[PATCH v17 1/4] PCI/DOE: Rename DOE protocol to feature

[PATCH v17 1/4] PCI/DOE: Rename DOE protocol to feature

[Alistair Francis]

DOE r1.1 replaced all occurrences of "protocol" with the term "feature"
or "Data Object Type".

PCIe r6.1 (which was published July 24) incorporated that change.

Rename the existing terms protocol with feature.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
---
v17:
 - No changes
v16:
 - No changes
v15:
 - No changes
v14:
 - No changes
v13:
 - No changes
v12:
 - No changes
v11:
 - No changes
v10:
 - Split original patch into two
v9:
 - Rename two more DOE macros
v8:
 - Rename prot to feat as well
v7:
 - Initial patch

 drivers/pci/doe.c | 88 +++++++++++++++++++++++------------------------
 1 file changed, 44 insertions(+), 44 deletions(-)

diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
index 7bd7892c5222..2f36262e76f8 100644
--- a/drivers/pci/doe.c
+++ b/drivers/pci/doe.c
@@ -22,7 +22,7 @@
 
 #include "pci.h"
 
-#define PCI_DOE_PROTOCOL_DISCOVERY 0
+#define PCI_DOE_FEATURE_DISCOVERY 0
 
 /* Timeout of 1 second from 6.30.2 Operation, PCI Spec r6.0 */
 #define PCI_DOE_TIMEOUT HZ
@@ -43,7 +43,7 @@
  *
  * @pdev: PCI device this mailbox belongs to
  * @cap_offset: Capability offset
- * @prots: Array of protocols supported (encoded as long values)
+ * @feats: Array of features supported (encoded as long values)
  * @wq: Wait queue for work item
  * @work_queue: Queue of pci_doe_work items
  * @flags: Bit array of PCI_DOE_FLAG_* flags
@@ -51,14 +51,14 @@
 struct pci_doe_mb {
 	struct pci_dev *pdev;
 	u16 cap_offset;
-	struct xarray prots;
+	struct xarray feats;
 
 	wait_queue_head_t wq;
 	struct workqueue_struct *work_queue;
 	unsigned long flags;
 };
 
-struct pci_doe_protocol {
+struct pci_doe_feature {
 	u16 vid;
 	u8 type;
 };
@@ -66,7 +66,7 @@ struct pci_doe_protocol {
 /**
  * struct pci_doe_task - represents a single query/response
  *
- * @prot: DOE Protocol
+ * @feat: DOE Feature
  * @request_pl: The request payload
  * @request_pl_sz: Size of the request payload (bytes)
  * @response_pl: The response payload
@@ -78,7 +78,7 @@ struct pci_doe_protocol {
  * @doe_mb: Used internally by the mailbox
  */
 struct pci_doe_task {
-	struct pci_doe_protocol prot;
+	struct pci_doe_feature feat;
 	const __le32 *request_pl;
 	size_t request_pl_sz;
 	__le32 *response_pl;
@@ -183,8 +183,8 @@ static int pci_doe_send_req(struct pci_doe_mb *doe_mb,
 		length = 0;
 
 	/* Write DOE Header */
-	val = FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_VID, task->prot.vid) |
-		FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, task->prot.type);
+	val = FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_VID, task->feat.vid) |
+		FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, task->feat.type);
 	pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, val);
 	pci_write_config_dword(pdev, offset + PCI_DOE_WRITE,
 			       FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH,
@@ -229,12 +229,12 @@ static int pci_doe_recv_resp(struct pci_doe_mb *doe_mb, struct pci_doe_task *tas
 	int i = 0;
 	u32 val;
 
-	/* Read the first dword to get the protocol */
+	/* Read the first dword to get the feature */
 	pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
-	if ((FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val) != task->prot.vid) ||
-	    (FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val) != task->prot.type)) {
-		dev_err_ratelimited(&pdev->dev, "[%x] expected [VID, Protocol] = [%04x, %02x], got [%04x, %02x]\n",
-				    doe_mb->cap_offset, task->prot.vid, task->prot.type,
+	if ((FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val) != task->feat.vid) ||
+	    (FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val) != task->feat.type)) {
+		dev_err_ratelimited(&pdev->dev, "[%x] expected [VID, Feature] = [%04x, %02x], got [%04x, %02x]\n",
+				    doe_mb->cap_offset, task->feat.vid, task->feat.type,
 				    FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_VID, val),
 				    FIELD_GET(PCI_DOE_DATA_OBJECT_HEADER_1_TYPE, val));
 		return -EIO;
@@ -396,7 +396,7 @@ static void pci_doe_task_complete(struct pci_doe_task *task)
 }
 
 static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 capver, u8 *index, u16 *vid,
-			     u8 *protocol)
+			     u8 *feature)
 {
 	u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX,
 				    *index) |
@@ -407,7 +407,7 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 capver, u8 *index, u1
 	u32 response_pl;
 	int rc;
 
