio.dtsi
@@ -172,6 +172,19 @@ lsio_mu6: mailbox@5d210000 {
                status = "disabled";
        };

+       lsio_mu12: mailbox@5d270000 {
+               compatible = "fsl,imx6sx-mu-MSI";
+               msi-controller;
+               interrupt-controller;
+               reg = <0x5d270000 0x10000>,     /* A side */
+                     <0x5d300000 0x10000>;     /* B side */
+               reg-names = "a", "b";
+               interrupts = <GIC_SPI 191 IRQ_TYPE_LEVEL_HIGH>;
+               power-domains = <&pd IMX_SC_R_MU_12A>,
+                               <&pd IMX_SC_R_MU_12B>;
+               power-domain-names = "a", "b";
+       };
+

Change Log
- Change from v3 to v4
  Fixed dt-binding document according to Krzysztof Kozlowski's feedback
  Fixed irqchip-imx-mu-worked-as-msi-controller according to Marc Zyngier's
        comments.

	There are still two important points, which I am not sure.
	1. clean irq_set_affinity after platform_msi_create_irq_domain.
	   Some function, like platform_msi_write_msg() is static.
	   so I have to set MSI_FLAG_USE_DEF_CHIP_OPS flags, which will
	   set irq_set_affinity to default one.
	2. about comments

	> +	msi_data->msi_domain = platform_msi_create_irq_domain(
	> +				of_node_to_fwnode(msi_data->pdev->dev.of_node),
	> +				&imx_mu_msi_domain_info,
	> +				msi_data->parent);

	"And you don't get an error due to the fact that you use the same
	fwnode for both domains without overriding the domain bus token?"

 	I did not understand yet. 

  Fixed static check warning, reported by Dan Carpenter
	pcie: endpoint: pci-epf-vntb: add endpoint MSI support

- Change from v2 to v3
  Fixed dt-binding docment check failure
  Fixed typo a cover letter.
  Change according Bjorn's comments at patch 
	pcie: endpoint: pci-epf-vntb: add endpoint MSI support
	 

- from V1 to V2
  Fixed fsl,mu-msi.yaml's problem
  Fixed irq-imx-mu-msi.c problem according Marc Zyngier's feeback 
  Added a new patch to allow pass down .pm by IRQCHIP_PLATFORM_DRIVER_END

-- 
2.35.1


^ permalink raw reply	[flat|nested] 11+ messages in thread

* [PATCH v4 1/4] irqchip: allow pass down .pm field at IRQCHIP_PLATFORM_DRIVER_END
  2022-08-12 21:52 [PATCH v4 0/4] PCI EP driver support MSI doorbell from host Frank Li
@ 2022-08-12 21:52 ` Frank Li
  2022-08-12 21:52 ` [PATCH v4 2/4] irqchip: imx mu worked as msi controller Frank Li
                   ` (2 subsequent siblings)
  3 siblings, 0 replies; 11+ messages in thread
From: Frank Li @ 2022-08-12 21:52 UTC (permalink / raw
  To: maz, tglx, robh+dt, krzysztof.kozlowski+dt, shawnguo, s.hauer, kw,
	bhelgaas
  Cc: kernel, devicetree, linux-arm-kernel, linux-pci, peng.fan,
	aisheng.dong, jdmason, kernel, festevam, linux-imx, kishon,
	lorenzo.pieralisi, ntb, lznuaa

IRQCHIP_PLATFORM_DRIVER_* compilation define platform_driver
for irqchip. But can't set .pm field of platform_driver.
Added variadic macros to set .pm field or other field if need.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
 include/linux/irqchip.h | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/include/linux/irqchip.h b/include/linux/irqchip.h
index 3a091d0710ae1..d5e6024cb2a8c 100644
--- a/include/linux/irqchip.h
+++ b/include/linux/irqchip.h
@@ -44,7 +44,8 @@ static const struct of_device_id drv_name##_irqchip_match_table[] = {
 #define IRQCHIP_MATCH(compat, fn) { .compatible = compat,		\
 				    .data = typecheck_irq_init_cb(fn), },
 
-#define IRQCHIP_PLATFORM_DRIVER_END(drv_name)				\
+
+#define IRQCHIP_PLATFORM_DRIVER_END(drv_name, ...)			\
 	{},								\
 };									\
 MODULE_DEVICE_TABLE(of, drv_name##_irqchip_match_table);		\
@@ -56,6 +57,7 @@ static struct platform_driver drv_name##_driver = {			\
 		.owner = THIS_MODULE,					\
 		.of_match_table = drv_name##_irqchip_match_table,	\
 		.suppress_bind_attrs = true,				\
+		__VA_ARGS__						\
 	},								\
 };									\
 builtin_platform_driver(drv_name##_driver)
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* [PATCH v4 2/4] irqchip: imx mu worked as msi controller
  2022-08-12 21:52 [PATCH v4 0/4] PCI EP driver support MSI doorbell from host Frank Li
  2022-08-12 21:52 ` [PATCH v4 1/4] irqchip: allow pass down .pm field at IRQCHIP_PLATFORM_DRIVER_END Frank Li
@ 2022-08-12 21:52 ` Frank Li
  2022-08-13  9:19   ` Marc Zyngier
  2022-08-13 11:57   ` Marc Zyngier
  2022-08-12 21:52 ` [PATCH v4 3/4] dt-bindings: irqchip: imx mu work " Frank Li
  2022-08-12 21:52 ` [PATCH v4 4/4] pcie: endpoint: pci-epf-vntb: add endpoint MSI support Frank Li
  3 siblings, 2 replies; 11+ messages in thread
From: Frank Li @ 2022-08-12 21:52 UTC (permalink / raw
  To: maz, tglx, robh+dt, krzysztof.kozlowski+dt, shawnguo, s.hauer, kw,
	bhelgaas
  Cc: kernel, devicetree, linux-arm-kernel, linux-pci, peng.fan,
	aisheng.dong, jdmason, kernel, festevam, linux-imx, kishon,
	lorenzo.pieralisi, ntb, lznuaa

MU support generate irq by write data to a register.
This patch make mu worked as msi controller.
So MU can do doorbell by using standard msi api.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/irqchip/Kconfig          |   7 +
 drivers/irqchip/Makefile         |   1 +
 drivers/irqchip/irq-imx-mu-msi.c | 443 +++++++++++++++++++++++++++++++
 3 files changed, 451 insertions(+)
 create mode 100644 drivers/irqchip/irq-imx-mu-msi.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 5e4e50122777d..4599471d880c0 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -470,6 +470,13 @@ config IMX_INTMUX
 	help
 	  Support for the i.MX INTMUX interrupt multiplexer.
 
