From 0834d6f4abd0ca35b5706d267a6e4b78303a95de Mon Sep 17 00:00:00 2001 From: Niklas Cassel Date: Thu, 12 Mar 2026 14:02:29 +0100 Subject: PCI: endpoint: Do not mark the BAR succeeding a 64-bit BAR as BAR_RESERVED A BAR that can only be configured as a 64-bit BAR by an EPC driver is marked as such using the "only_64bit" flag. Currently, the documentation says that an EPC driver should explicitly mark the BAR succeeding an "only_64bit" BAR as BAR_RESERVED. However, a 64-bit BAR will always take up two BARs. It is thus redundant to mark both BARs. pci_epc_get_next_free_bar() already skips the BAR succeeding a "only_64bit" BAR, regardless if the succeeding BAR is marked as BAR_RESERVED or not. Thus, drop the BAR_RESERVED for a BAR succeeding a "only_64bit" BAR. No functional changes. Suggested-by: Manivannan Sadhasivam Signed-off-by: Niklas Cassel Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20260312130229.2282001-13-cassel@kernel.org --- include/linux/pci-epc.h | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h index c021c7af175f..c981ea7d52c0 100644 --- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -206,8 +206,7 @@ enum pci_epc_bar_type { * @fixed_size: the fixed size, only applicable if type is BAR_FIXED_MASK. * @only_64bit: if true, an EPF driver is not allowed to choose if this BAR * should be configured as 32-bit or 64-bit, the EPF driver must - * configure this BAR as 64-bit. Additionally, the BAR succeeding - * this BAR must be set to type BAR_RESERVED. + * configure this BAR as 64-bit. * * only_64bit should not be set on a BAR of type BAR_RESERVED. * (If BARx is a 64-bit BAR that an EPF driver is not allowed to -- cgit v1.2.3 From 27ce1d8ecb9b9ae025b9e9e199845624bc950998 Mon Sep 17 00:00:00 2001 From: Manikanta Maddireddy Date: Thu, 12 Mar 2026 14:02:30 +0100 Subject: PCI: endpoint: Allow only_64bit on BAR_RESERVED Remove the documentation that forbids setting only_64bit on a BAR of type BAR_RESERVED. When a reserved BAR is 64-bit by default, setting only_64bit is the most accurate description. If we later add support to disable a reserved BAR (e.g. disable_bar() for BARs that were never set via set_bar()), the implementation will need to clear the adjacent BAR (upper 32 bits) as well; having only_64bit set documents that requirement. Signed-off-by: Manikanta Maddireddy Signed-off-by: Niklas Cassel Signed-off-by: Manivannan Sadhasivam Link: https://patch.msgid.link/20260312130229.2282001-14-cassel@kernel.org --- include/linux/pci-epc.h | 5 ----- 1 file changed, 5 deletions(-) (limited to 'include/linux') diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h index c981ea7d52c0..5c59f5606869 100644 --- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -207,11 +207,6 @@ enum pci_epc_bar_type { * @only_64bit: if true, an EPF driver is not allowed to choose if this BAR * should be configured as 32-bit or 64-bit, the EPF driver must * configure this BAR as 64-bit. - * - * only_64bit should not be set on a BAR of type BAR_RESERVED. - * (If BARx is a 64-bit BAR that an EPF driver is not allowed to - * touch, then both BARx and BARx+1 must be set to type - * BAR_RESERVED.) */ struct pci_epc_bar_desc { enum pci_epc_bar_type type; -- cgit v1.2.3 From f51644eb40a73677fcd0c92d8174eddde5d0be0e Mon Sep 17 00:00:00 2001 From: Koichiro Den Date: Thu, 12 Mar 2026 14:02:31 +0100 Subject: PCI: endpoint: Describe reserved subregions within BARs Some endpoint controllers expose platform-owned, fixed register windows within a BAR that EPF drivers must not reprogram (e.g. a BAR marked BAR_RESERVED). Even in that case, EPF drivers may need to reference a well-defined subset of that BAR, e.g. to reuse an integrated DMA controller MMIO window as a doorbell target. Introduce struct pci_epc_bar_rsvd_region and extend struct pci_epc_bar_desc so EPC drivers can advertise such fixed subregions in a controller-agnostic way. No functional change for existing users. Signed-off-by: Koichiro Den Signed-off-by: Niklas Cassel Signed-off-by: Manivannan Sadhasivam Tested-by: Manikanta Maddireddy Tested-by: Koichiro Den Reviewed-by: Frank Li Link: https://patch.msgid.link/20260312130229.2282001-15-cassel@kernel.org --- include/linux/pci-epc.h | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h index 5c59f5606869..ebcdf70aa9b9 100644 --- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -200,6 +200,30 @@ enum pci_epc_bar_type { BAR_RESERVED, }; +/** + * enum pci_epc_bar_rsvd_region_type - type of a fixed subregion behind a BAR + * @PCI_EPC_BAR_RSVD_DMA_CTRL_MMIO: Integrated DMA controller MMIO window + * + * BARs marked BAR_RESERVED are owned by the SoC/EPC hardware and must not be + * reprogrammed by EPF drivers. Some of them still expose fixed subregions that + * EPFs may want to reference (e.g. embedded doorbell fallback). + */ +enum pci_epc_bar_rsvd_region_type { + PCI_EPC_BAR_RSVD_DMA_CTRL_MMIO = 0, +}; + +/** + * struct pci_epc_bar_rsvd_region - fixed subregion behind a BAR + * @type: reserved region type + * @offset: offset within the BAR aperture + * @size: size of the reserved region + */ +struct pci_epc_bar_rsvd_region { + enum pci_epc_bar_rsvd_region_type type; + resource_size_t offset; + resource_size_t size; +}; + /** * struct pci_epc_bar_desc - hardware description for a BAR * @type: the type of the BAR @@ -207,11 +231,15 @@ enum pci_epc_bar_type { * @only_64bit: if true, an EPF driver is not allowed to choose if this BAR * should be configured as 32-bit or 64-bit, the EPF driver must * configure this BAR as 64-bit. + * @nr_rsvd_regions: number of fixed subregions described for BAR_RESERVED + * @rsvd_regions: fixed subregions behind BAR_RESERVED */ struct pci_epc_bar_desc { enum pci_epc_bar_type type; u64 fixed_size; bool only_64bit; + u8 nr_rsvd_regions; + const struct pci_epc_bar_rsvd_region *rsvd_regions; }; /** -- cgit v1.2.3 From 33642e9e36dc084e4fc9245a266c9843bc8303b9 Mon Sep 17 00:00:00 2001 From: Niklas Cassel Date: Thu, 12 Mar 2026 14:02:33 +0100 Subject: PCI: endpoint: Introduce pci_epc_bar_type BAR_DISABLED Add a pci_epc_bar_type BAR_DISABLED to more clearly differentiate from BAR_RESERVED. This BAR type will only be used to describe a BAR that the EPC driver should disable, and will thus never be available to an EPF driver. (Unlike BAR_RESERVED, which will never be disabled by default by an EPC driver.) Co-developed-by: Manikanta Maddireddy Signed-off-by: Manikanta Maddireddy Signed-off-by: Niklas Cassel Signed-off-by: Manivannan Sadhasivam Tested-by: Koichiro Den Tested-by: Manikanta Maddireddy Reviewed-by: Frank Li Reviewed-by: Manikanta Maddireddy Link: https://patch.msgid.link/20260312130229.2282001-17-cassel@kernel.org --- drivers/pci/endpoint/pci-epc-core.c | 5 +++-- include/linux/pci-epc.h | 10 +++++++++- 2 files changed, 12 insertions(+), 3 deletions(-) (limited to 'include/linux') diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c index e546b3dbb240..6c3c58185fc5 100644 --- a/drivers/pci/endpoint/pci-epc-core.c +++ b/drivers/pci/endpoint/pci-epc-core.c @@ -103,8 +103,9 @@ enum pci_barno pci_epc_get_next_free_bar(const struct pci_epc_features bar++; for (i = bar; i < PCI_STD_NUM_BARS; i++) { - /* If the BAR is not reserved, return it. */ - if (epc_features->bar[i].type != BAR_RESERVED) + /* If the BAR is not reserved or disabled, return it. */ + if (epc_features->bar[i].type != BAR_RESERVED && + epc_features->bar[i].type != BAR_DISABLED) return i; } diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h index ebcdf70aa9b9..334c2b7578d0 100644 --- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -191,13 +191,21 @@ struct pci_epc { * @BAR_RESIZABLE: The BAR implements the PCI-SIG Resizable BAR Capability. * NOTE: An EPC driver can currently only set a single supported * size. - * @BAR_RESERVED: The BAR should not be touched by an EPF driver. + * @BAR_RESERVED: Used for HW-backed BARs (e.g. MSI-X table, DMA regs). The BAR + * should not be disabled by an EPC driver. The BAR should not be + * reprogrammed by an EPF driver. An EPF driver is allowed to + * disable the BAR if absolutely necessary. (However, right now + * there is no EPC operation to disable a BAR that has not been + * programmed using pci_epc_set_bar().) + * @BAR_DISABLED: The BAR should be disabled by an EPC driver. The BAR will be + * unavailable to an EPF driver. */ enum pci_epc_bar_type { BAR_PROGRAMMABLE = 0, BAR_FIXED, BAR_RESIZABLE, BAR_RESERVED, + BAR_DISABLED, }; /** -- cgit v1.2.3 From 362a4549f2acfb03390ddfcd91041e65a11a739f Mon Sep 17 00:00:00 2001 From: Koichiro Den Date: Fri, 6 Mar 2026 12:14:41 +0900 Subject: NTB: core: Add .get_dma_dev() callback to ntb_dev_ops Some NTB implementations are backed by a PCI function that is