-	rc = pci_doe(doe_mb, PCI_VENDOR_ID_PCI_SIG, PCI_DOE_PROTOCOL_DISCOVERY,
+	rc = pci_doe(doe_mb, PCI_VENDOR_ID_PCI_SIG, PCI_DOE_FEATURE_DISCOVERY,
 		     &request_pl_le, sizeof(request_pl_le),
 		     &response_pl_le, sizeof(response_pl_le));
 	if (rc < 0)
@@ -418,7 +418,7 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 capver, u8 *index, u1
 
 	response_pl = le32_to_cpu(response_pl_le);
 	*vid = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID, response_pl);
-	*protocol = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL,
+	*feature = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL,
 			      response_pl);
 	*index = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX,
 			   response_pl);
@@ -426,12 +426,12 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 capver, u8 *index, u1
 	return 0;
 }
 
-static void *pci_doe_xa_prot_entry(u16 vid, u8 prot)
+static void *pci_doe_xa_feat_entry(u16 vid, u8 prot)
 {
 	return xa_mk_value((vid << 8) | prot);
 }
 
-static int pci_doe_cache_protocols(struct pci_doe_mb *doe_mb)
+static int pci_doe_cache_features(struct pci_doe_mb *doe_mb)
 {
 	u8 index = 0;
 	u8 xa_idx = 0;
@@ -450,11 +450,11 @@ static int pci_doe_cache_protocols(struct pci_doe_mb *doe_mb)
 			return rc;
 
 		pci_dbg(doe_mb->pdev,
-			"[%x] Found protocol %d vid: %x prot: %x\n",
+			"[%x] Found feature %d vid: %x prot: %x\n",
 			doe_mb->cap_offset, xa_idx, vid, prot);
 
-		rc = xa_insert(&doe_mb->prots, xa_idx++,
-			       pci_doe_xa_prot_entry(vid, prot), GFP_KERNEL);
+		rc = xa_insert(&doe_mb->feats, xa_idx++,
+			       pci_doe_xa_feat_entry(vid, prot), GFP_KERNEL);
 		if (rc)
 			return rc;
 	} while (index);
@@ -478,7 +478,7 @@ static void pci_doe_cancel_tasks(struct pci_doe_mb *doe_mb)
  * @pdev: PCI device to create the DOE mailbox for
  * @cap_offset: Offset of the DOE mailbox
  *
- * Create a single mailbox object to manage the mailbox protocol at the
+ * Create a single mailbox object to manage the mailbox feature at the
  * cap_offset specified.
  *
  * RETURNS: created mailbox object on success
@@ -497,7 +497,7 @@ static struct pci_doe_mb *pci_doe_create_mb(struct pci_dev *pdev,
 	doe_mb->pdev = pdev;
 	doe_mb->cap_offset = cap_offset;
 	init_waitqueue_head(&doe_mb->wq);
-	xa_init(&doe_mb->prots);
+	xa_init(&doe_mb->feats);
 
 	doe_mb->work_queue = alloc_ordered_workqueue("%s %s DOE [%x]", 0,
 						dev_bus_name(&pdev->dev),
@@ -520,11 +520,11 @@ static struct pci_doe_mb *pci_doe_create_mb(struct pci_dev *pdev,
 