+config IMX_MU_MSI
+	bool "i.MX MU work as MSI controller"
+	default y if ARCH_MXC
+	select IRQ_DOMAIN
+	help
+	  MU work as MSI controller to do general doorbell
+
 config LS1X_IRQ
 	bool "Loongson-1 Interrupt Controller"
 	depends on MACH_LOONGSON32
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 5d8e21d3dc6d8..870423746c783 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -98,6 +98,7 @@ obj-$(CONFIG_RISCV_INTC)		+= irq-riscv-intc.o
 obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
 obj-$(CONFIG_IMX_IRQSTEER)		+= irq-imx-irqsteer.o
 obj-$(CONFIG_IMX_INTMUX)		+= irq-imx-intmux.o
+obj-$(CONFIG_IMX_MU_MSI)		+= irq-imx-mu-msi.o
 obj-$(CONFIG_MADERA_IRQ)		+= irq-madera.o
 obj-$(CONFIG_LS1X_IRQ)			+= irq-ls1x.o
 obj-$(CONFIG_TI_SCI_INTR_IRQCHIP)	+= irq-ti-sci-intr.o
diff --git a/drivers/irqchip/irq-imx-mu-msi.c b/drivers/irqchip/irq-imx-mu-msi.c
new file mode 100644
index 0000000000000..bb111412d598f
--- /dev/null
+++ b/drivers/irqchip/irq-imx-mu-msi.c
@@ -0,0 +1,443 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * NXP MU worked as MSI controller
+ *
+ * Copyright (c) 2018 Pengutronix, Oleksij Rempel <o.rempel@pengutronix.de>
+ * Copyright 2022 NXP
+ *	Frank Li <Frank.Li@nxp.com>
+ *	Peng Fan <peng.fan@nxp.com>
+ *
+ * Based on drivers/mailbox/imx-mailbox.c
+ */
+#include <linux/clk.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/msi.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/of_irq.h>
+#include <linux/of_pci.h>
+#include <linux/of_platform.h>
+#include <linux/spinlock.h>
+#include <linux/dma-iommu.h>
+#include <linux/pm_runtime.h>
+#include <linux/pm_domain.h>
+
+
+#define IMX_MU_CHANS            4
+
+enum imx_mu_xcr {
+	IMX_MU_GIER,
+	IMX_MU_GCR,
+	IMX_MU_TCR,
+	IMX_MU_RCR,
+	IMX_MU_xCR_MAX,
+};
+
+enum imx_mu_xsr {
+	IMX_MU_SR,
+	IMX_MU_GSR,
+	IMX_MU_TSR,
+	IMX_MU_RSR,
+};
+
+enum imx_mu_type {
+	IMX_MU_V1 = BIT(0),
+	IMX_MU_V2 = BIT(1),
+	IMX_MU_V2_S4 = BIT(15),
+};
+
+/* Receive Interrupt Enable */
+#define IMX_MU_xCR_RIEn(data, x) ((data->cfg->type) & IMX_MU_V2 ? BIT(x) : BIT(24 + (3 - (x))))
+#define IMX_MU_xSR_RFn(data, x) ((data->cfg->type) & IMX_MU_V2 ? BIT(x) : BIT(24 + (3 - (x))))
+
+struct imx_mu_dcfg {
+	enum imx_mu_type type;
+	u32     xTR;            /* Transmit Register0 */
+	u32     xRR;            /* Receive Register0 */
+	u32     xSR[4];         /* Status Registers */
+	u32     xCR[4];         /* Control Registers */
+};
+
+struct imx_mu_msi {
+	spinlock_t			lock;
+	struct platform_device		*pdev;
+	struct irq_domain		*parent;
+	struct irq_domain		*msi_domain;
+	void __iomem			*regs;
+	phys_addr_t			msiir_addr;
+	const struct imx_mu_dcfg	*cfg;
+	unsigned long			used;
+	int				gic_irq;
+	struct clk			*clk;
+	struct device			*pd_a;
+	struct device			*pd_b;
+	struct device_link		*pd_link_a;
+	struct device_link		*pd_link_b;
+};
+
+static void imx_mu_write(struct imx_mu_msi *msi_data, u32 val, u32 offs)
+{
+	iowrite32(val, msi_data->regs + offs);
+}
+
+static u32 imx_mu_read(struct imx_mu_msi *msi_data, u32 offs)
+{
+	return ioread32(msi_data->regs + offs);
+}
+
+static u32 imx_mu_xcr_rmw(struct imx_mu_msi *msi_data, enum imx_mu_xcr type, u32 set, u32 clr)
+{
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&msi_data->lock, flags);
+	val = imx_mu_read(msi_data, msi_data->cfg->xCR[type]);
+	val &= ~clr;
+	val |= set;
+	imx_mu_write(msi_data, val, msi_data->cfg->xCR[type]);
+	spin_unlock_irqrestore(&msi_data->lock, flags);
+
+	return val;
+}
+
+static void imx_mu_msi_parent_mask_irq(struct irq_data *data)
+{
+	struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
+
+	imx_mu_xcr_rmw(msi_data, IMX_MU_RCR, 0, IMX_MU_xCR_RIEn(msi_data, data->hwirq));
+}
+
+static void imx_mu_msi_parent_unmask_irq(struct irq_data *data)
+{
+	struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
+
+	imx_mu_xcr_rmw(msi_data, IMX_MU_RCR, IMX_MU_xCR_RIEn(msi_data, data->hwirq), 0);
+}
+
+static void imx_mu_msi_parent_ack_irq(struct irq_data *data)
+{
+        struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
+
+        imx_mu_read(msi_data, msi_data->cfg->xRR + data->hwirq * 4);
+}
+
+static struct irq_chip imx_mu_msi_irq_chip = {
+	.name = "MU-MSI",
+	.irq_ack = irq_chip_ack_parent,
+};
+
+static struct msi_domain_ops imx_mu_msi_irq_ops = {
+};
+
+static struct msi_domain_info imx_mu_msi_domain_info = {
+	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
+	.ops	= &imx_mu_msi_irq_ops,
+	.chip	= &imx_mu_msi_irq_chip,
+};
+
+static void imx_mu_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
+{
+	struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
+	u64 addr = msi_data->msiir_addr + 4 * data->hwirq;
+
+	msg->address_hi = upper_32_bits(addr);
+	msg->address_lo = lower_32_bits(addr);
+	msg->data = data->hwirq;
+}
+
+static struct irq_chip imx_mu_msi_parent_chip = {
+	.name		= "MU",
+	.irq_mask	= imx_mu_msi_parent_mask_irq,
+	.irq_unmask	= imx_mu_msi_parent_unmask_irq,
+	.irq_ack	= imx_mu_msi_parent_ack_irq,
+	.irq_compose_msi_msg	= imx_mu_msi_compose_msg,
+};
+
+static int imx_mu_msi_domain_irq_alloc(struct irq_domain *domain,
+					unsigned int virq,
+					unsigned int nr_irqs,
+					void *args)
+{
+	struct imx_mu_msi *msi_data = domain->host_data;
+	unsigned long flags;
+	int pos, err = 0;
+
+	WARN_ON(nr_irqs != 1);
+
+	spin_lock_irqsave(&msi_data->lock, flags);
+	pos = find_first_zero_bit(&msi_data->used, IMX_MU_CHANS);
+	if (pos < IMX_MU_CHANS)
+		__set_bit(pos, &msi_data->used);
+	else
+		err = -ENOSPC;
+	spin_unlock_irqrestore(&msi_data->lock, flags);
+
+	if (err)
+		return err;
+
+	irq_domain_set_info(domain, virq, pos,
+			    &imx_mu_msi_parent_chip, msi_data,
+			    handle_edge_irq, NULL, NULL);
+	return 0;
+}
+
+static void imx_mu_msi_domain_irq_free(struct irq_domain *domain,
+				       unsigned int virq, unsigned int nr_irqs)
+{
+	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
+	struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(d);
+	unsigned long flags;
+
+	spin_lock_irqsave(&msi_data->lock, flags);
+	__clear_bit(d->hwirq, &msi_data->used);
+	spin_unlock_irqrestore(&msi_data->lock, flags);
+}
+
+static const struct irq_domain_ops imx_mu_msi_domain_ops = {
+	.alloc	= imx_mu_msi_domain_irq_alloc,
+	.free	= imx_mu_msi_domain_irq_free,
+};
+
+static void imx_mu_msi_irq_handler(struct irq_desc *desc)
+{
+	struct imx_mu_msi *msi_data = irq_desc_get_handler_data(desc);
+	u32 status;
+	int i;
+
+	status = imx_mu_read(msi_data, msi_data->cfg->xSR[IMX_MU_RSR]);
+
+	chained_irq_enter(irq_desc_get_chip(desc), desc);
+	for (i = 0; i < IMX_MU_CHANS; i++) {
+		if (status & IMX_MU_xSR_RFn(msi_data, i)) {
+			generic_handle_domain_irq(msi_data->msi_domain, i);
+		}
+	}
+	chained_irq_exit(irq_desc_get_chip(desc), desc);
+}
+
+static int imx_mu_msi_domains_init(struct imx_mu_msi *msi_data)
+{
+	struct fwnode_handle *fwnodes = of_node_to_fwnode(dev_of_node(&msi_data->pdev->dev));
+
+	/* Initialize MSI domain parent */
+	msi_data->parent = irq_domain_create_linear(fwnodes,
+						    IMX_MU_CHANS,
+						    &imx_mu_msi_domain_ops,
+						    msi_data);
+	if (!msi_data->parent) {
+		dev_err(&msi_data->pdev->dev, "failed to create IRQ domain\n");
+		return -ENOMEM;
+	}
+
+	msi_data->msi_domain = platform_msi_create_irq_domain(
+				of_node_to_fwnode(msi_data->pdev->dev.of_node),
+				&imx_mu_msi_domain_info,
+				msi_data->parent);
+
+	if (!msi_data->msi_domain) {
+		dev_err(&msi_data->pdev->dev, "failed to create MSI domain\n");
+		irq_domain_remove(msi_data->parent);
+		return -ENOMEM;
+	}
+
+	/* clean irq_set_affinity again because it is chained irq */
+	imx_mu_msi_irq_chip.irq_set_affinity = NULL;
+
+	irq_domain_set_pm_device(msi_data->msi_domain, &msi_data->pdev->dev);
+
+	return 0;
+}
+
+/* Register offset of different version MU IP */
+static const struct imx_mu_dcfg imx_mu_cfg_imx6sx = {
+	.xTR    = 0x0,
+	.xRR    = 0x10,
+	.xSR    = {0x20, 0x20, 0x20, 0x20},
+	.xCR    = {0x24, 0x24, 0x24, 0x24},
+};
+
+static const struct imx_mu_dcfg imx_mu_cfg_imx7ulp = {
+	.xTR    = 0x20,
+	.xRR    = 0x40,
+	.xSR    = {0x60, 0x60, 0x60, 0x60},
+	.xCR    = {0x64, 0x64, 0x64, 0x64},
+};
+
+static const struct imx_mu_dcfg imx_mu_cfg_imx8ulp = {
+	.type   = IMX_MU_V2,
+	.xTR    = 0x200,
+	.xRR    = 0x280,
+	.xSR    = {0xC, 0x118, 0x124, 0x12C},
+	.xCR    = {0x110, 0x114, 0x120, 0x128},
+};
+
+static const struct imx_mu_dcfg imx_mu_cfg_imx8ulp_s4 = {
+
+	.type   = IMX_MU_V2 | IMX_MU_V2_S4,
+	.xTR    = 0x200,
+	.xRR    = 0x280,
+	.xSR    = {0xC, 0x118, 0x124, 0x12C},
+	.xCR    = {0x110, 0x114, 0x120, 0x128},
+};
+
+static int __init imx_mu_of_init(struct device_node *dn,
+				 struct device_node *parent,
+				 const struct imx_mu_dcfg *cfg)
+{
+	struct platform_device *pdev = of_find_device_by_node(dn);
+	struct imx_mu_msi *msi_data, *priv;
+	struct resource *res;
+	struct device *dev;
+	int ret;
+
+	if (!pdev)
+		return -ENODEV;
+
+	dev = &pdev->dev;
+
+	priv = msi_data = devm_kzalloc(&pdev->dev, sizeof(*msi_data), GFP_KERNEL);
+	if (!msi_data)
+		return -ENOMEM;
+
+	msi_data->cfg = cfg;
+
+	msi_data->regs = devm_platform_ioremap_resource_byname(pdev, "a");
+	if (IS_ERR(msi_data->regs)) {
+		dev_err(&pdev->dev, "failed to initialize 'regs'\n");
+		return PTR_ERR(msi_data->regs);
+	}
+
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "b");
+	if (!res)
+		return -EIO;
+
+	msi_data->msiir_addr = res->start + msi_data->cfg->xTR;
+
+	msi_data->pdev = pdev;
+
+	msi_data->gic_irq = platform_get_irq(msi_data->pdev, 0);
+	if (msi_data->gic_irq <= 0)
+		return -ENODEV;
+
+	platform_set_drvdata(pdev, msi_data);
+
+	msi_data->clk = devm_clk_get(dev, NULL);
+	if (IS_ERR(msi_data->clk)) {
+		if (PTR_ERR(msi_data->clk) != -ENOENT)
+			return PTR_ERR(msi_data->clk);
+
+		msi_data->clk = NULL;
+	}
+
+	ret = clk_prepare_enable(msi_data->clk);
+	if (ret) {
+		dev_err(dev, "Failed to enable clock\n");
+		return ret;
+	}
+
+	priv->pd_a = dev_pm_domain_attach_by_name(dev, "a");
+	if (IS_ERR(priv->pd_a))
+		return PTR_ERR(priv->pd_a);
+
+	priv->pd_link_a = device_link_add(dev, priv->pd_a,
+			DL_FLAG_STATELESS |
+			DL_FLAG_PM_RUNTIME |
+			DL_FLAG_RPM_ACTIVE);
+
+	if (!priv->pd_link_a) {
+		dev_err(dev, "Failed to add device_link to mu a.\n");
+		return -EINVAL;
+	}
+
+	priv->pd_b = dev_pm_domain_attach_by_name(dev, "b");
+	if (IS_ERR(priv->pd_b))
+		return PTR_ERR(priv->pd_b);
+
+	priv->pd_link_b = device_link_add(dev, priv->pd_b,
+			DL_FLAG_STATELESS |
+			DL_FLAG_PM_RUNTIME |
+			DL_FLAG_RPM_ACTIVE);
+
+	if (!priv->pd_link_b) {
+		dev_err(dev, "Failed to add device_link to mu a.\n");
+		return -EINVAL;
+	}
+
+	ret = imx_mu_msi_domains_init(msi_data);
+	if (ret)
+		return ret;
+
+	irq_set_chained_handler_and_data(msi_data->gic_irq,
+					 imx_mu_msi_irq_handler,
+					 msi_data);
+
+	pm_runtime_enable(dev);
+
+	return 0;
+}
+
+static int __maybe_unused imx_mu_runtime_suspend(struct device *dev)
+{
+	struct imx_mu_msi *priv = dev_get_drvdata(dev);
+
+	clk_disable_unprepare(priv->clk);
+
+	return 0;
+}
+
+static int __maybe_unused imx_mu_runtime_resume(struct device *dev)
+{
+	struct imx_mu_msi *priv = dev_get_drvdata(dev);
+	int ret;
+
+	ret = clk_prepare_enable(priv->clk);
+	if (ret)
+		dev_err(dev, "failed to enable clock\n");
+
+	return ret;
+}
+
+static const struct dev_pm_ops imx_mu_pm_ops = {
+	SET_RUNTIME_PM_OPS(imx_mu_runtime_suspend,
+			   imx_mu_runtime_resume, NULL)
+};
+
+static int __init imx_mu_imx7ulp_of_init(struct device_node *dn,
+					 struct device_node *parent)
+{
+	return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx7ulp);
+}
+
+static int __init imx_mu_imx6sx_of_init(struct device_node *dn,
+					struct device_node *parent)
+{
+	return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx6sx);
+}
+
+static int __init imx_mu_imx8ulp_of_init(struct device_node *dn,
+					 struct device_node *parent)
+{
+	return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx8ulp);
+}
+
+static int __init imx_mu_imx8ulp_s4_of_init(struct device_node *dn,
+					    struct device_node *parent)
+{
+	return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx8ulp_s4);
+}
+
+IRQCHIP_PLATFORM_DRIVER_BEGIN(imx_mu_msi)
+IRQCHIP_MATCH("fsl,imx7ulp-mu-msi", imx_mu_imx7ulp_of_init)
+IRQCHIP_MATCH("fsl,imx6sx-mu-msi", imx_mu_imx6sx_of_init)
+IRQCHIP_MATCH("fsl,imx8ulp-mu-msi", imx_mu_imx8ulp_of_init)
+IRQCHIP_MATCH("fsl,imx8ulp-mu-msi-s4", imx_mu_imx8ulp_s4_of_init)
+IRQCHIP_PLATFORM_DRIVER_END(imx_mu_msi, .pm = &imx_mu_pm_ops)
+
+
+MODULE_AUTHOR("Frank Li <Frank.Li@nxp.com>");
+MODULE_DESCRIPTION("Freescale MU work as MSI controller driver");
+MODULE_LICENSE("GPL");
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* [PATCH v4 3/4] dt-bindings: irqchip: imx mu work as msi controller
  2022-08-12 21:52 [PATCH v4 0/4] PCI EP driver support MSI doorbell from host Frank Li
  2022-08-12 21:52 ` [PATCH v4 1/4] irqchip: allow pass down .pm field at IRQCHIP_PLATFORM_DRIVER_END Frank Li
  2022-08-12 21:52 ` [PATCH v4 2/4] irqchip: imx mu worked as msi controller Frank Li
@ 2022-08-12 21:52 ` Frank Li
  2022-08-14 20:41   ` Rob Herring
  2022-08-12 21:52 ` [PATCH v4 4/4] pcie: endpoint: pci-epf-vntb: add endpoint MSI support Frank Li
  3 siblings, 1 reply; 11+ messages in thread
From: Frank Li @ 2022-08-12 21:52 UTC (permalink / raw
  To: maz, tglx, robh+dt, krzysztof.kozlowski+dt, shawnguo, s.hauer, kw,
	bhelgaas
  Cc: kernel, devicetree, linux-arm-kernel, linux-pci, peng.fan,
	aisheng.dong, jdmason, kernel, festevam, linux-imx, kishon,
	lorenzo.pieralisi, ntb, lznuaa