not the right struct device to use with DMA API helpers (e.g. due to IOMMU topology, or because the NTB device is virtual). Add an optional .get_dma_dev() callback to struct ntb_dev_ops and provide a helper, ntb_get_dma_dev(), so NTB clients can use the appropriate struct device for DMA allocations and mappings. If the callback is not implemented, ntb_get_dma_dev() returns the current default (ntb->dev.parent). Drivers that implement .get_dma_dev() must return a non-NULL device. Suggested-by: Frank Li Signed-off-by: Koichiro Den Signed-off-by: Manivannan Sadhasivam [bhelgaas: format doc] Signed-off-by: Bjorn Helgaas Reviewed-by: Dave Jiang Link: https://patch.msgid.link/20260306031443.1911860-2-den@valinux.co.jp --- include/linux/ntb.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'include/linux') diff --git a/include/linux/ntb.h b/include/linux/ntb.h index 8ff9d663096b..879c3e89e026 100644 --- a/include/linux/ntb.h +++ b/include/linux/ntb.h @@ -256,6 +256,7 @@ static inline int ntb_ctx_ops_is_valid(const struct ntb_ctx_ops *ops) * @msg_clear_mask: See ntb_msg_clear_mask(). * @msg_read: See ntb_msg_read(). * @peer_msg_write: See ntb_peer_msg_write(). + * @get_dma_dev: See ntb_get_dma_dev(). */ struct ntb_dev_ops { int (*port_number)(struct ntb_dev *ntb); @@ -329,6 +330,7 @@ struct ntb_dev_ops { int (*msg_clear_mask)(struct ntb_dev *ntb, u64 mask_bits); u32 (*msg_read)(struct ntb_dev *ntb, int *pidx, int midx); int (*peer_msg_write)(struct ntb_dev *ntb, int pidx, int midx, u32 msg); + struct device *(*get_dma_dev)(struct ntb_dev *ntb); }; static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops *ops) @@ -391,6 +393,8 @@ static inline int ntb_dev_ops_is_valid(const struct ntb_dev_ops *ops) /* !ops->msg_clear_mask == !ops->msg_count && */ !ops->msg_read == !ops->msg_count && !ops->peer_msg_write == !ops->msg_count && + + /* ops->get_dma_dev is optional */ 1; } @@ -1563,6 +1567,26 @@ static inline int ntb_peer_msg_write(struct ntb_dev *ntb, int pidx, int midx, return ntb->ops->peer_msg_write(ntb, pidx, midx, msg); } +/** + * ntb_get_dma_dev() - get the device to use for DMA allocations/mappings + * @ntb: NTB device context. + * + * Return a struct device suitable for DMA API allocations and mappings. + * This is typically the parent of the NTB device, but may be overridden by a + * driver by implementing .get_dma_dev(). + * + * Drivers that implement .get_dma_dev() must return a non-NULL pointer. + * + * Return: device pointer to use for DMA operations. + */ +static inline struct device *ntb_get_dma_dev(struct ntb_dev *ntb) +{ + if (!ntb->ops->get_dma_dev) + return ntb->dev.parent; + + return ntb->ops->get_dma_dev(ntb); +} + /** * ntb_peer_resource_idx() - get a resource index for a given peer idx * @ntb: NTB device context. -- cgit v1.2.3 From 5f352433ea39171e19fbb3a7e18d983510176854 Mon Sep 17 00:00:00 2001 From: Manikanta Maddireddy Date: Tue, 24 Mar 2026 13:38:54 +0530 Subject: PCI: endpoint: Add reserved region type for MSI-X Table and PBA Add PCI_EPC_BAR_RSVD_MSIX_TBL_RAM and PCI_EPC_BAR_RSVD_MSIX_PBA_RAM to enum pci_epc_bar_rsvd_region_type so that Endpoint controllers can describe hardware-owned MSI-X Table and PBA (Pending Bit Array) regions behind a BAR_RESERVED BAR. Signed-off-by: Manikanta Maddireddy Signed-off-by: Manivannan Sadhasivam Reviewed-by: Niklas Cassel Link: https://patch.msgid.link/20260324080857.916263-2-mmaddireddy@nvidia.com --- include/linux/pci-epc.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'include/linux') diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h index 334c2b7578d0..1eca1264815b 100644 --- a/include/linux/pci-epc.h +++ b/include/linux/pci-epc.h @@ -211,6 +211,8 @@ enum pci_epc_bar_type { /** * enum pci_epc_bar_rsvd_region_type - type of a fixed subregion behind a BAR * @PCI_EPC_BAR_RSVD_DMA_CTRL_MMIO: Integrated DMA controller MMIO window + * @PCI_EPC_BAR_RSVD_MSIX_TBL_RAM: MSI-X table structure + * @PCI_EPC_BAR_RSVD_MSIX_PBA_RAM: MSI-X PBA structure * * BARs marked BAR_RESERVED are owned by the SoC/EPC hardware and must not be * reprogrammed by EPF drivers. Some of them still expose fixed subregions that @@ -218,6 +220,8 @@ enum pci_epc_bar_type { */ enum pci_epc_bar_rsvd_region_type { PCI_EPC_BAR_RSVD_DMA_CTRL_MMIO = 0, + PCI_EPC_BAR_RSVD_MSIX_TBL_RAM, + PCI_EPC_BAR_RSVD_MSIX_PBA_RAM, }; /** -- cgit v1.2.3