 	/*
 	 * The state machine and the mailbox should be in sync now;
-	 * Use the mailbox to query protocols.
+	 * Use the mailbox to query features.
 	 */
-	rc = pci_doe_cache_protocols(doe_mb);
+	rc = pci_doe_cache_features(doe_mb);
 	if (rc) {
-		pci_err(pdev, "[%x] failed to cache protocols : %d\n",
+		pci_err(pdev, "[%x] failed to cache features : %d\n",
 			doe_mb->cap_offset, rc);
 		goto err_cancel;
 	}
@@ -533,7 +533,7 @@ static struct pci_doe_mb *pci_doe_create_mb(struct pci_dev *pdev,
 
 err_cancel:
 	pci_doe_cancel_tasks(doe_mb);
-	xa_destroy(&doe_mb->prots);
+	xa_destroy(&doe_mb->feats);
 err_destroy_wq:
 	destroy_workqueue(doe_mb->work_queue);
 err_free:
@@ -551,31 +551,31 @@ static struct pci_doe_mb *pci_doe_create_mb(struct pci_dev *pdev,
 static void pci_doe_destroy_mb(struct pci_doe_mb *doe_mb)
 {
 	pci_doe_cancel_tasks(doe_mb);
-	xa_destroy(&doe_mb->prots);
+	xa_destroy(&doe_mb->feats);
 	destroy_workqueue(doe_mb->work_queue);
 	kfree(doe_mb);
 }
 
 /**
- * pci_doe_supports_prot() - Return if the DOE instance supports the given
- *			     protocol
+ * pci_doe_supports_feat() - Return if the DOE instance supports the given
+ *			     feature
  * @doe_mb: DOE mailbox capability to query
- * @vid: Protocol Vendor ID
- * @type: Protocol type
+ * @vid: Feature Vendor ID
+ * @type: Feature type
  *
- * RETURNS: True if the DOE mailbox supports the protocol specified
+ * RETURNS: True if the DOE mailbox supports the feature specified
  */
-static bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type)
+static bool pci_doe_supports_feat(struct pci_doe_mb *doe_mb, u16 vid, u8 type)
 {
 	unsigned long index;
 	void *entry;
 
-	/* The discovery protocol must always be supported */
-	if (vid == PCI_VENDOR_ID_PCI_SIG && type == PCI_DOE_PROTOCOL_DISCOVERY)
+	/* The discovery feature must always be supported */
+	if (vid == PCI_VENDOR_ID_PCI_SIG && type == PCI_DOE_FEATURE_DISCOVERY)
 		return true;
 
-	xa_for_each(&doe_mb->prots, index, entry)
-		if (entry == pci_doe_xa_prot_entry(vid, type))
+	xa_for_each(&doe_mb->feats, index, entry)
+		if (entry == pci_doe_xa_feat_entry(vid, type))
 			return true;
 
 	return false;
@@ -603,7 +603,7 @@ static bool pci_doe_supports_prot(struct pci_doe_mb *doe_mb, u16 vid, u8 type)
 static int pci_doe_submit_task(struct pci_doe_mb *doe_mb,
 			       struct pci_doe_task *task)
 {
-	if (!pci_doe_supports_prot(doe_mb, task->prot.vid, task->prot.type))
+	if (!pci_doe_supports_feat(doe_mb, task->feat.vid, task->feat.type))
 		return -EINVAL;
 
 	if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags))
@@ -649,8 +649,8 @@ int pci_doe(struct pci_doe_mb *doe_mb, u16 vendor, u8 type,
 {
 	DECLARE_COMPLETION_ONSTACK(c);
 	struct pci_doe_task task = {
-		.prot.vid = vendor,
-		.prot.type = type,
+		.feat.vid = vendor,
+		.feat.type = type,
 		.request_pl = request,
 		.request_pl_sz = request_sz,
 		.response_pl = response,
@@ -675,9 +675,9 @@ EXPORT_SYMBOL_GPL(pci_doe);
  *
  * @pdev: PCI device
  * @vendor: Vendor ID
- * @type: Data Object Type
+ * @prot: Data Object Type
  *
- * Find first DOE mailbox of a PCI device which supports the given protocol.
+ * Find first DOE mailbox of a PCI device which supports the given feature.
  *
  * RETURNS: Pointer to the DOE mailbox or NULL if none was found.
  */
@@ -688,7 +688,7 @@ struct pci_doe_mb *pci_find_doe_mailbox(struct pci_dev *pdev, u16 vendor,
 	unsigned long index;
 
 	xa_for_each(&pdev->doe_mbs, index, doe_mb)
-		if (pci_doe_supports_prot(doe_mb, vendor, type))
+		if (pci_doe_supports_feat(doe_mb, vendor, type))
 			return doe_mb;
 
 	return NULL;
-- 
2.48.1

[PATCH v17 2/4] PCI/DOE: Rename Discovery Response Data Object Contents to type

[Alistair Francis]

PCIe r6.1 (which was published July 24) describes a "Vendor ID", a
"Data Object Type" and "Next Index" as the fields in the DOE
Discovery Response Data Object. The DOE driver currently uses
both the terms type and prot for the second element.