I.MX mu support generate irq by write a register. Provide msi controller
support so other driver such as PCI EP can use it by standard msi
interface as doorbell.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
 .../interrupt-controller/fsl,mu-msi.yaml      | 93 +++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/fsl,mu-msi.yaml

diff --git a/Documentation/devicetree/bindings/interrupt-controller/fsl,mu-msi.yaml b/Documentation/devicetree/bindings/interrupt-controller/fsl,mu-msi.yaml
new file mode 100644
index 0000000000000..f60fa8b686879
--- /dev/null
+++ b/Documentation/devicetree/bindings/interrupt-controller/fsl,mu-msi.yaml
@@ -0,0 +1,93 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/interrupt-controller/fsl,mu-msi.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: NXP i.MX Messaging Unit (MU) work as msi controller
+
+maintainers:
+  - Frank Li <Frank.Li@nxp.com>
+
+description: |
+  The Messaging Unit module enables two processors within the SoC to
+  communicate and coordinate by passing messages (e.g. data, status
+  and control) through the MU interface. The MU also provides the ability
+  for one processor (A side) to signal the other processor (B side) using
+  interrupts.
+
+  Because the MU manages the messaging between processors, the MU uses
+  different clocks (from each side of the different peripheral buses).
+  Therefore, the MU must synchronize the accesses from one side to the
+  other. The MU accomplishes synchronization using two sets of matching
+  registers (Processor A-facing, Processor B-facing).
+
+  MU can work as msi interrupt controller to do doorbell
+
+allOf:
+  - $ref: /schemas/interrupt-controller/msi-controller.yaml#
+
+properties:
+  compatible:
+    enum:
+      - fsl,imx6sx-mu-msi
+      - fsl,imx7ulp-mu-msi
+      - fsl,imx8ulp-mu-msi
+      - fsl,imx8ulp-mu-msi-s4
+
+  reg:
+    items:
+      - description: a side register base address
+      - description: b side register base address
+
+  reg-names:
+    items:
+      - const: a
+      - const: b
+
+  interrupts:
+    description: a side interrupt number.
+
+  clocks:
+    maxItems: 1
+
+  power-domains:
+    items:
+      - description: a side power domain
+      - description: b side power domain
+
+  power-domain-names:
+    items:
+      - const: a
+      - const: b
+
+  interrupt-controller: true
+
+  msi-controller: true
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - interrupt-controller
+  - msi-controller
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
+    #include <dt-bindings/firmware/imx/rsrc.h>
+
+    lsio_mu12: msi-controller@5d270000 {
+        compatible = "fsl,imx6sx-mu-msi";
+        msi-controller;
+        interrupt-controller;
+        reg = <0x5d270000 0x10000>,     /* A side */
+              <0x5d300000 0x10000>;     /* B side */
+        reg-names = "a", "b";
+        interrupts = <GIC_SPI 191 IRQ_TYPE_LEVEL_HIGH>;
+        power-domains = <&pd IMX_SC_R_MU_12A>,
+                        <&pd IMX_SC_R_MU_12B>;
+        power-domain-names = "a", "b";
+    };
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* [PATCH v4 4/4] pcie: endpoint: pci-epf-vntb: add endpoint MSI support
  2022-08-12 21:52 [PATCH v4 0/4] PCI EP driver support MSI doorbell from host Frank Li
                   ` (2 preceding siblings ...)
  2022-08-12 21:52 ` [PATCH v4 3/4] dt-bindings: irqchip: imx mu work " Frank Li
@ 2022-08-12 21:52 ` Frank Li
  3 siblings, 0 replies; 11+ messages in thread
From: Frank Li @ 2022-08-12 21:52 UTC (permalink / raw
  To: maz, tglx, robh+dt, krzysztof.kozlowski+dt, shawnguo, s.hauer, kw,
	bhelgaas
  Cc: kernel, devicetree, linux-arm-kernel, linux-pci, peng.fan,
	aisheng.dong, jdmason, kernel, festevam, linux-imx, kishon,
	lorenzo.pieralisi, ntb, lznuaa

                        ┌───────┐          ┌──────────┐
                        │       │          │          │
      ┌─────────────┐   │       │          │ PCI Host │
      │ MSI         │◄┐ │       │          │          │
      │ Controller  │ │ │       │          │          │
      └─────────────┘ └─┼───────┼──────────┼─BAR0     │
                        │ PCI   │          │ BAR1     │
                        │ Func  │          │ BAR2     │
                        │       │          │ BAR3     │
                        │       │          │ BAR4     │
                        │       ├─────────►│          │
                        └───────┘          └──────────┘

Linux supports endpoint functions. PCI Host write BAR<n> space like write
to memory. The EP side can't know memory changed by the host driver.

PCI Spec has not defined a standard method to do that. Only define MSI(x)
to let EP notified RC status change.

The basic idea is to trigger an IRQ when PCI RC writes to a memory
address. That's what MSI controller provided. EP drivers just need to
request a platform MSI interrupt, struct msi_msg *msg will pass down a
memory address and data. EP driver will map such memory address to one of
PCI BAR<n>.  Host just writes such an address to trigger EP side irq.

Add MSI support for pci-epf-vntb. pci-epf-vntb driver query if system
have MSI controller. Setup doorbell address according to struct msi_msg.

So PCIe host can write this doorbell address to triger EP side's irq.

If no MSI controller exist, fall back to software polling.

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
 drivers/pci/endpoint/functions/pci-epf-vntb.c | 134 +++++++++++++++---
 1 file changed, 112 insertions(+), 22 deletions(-)

diff --git a/drivers/pci/endpoint/functions/pci-epf-vntb.c b/drivers/pci/endpoint/functions/pci-epf-vntb.c
index 1466dd1904175..ad4f7ec8a39fc 100644
--- a/drivers/pci/endpoint/functions/pci-epf-vntb.c
+++ b/drivers/pci/endpoint/functions/pci-epf-vntb.c
@@ -44,6 +44,7 @@
 #include <linux/pci-epc.h>
 #include <linux/pci-epf.h>
 #include <linux/ntb.h>
+#include <linux/msi.h>
 
 static struct workqueue_struct *kpcintb_workqueue;
 
@@ -143,6 +144,8 @@ struct epf_ntb {
 	void __iomem *vpci_mw_addr[MAX_MW];
 
 	struct delayed_work cmd_handler;
+
+	int msi_virqbase;
 };
 
 #define to_epf_ntb(epf_group) container_of((epf_group), struct epf_ntb, group)
@@ -253,7 +256,7 @@ static void epf_ntb_cmd_handler(struct work_struct *work)
 
 	ntb = container_of(work, struct epf_ntb, cmd_handler.work);
 
-	for (i = 1; i < ntb->db_count; i++) {
+	for (i = 1; i < ntb->db_count && !ntb->epf_db_phy; i++) {
 		if (readl(ntb->epf_db + i * 4)) {
 			if (readl(ntb->epf_db + i * 4))
 				ntb->db |= 1 << (i - 1);
@@ -454,11 +457,9 @@ static int epf_ntb_config_spad_bar_alloc(struct epf_ntb *ntb)
 	ctrl->num_mws = ntb->num_mws;
 	ntb->spad_size = spad_size;
 
-	ctrl->db_entry_size = 4;
-
 	for (i = 0; i < ntb->db_count; i++) {
 		ntb->reg->db_data[i] = 1 + i;
-		ntb->reg->db_offset[i] = 0;
+		ntb->reg->db_offset[i] = 4 * i;
 	}
 
 	return 0;
@@ -509,6 +510,28 @@ static int epf_ntb_configure_interrupt(struct epf_ntb *ntb)
 	return 0;
 }
 
+static int epf_ntb_db_size(struct epf_ntb *ntb)
+{
+	const struct pci_epc_features *epc_features;
+	size_t size = 4 * ntb->db_count;
+	u32 align;
+
+	epc_features = pci_epc_get_features(ntb->epf->epc,
+					    ntb->epf->func_no,
+					    ntb->epf->vfunc_no);
+	align = epc_features->align;
+
+	if (size < 128)
+		size = 128;
+
+	if (align)
+		size = ALIGN(size, align);
+	else
+		size = roundup_pow_of_two(size);
+
+	return size;
+}
+
 /**
  * epf_ntb_db_bar_init() - Configure Doorbell window BARs
  * @ntb: NTB device that facilitates communication between HOST and vHOST
@@ -520,35 +543,33 @@ static int epf_ntb_db_bar_init(struct epf_ntb *ntb)
 	struct device *dev = &ntb->epf->dev;
 	int ret;
 	struct pci_epf_bar *epf_bar;
-	void __iomem *mw_addr;
+	void __iomem *mw_addr = NULL;
 	enum pci_barno barno;
-	size_t size = 4 * ntb->db_count;
+	size_t size;
 
 	epc_features = pci_epc_get_features(ntb->epf->epc,
 					    ntb->epf->func_no,
 					    ntb->epf->vfunc_no);
 	align = epc_features->align;
-
-	if (size < 128)
-		size = 128;
-
-	if (align)
-		size = ALIGN(size, align);
-	else
-		size = roundup_pow_of_two(size);
+	size = epf_ntb_db_size(ntb);
 
 	barno = ntb->epf_ntb_bar[BAR_DB];
+	epf_bar = &ntb->epf->bar[barno];
 
-	mw_addr = pci_epf_alloc_space(ntb->epf, size, barno, align, 0);
-	if (!mw_addr) {
-		dev_err(dev, "Failed to allocate OB address\n");
-		return -ENOMEM;
+	if (!ntb->epf_db_phy) {
+		mw_addr = pci_epf_alloc_space(ntb->epf, size, barno, align, 0);
+		if (!mw_addr) {
+			dev_err(dev, "Failed to allocate OB address\n");
+			return -ENOMEM;
+		}
+	} else {
+		epf_bar->phys_addr = ntb->epf_db_phy;
+		epf_bar->barno = barno;
+		epf_bar->size = size;
 	}
 
 	ntb->epf_db = mw_addr;
 
-	epf_bar = &ntb->epf->bar[barno];
-
 	ret = pci_epc_set_bar(ntb->epf->epc, ntb->epf->func_no, ntb->epf->vfunc_no, epf_bar);
 	if (ret) {
 		dev_err(dev, "Doorbell BAR set failed\n");
@@ -704,6 +725,74 @@ static int epf_ntb_init_epc_bar(struct epf_ntb *ntb)
 	return 0;
 }
 
+static void epf_ntb_write_msi_msg(struct msi_desc *desc, struct msi_msg *msg)
+{
+	struct epf_ntb *ntb = dev_get_drvdata(desc->dev);
+	struct epf_ntb_ctrl *reg = ntb->reg;
+	int size = epf_ntb_db_size(ntb);
+	u64 addr;
+
+	addr = msg->address_hi;
+	addr <<= 32;
+	addr |= msg->address_lo;
+
+	reg->db_data[desc->msi_index] = msg->data;
+
+	if (desc->msi_index == 0)
+		ntb->epf_db_phy = round_down(addr, size);
+
+	reg->db_offset[desc->msi_index] = addr - ntb->epf_db_phy;
+}
+
+static irqreturn_t epf_ntb_interrupt_handler(int irq, void *data)
+{
+	struct epf_ntb *ntb = data;
+	int index;
+
+	index = irq - ntb->msi_virqbase;
+	ntb->db |= 1 << (index - 1);
+	ntb_db_event(&ntb->ntb, index);
+
+	return IRQ_HANDLED;
+}
+
+static void epf_ntb_epc_msi_init(struct epf_ntb *ntb)
+{
+	struct device *dev = &ntb->epf->dev;
+	struct irq_domain *domain;
+	int virq;
+	int ret;
+	int i;
+
+	domain = dev_get_msi_domain(ntb->epf->epc->dev.parent);
+	if (!domain)
+		return;
+
+	dev_set_msi_domain(dev, domain);
+
+	if (platform_msi_domain_alloc_irqs(&ntb->epf->dev,
+		ntb->db_count,
+		epf_ntb_write_msi_msg)) {
+		dev_info(dev, "Can't allocate MSI, fall back to poll mode\n");
+		return;
+	}
+
+	dev_info(dev, "vntb use MSI as doorbell\n");
+
+	for (i = 0; i < ntb->db_count; i++) {
+		virq = msi_get_virq(dev, i);
+		ret = devm_request_irq(dev, virq,
+			       epf_ntb_interrupt_handler, 0,
+			       "ntb", ntb);
+
+		if (ret)
+			dev_err(dev, "devm_request_irq() failure\n");
+
+		if (!i)
+			ntb->msi_virqbase = virq;
+	}
+}
+
 /**
  * epf_ntb_epc_init() - Initialize NTB interface
  * @ntb: NTB device that facilitates communication between HOST and vHOST2
@@ -1299,14 +1388,15 @@ static int epf_ntb_bind(struct pci_epf *epf)
 		goto err_bar_alloc;
 	}
 
