From: Vidya Sagar <vidyas@nvidia.com>
To: <lpieralisi@kernel.org>, <kw@linux.com>, <robh@kernel.org>,
<bhelgaas@google.com>, <krzysztof.kozlowski+dt@linaro.org>,
<conor+dt@kernel.org>, <will@kernel.org>,
<frowand.list@gmail.com>
Cc: <linux-pci@vger.kernel.org>, <devicetree@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
<linux-arm-kernel@lists.infradead.org>, <treding@nvidia.com>,
<jonathanh@nvidia.com>, <kthota@nvidia.com>,
<mmaddireddy@nvidia.com>, <vidyas@nvidia.com>,
<sagar.tv@gmail.com>, "kernel test robot" <lkp@intel.com>
Subject: [PATCH V2 2/2] PCI: Add support for "preserve-boot-config" property
Date: Wed, 10 Jan 2024 08:37:25 +0530 [thread overview]
Message-ID: <20240110030725.710547-3-vidyas@nvidia.com> (raw)
In-Reply-To: <20240110030725.710547-1-vidyas@nvidia.com>
Add support for "preserve-boot-config" property that can be used to
selectively (i.e. per host bridge) instruct the kernel to preserve the
boot time configuration done by the platform firmware.
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
---
V2:
* Addressed issues reported by kernel test robot <lkp@intel.com>
drivers/pci/controller/pci-host-common.c | 5 ++++-
drivers/pci/of.c | 18 ++++++++++++++++++
drivers/pci/probe.c | 2 +-
include/linux/of_pci.h | 6 ++++++
4 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
index 6be3266cd7b5..d3475dc9ec44 100644
--- a/drivers/pci/controller/pci-host-common.c
+++ b/drivers/pci/controller/pci-host-common.c
@@ -68,13 +68,16 @@ int pci_host_common_probe(struct platform_device *pdev)
of_pci_check_probe_only();
+ bridge->preserve_config =
+ of_pci_check_preserve_boot_config(dev->of_node);
+
/* Parse and map our Configuration Space windows */
cfg = gen_pci_init(dev, bridge, ops);
if (IS_ERR(cfg))
return PTR_ERR(cfg);
/* Do not reassign resources if probe only */
- if (!pci_has_flag(PCI_PROBE_ONLY))
+ if (!(pci_has_flag(PCI_PROBE_ONLY) || bridge->preserve_config))
pci_add_flags(PCI_REASSIGN_ALL_BUS);
bridge->sysdata = cfg;
diff --git a/drivers/pci/of.c b/drivers/pci/of.c
index 51e3dd0ea5ab..ed3c0dd9804e 100644
--- a/drivers/pci/of.c
+++ b/drivers/pci/of.c
@@ -258,6 +258,24 @@ void of_pci_check_probe_only(void)
}
EXPORT_SYMBOL_GPL(of_pci_check_probe_only);
+/**
+ * of_pci_check_preserve_boot_config - Return true if the boot configuration
+ * needs to be preserved
+ * @node: Device tree node with the domain information.
+ *
+ * This function looks for a property called "preserve-boot-config" for a given
+ * PCIe controller's node and returns true if found. Having this property
+ * for a PCIe controller ensures that the kernel doesn't re-enumerate and
+ * reconfigure the BAR resources that are already done by the platform firmware.
+ *
+ * Return: true if the property exists false otherwise.
+ */
+bool of_pci_check_preserve_boot_config(struct device_node *node)
+{
+ return of_property_read_bool(node, "preserve-boot-config");
+}
+EXPORT_SYMBOL_GPL(of_pci_check_preserve_boot_config);
+
/**
* devm_of_pci_get_host_bridge_resources() - Resource-managed parsing of PCI
* host bridge resources from DT
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 795534589b98..79d0ac34f567 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -3085,7 +3085,7 @@ int pci_host_probe(struct pci_host_bridge *bridge)
* ioport_resource trees in either pci_bus_claim_resources()
* or pci_bus_assign_resources().
*/
- if (pci_has_flag(PCI_PROBE_ONLY)) {
+ if (pci_has_flag(PCI_PROBE_ONLY) || bridge->preserve_config) {
pci_bus_claim_resources(bus);
} else {
pci_bus_size_bridges(bus);
diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h
index 29658c0ee71f..ba5532005125 100644
--- a/include/linux/of_pci.h
+++ b/include/linux/of_pci.h
@@ -13,6 +13,7 @@ struct device_node *of_pci_find_child_device(struct device_node *parent,
unsigned int devfn);
int of_pci_get_devfn(struct device_node *np);
void of_pci_check_probe_only(void);
+bool of_pci_check_preserve_boot_config(struct device_node *node);
#else
static inline struct device_node *of_pci_find_child_device(struct device_node *parent,
unsigned int devfn)
@@ -26,6 +27,11 @@ static inline int of_pci_get_devfn(struct device_node *np)
}
static inline void of_pci_check_probe_only(void) { }
+
+static inline bool of_pci_check_preserve_boot_config(struct device_node *node)
+{
+ return false;
+}
#endif
#if IS_ENABLED(CONFIG_OF_IRQ)
--
2.25.1
next prev parent reply other threads:[~2024-01-10 3:08 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-10 3:07 [PATCH V2 0/2] Add support to preserve boot config in the DT flow Vidya Sagar
2024-01-10 3:07 ` [PATCH V2 1/2] dt-bindings: Add PCIe "preserve-boot-config" property Vidya Sagar
2024-01-12 14:33 ` Rob Herring
2024-01-10 3:07 ` Vidya Sagar [this message]
2024-01-12 16:58 ` [PATCH V2 2/2] PCI: Add support for " Bjorn Helgaas
2024-01-15 14:32 ` Vidya Sagar
2024-01-16 16:55 ` Rob Herring
2024-01-19 17:31 ` Bjorn Helgaas
2024-01-12 16:59 ` Bjorn Helgaas
2024-02-22 12:41 ` [PATCH V3] PCI: Add support for preserving boot configuration Vidya Sagar
2024-02-22 17:06 ` Bjorn Helgaas
2024-02-22 21:18 ` Vidya Sagar
2024-02-22 22:08 ` Bjorn Helgaas
2024-02-23 8:00 ` [PATCH V4] " Vidya Sagar
2024-03-05 14:10 ` Rob Herring
2024-03-05 14:24 ` Rob Herring
2024-04-01 7:50 ` [PATCH V5] " Vidya Sagar
2024-04-02 16:01 ` Rob Herring
2024-04-10 7:44 ` Vidya Sagar
2024-04-10 20:50 ` Bjorn Helgaas
2024-04-18 17:31 ` Vidya Sagar
2024-04-18 17:40 ` [PATCH V6] " Vidya Sagar
2024-04-21 19:03 ` Bjorn Helgaas
2024-04-21 19:09 ` [PATCH v7-incomplete 0/3] " Bjorn Helgaas
2024-04-21 19:09 ` [PATCH v7-incomplete 1/3] PCI: Move PRESERVE_BOOT_CONFIG _DSM evaluation to pci_register_host_bridge() Bjorn Helgaas
2024-04-22 7:45 ` Andy Shevchenko
2024-04-21 19:09 ` [PATCH v7-incomplete 2/3] PCI: of: Add of_pci_preserve_config() for per-host bridge support Bjorn Helgaas
2024-04-21 19:09 ` [PATCH v7-incomplete 3/3] PCI: Unify ACPI and DT 'preserve config' support Bjorn Helgaas
2024-04-22 7:43 ` Andy Shevchenko
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