{"id":2223138,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2223138/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/patch/20260414141514.1341429-2-den@valinux.co.jp/","project":{"id":28,"url":"http://patchwork.ozlabs.org/api/1.1/projects/28/?format=json","name":"Linux PCI development","link_name":"linux-pci","list_id":"linux-pci.vger.kernel.org","list_email":"linux-pci@vger.kernel.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"<20260414141514.1341429-2-den@valinux.co.jp>","date":"2026-04-14T14:15:08","name":"[v14,1/7] PCI: endpoint: Add auxiliary resource query API","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"6edb8a12a16eebb6187a89a1e85ab2bc852c898d","submitter":{"id":91573,"url":"http://patchwork.ozlabs.org/api/1.1/people/91573/?format=json","name":"Koichiro Den","email":"den@valinux.co.jp"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/linux-pci/patch/20260414141514.1341429-2-den@valinux.co.jp/mbox/","series":[{"id":499855,"url":"http://patchwork.ozlabs.org/api/1.1/series/499855/?format=json","web_url":"http://patchwork.ozlabs.org/project/linux-pci/list/?series=499855","date":"2026-04-14T14:15:08","name":"PCI: endpoint: pci-ep-msi: Add embedded doorbell fallback","version":14,"mbox":"http://patchwork.ozlabs.org/series/499855/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2223138/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2223138/checks/","tags":{},"headers":{"Return-Path":"\n ","X-Original-To":["incoming@patchwork.ozlabs.org","linux-pci@vger.kernel.org"],"Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=valinux.co.jp header.i=@valinux.co.jp\n header.a=rsa-sha256 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","X-OriginatorOrg":"valinux.co.jp","X-MS-Exchange-CrossTenant-Network-Message-Id":"\n 6cced81d-566d-4a77-973b-08de9a30686b","X-MS-Exchange-CrossTenant-AuthSource":"TY7P286MB7722.JPNP286.PROD.OUTLOOK.COM","X-MS-Exchange-CrossTenant-AuthAs":"Internal","X-MS-Exchange-CrossTenant-OriginalArrivalTime":"14 Apr 2026 14:16:23.4654\n (UTC)","X-MS-Exchange-CrossTenant-FromEntityHeader":"Hosted","X-MS-Exchange-CrossTenant-Id":"7a57bee8-f73d-4c5f-a4f7-d72c91c8c111","X-MS-Exchange-CrossTenant-MailboxType":"HOSTED","X-MS-Exchange-CrossTenant-UserPrincipalName":"\n leFoA9I8YDZRW1hE1DkojXrrUK4nh2IIHt067mYdvzSL7m0nwBh/6yrQfhsowZcn9s2GzeEok7a3SqSuV6VKCg==","X-MS-Exchange-Transport-CrossTenantHeadersStamped":"TY3P286MB2529"},"content":"Endpoint controller drivers may integrate auxiliary blocks (e.g. DMA\nengines) whose register windows and descriptor memories metadata need to\nbe exposed to a remote peer. Endpoint function drivers need a generic\nway to discover such resources without hard-coding controller-specific\nhelpers.\n\nAdd pci_epc_get_aux_resources_count() / pci_epc_get_aux_resources() and\nthe corresponding pci_epc_ops callbacks. The count helper returns the\nnumber of available resources, while the get helper fills a\ncaller-provided array of resources described by type, physical address\nand size, plus type-specific metadata.\n\nSuggested-by: Manivannan Sadhasivam \nSuggested-by: Frank Li \nSigned-off-by: Koichiro Den \n---\nChanges in v14:\n - Fix whitespace and alignment issues reported by checkpatch.pl.