+	epf_set_drvdata(epf, ntb);
+	epf_ntb_epc_msi_init(ntb);
+
 	ret = epf_ntb_epc_init(ntb);
 	if (ret) {
 		dev_err(dev, "Failed to initialize EPC\n");
 		goto err_bar_alloc;
 	}
 
-	epf_set_drvdata(epf, ntb);
-
 	pci_space[0] = (ntb->vntb_pid << 16) | ntb->vntb_vid;
 	pci_vntb_table[0].vendor = ntb->vntb_vid;
 	pci_vntb_table[0].device = ntb->vntb_pid;
-- 
2.35.1


^ permalink raw reply related	[flat|nested] 11+ messages in thread

* Re: [PATCH v4 2/4] irqchip: imx mu worked as msi controller
  2022-08-12 21:52 ` [PATCH v4 2/4] irqchip: imx mu worked as msi controller Frank Li
@ 2022-08-13  9:19   ` Marc Zyngier
  2022-08-14  3:12     ` [EXT] " Frank Li
  2022-08-13 11:57   ` Marc Zyngier
  1 sibling, 1 reply; 11+ messages in thread
From: Marc Zyngier @ 2022-08-13  9:19 UTC (permalink / raw
  To: Frank Li
  Cc: tglx, robh+dt, krzysztof.kozlowski+dt, shawnguo, s.hauer, kw,
	bhelgaas, kernel, devicetree, linux-arm-kernel, linux-pci,
	peng.fan, aisheng.dong, jdmason, kernel, festevam, linux-imx,
	kishon, lorenzo.pieralisi, ntb, lznuaa

Frank,

The patch title needs work:

"irqchip: Add IMX MU MSI controller driver"

On Fri, 12 Aug 2022 22:52:40 +0100,
Frank Li <Frank.Li@nxp.com> wrote:
> 
> MU support generate irq by write data to a register.

"The MU block found in a number of Freescale/NXP SoCs supports
generating IRQs by writing data to a register."

> This patch make mu worked as msi controller.

Please see Documentation/process/submitting-patches.rst, and the
requirement to avoid wordings such as "This patch".

> So MU can do doorbell by using standard msi api.

"This enables the MU block to be used as a MSI controller, by
leveraging the platform-MSI API"

>
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
>  drivers/irqchip/Kconfig          |   7 +
>  drivers/irqchip/Makefile         |   1 +
>  drivers/irqchip/irq-imx-mu-msi.c | 443 +++++++++++++++++++++++++++++++
>  3 files changed, 451 insertions(+)
>  create mode 100644 drivers/irqchip/irq-imx-mu-msi.c
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 5e4e50122777d..4599471d880c0 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -470,6 +470,13 @@ config IMX_INTMUX
>  	help
>  	  Support for the i.MX INTMUX interrupt multiplexer.
>  
> +config IMX_MU_MSI
> +	bool "i.MX MU work as MSI controller"
> +	default y if ARCH_MXC
> +	select IRQ_DOMAIN
> +	help
> +	  MU work as MSI controller to do general doorbell
> +
>  config LS1X_IRQ
>  	bool "Loongson-1 Interrupt Controller"
>  	depends on MACH_LOONGSON32
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index 5d8e21d3dc6d8..870423746c783 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -98,6 +98,7 @@ obj-$(CONFIG_RISCV_INTC)		+= irq-riscv-intc.o
>  obj-$(CONFIG_SIFIVE_PLIC)		+= irq-sifive-plic.o
>  obj-$(CONFIG_IMX_IRQSTEER)		+= irq-imx-irqsteer.o
>  obj-$(CONFIG_IMX_INTMUX)		+= irq-imx-intmux.o
> +obj-$(CONFIG_IMX_MU_MSI)		+= irq-imx-mu-msi.o
>  obj-$(CONFIG_MADERA_IRQ)		+= irq-madera.o
>  obj-$(CONFIG_LS1X_IRQ)			+= irq-ls1x.o
>  obj-$(CONFIG_TI_SCI_INTR_IRQCHIP)	+= irq-ti-sci-intr.o
> diff --git a/drivers/irqchip/irq-imx-mu-msi.c b/drivers/irqchip/irq-imx-mu-msi.c
> new file mode 100644
> index 0000000000000..bb111412d598f
> --- /dev/null
> +++ b/drivers/irqchip/irq-imx-mu-msi.c
> @@ -0,0 +1,443 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * NXP MU worked as MSI controller

Freescale? Or NXP? Please make up your mind.

> + *
> + * Copyright (c) 2018 Pengutronix, Oleksij Rempel <o.rempel@pengutronix.de>
> + * Copyright 2022 NXP
> + *	Frank Li <Frank.Li@nxp.com>
> + *	Peng Fan <peng.fan@nxp.com>
> + *
> + * Based on drivers/mailbox/imx-mailbox.c
> + */
> +#include <linux/clk.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/msi.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip/chained_irq.h>
> +#include <linux/irqchip.h>
> +#include <linux/irqdomain.h>
> +#include <linux/of_irq.h>
> +#include <linux/of_pci.h>
> +#include <linux/of_platform.h>
> +#include <linux/spinlock.h>
> +#include <linux/dma-iommu.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/pm_domain.h>
> +
> +
> +#define IMX_MU_CHANS            4
> +
> +enum imx_mu_xcr {
> +	IMX_MU_GIER,
> +	IMX_MU_GCR,
> +	IMX_MU_TCR,
> +	IMX_MU_RCR,
> +	IMX_MU_xCR_MAX,
> +};
> +
> +enum imx_mu_xsr {
> +	IMX_MU_SR,
> +	IMX_MU_GSR,
> +	IMX_MU_TSR,
> +	IMX_MU_RSR,
> +};
> +
> +enum imx_mu_type {
> +	IMX_MU_V1 = BIT(0),
> +	IMX_MU_V2 = BIT(1),
> +	IMX_MU_V2_S4 = BIT(15),
> +};
> +
> +/* Receive Interrupt Enable */
> +#define IMX_MU_xCR_RIEn(data, x) ((data->cfg->type) & IMX_MU_V2 ? BIT(x) : BIT(24 + (3 - (x))))
> +#define IMX_MU_xSR_RFn(data, x) ((data->cfg->type) & IMX_MU_V2 ? BIT(x) : BIT(24 + (3 - (x))))
> +
> +struct imx_mu_dcfg {
> +	enum imx_mu_type type;
> +	u32     xTR;            /* Transmit Register0 */
> +	u32     xRR;            /* Receive Register0 */
> +	u32     xSR[4];         /* Status Registers */
> +	u32     xCR[4];         /* Control Registers */
> +};
> +
> +struct imx_mu_msi {
> +	spinlock_t			lock;
> +	struct platform_device		*pdev;

This pointer isn't useful. It is only used in
imx_mu_msi_domains_init(), which could take it as a parameter.

> +	struct irq_domain		*parent;

This pointer isn't useful. It is only used in the same function, and
could well be a local variable.

> +	struct irq_domain		*msi_domain;
> +	void __iomem			*regs;
> +	phys_addr_t			msiir_addr;
> +	const struct imx_mu_dcfg	*cfg;
> +	unsigned long			used;
> +	int				gic_irq;

This variable is only used in a single function.

> +	struct clk			*clk;
> +	struct device			*pd_a;
> +	struct device			*pd_b;
> +	struct device_link		*pd_link_a;
> +	struct device_link		*pd_link_b;

Same thing. All this pd_* stuff is *never* used outside of a single
function.

> +};
> +
> +static void imx_mu_write(struct imx_mu_msi *msi_data, u32 val, u32 offs)
> +{
> +	iowrite32(val, msi_data->regs + offs);
> +}
> +
> +static u32 imx_mu_read(struct imx_mu_msi *msi_data, u32 offs)
> +{
> +	return ioread32(msi_data->regs + offs);
> +}
> +
> +static u32 imx_mu_xcr_rmw(struct imx_mu_msi *msi_data, enum imx_mu_xcr type, u32 set, u32 clr)
> +{
> +	unsigned long flags;
> +	u32 val;
> +
> +	spin_lock_irqsave(&msi_data->lock, flags);

This needs to be a raw spinlock.

> +	val = imx_mu_read(msi_data, msi_data->cfg->xCR[type]);
> +	val &= ~clr;
> +	val |= set;
> +	imx_mu_write(msi_data, val, msi_data->cfg->xCR[type]);
> +	spin_unlock_irqrestore(&msi_data->lock, flags);
> +
> +	return val;
> +}
> +
> +static void imx_mu_msi_parent_mask_irq(struct irq_data *data)
> +{
> +	struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
> +
> +	imx_mu_xcr_rmw(msi_data, IMX_MU_RCR, 0, IMX_MU_xCR_RIEn(msi_data, data->hwirq));
> +}
> +
> +static void imx_mu_msi_parent_unmask_irq(struct irq_data *data)
> +{
> +	struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
> +
> +	imx_mu_xcr_rmw(msi_data, IMX_MU_RCR, IMX_MU_xCR_RIEn(msi_data, data->hwirq), 0);
> +}
> +
> +static void imx_mu_msi_parent_ack_irq(struct irq_data *data)
> +{
> +        struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
> +
> +        imx_mu_read(msi_data, msi_data->cfg->xRR + data->hwirq * 4);
> +}
> +
> +static struct irq_chip imx_mu_msi_irq_chip = {
> +	.name = "MU-MSI",
> +	.irq_ack = irq_chip_ack_parent,

Crucially, no irq_write_msi_msg callback. So we happily inherit
platform_msi_write_msg() and use the per descriptor write_msg()
callback. Who sets this? Nobody.

So I suspect you're hiding it somewhere else, and I really want to see
this code. I really don't see a good reason why it should be anywhere
else.

> +};
> +
> +static struct msi_domain_ops imx_mu_msi_irq_ops = {
> +};
> +
> +static struct msi_domain_info imx_mu_msi_domain_info = {
> +	.flags	= (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS),
> +	.ops	= &imx_mu_msi_irq_ops,
> +	.chip	= &imx_mu_msi_irq_chip,
> +};
> +
> +static void imx_mu_msi_compose_msg(struct irq_data *data, struct msi_msg *msg)
> +{
> +	struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
> +	u64 addr = msi_data->msiir_addr + 4 * data->hwirq;
> +
> +	msg->address_hi = upper_32_bits(addr);
> +	msg->address_lo = lower_32_bits(addr);
> +	msg->data = data->hwirq;
> +}
> +
> +static struct irq_chip imx_mu_msi_parent_chip = {
> +	.name		= "MU",
> +	.irq_mask	= imx_mu_msi_parent_mask_irq,
> +	.irq_unmask	= imx_mu_msi_parent_unmask_irq,
> +	.irq_ack	= imx_mu_msi_parent_ack_irq,
> +	.irq_compose_msi_msg	= imx_mu_msi_compose_msg,

Please be consistent in the naming.