This patch renames all uses of the DOE Discovery Response Data Object
to use type as the second element of the object header, instead of
type/prot as it currently is.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
v17:
 - No changes
v16:
 - No changes
v15:
 - No changes
v14
 - No changes
v13
 - No changes
v12:
 - Use PCI_DOE_DATA_OBJECT_DISC_RSP_3_TYPE for PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL
v11:
 - Avoid breaking changes to userspace header
v10:
 - Split original patch into two
v9:
 - Rename two more DOE macros
v8:
 - Rename prot to feat as well
v7:
 - Initial patch

 drivers/pci/doe.c             | 18 +++++++++---------
 include/uapi/linux/pci_regs.h |  5 ++++-
 2 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
index 2f36262e76f8..f4508d75ce69 100644
--- a/drivers/pci/doe.c
+++ b/drivers/pci/doe.c
@@ -418,7 +418,7 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 capver, u8 *index, u1
 
 	response_pl = le32_to_cpu(response_pl_le);
 	*vid = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID, response_pl);
-	*feature = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL,
+	*feature = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_TYPE,
 			      response_pl);
 	*index = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX,
 			   response_pl);
@@ -426,9 +426,9 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 capver, u8 *index, u1
 	return 0;
 }
 
-static void *pci_doe_xa_feat_entry(u16 vid, u8 prot)
+static void *pci_doe_xa_feat_entry(u16 vid, u8 type)
 {
-	return xa_mk_value((vid << 8) | prot);
+	return xa_mk_value((vid << 8) | type);
 }
 
 static int pci_doe_cache_features(struct pci_doe_mb *doe_mb)
@@ -442,19 +442,19 @@ static int pci_doe_cache_features(struct pci_doe_mb *doe_mb)
 	do {
 		int rc;
 		u16 vid;
-		u8 prot;
+		u8 type;
 
 		rc = pci_doe_discovery(doe_mb, PCI_EXT_CAP_VER(hdr), &index,
-				       &vid, &prot);
+				       &vid, &type);
 		if (rc)
 			return rc;
 
 		pci_dbg(doe_mb->pdev,
-			"[%x] Found feature %d vid: %x prot: %x\n",
-			doe_mb->cap_offset, xa_idx, vid, prot);
+			"[%x] Found feature %d vid: %x type: %x\n",
+			doe_mb->cap_offset, xa_idx, vid, type);
 
 		rc = xa_insert(&doe_mb->feats, xa_idx++,
-			       pci_doe_xa_feat_entry(vid, prot), GFP_KERNEL);
+			       pci_doe_xa_feat_entry(vid, type), GFP_KERNEL);
 		if (rc)
 			return rc;
 	} while (index);
@@ -675,7 +675,7 @@ EXPORT_SYMBOL_GPL(pci_doe);
  *
  * @pdev: PCI device
  * @vendor: Vendor ID
- * @prot: Data Object Type
+ * @type: Data Object Type
  *
  * Find first DOE mailbox of a PCI device which supports the given feature.
  *
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 3445c4970e4d..7f9af95e2e6a 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -1205,9 +1205,12 @@
 #define PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX		0x000000ff
 #define PCI_DOE_DATA_OBJECT_DISC_REQ_3_VER		0x0000ff00
 #define PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID		0x0000ffff
-#define PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL		0x00ff0000
+#define PCI_DOE_DATA_OBJECT_DISC_RSP_3_TYPE		0x00ff0000
 #define PCI_DOE_DATA_OBJECT_DISC_RSP_3_NEXT_INDEX	0xff000000
 
+/* Deprecated old name, replaced with PCI_DOE_DATA_OBJECT_DISC_RSP_3_TYPE */
+#define PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL		PCI_DOE_DATA_OBJECT_DISC_RSP_3_TYPE
+
 /* Compute Express Link (CXL r3.1, sec 8.1.5) */
 #define PCI_DVSEC_CXL_PORT				3
 #define PCI_DVSEC_CXL_PORT_CTL				0x0c
-- 
2.48.1

[PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs

[Alistair Francis]

The PCIe 6 specification added support for the Data Object
Exchange (DOE).
When DOE is supported the DOE Discovery Feature must be implemented per
PCIe r6.1 sec 6.30.1.1. DOE allows a requester to obtain
information about the other DOE features supported by the device.