\n\n drivers/pci/endpoint/pci-epc-core.c | 80 +++++++++++++++++++++++++++++\n include/linux/pci-epc.h | 54 +++++++++++++++++++\n 2 files changed, 134 insertions(+)","diff":"diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c\nindex 6c3c58185fc5..831b40458dcd 100644\n--- a/drivers/pci/endpoint/pci-epc-core.c\n+++ b/drivers/pci/endpoint/pci-epc-core.c\n@@ -156,6 +156,86 @@ const struct pci_epc_features *pci_epc_get_features(struct pci_epc *epc,\n }\n EXPORT_SYMBOL_GPL(pci_epc_get_features);\n \n+/**\n+ * pci_epc_get_aux_resources_count() - get the number of EPC-provided auxiliary resources\n+ * @epc: EPC device\n+ * @func_no: function number\n+ * @vfunc_no: virtual function number\n+ *\n+ * Some EPC backends integrate auxiliary blocks (e.g. DMA engines) whose control\n+ * registers and/or descriptor memories can be exposed to the host by mapping\n+ * them into BAR space. This helper queries how many such resources the backend\n+ * provides.\n+ *\n+ * Return: the number of available resources on success, -EOPNOTSUPP if the\n+ * backend does not support auxiliary resource queries, or another -errno on\n+ * failure.\n+ */\n+int pci_epc_get_aux_resources_count(struct pci_epc *epc, u8 func_no,\n+\t\t\t\t u8 vfunc_no)\n+{\n+\tint count;\n+\n+\tif (!epc || !epc->ops)\n+\t\treturn -EINVAL;\n+\n+\tif (!pci_epc_function_is_valid(epc, func_no, vfunc_no))\n+\t\treturn -EINVAL;\n+\n+\tif (!epc->ops->get_aux_resources_count)\n+\t\treturn -EOPNOTSUPP;\n+\n+\tmutex_lock(&epc->lock);\n+\tcount = epc->ops->get_aux_resources_count(epc, func_no,\n+\t\t\t\t\t\t vfunc_no);\n+\tmutex_unlock(&epc->lock);\n+\n+\treturn count;\n+}\n+EXPORT_SYMBOL_GPL(pci_epc_get_aux_resources_count);\n+\n+/**\n+ * pci_epc_get_aux_resources() - query EPC-provided auxiliary resources\n+ * @epc: EPC device\n+ * @func_no: function number\n+ * @vfunc_no: virtual function number\n+ * @resources: output array\n+ * @num_resources: size of @resources array in entries\n+ *\n+ * Some EPC backends integrate auxiliary blocks (e.g. DMA engines) whose control\n+ * registers and/or descriptor memories can be exposed to the host by mapping\n+ * them into BAR space. This helper queries the backend for such resources.\n+ *\n+ * Return: 0 on success, -EOPNOTSUPP if the backend does not support auxiliary\n+ * resource queries, or another -errno on failure.\n+ */\n+int pci_epc_get_aux_resources(struct pci_epc *epc, u8 func_no, u8 vfunc_no,\n+\t\t\t struct pci_epc_aux_resource *resources,\n+\t\t\t int num_resources)\n+{\n+\tint ret;\n+\n+\tif (!resources || num_resources <= 0)\n+\t\treturn -EINVAL;\n+\n+\tif (!epc || !epc->ops)\n+\t\treturn -EINVAL;\n+\n+\tif (!pci_epc_function_is_valid(epc, func_no, vfunc_no))\n+\t\treturn -EINVAL;\n+\n+\tif (!epc->ops->get_aux_resources)\n+\t\treturn -EOPNOTSUPP;\n+\n+\tmutex_lock(&epc->lock);\n+\tret = epc->ops->get_aux_resources(epc, func_no, vfunc_no, resources,\n+\t\t\t\t\t num_resources);\n+\tmutex_unlock(&epc->lock);\n+\n+\treturn ret;\n+}\n+EXPORT_SYMBOL_GPL(pci_epc_get_aux_resources);\n+\n /**\n * pci_epc_stop() - stop the PCI link\n * @epc: the link of the EPC device that has to be stopped\ndiff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h\nindex 1eca1264815b..f247cf9bcf1a 