> +};
> +
> +static int imx_mu_msi_domain_irq_alloc(struct irq_domain *domain,
> +					unsigned int virq,
> +					unsigned int nr_irqs,
> +					void *args)
> +{
> +	struct imx_mu_msi *msi_data = domain->host_data;
> +	unsigned long flags;
> +	int pos, err = 0;
> +
> +	WARN_ON(nr_irqs != 1);
> +
> +	spin_lock_irqsave(&msi_data->lock, flags);
> +	pos = find_first_zero_bit(&msi_data->used, IMX_MU_CHANS);
> +	if (pos < IMX_MU_CHANS)
> +		__set_bit(pos, &msi_data->used);
> +	else
> +		err = -ENOSPC;
> +	spin_unlock_irqrestore(&msi_data->lock, flags);
> +
> +	if (err)
> +		return err;
> +
> +	irq_domain_set_info(domain, virq, pos,
> +			    &imx_mu_msi_parent_chip, msi_data,
> +			    handle_edge_irq, NULL, NULL);
> +	return 0;
> +}
> +
> +static void imx_mu_msi_domain_irq_free(struct irq_domain *domain,
> +				       unsigned int virq, unsigned int nr_irqs)
> +{
> +	struct irq_data *d = irq_domain_get_irq_data(domain, virq);
> +	struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(d);
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&msi_data->lock, flags);
> +	__clear_bit(d->hwirq, &msi_data->used);
> +	spin_unlock_irqrestore(&msi_data->lock, flags);
> +}
> +
> +static const struct irq_domain_ops imx_mu_msi_domain_ops = {
> +	.alloc	= imx_mu_msi_domain_irq_alloc,
> +	.free	= imx_mu_msi_domain_irq_free,
> +};
> +
> +static void imx_mu_msi_irq_handler(struct irq_desc *desc)
> +{
> +	struct imx_mu_msi *msi_data = irq_desc_get_handler_data(desc);
> +	u32 status;
> +	int i;
> +
> +	status = imx_mu_read(msi_data, msi_data->cfg->xSR[IMX_MU_RSR]);
> +
> +	chained_irq_enter(irq_desc_get_chip(desc), desc);
> +	for (i = 0; i < IMX_MU_CHANS; i++) {
> +		if (status & IMX_MU_xSR_RFn(msi_data, i)) {
> +			generic_handle_domain_irq(msi_data->msi_domain, i);
> +		}
> +	}
> +	chained_irq_exit(irq_desc_get_chip(desc), desc);

Do yourself a favour, and compute irq_desc_get_chip(desc) once, just
like for most irqchips.

> +}
> +
> +static int imx_mu_msi_domains_init(struct imx_mu_msi *msi_data)
> +{
> +	struct fwnode_handle *fwnodes = of_node_to_fwnode(dev_of_node(&msi_data->pdev->dev));

How about dev_fwnode()?

> +
> +	/* Initialize MSI domain parent */
> +	msi_data->parent = irq_domain_create_linear(fwnodes,
> +						    IMX_MU_CHANS,
> +						    &imx_mu_msi_domain_ops,
> +						    msi_data);

Consider setting the bus_token attribute for this domain to something
that isn't the default, as it otherwise clashes with the following
creation.

> +	if (!msi_data->parent) {
> +		dev_err(&msi_data->pdev->dev, "failed to create IRQ domain\n");
> +		return -ENOMEM;
> +	}
> +
> +	msi_data->msi_domain = platform_msi_create_irq_domain(
> +				of_node_to_fwnode(msi_data->pdev->dev.of_node),

Why aren't you using the 'fwnodes' variable here?

> +				&imx_mu_msi_domain_info,
> +				msi_data->parent);
> +
> +	if (!msi_data->msi_domain) {
> +		dev_err(&msi_data->pdev->dev, "failed to create MSI domain\n");
> +		irq_domain_remove(msi_data->parent);
> +		return -ENOMEM;
> +	}
> +
> +	/* clean irq_set_affinity again because it is chained irq */
> +	imx_mu_msi_irq_chip.irq_set_affinity = NULL;

NAK. The way to do this is to provide a callback that returns -EINVAL,
not to try and adjust things after the facts.

> +
> +	irq_domain_set_pm_device(msi_data->msi_domain, &msi_data->pdev->dev);
> +
> +	return 0;
> +}
> +
> +/* Register offset of different version MU IP */
> +static const struct imx_mu_dcfg imx_mu_cfg_imx6sx = {
> +	.xTR    = 0x0,
> +	.xRR    = 0x10,
> +	.xSR    = {0x20, 0x20, 0x20, 0x20},
> +	.xCR    = {0x24, 0x24, 0x24, 0x24},
> +};
> +
> +static const struct imx_mu_dcfg imx_mu_cfg_imx7ulp = {
> +	.xTR    = 0x20,
> +	.xRR    = 0x40,
> +	.xSR    = {0x60, 0x60, 0x60, 0x60},
> +	.xCR    = {0x64, 0x64, 0x64, 0x64},
> +};
> +
> +static const struct imx_mu_dcfg imx_mu_cfg_imx8ulp = {
> +	.type   = IMX_MU_V2,
> +	.xTR    = 0x200,
> +	.xRR    = 0x280,
> +	.xSR    = {0xC, 0x118, 0x124, 0x12C},
> +	.xCR    = {0x110, 0x114, 0x120, 0x128},
> +};
> +
> +static const struct imx_mu_dcfg imx_mu_cfg_imx8ulp_s4 = {
> +
> +	.type   = IMX_MU_V2 | IMX_MU_V2_S4,
> +	.xTR    = 0x200,
> +	.xRR    = 0x280,
> +	.xSR    = {0xC, 0x118, 0x124, 0x12C},
> +	.xCR    = {0x110, 0x114, 0x120, 0x128},
> +};
> +
> +static int __init imx_mu_of_init(struct device_node *dn,
> +				 struct device_node *parent,
> +				 const struct imx_mu_dcfg *cfg)
> +{
> +	struct platform_device *pdev = of_find_device_by_node(dn);
> +	struct imx_mu_msi *msi_data, *priv;
> +	struct resource *res;
> +	struct device *dev;
> +	int ret;
> +
> +	if (!pdev)
> +		return -ENODEV;
> +
> +	dev = &pdev->dev;
> +
> +	priv = msi_data = devm_kzalloc(&pdev->dev, sizeof(*msi_data), GFP_KERNEL);
> +	if (!msi_data)
> +		return -ENOMEM;
> +
> +	msi_data->cfg = cfg;
> +
> +	msi_data->regs = devm_platform_ioremap_resource_byname(pdev, "a");
> +	if (IS_ERR(msi_data->regs)) {
> +		dev_err(&pdev->dev, "failed to initialize 'regs'\n");
> +		return PTR_ERR(msi_data->regs);
> +	}
> +
> +	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "b");
> +	if (!res)
> +		return -EIO;
> +
> +	msi_data->msiir_addr = res->start + msi_data->cfg->xTR;
> +
> +	msi_data->pdev = pdev;
> +
> +	msi_data->gic_irq = platform_get_irq(msi_data->pdev, 0);
> +	if (msi_data->gic_irq <= 0)
> +		return -ENODEV;
> +
> +	platform_set_drvdata(pdev, msi_data);
> +
> +	msi_data->clk = devm_clk_get(dev, NULL);
> +	if (IS_ERR(msi_data->clk)) {
> +		if (PTR_ERR(msi_data->clk) != -ENOENT)
> +			return PTR_ERR(msi_data->clk);
> +
> +		msi_data->clk = NULL;
> +	}
> +
> +	ret = clk_prepare_enable(msi_data->clk);
> +	if (ret) {
> +		dev_err(dev, "Failed to enable clock\n");
> +		return ret;
> +	}
> +
> +	priv->pd_a = dev_pm_domain_attach_by_name(dev, "a");

I'm sorry, but you'll have to come up with something slightly more
descriptive than "a" or "b". At least add a qualifier to it. Same
thing for the DT by the way.

> +	if (IS_ERR(priv->pd_a))
> +		return PTR_ERR(priv->pd_a);
> +
> +	priv->pd_link_a = device_link_add(dev, priv->pd_a,
> +			DL_FLAG_STATELESS |
> +			DL_FLAG_PM_RUNTIME |
> +			DL_FLAG_RPM_ACTIVE);
> +
> +	if (!priv->pd_link_a) {
> +		dev_err(dev, "Failed to add device_link to mu a.\n");
> +		return -EINVAL;
> +	}
> +
> +	priv->pd_b = dev_pm_domain_attach_by_name(dev, "b");
> +	if (IS_ERR(priv->pd_b))
> +		return PTR_ERR(priv->pd_b);
> +
> +	priv->pd_link_b = device_link_add(dev, priv->pd_b,
> +			DL_FLAG_STATELESS |
> +			DL_FLAG_PM_RUNTIME |
> +			DL_FLAG_RPM_ACTIVE);
> +
> +	if (!priv->pd_link_b) {
> +		dev_err(dev, "Failed to add device_link to mu a.\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = imx_mu_msi_domains_init(msi_data);
> +	if (ret)
> +		return ret;

How about the clocks, the links, and everything else that has been
allocated, enabled?

> +
> +	irq_set_chained_handler_and_data(msi_data->gic_irq,
> +					 imx_mu_msi_irq_handler,
> +					 msi_data);
> +
> +	pm_runtime_enable(dev);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused imx_mu_runtime_suspend(struct device *dev)
> +{
> +	struct imx_mu_msi *priv = dev_get_drvdata(dev);
> +
> +	clk_disable_unprepare(priv->clk);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused imx_mu_runtime_resume(struct device *dev)
> +{
> +	struct imx_mu_msi *priv = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = clk_prepare_enable(priv->clk);
> +	if (ret)
> +		dev_err(dev, "failed to enable clock\n");
> +
> +	return ret;
> +}
> +
> +static const struct dev_pm_ops imx_mu_pm_ops = {
> +	SET_RUNTIME_PM_OPS(imx_mu_runtime_suspend,
> +			   imx_mu_runtime_resume, NULL)
> +};
> +
> +static int __init imx_mu_imx7ulp_of_init(struct device_node *dn,
> +					 struct device_node *parent)
> +{
> +	return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx7ulp);
> +}
> +
> +static int __init imx_mu_imx6sx_of_init(struct device_node *dn,
> +					struct device_node *parent)
> +{
> +	return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx6sx);
> +}
> +
> +static int __init imx_mu_imx8ulp_of_init(struct device_node *dn,
> +					 struct device_node *parent)
> +{
> +	return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx8ulp);
> +}
> +
> +static int __init imx_mu_imx8ulp_s4_of_init(struct device_node *dn,
> +					    struct device_node *parent)
> +{
> +	return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx8ulp_s4);
> +}
> +
> +IRQCHIP_PLATFORM_DRIVER_BEGIN(imx_mu_msi)
> +IRQCHIP_MATCH("fsl,imx7ulp-mu-msi", imx_mu_imx7ulp_of_init)
> +IRQCHIP_MATCH("fsl,imx6sx-mu-msi", imx_mu_imx6sx_of_init)
> +IRQCHIP_MATCH("fsl,imx8ulp-mu-msi", imx_mu_imx8ulp_of_init)
> +IRQCHIP_MATCH("fsl,imx8ulp-mu-msi-s4", imx_mu_imx8ulp_s4_of_init)
> +IRQCHIP_PLATFORM_DRIVER_END(imx_mu_msi, .pm = &imx_mu_pm_ops)
> +
> +
> +MODULE_AUTHOR("Frank Li <Frank.Li@nxp.com>");
> +MODULE_DESCRIPTION("Freescale MU work as MSI controller driver");

Please come up with a better description. Something like
"Freescale MU MSI controller driver"

> +MODULE_LICENSE("GPL");

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v4 2/4] irqchip: imx mu worked as msi controller
  2022-08-12 21:52 ` [PATCH v4 2/4] irqchip: imx mu worked as msi controller Frank Li
  2022-08-13  9:19   ` Marc Zyngier
@ 2022-08-13 11:57   ` Marc Zyngier
  2022-08-14  2:53     ` [EXT] " Frank Li
  1 sibling, 1 reply; 11+ messages in thread
From: Marc Zyngier @ 2022-08-13 11:57 UTC (permalink / raw
  To: Frank Li
  Cc: tglx, robh+dt, krzysztof.kozlowski+dt, shawnguo, s.hauer, kw,
	bhelgaas, devicetree, linux-arm-kernel, linux-pci, peng.fan,
	aisheng.dong, jdmason, kernel, festevam, linux-imx, kishon,
	lorenzo.pieralisi, ntb, lznuaa

On Fri, 12 Aug 2022 22:52:40 +0100,
Frank Li <Frank.Li@nxp.com> wrote:
> 
> MU support generate irq by write data to a register.
> This patch make mu worked as msi controller.
> So MU can do doorbell by using standard msi api.
> 
> Signed-off-by: Frank Li <Frank.Li@nxp.com>

May I add that it wouldn't hurt if you checked what addresses you send
your patches to? For example, 'kernel@vger.kernel.org' doesn't exist
(maybe you meant linux-kernel@...).

I will not take patches that haven't been posted to LKML (and I
shouldn't have reviewed it the first place).