The kernel is already querying the DOE features supported and cacheing
the values. Expose the values in sysfs to allow user space to
determine which DOE features are supported by the PCIe device.

By exposing the information to userspace tools like lspci can relay the
information to users. By listing all of the supported features we can
allow userspace to parse the list, which might include
vendor specific features as well as yet to be supported features.

As the DOE Discovery feature must always be supported we treat it as a
special named attribute case. This allows the usual PCI attribute_group
handling to correctly create the doe_features directory when registering
pci_doe_sysfs_group (otherwise it doesn't and sysfs_add_file_to_group()
will seg fault).

After this patch is supported you can see something like this when
attaching a DOE device

$ ls /sys/devices/pci0000:00/0000:00:02.0//doe*
0001:01        0001:02        doe_discovery

Signed-off-by: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
Using dev->groups and device_add() path as discussed earlier [1]
doesn't work nicley as the pci_doe_sysfs_group is global.

We end up needing to create a per device instance of dev->groups
that is dynamically modified at init and appended to pci_dev_attr_groups.

Something similar to:
https://elixir.bootlin.com/linux/latest/source/drivers/iio/industrialio-core.c#L2029
except in this case groups is already assigned.

It's complex and doesn't provide any advantages compared to the approach
in this patch, where we can just use sysfs_add_file_to_group() to add
the sysfs attributes. This aligns with other PCIe DOE related sysfs
patches, such as [2]

1: https://lore.kernel.org/all/20231019165829.GA1381099@bhelgaas/
2: https://lore.kernel.org/all/77f549685f994981c010aebb1e9057aa3555b18a.1719771133.git.lukas@wunner.de/

v17:
 - Replace protocol with feature
 - Use pci_warn() at failure places instead of checking pci_doe_sysfs_init()
   return value
v16:
 - Rebase
v15:
 - Move init/teardown from pci_{create,remove}_resource_files()
 - Remove `if (IS_ENABLED(CONFIG_PCI_DOE))` checks
v14:
 - Revert back to v12 with extra pci_remove_resource_files() call
v13:
 - Drop pci_doe_sysfs_init() and use pci_doe_sysfs_group
     - As discussed in https://lore.kernel.org/all/20231019165829.GA1381099@bhelgaas/
       we can just modify pci_doe_sysfs_group at the DOE init and let
       device_add() handle the sysfs attributes.
v12:
 - Drop pci_doe_features_sysfs_attr_visible()
v11:
 - Gracefully handle multiple entried of same feature
 - Minor fixes and code cleanups
v10:
 - Rebase to use DEFINE_SYSFS_GROUP_VISIBLE and remove
   special setup function
v9:
 - Add a teardown function
 - Rename functions to be clearer
 - Tidy up the commit message
 - Remove #ifdef from header
v8:
 - Inlucde an example in the docs
 - Fixup removing a file that wasn't added
 - Remove a blank line
v7:
 - Fixup the #ifdefs to keep the test robot happy
v6:
 - Use "feature" instead of protocol
 - Don't use any devm_* functions
 - Add two more patches to the series
v5:
 - Return the file name as the file contents
 - Code cleanups and simplifications
v4:
 - Fixup typos in the documentation
 - Make it clear that the file names contain the information
 - Small code cleanups
 - Remove most #ifdefs
 - Remove extra NULL assignment
v3:
 - Expose each DOE feature as a separate file
v2:
 - Add documentation
 - Code cleanups

