From: Koichiro Den <den@valinux.co.jp>
To: "Jon Mason" <jdmason@kudzu.us>,
"Dave Jiang" <dave.jiang@intel.com>,
"Allen Hubbe" <allenbh@gmail.com>,
"Manivannan Sadhasivam" <mani@kernel.org>,
"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
"Kishon Vijay Abraham I" <kishon@kernel.org>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Frank Li" <Frank.Li@nxp.com>,
"Jerome Brunet" <jbrunet@baylibre.com>,
"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
"Niklas Cassel" <cassel@kernel.org>
Cc: linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org,
ntb@lists.linux.dev
Subject: [PATCH v4 10/12] NTB: epf: Report 0-based doorbell vector via ntb_db_event()
Date: Wed, 13 May 2026 11:49:21 +0900 [thread overview]
Message-ID: <20260513024923.451765-11-den@valinux.co.jp> (raw)
In-Reply-To: <20260513024923.451765-1-den@valinux.co.jp>
ntb_db_event() expects the vector number to be relative to the first
doorbell vector starting at 0.
Vector 0 is reserved for link events in the EPF driver, so doorbells
start at vector 1. However, both supported peers (ntb_hw_epf with
pci-epf-ntb, and pci-epf-vntb) have historically skipped vector 1 and
started doorbells at vector 2.
Pass (irq_no - 2) to ntb_db_event() so doorbells are reported as 0..N-1.
If irq_no == 1 is ever observed, warn and ignore it, since the slot is
reserved in the legacy layout and reporting it as DB#0 would collide with
the real DB#0 slot.
Fixes: 812ce2f8d14e ("NTB: Add support for EPF PCI Non-Transparent Bridge")
Suggested-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
Changes since v3:
- Ignore the reserved legacy slot instead of reporting it as DB#0.
- Drop a Reviewed-by tag due to the behavior change.
drivers/ntb/hw/epf/ntb_hw_epf.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c b/drivers/ntb/hw/epf/ntb_hw_epf.c
index c0bab3292075..7b0fc7ef00c6 100644
--- a/drivers/ntb/hw/epf/ntb_hw_epf.c
+++ b/drivers/ntb/hw/epf/ntb_hw_epf.c
@@ -81,6 +81,12 @@ enum epf_ntb_bar {
NTB_BAR_NUM,
};
+enum epf_irq_slot {
+ EPF_IRQ_LINK = 0,
+ EPF_IRQ_RESERVED_DB, /* Historically skipped slot */
+ EPF_IRQ_DB_START,
+};
+
#define NTB_EPF_MAX_MW_COUNT (NTB_BAR_NUM - BAR_MW1)
struct ntb_epf_dev {
@@ -334,10 +340,14 @@ static irqreturn_t ntb_epf_vec_isr(int irq, void *dev)
irq_no = irq - ndev->irq_base;
ndev->db_val = irq_no + 1;
- if (irq_no == 0)
+ if (irq_no == EPF_IRQ_LINK) {
ntb_link_event(&ndev->ntb);
- else
- ntb_db_event(&ndev->ntb, irq_no);
+ } else if (irq_no == EPF_IRQ_RESERVED_DB) {
+ dev_warn_ratelimited(ndev->dev,
+ "Unexpected reserved doorbell slot IRQ received\n");
+ } else {
+ ntb_db_event(&ndev->ntb, irq_no - EPF_IRQ_DB_START);
+ }
return IRQ_HANDLED;
}
--
2.51.0
next prev parent reply other threads:[~2026-05-13 2:49 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-13 2:49 [PATCH v4 00/12] PCI: endpoint: pci-epf-vntb / NTB: epf: Enable per-doorbell bit handling Koichiro Den
2026-05-13 2:49 ` [PATCH v4 01/12] PCI: endpoint: pci-epf-vntb: Document legacy MSI doorbell offset Koichiro Den
2026-05-13 2:49 ` [PATCH v4 02/12] PCI: endpoint: pci-epf-vntb: Defer pci_epc_raise_irq() out of atomic context Koichiro Den
2026-05-14 18:53 ` Frank Li
2026-05-13 2:49 ` [PATCH v4 03/12] PCI: endpoint: pci-epf-vntb: Report 0-based doorbell vector via ntb_db_event() Koichiro Den
2026-05-13 2:49 ` [PATCH v4 04/12] PCI: endpoint: pci-epf-vntb: Reject unusable doorbell counts Koichiro Den
2026-05-14 18:55 ` Frank Li
2026-05-13 2:49 ` [PATCH v4 05/12] PCI: endpoint: pci-epf-vntb: Guard configfs writes after EPC attach Koichiro Den
2026-05-14 18:57 ` Frank Li
2026-05-13 2:49 ` [PATCH v4 06/12] PCI: endpoint: pci-epf-vntb: Exclude reserved slots from db_valid_mask Koichiro Den
2026-05-13 2:49 ` [PATCH v4 07/12] PCI: endpoint: pci-epf-vntb: Implement db_vector_count/mask for doorbells Koichiro Den
2026-05-14 19:02 ` Frank Li
2026-05-13 2:49 ` [PATCH v4 08/12] NTB: epf: Document legacy doorbell slot offset in ntb_epf_peer_db_set() Koichiro Den
2026-05-13 2:49 ` [PATCH v4 09/12] NTB: epf: Make db_valid_mask cover only real doorbell bits Koichiro Den
2026-05-26 22:21 ` Dave Jiang
2026-05-13 2:49 ` Koichiro Den [this message]
2026-05-14 19:03 ` [PATCH v4 10/12] NTB: epf: Report 0-based doorbell vector via ntb_db_event() Frank Li
2026-05-26 22:28 ` Dave Jiang
2026-05-13 2:49 ` [PATCH v4 11/12] NTB: epf: Fix doorbell bitmask and IRQ vector handling Koichiro Den
2026-05-14 19:06 ` Frank Li
2026-05-26 22:36 ` Dave Jiang
2026-05-13 2:49 ` [PATCH v4 12/12] NTB: epf: Implement db_vector_count/mask for doorbells Koichiro Den
2026-05-26 22:47 ` Dave Jiang
2026-06-23 16:31 ` Bjorn Helgaas
2026-06-24 1:35 ` Koichiro Den
2026-05-19 14:42 ` [PATCH v4 00/12] PCI: endpoint: pci-epf-vntb / NTB: epf: Enable per-doorbell bit handling Manivannan Sadhasivam
2026-05-19 21:29 ` Dave Jiang
2026-05-21 6:29 ` Koichiro Den
2026-05-26 14:45 ` Dave Jiang
2026-05-26 15:56 ` Koichiro Den
2026-05-26 16:27 ` Dave Jiang
2026-05-27 9:09 ` Manivannan Sadhasivam
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