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* RE: [EXT] Re: [PATCH v4 2/4] irqchip: imx mu worked as msi controller
  2022-08-13 11:57   ` Marc Zyngier
@ 2022-08-14  2:53     ` Frank Li
  0 siblings, 0 replies; 11+ messages in thread
From: Frank Li @ 2022-08-14  2:53 UTC (permalink / raw
  To: Marc Zyngier
  Cc: tglx@linutronix.de, robh+dt@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, shawnguo@kernel.org,
	s.hauer@pengutronix.de, kw@linux.com, bhelgaas@google.com,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-pci@vger.kernel.org, Peng Fan, Aisheng Dong,
	jdmason@kudzu.us, kernel@pengutronix.de, festevam@gmail.com,
	dl-linux-imx, kishon@ti.com, lorenzo.pieralisi@arm.com,
	ntb@lists.linux.dev, lznuaa@gmail.com



> -----Original Message-----
> From: Marc Zyngier <maz@kernel.org>
> Sent: Saturday, August 13, 2022 6:57 AM
> To: Frank Li <frank.li@nxp.com>
> Cc: tglx@linutronix.de; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; shawnguo@kernel.org;
> s.hauer@pengutronix.de; kw@linux.com; bhelgaas@google.com;
> devicetree@vger.kernel.org; linux-arm-kernel@lists.infradead.org; linux-
> pci@vger.kernel.org; Peng Fan <peng.fan@nxp.com>; Aisheng Dong
> <aisheng.dong@nxp.com>; jdmason@kudzu.us; kernel@pengutronix.de;
> festevam@gmail.com; dl-linux-imx <linux-imx@nxp.com>; kishon@ti.com;
> lorenzo.pieralisi@arm.com; ntb@lists.linux.dev; lznuaa@gmail.com
> Subject: [EXT] Re: [PATCH v4 2/4] irqchip: imx mu worked as msi controller
> 
> Caution: EXT Email
> 
> On Fri, 12 Aug 2022 22:52:40 +0100,
> Frank Li <Frank.Li@nxp.com> wrote:
> >
> > MU support generate irq by write data to a register.
> > This patch make mu worked as msi controller.
> > So MU can do doorbell by using standard msi api.
> >
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> 
> May I add that it wouldn't hurt if you checked what addresses you send
> your patches to? For example, 'kernel@vger.kernel.org' doesn't exist
> (maybe you meant linux-kernel@...).

[Frank Li] Thanks. Strang, My email system have not report error.  

> 
> I will not take patches that haven't been posted to LKML (and I
> shouldn't have reviewed it the first place).
> 
> Thanks,
> 
>         M.
> 
> --
> Without deviation from the norm, progress is not possible.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* RE: [EXT] Re: [PATCH v4 2/4] irqchip: imx mu worked as msi controller
  2022-08-13  9:19   ` Marc Zyngier
@ 2022-08-14  3:12     ` Frank Li
  2022-08-15  8:58       ` Marc Zyngier
  0 siblings, 1 reply; 11+ messages in thread
From: Frank Li @ 2022-08-14  3:12 UTC (permalink / raw
  To: Marc Zyngier
  Cc: tglx@linutronix.de, robh+dt@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, shawnguo@kernel.org,
	s.hauer@pengutronix.de, kw@linux.com, bhelgaas@google.com,
	kernel@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-pci@vger.kernel.org,
	Peng Fan, Aisheng Dong, jdmason@kudzu.us, kernel@pengutronix.de,
	festevam@gmail.com, dl-linux-imx, kishon@ti.com,
	lorenzo.pieralisi@arm.com, ntb@lists.linux.dev, lznuaa@gmail.com



> -----Original Message-----
> From: Marc Zyngier <maz@kernel.org>
> Sent: Saturday, August 13, 2022 4:19 AM
> To: Frank Li <frank.li@nxp.com>
> Cc: tglx@linutronix.de; robh+dt@kernel.org;
> krzysztof.kozlowski+dt@linaro.org; shawnguo@kernel.org;
> s.hauer@pengutronix.de; kw@linux.com; bhelgaas@google.com;
> kernel@vger.kernel.org; devicetree@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-pci@vger.kernel.org; Peng Fan
> <peng.fan@nxp.com>; Aisheng Dong <aisheng.dong@nxp.com>;
> jdmason@kudzu.us; kernel@pengutronix.de; festevam@gmail.com; dl-linux-
> imx <linux-imx@nxp.com>; kishon@ti.com; lorenzo.pieralisi@arm.com;
> ntb@lists.linux.dev; lznuaa@gmail.com
> Subject: [EXT] Re: [PATCH v4 2/4] irqchip: imx mu worked as msi controller
> 
> Caution: EXT Email
> 
> Frank,
> 
> The patch title needs work:
> 
> "irqchip: Add IMX MU MSI controller driver"
> 
> On Fri, 12 Aug 2022 22:52:40 +0100,
> Frank Li <Frank.Li@nxp.com> wrote:
> >
> > MU support generate irq by write data to a register.
> 
> "The MU block found in a number of Freescale/NXP SoCs supports
> generating IRQs by writing data to a register."
> 
> > This patch make mu worked as msi controller.
> 
> Please see Documentation/process/submitting-patches.rst, and the
> requirement to avoid wordings such as "This patch".
> 
> > So MU can do doorbell by using standard msi api.
> 
> "This enables the MU block to be used as a MSI controller, by
> leveraging the platform-MSI API"
> 
> >
> > Signed-off-by: Frank Li <Frank.Li@nxp.com>
> > ---
> >  drivers/irqchip/Kconfig          |   7 +
> >  drivers/irqchip/Makefile         |   1 +
> >  drivers/irqchip/irq-imx-mu-msi.c | 443
> +++++++++++++++++++++++++++++++
> >  3 files changed, 451 insertions(+)
> >  create mode 100644 drivers/irqchip/irq-imx-mu-msi.c
> >
> > diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> > index 5e4e50122777d..4599471d880c0 100644
> > --- a/drivers/irqchip/Kconfig
> > +++ b/drivers/irqchip/Kconfig
> > @@ -470,6 +470,13 @@ config IMX_INTMUX
> >       help
> >         Support for the i.MX INTMUX interrupt multiplexer.
> >
> > +config IMX_MU_MSI
> > +     bool "i.MX MU work as MSI controller"
> > +     default y if ARCH_MXC
> > +     select IRQ_DOMAIN
> > +     help
> > +       MU work as MSI controller to do general doorbell
> > +
> >  config LS1X_IRQ
> >       bool "Loongson-1 Interrupt Controller"
> >       depends on MACH_LOONGSON32
> > diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> > index 5d8e21d3dc6d8..870423746c783 100644
> > --- a/drivers/irqchip/Makefile
> > +++ b/drivers/irqchip/Makefile
> > @@ -98,6 +98,7 @@ obj-$(CONFIG_RISCV_INTC)            += irq-riscv-intc.o
> >  obj-$(CONFIG_SIFIVE_PLIC)            += irq-sifive-plic.o
> >  obj-$(CONFIG_IMX_IRQSTEER)           += irq-imx-irqsteer.o
> >  obj-$(CONFIG_IMX_INTMUX)             += irq-imx-intmux.o
> > +obj-$(CONFIG_IMX_MU_MSI)             += irq-imx-mu-msi.o
> >  obj-$(CONFIG_MADERA_IRQ)             += irq-madera.o
> >  obj-$(CONFIG_LS1X_IRQ)                       += irq-ls1x.o
> >  obj-$(CONFIG_TI_SCI_INTR_IRQCHIP)    += irq-ti-sci-intr.o
> > diff --git a/drivers/irqchip/irq-imx-mu-msi.c b/drivers/irqchip/irq-imx-mu-
> msi.c
> > new file mode 100644
> > index 0000000000000..bb111412d598f
> > --- /dev/null
> > +++ b/drivers/irqchip/irq-imx-mu-msi.c
> > @@ -0,0 +1,443 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * NXP MU worked as MSI controller
> 
> Freescale? Or NXP? Please make up your mind.


[Frank Li] NXP and freescale is the same thing. 
It is mux used at many place. 
 
> 
> > + *
> > + * Copyright (c) 2018 Pengutronix, Oleksij Rempel
> <o.rempel@pengutronix.de>
> > + * Copyright 2022 NXP
> > + *   Frank Li <Frank.Li@nxp.com>
> > + *   Peng Fan <peng.fan@nxp.com>
> > + *
> > + * Based on drivers/mailbox/imx-mailbox.c
> > + */
> > +#include <linux/clk.h>
> > +#include <linux/kernel.h>
> > +#include <linux/module.h>
> > +#include <linux/msi.h>
> > +#include <linux/interrupt.h>
> > +#include <linux/irq.h>
> > +#include <linux/irqchip/chained_irq.h>
> > +#include <linux/irqchip.h>
> > +#include <linux/irqdomain.h>
> > +#include <linux/of_irq.h>
> > +#include <linux/of_pci.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/spinlock.h>
> > +#include <linux/dma-iommu.h>
> > +#include <linux/pm_runtime.h>
> > +#include <linux/pm_domain.h>
> > +
> > +
> > +#define IMX_MU_CHANS            4
> > +
> > +enum imx_mu_xcr {
> > +     IMX_MU_GIER,
> > +     IMX_MU_GCR,
> > +     IMX_MU_TCR,
> > +     IMX_MU_RCR,
> > +     IMX_MU_xCR_MAX,
> > +};
> > +
> > +enum imx_mu_xsr {
> > +     IMX_MU_SR,
> > +     IMX_MU_GSR,
> > +     IMX_MU_TSR,
> > +     IMX_MU_RSR,
> > +};
> > +
> > +enum imx_mu_type {
> > +     IMX_MU_V1 = BIT(0),
> > +     IMX_MU_V2 = BIT(1),
> > +     IMX_MU_V2_S4 = BIT(15),
> > +};
> > +
> > +/* Receive Interrupt Enable */
> > +#define IMX_MU_xCR_RIEn(data, x) ((data->cfg->type) & IMX_MU_V2 ?
> BIT(x) : BIT(24 + (3 - (x))))
> > +#define IMX_MU_xSR_RFn(data, x) ((data->cfg->type) & IMX_MU_V2 ?
> BIT(x) : BIT(24 + (3 - (x))))
> > +
> > +struct imx_mu_dcfg {
> > +     enum imx_mu_type type;
> > +     u32     xTR;            /* Transmit Register0 */
> > +     u32     xRR;            /* Receive Register0 */
> > +     u32     xSR[4];         /* Status Registers */
> > +     u32     xCR[4];         /* Control Registers */
> > +};
> > +
> > +struct imx_mu_msi {
> > +     spinlock_t                      lock;
> > +     struct platform_device          *pdev;
> 
> This pointer isn't useful. It is only used in
> imx_mu_msi_domains_init(), which could take it as a parameter.
> 
> > +     struct irq_domain               *parent;
> 
> This pointer isn't useful. It is only used in the same function, and
> could well be a local variable.
> 
> > +     struct irq_domain               *msi_domain;
> > +     void __iomem                    *regs;
> > +     phys_addr_t                     msiir_addr;
> > +     const struct imx_mu_dcfg        *cfg;
> > +     unsigned long                   used;
> > +     int                             gic_irq;
> 
> This variable is only used in a single function.
> 
> > +     struct clk                      *clk;
> > +     struct device                   *pd_a;
> > +     struct device                   *pd_b;
> > +     struct device_link              *pd_link_a;
> > +     struct device_link              *pd_link_b;
> 
> Same thing. All this pd_* stuff is *never* used outside of a single
> function.
> 
> > +};
> > +
> > +static void imx_mu_write(struct imx_mu_msi *msi_data, u32 val, u32 offs)
> > +{
> > +     iowrite32(val, msi_data->regs + offs);
> > +}
> > +
> > +static u32 imx_mu_read(struct imx_mu_msi *msi_data, u32 offs)
> > +{
> > +     return ioread32(msi_data->regs + offs);
> > +}
> > +
> > +static u32 imx_mu_xcr_rmw(struct imx_mu_msi *msi_data, enum
> imx_mu_xcr type, u32 set, u32 clr)
> > +{
> > +     unsigned long flags;
> > +     u32 val;
> > +
> > +     spin_lock_irqsave(&msi_data->lock, flags);
> 
> This needs to be a raw spinlock.
> 
> > +     val = imx_mu_read(msi_data, msi_data->cfg->xCR[type]);
> > +     val &= ~clr;
> > +     val |= set;
> > +     imx_mu_write(msi_data, val, msi_data->cfg->xCR[type]);
> > +     spin_unlock_irqrestore(&msi_data->lock, flags);
> > +
> > +     return val;
> > +}
> > +
> > +static void imx_mu_msi_parent_mask_irq(struct irq_data *data)
> > +{
> > +     struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
> > +
> > +     imx_mu_xcr_rmw(msi_data, IMX_MU_RCR, 0,
> IMX_MU_xCR_RIEn(msi_data, data->hwirq));
> > +}
> > +
> > +static void imx_mu_msi_parent_unmask_irq(struct irq_data *data)
> > +{
> > +     struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
> > +
> > +     imx_mu_xcr_rmw(msi_data, IMX_MU_RCR,
> IMX_MU_xCR_RIEn(msi_data, data->hwirq), 0);
> > +}
> > +
> > +static void imx_mu_msi_parent_ack_irq(struct irq_data *data)
> > +{
> > +        struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
> > +
> > +        imx_mu_read(msi_data, msi_data->cfg->xRR + data->hwirq * 4);
> > +}
> > +
> > +static struct irq_chip imx_mu_msi_irq_chip = {
> > +     .name = "MU-MSI",
> > +     .irq_ack = irq_chip_ack_parent,
> 
> Crucially, no irq_write_msi_msg callback. So we happily inherit
> platform_msi_write_msg() and use the per descriptor write_msg()
> callback. Who sets this? Nobody.

