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 12/12] NTB: epf: Implement db_vector_count/mask for doorbells
Date: Wed, 13 May 2026 11:49:23 +0900 [thread overview]
Message-ID: <20260513024923.451765-13-den@valinux.co.jp> (raw)
In-Reply-To: <20260513024923.451765-1-den@valinux.co.jp>
Implement .db_vector_count and .db_vector_mask so ntb core/clients can
map doorbell events to per-vector work.
Report vectors as 0..(db_count - 2) (skipping the unused slot) and return
BIT_ULL(db_vector) for the corresponding doorbell bit. Use
ntb_epf_db_vector_count() for bounds checks in ntb_epf_db_vector_mask(), so
the same lower-bound guard is applied before building the bitmask.
Signed-off-by: Koichiro Den <den@valinux.co.jp>
---
Changes since v3:
- Reuse ntb_epf_db_vector_count() from ntb_epf_db_vector_mask() for bounds.
- Return 0 when db_count is below NTB_EPF_MIN_DB_COUNT.
- Drop Reviewed-by tags due to the changes.
drivers/ntb/hw/epf/ntb_hw_epf.c | 32 ++++++++++++++++++++++++++++++++
1 file changed, 32 insertions(+)
diff --git a/drivers/ntb/hw/epf/ntb_hw_epf.c b/drivers/ntb/hw/epf/ntb_hw_epf.c
index 10618e462229..af5755472842 100644
--- a/drivers/ntb/hw/epf/ntb_hw_epf.c
+++ b/drivers/ntb/hw/epf/ntb_hw_epf.c
@@ -434,6 +434,36 @@ static u64 ntb_epf_db_valid_mask(struct ntb_dev *ntb)
return ntb_ndev(ntb)->db_valid_mask;
}
+static int ntb_epf_db_vector_count(struct ntb_dev *ntb)
+{
+ struct ntb_epf_dev *ndev = ntb_ndev(ntb);
+ unsigned int db_count = ndev->db_count;
+
+ /*
+ * db_count includes an extra skipped slot due to the legacy
+ * doorbell layout. Expose only the real doorbell vectors.
+ */
+ if (db_count < NTB_EPF_MIN_DB_COUNT)
+ return 0;
+
+ return db_count - 1;
+}
+
+static u64 ntb_epf_db_vector_mask(struct ntb_dev *ntb, int db_vector)
+{
+ int nr_vec;
+
+ /*
+ * db_count includes one skipped slot in the legacy layout. Valid
+ * doorbell vectors are therefore [0 .. (db_count - 2)].
+ */
+ nr_vec = ntb_epf_db_vector_count(ntb);
+ if (db_vector < 0 || db_vector >= nr_vec)
+ return 0;
+
+ return BIT_ULL(db_vector);
+}
+
static int ntb_epf_db_set_mask(struct ntb_dev *ntb, u64 db_bits)
{
return 0;
@@ -568,6 +598,8 @@ static const struct ntb_dev_ops ntb_epf_ops = {
.spad_count = ntb_epf_spad_count,
.peer_mw_count = ntb_epf_peer_mw_count,
.db_valid_mask = ntb_epf_db_valid_mask,
+ .db_vector_count = ntb_epf_db_vector_count,
+ .db_vector_mask = ntb_epf_db_vector_mask,
.db_set_mask = ntb_epf_db_set_mask,
.mw_set_trans = ntb_epf_mw_set_trans,
.mw_clear_trans = ntb_epf_mw_clear_trans,
--
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 ` [PATCH v4 10/12] NTB: epf: Report 0-based doorbell vector via ntb_db_event() Koichiro Den
2026-05-14 19:03 ` 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 ` Koichiro Den [this message]
2026-05-26 22:47 ` [PATCH v4 12/12] NTB: epf: Implement db_vector_count/mask for doorbells 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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