100644\n--- a/include/linux/pci-epc.h\n+++ b/include/linux/pci-epc.h\n@@ -61,6 +61,47 @@ struct pci_epc_map {\n \tvoid __iomem\t*virt_addr;\n };\n \n+/**\n+ * enum pci_epc_aux_resource_type - auxiliary resource type identifiers\n+ * @PCI_EPC_AUX_DOORBELL_MMIO: Doorbell MMIO, that might be outside the DMA\n+ * controller register window\n+ *\n+ * EPC backends may expose auxiliary blocks (e.g. DMA engines) by mapping their\n+ * register windows and descriptor memories into BAR space. This enum\n+ * identifies the type of each exposable resource.\n+ */\n+enum pci_epc_aux_resource_type {\n+\tPCI_EPC_AUX_DOORBELL_MMIO,\n+};\n+\n+/**\n+ * struct pci_epc_aux_resource - a physical auxiliary resource that may be\n+ * exposed for peer use\n+ * @type: resource type, see enum pci_epc_aux_resource_type\n+ * @phys_addr: physical base address of the resource\n+ * @size: size of the resource in bytes\n+ * @bar: BAR number where this resource is already exposed to the RC\n+ * (NO_BAR if not)\n+ * @bar_offset: offset within @bar where the resource starts (valid iff\n+ * @bar != NO_BAR)\n+ * @u: type-specific metadata\n+ */\n+struct pci_epc_aux_resource {\n+\tenum pci_epc_aux_resource_type type;\n+\tphys_addr_t phys_addr;\n+\tresource_size_t size;\n+\tenum pci_barno bar;\n+\tresource_size_t bar_offset;\n+\n+\tunion {\n+\t\t/* PCI_EPC_AUX_DOORBELL_MMIO */\n+\t\tstruct {\n+\t\t\tint irq; /* IRQ number for the doorbell handler */\n+\t\t\tu32 data; /* write value to ring the doorbell */\n+\t\t} db_mmio;\n+\t} u;\n+};\n+\n /**\n * struct pci_epc_ops - set of function pointers for performing EPC operations\n * @write_header: ops to populate configuration space header\n@@ -84,6 +125,9 @@ struct pci_epc_map {\n * @start: ops to start the PCI link\n * @stop: ops to stop the PCI link\n * @get_features: ops to get the features supported by the EPC\n+ * @get_aux_resources_count: ops to get the number of controller-owned\n+ * auxiliary resources\n+ * @get_aux_resources: ops to retrieve controller-owned auxiliary resources\n * @owner: the module owner containing the ops\n */\n struct pci_epc_ops {\n@@ -115,6 +159,11 @@ struct pci_epc_ops {\n \tvoid\t(*stop)(struct pci_epc *epc);\n \tconst struct pci_epc_features* (*get_features)(struct pci_epc *epc,\n \t\t\t\t\t\t u8 func_no, u8 vfunc_no);\n+\tint\t(*get_aux_resources_count)(struct pci_epc *epc, u8 func_no,\n+\t\t\t\t\t u8 vfunc_no);\n+\tint\t(*get_aux_resources)(struct pci_epc *epc, u8 func_no, u8 vfunc_no,\n+\t\t\t\t struct pci_epc_aux_resource *resources,\n+\t\t\t\t int num_resources);\n \tstruct module *owner;\n };\n \n@@ -343,6 +392,11 @@ int pci_epc_start(struct pci_epc *epc);\n void pci_epc_stop(struct pci_epc *epc);\n const struct pci_epc_features *pci_epc_get_features(struct pci_epc *epc,\n \t\t\t\t\t\t u8 func_no, u8 vfunc_no);\n+int pci_epc_get_aux_resources_count(struct pci_epc *epc, u8 func_no,\n+\t\t\t\t u8 vfunc_no);\n+int pci_epc_get_aux_resources(struct pci_epc *epc, u8 func_no, u8 vfunc_no,\n+\t\t\t struct pci_epc_aux_resource *resources,\n+\t\t\t int num_resources);\n enum pci_barno\n pci_epc_get_first_free_bar(const struct pci_epc_features *epc_features);\n enum pci_barno pci_epc_get_next_free_bar(const struct pci_epc_features\n","prefixes":["v14","1/7"]}