[Frank Li] when set flag MSI_FLAG_USE_DEF_CHIP_OPS, 
 irq_write_msi_msg callback will be set at function platform_msi_update_chip_ops();

> 
> So I suspect you're hiding it somewhere else, and I really want to see
> this code. I really don't see a good reason why it should be anywhere
> else.
> 
> > +};
> > +
> > +static struct msi_domain_ops imx_mu_msi_irq_ops = {
> > +};
> > +
> > +static struct msi_domain_info imx_mu_msi_domain_info = {
> > +     .flags  = (MSI_FLAG_USE_DEF_DOM_OPS |
> MSI_FLAG_USE_DEF_CHIP_OPS),
> > +     .ops    = &imx_mu_msi_irq_ops,
> > +     .chip   = &imx_mu_msi_irq_chip,
> > +};
> > +
> > +static void imx_mu_msi_compose_msg(struct irq_data *data, struct
> msi_msg *msg)
> > +{
> > +     struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(data);
> > +     u64 addr = msi_data->msiir_addr + 4 * data->hwirq;
> > +
> > +     msg->address_hi = upper_32_bits(addr);
> > +     msg->address_lo = lower_32_bits(addr);
> > +     msg->data = data->hwirq;
> > +}
> > +
> > +static struct irq_chip imx_mu_msi_parent_chip = {
> > +     .name           = "MU",
> > +     .irq_mask       = imx_mu_msi_parent_mask_irq,
> > +     .irq_unmask     = imx_mu_msi_parent_unmask_irq,
> > +     .irq_ack        = imx_mu_msi_parent_ack_irq,
> > +     .irq_compose_msi_msg    = imx_mu_msi_compose_msg,
> 
> Please be consistent in the naming.
> 
> > +};
> > +
> > +static int imx_mu_msi_domain_irq_alloc(struct irq_domain *domain,
> > +                                     unsigned int virq,
> > +                                     unsigned int nr_irqs,
> > +                                     void *args)
> > +{
> > +     struct imx_mu_msi *msi_data = domain->host_data;
> > +     unsigned long flags;
> > +     int pos, err = 0;
> > +
> > +     WARN_ON(nr_irqs != 1);
> > +
> > +     spin_lock_irqsave(&msi_data->lock, flags);
> > +     pos = find_first_zero_bit(&msi_data->used, IMX_MU_CHANS);
> > +     if (pos < IMX_MU_CHANS)
> > +             __set_bit(pos, &msi_data->used);
> > +     else
> > +             err = -ENOSPC;
> > +     spin_unlock_irqrestore(&msi_data->lock, flags);
> > +
> > +     if (err)
> > +             return err;
> > +
> > +     irq_domain_set_info(domain, virq, pos,
> > +                         &imx_mu_msi_parent_chip, msi_data,
> > +                         handle_edge_irq, NULL, NULL);
> > +     return 0;
> > +}
> > +
> > +static void imx_mu_msi_domain_irq_free(struct irq_domain *domain,
> > +                                    unsigned int virq, unsigned int nr_irqs)
> > +{
> > +     struct irq_data *d = irq_domain_get_irq_data(domain, virq);
> > +     struct imx_mu_msi *msi_data = irq_data_get_irq_chip_data(d);
> > +     unsigned long flags;
> > +
> > +     spin_lock_irqsave(&msi_data->lock, flags);
> > +     __clear_bit(d->hwirq, &msi_data->used);
> > +     spin_unlock_irqrestore(&msi_data->lock, flags);
> > +}
> > +
> > +static const struct irq_domain_ops imx_mu_msi_domain_ops = {
> > +     .alloc  = imx_mu_msi_domain_irq_alloc,
> > +     .free   = imx_mu_msi_domain_irq_free,
> > +};
> > +
> > +static void imx_mu_msi_irq_handler(struct irq_desc *desc)
> > +{
> > +     struct imx_mu_msi *msi_data = irq_desc_get_handler_data(desc);
> > +     u32 status;
> > +     int i;
> > +
> > +     status = imx_mu_read(msi_data, msi_data->cfg->xSR[IMX_MU_RSR]);
> > +
> > +     chained_irq_enter(irq_desc_get_chip(desc), desc);
> > +     for (i = 0; i < IMX_MU_CHANS; i++) {
> > +             if (status & IMX_MU_xSR_RFn(msi_data, i)) {
> > +                     generic_handle_domain_irq(msi_data->msi_domain, i);
> > +             }
> > +     }
> > +     chained_irq_exit(irq_desc_get_chip(desc), desc);
> 
> Do yourself a favour, and compute irq_desc_get_chip(desc) once, just
> like for most irqchips.
> 
> > +}
> > +
> > +static int imx_mu_msi_domains_init(struct imx_mu_msi *msi_data)
> > +{
> > +     struct fwnode_handle *fwnodes =
> of_node_to_fwnode(dev_of_node(&msi_data->pdev->dev));
> 
> How about dev_fwnode()?
> 
> > +
> > +     /* Initialize MSI domain parent */
> > +     msi_data->parent = irq_domain_create_linear(fwnodes,
> > +                                                 IMX_MU_CHANS,
> > +                                                 &imx_mu_msi_domain_ops,
> > +                                                 msi_data);
> 
> Consider setting the bus_token attribute for this domain to something
> that isn't the default, as it otherwise clashes with the following
> creation.

[Frank Li] Any suggestion? Which bus_token is good? 

> 
> > +     if (!msi_data->parent) {
> > +             dev_err(&msi_data->pdev->dev, "failed to create IRQ domain\n");
> > +             return -ENOMEM;
> > +     }
> > +
> > +     msi_data->msi_domain = platform_msi_create_irq_domain(
> > +                             of_node_to_fwnode(msi_data->pdev->dev.of_node),
> 
> Why aren't you using the 'fwnodes' variable here?
> 
> > +                             &imx_mu_msi_domain_info,
> > +                             msi_data->parent);
> > +
> > +     if (!msi_data->msi_domain) {
> > +             dev_err(&msi_data->pdev->dev, "failed to create MSI domain\n");
> > +             irq_domain_remove(msi_data->parent);
> > +             return -ENOMEM;
> > +     }
> > +
> > +     /* clean irq_set_affinity again because it is chained irq */
> > +     imx_mu_msi_irq_chip.irq_set_affinity = NULL;
> 
> NAK. The way to do this is to provide a callback that returns -EINVAL,
> not to try and adjust things after the facts.
> 
> > +
> > +     irq_domain_set_pm_device(msi_data->msi_domain, &msi_data-
> >pdev->dev);
> > +
> > +     return 0;
> > +}
> > +
> > +/* Register offset of different version MU IP */
> > +static const struct imx_mu_dcfg imx_mu_cfg_imx6sx = {
> > +     .xTR    = 0x0,
> > +     .xRR    = 0x10,
> > +     .xSR    = {0x20, 0x20, 0x20, 0x20},
> > +     .xCR    = {0x24, 0x24, 0x24, 0x24},
> > +};
> > +
> > +static const struct imx_mu_dcfg imx_mu_cfg_imx7ulp = {
> > +     .xTR    = 0x20,
> > +     .xRR    = 0x40,
> > +     .xSR    = {0x60, 0x60, 0x60, 0x60},
> > +     .xCR    = {0x64, 0x64, 0x64, 0x64},
> > +};
> > +
> > +static const struct imx_mu_dcfg imx_mu_cfg_imx8ulp = {
> > +     .type   = IMX_MU_V2,
> > +     .xTR    = 0x200,
> > +     .xRR    = 0x280,
> > +     .xSR    = {0xC, 0x118, 0x124, 0x12C},
> > +     .xCR    = {0x110, 0x114, 0x120, 0x128},
> > +};
> > +
> > +static const struct imx_mu_dcfg imx_mu_cfg_imx8ulp_s4 = {
> > +
> > +     .type   = IMX_MU_V2 | IMX_MU_V2_S4,
> > +     .xTR    = 0x200,
> > +     .xRR    = 0x280,
> > +     .xSR    = {0xC, 0x118, 0x124, 0x12C},
> > +     .xCR    = {0x110, 0x114, 0x120, 0x128},
> > +};
> > +
> > +static int __init imx_mu_of_init(struct device_node *dn,
> > +                              struct device_node *parent,
> > +                              const struct imx_mu_dcfg *cfg)
> > +{
> > +     struct platform_device *pdev = of_find_device_by_node(dn);
> > +     struct imx_mu_msi *msi_data, *priv;
> > +     struct resource *res;
> > +     struct device *dev;
> > +     int ret;
> > +
> > +     if (!pdev)
> > +             return -ENODEV;
> > +
> > +     dev = &pdev->dev;
> > +
> > +     priv = msi_data = devm_kzalloc(&pdev->dev, sizeof(*msi_data),
> GFP_KERNEL);
> > +     if (!msi_data)
> > +             return -ENOMEM;
> > +
> > +     msi_data->cfg = cfg;
> > +
> > +     msi_data->regs = devm_platform_ioremap_resource_byname(pdev,
> "a");
> > +     if (IS_ERR(msi_data->regs)) {
> > +             dev_err(&pdev->dev, "failed to initialize 'regs'\n");
> > +             return PTR_ERR(msi_data->regs);
> > +     }
> > +
> > +     res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "b");
> > +     if (!res)
> > +             return -EIO;
> > +
> > +     msi_data->msiir_addr = res->start + msi_data->cfg->xTR;
> > +
> > +     msi_data->pdev = pdev;
> > +
> > +     msi_data->gic_irq = platform_get_irq(msi_data->pdev, 0);
> > +     if (msi_data->gic_irq <= 0)
> > +             return -ENODEV;
> > +
> > +     platform_set_drvdata(pdev, msi_data);
> > +
> > +     msi_data->clk = devm_clk_get(dev, NULL);
> > +     if (IS_ERR(msi_data->clk)) {
> > +             if (PTR_ERR(msi_data->clk) != -ENOENT)
> > +                     return PTR_ERR(msi_data->clk);
> > +
> > +             msi_data->clk = NULL;
> > +     }
> > +
> > +     ret = clk_prepare_enable(msi_data->clk);
> > +     if (ret) {
> > +             dev_err(dev, "Failed to enable clock\n");
> > +             return ret;
> > +     }
> > +
> > +     priv->pd_a = dev_pm_domain_attach_by_name(dev, "a");
> 
> I'm sorry, but you'll have to come up with something slightly more
> descriptive than "a" or "b". At least add a qualifier to it. Same
> thing for the DT by the way.

[Frank Li] MU spec using  term "A side" and "B side".  So I think "a" and "b"
is enough.  

Or do you think "a-side" is better?  

> 
> > +     if (IS_ERR(priv->pd_a))
> > +             return PTR_ERR(priv->pd_a);
> > +
> > +     priv->pd_link_a = device_link_add(dev, priv->pd_a,
> > +                     DL_FLAG_STATELESS |
> > +                     DL_FLAG_PM_RUNTIME |
> > +                     DL_FLAG_RPM_ACTIVE);
> > +
> > +     if (!priv->pd_link_a) {
> > +             dev_err(dev, "Failed to add device_link to mu a.\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     priv->pd_b = dev_pm_domain_attach_by_name(dev, "b");
> > +     if (IS_ERR(priv->pd_b))
> > +             return PTR_ERR(priv->pd_b);
> > +
> > +     priv->pd_link_b = device_link_add(dev, priv->pd_b,
> > +                     DL_FLAG_STATELESS |
> > +                     DL_FLAG_PM_RUNTIME |
> > +                     DL_FLAG_RPM_ACTIVE);
> > +
> > +     if (!priv->pd_link_b) {
> > +             dev_err(dev, "Failed to add device_link to mu a.\n");
> > +             return -EINVAL;
> > +     }
> > +
> > +     ret = imx_mu_msi_domains_init(msi_data);
> > +     if (ret)
> > +             return ret;
> 
> How about the clocks, the links, and everything else that has been
> allocated, enabled?
> 
> > +
> > +     irq_set_chained_handler_and_data(msi_data->gic_irq,
> > +                                      imx_mu_msi_irq_handler,
> > +                                      msi_data);
> > +
> > +     pm_runtime_enable(dev);
> > +
> > +     return 0;
> > +}
> > +
> > +static int __maybe_unused imx_mu_runtime_suspend(struct device *dev)
> > +{
> > +     struct imx_mu_msi *priv = dev_get_drvdata(dev);
> > +
> > +     clk_disable_unprepare(priv->clk);
> > +
> > +     return 0;
> > +}
> > +
> > +static int __maybe_unused imx_mu_runtime_resume(struct device *dev)
> > +{
> > +     struct imx_mu_msi *priv = dev_get_drvdata(dev);
> > +     int ret;
> > +
> > +     ret = clk_prepare_enable(priv->clk);
> > +     if (ret)
> > +             dev_err(dev, "failed to enable clock\n");
> > +
> > +     return ret;
> > +}
> > +
> > +static const struct dev_pm_ops imx_mu_pm_ops = {
> > +     SET_RUNTIME_PM_OPS(imx_mu_runtime_suspend,
> > +                        imx_mu_runtime_resume, NULL)
> > +};
> > +
> > +static int __init imx_mu_imx7ulp_of_init(struct device_node *dn,
> > +                                      struct device_node *parent)
> > +{
> > +     return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx7ulp);
> > +}
> > +
> > +static int __init imx_mu_imx6sx_of_init(struct device_node *dn,
> > +                                     struct device_node *parent)
> > +{
> > +     return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx6sx);
> > +}
> > +
> > +static int __init imx_mu_imx8ulp_of_init(struct device_node *dn,
> > +                                      struct device_node *parent)
> > +{
> > +     return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx8ulp);
> > +}
> > +
> > +static int __init imx_mu_imx8ulp_s4_of_init(struct device_node *dn,
> > +                                         struct device_node *parent)
> > +{
> > +     return imx_mu_of_init(dn, parent, &imx_mu_cfg_imx8ulp_s4);
> > +}
> > +
> > +IRQCHIP_PLATFORM_DRIVER_BEGIN(imx_mu_msi)
> > +IRQCHIP_MATCH("fsl,imx7ulp-mu-msi", imx_mu_imx7ulp_of_init)
> > +IRQCHIP_MATCH("fsl,imx6sx-mu-msi", imx_mu_imx6sx_of_init)
> > +IRQCHIP_MATCH("fsl,imx8ulp-mu-msi", imx_mu_imx8ulp_of_init)
> > +IRQCHIP_MATCH("fsl,imx8ulp-mu-msi-s4", imx_mu_imx8ulp_s4_of_init)
> > +IRQCHIP_PLATFORM_DRIVER_END(imx_mu_msi, .pm =
> &imx_mu_pm_ops)
> > +
> > +
> > +MODULE_AUTHOR("Frank Li <Frank.Li@nxp.com>");
> > +MODULE_DESCRIPTION("Freescale MU work as MSI controller driver");
> 
> Please come up with a better description. Something like
> "Freescale MU MSI controller driver"
> 
> > +MODULE_LICENSE("GPL");
> 
> Thanks,
> 
>         M.
> 
> --
> Without deviation from the norm, progress is not possible.

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [PATCH v4 3/4] dt-bindings: irqchip: imx mu work as msi controller
  2022-08-12 21:52 ` [PATCH v4 3/4] dt-bindings: irqchip: imx mu work " Frank Li
@ 2022-08-14 20:41   ` Rob Herring
  0 siblings, 0 replies; 11+ messages in thread
From: Rob Herring @ 2022-08-14 20:41 UTC (permalink / raw
  To: Frank Li
  Cc: maz, tglx, krzysztof.kozlowski+dt, shawnguo, s.hauer, kw,
	bhelgaas, kernel, devicetree, linux-arm-kernel, linux-pci,
	peng.fan, aisheng.dong, jdmason, kernel, festevam, linux-imx,
	kishon, lorenzo.pieralisi, ntb, lznuaa

On Fri, Aug 12, 2022 at 04:52:41PM -0500, Frank Li wrote:
> I.MX mu support generate irq by write a register. Provide msi controller
> support so other driver such as PCI EP can use it by standard msi
> interface as doorbell.
> 
> Signed-off-by: Frank Li <Frank.Li@nxp.com>
> ---
>  .../interrupt-controller/fsl,mu-msi.yaml      | 93 +++++++++++++++++++
>  1 file changed, 93 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/fsl,mu-msi.yaml
> 
> diff --git a/Documentation/devicetree/bindings/interrupt-controller/fsl,mu-msi.yaml b/Documentation/devicetree/bindings/interrupt-controller/fsl,mu-msi.yaml
> new file mode 100644
> index 0000000000000..f60fa8b686879
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/interrupt-controller/fsl,mu-msi.yaml
> @@ -0,0 +1,93 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/interrupt-controller/fsl,mu-msi.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: NXP i.MX Messaging Unit (MU) work as msi controller
> +
> +maintainers:
> +  - Frank Li <Frank.Li@nxp.com>
> +
> +description: |
> +  The Messaging Unit module enables two processors within the SoC to
> +  communicate and coordinate by passing messages (e.g. data, status
> +  and control) through the MU interface. The MU also provides the ability
> +  for one processor (A side) to signal the other processor (B side) using
> +  interrupts.
> +
> +  Because the MU manages the messaging between processors, the MU uses
> +  different clocks (from each side of the different peripheral buses).
> +  Therefore, the MU must synchronize the accesses from one side to the
> +  other. The MU accomplishes synchronization using two sets of matching
> +  registers (Processor A-facing, Processor B-facing).
> +
> +  MU can work as msi interrupt controller to do doorbell
> +
> +allOf:
> +  - $ref: /schemas/interrupt-controller/msi-controller.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - fsl,imx6sx-mu-msi
> +      - fsl,imx7ulp-mu-msi
> +      - fsl,imx8ulp-mu-msi
> +      - fsl,imx8ulp-mu-msi-s4
> +
> +  reg:
> +    items:
> +      - description: a side register base address
> +      - description: b side register base address
> +
> +  reg-names:
> +    items:
> +      - const: a
> +      - const: b
> +
> +  interrupts:
> +    description: a side interrupt number.

How many?

> +
> +  clocks:
> +    maxItems: 1
> +
> +  power-domains:
> +    items:
> +      - description: a side power domain
> +      - description: b side power domain
> +
> +  power-domain-names:
> +    items:
> +      - const: a
> +      - const: b
> +
> +  interrupt-controller: true
> +
> +  msi-controller: true

#msi-cells?

(Missing is treated as 0, but new bindings should be explicit)

> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - interrupt-controller
> +  - msi-controller
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/arm-gic.h>
> +    #include <dt-bindings/firmware/imx/rsrc.h>
> +
> +    lsio_mu12: msi-controller@5d270000 {

Drop unused labels.

> +        compatible = "fsl,imx6sx-mu-msi";
> +        msi-controller;
> +        interrupt-controller;
> +        reg = <0x5d270000 0x10000>,     /* A side */
> +              <0x5d300000 0x10000>;     /* B side */
> +        reg-names = "a", "b";
> +        interrupts = <GIC_SPI 191 IRQ_TYPE_LEVEL_HIGH>;
> +        power-domains = <&pd IMX_SC_R_MU_12A>,
> +                        <&pd IMX_SC_R_MU_12B>;
> +        power-domain-names = "a", "b";
> +    };
> -- 
> 2.35.1
> 
> 

^ permalink raw reply	[flat|nested] 11+ messages in thread

* Re: [EXT] Re: [PATCH v4 2/4] irqchip: imx mu worked as msi controller
  2022-08-14  3:12     ` [EXT] " Frank Li
@ 2022-08-15  8:58       ` Marc Zyngier
  0 siblings, 0 replies; 11+ messages in thread
From: Marc Zyngier @ 2022-08-15  8:58 UTC (permalink / raw
  To: Frank Li
  Cc: tglx@linutronix.de, robh+dt@kernel.org,
	krzysztof.kozlowski+dt@linaro.org, shawnguo@kernel.org,
	s.hauer@pengutronix.de, kw@linux.com, bhelgaas@google.com,
	devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-pci@vger.kernel.org, Peng Fan, Aisheng Dong,
	jdmason@kudzu.us, kernel@pengutronix.de, festevam@gmail.com,
	dl-linux-imx, kishon@ti.com, lorenzo.pieralisi@arm.com,
	ntb@lists.linux.dev, lznuaa@gmail.com

On Sun, 14 Aug 2022 04:12:01 +0100,
Frank Li <frank.li@nxp.com> wrote:

> > > new file mode 100644
> > > index 0000000000000..bb111412d598f
> > > --- /dev/null
> > > +++ b/drivers/irqchip/irq-imx-mu-msi.c
> > > @@ -0,0 +1,443 @@
> > > +// SPDX-License-Identifier: GPL-2.0-only
> > > +/*
> > > + * NXP MU worked as MSI controller
> > 
> > Freescale? Or NXP? Please make up your mind.
> 
> 
> [Frank Li] NXP and freescale is the same thing. 
> It is mux used at many place.

Pick one, and stick to it. Having two names for the same thing is
pointlessly confusing.

> > > +static struct irq_chip imx_mu_msi_irq_chip = {
> > > +     .name = "MU-MSI",
> > > +     .irq_ack = irq_chip_ack_parent,
> > 
> > Crucially, no irq_write_msi_msg callback. So we happily inherit
> > platform_msi_write_msg() and use the per descriptor write_msg()
> > callback. Who sets this? Nobody.
> 
> [Frank Li] when set flag MSI_FLAG_USE_DEF_CHIP_OPS, 
>  irq_write_msi_msg callback will be set at function platform_msi_update_chip_ops();

That wasn't my question. But never mind, I found the call to
platform_msi_domain_alloc_irqs() in patch #4.

> > > +
> > > +     /* Initialize MSI domain parent */
> > > +     msi_data->parent = irq_domain_create_linear(fwnodes,
> > > +                                                 IMX_MU_CHANS,
> > > +                                                 &imx_mu_msi_domain_ops,
> > > +                                                 msi_data);
> > 
> > Consider setting the bus_token attribute for this domain to something
> > that isn't the default, as it otherwise clashes with the following
> > creation.
> 
> [Frank Li] Any suggestion? Which bus_token is good?

DOMAIN_BUS_NEXUS is what other drivers use.

> > > +     priv->pd_a = dev_pm_domain_attach_by_name(dev, "a");
> > 
> > I'm sorry, but you'll have to come up with something slightly more
> > descriptive than "a" or "b". At least add a qualifier to it. Same
> > thing for the DT by the way.
> 
> [Frank Li] MU spec using  term "A side" and "B side".  So I think "a" and "b"
> is enough.

No, it really isn't.

> 
> Or do you think "a-side" is better?

No, I would like something fully descriptive. The DT actually has
"Processor A-facing", which seems like a reasonable description.

	M.

-- 
Without deviation from the norm, progress is not possible.

^ permalink raw reply	[flat|nested] 11+ messages in thread

end of thread, other threads:[~2022-08-15  8:58 UTC | newest]

Thread overview: 11+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2022-08-12 21:52 [PATCH v4 0/4] PCI EP driver support MSI doorbell from host Frank Li
2022-08-12 21:52 ` [PATCH v4 1/4] irqchip: allow pass down .pm field at IRQCHIP_PLATFORM_DRIVER_END Frank Li
2022-08-12 21:52 ` [PATCH v4 2/4] irqchip: imx mu worked as msi controller Frank Li
2022-08-13  9:19   ` Marc Zyngier
2022-08-14  3:12     ` [EXT] " Frank Li
2022-08-15  8:58       ` Marc Zyngier
2022-08-13 11:57   ` Marc Zyngier
2022-08-14  2:53     ` [EXT] " Frank Li
2022-08-12 21:52 ` [PATCH v4 3/4] dt-bindings: irqchip: imx mu work " Frank Li
2022-08-14 20:41   ` Rob Herring
2022-08-12 21:52 ` [PATCH v4 4/4] pcie: endpoint: pci-epf-vntb: add endpoint MSI support Frank Li

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