 Documentation/ABI/testing/sysfs-bus-pci |  28 +++++
 drivers/pci/doe.c                       | 148 ++++++++++++++++++++++++
 drivers/pci/pci-sysfs.c                 |   3 +
 drivers/pci/pci.h                       |   9 ++
 drivers/pci/probe.c                     |   2 +
 drivers/pci/remove.c                    |   1 +
 6 files changed, 191 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci
index 5da6a14dc326..874de7325d2b 100644
--- a/Documentation/ABI/testing/sysfs-bus-pci
+++ b/Documentation/ABI/testing/sysfs-bus-pci
@@ -583,3 +583,31 @@ Description:
 		enclosure-specific indications "specific0" to "specific7",
 		hence the corresponding led class devices are unavailable if
 		the DSM interface is used.
+
+What:		/sys/bus/pci/devices/.../doe_features
+Date:		March 2025
+Contact:	Linux PCI developers <linux-pci@vger.kernel.org>
+Description:
+		This directory contains a list of the supported
+		Data Object Exchange (DOE) features. The features are
+		the file name. The contents of each file is the raw vendor id and
+		data object feature values.
+
+		The value comes from the device and specifies the vendor and
+		data object type supported. The lower (RHS of the colon) is
+		the data object type in hex. The upper (LHS of the colon)
+		is the vendor ID.
+
+		As all DOE devices must support the DOE discovery feature, if
+		DOE is supported you will at least see the doe_discovery file, with
+		this contents
+
+		# cat doe_features/doe_discovery
+		0001:00
+
+		If the device supports other features you will see other files
+		as well. For example is CMA/SPDM and secure CMA/SPDM are supported
+		the doe_features directory will look like this
+
+		# ls doe_features
+		0001:01        0001:02        doe_discovery
diff --git a/drivers/pci/doe.c b/drivers/pci/doe.c
index f4508d75ce69..5e55eb40160c 100644
--- a/drivers/pci/doe.c
+++ b/drivers/pci/doe.c
@@ -14,10 +14,12 @@
 
 #include <linux/bitfield.h>
 #include <linux/delay.h>
+#include <linux/device.h>
 #include <linux/jiffies.h>
 #include <linux/mutex.h>
 #include <linux/pci.h>
 #include <linux/pci-doe.h>
+#include <linux/sysfs.h>
 #include <linux/workqueue.h>
 
 #include "pci.h"
@@ -47,6 +49,7 @@
  * @wq: Wait queue for work item
  * @work_queue: Queue of pci_doe_work items
  * @flags: Bit array of PCI_DOE_FLAG_* flags
+ * @sysfs_attrs: Array of sysfs device attributes
  */
 struct pci_doe_mb {
 	struct pci_dev *pdev;
@@ -56,6 +59,10 @@ struct pci_doe_mb {
 	wait_queue_head_t wq;
 	struct workqueue_struct *work_queue;
 	unsigned long flags;
+
+#ifdef CONFIG_SYSFS
+	struct device_attribute *sysfs_attrs;
+#endif
 };
 
 struct pci_doe_feature {
@@ -92,6 +99,147 @@ struct pci_doe_task {
 	struct pci_doe_mb *doe_mb;
 };
 
+#ifdef CONFIG_SYSFS
+static ssize_t doe_discovery_show(struct device *dev,
+				  struct device_attribute *attr,
+				  char *buf)
+{
+	return sysfs_emit(buf, "0001:00\n");
+}
+DEVICE_ATTR_RO(doe_discovery);
+
+static struct attribute *pci_doe_sysfs_feature_attrs[] = {
+	&dev_attr_doe_discovery.attr,
+	NULL
+};
+
+static bool pci_doe_features_sysfs_group_visible(struct kobject *kobj)
+{
+	struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj));
+
+	return !xa_empty(&pdev->doe_mbs);
+}
+DEFINE_SIMPLE_SYSFS_GROUP_VISIBLE(pci_doe_features_sysfs)
+
+const struct attribute_group pci_doe_sysfs_group = {
+	.name	    = "doe_features",
+	.attrs	    = pci_doe_sysfs_feature_attrs,
+	.is_visible = SYSFS_GROUP_VISIBLE(pci_doe_features_sysfs),
+};
+
+static ssize_t pci_doe_sysfs_feature_show(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	return sysfs_emit(buf, "%s\n", attr->attr.name);
+}
+
+static void pci_doe_sysfs_feature_remove(struct pci_dev *pdev,
+					 struct pci_doe_mb *doe_mb)
+{
+	struct device_attribute *attrs = doe_mb->sysfs_attrs;
+	struct device *dev = &pdev->dev;
+	unsigned long i;
+	void *entry;
+
+	if (!attrs)
+		return;
+
+	doe_mb->sysfs_attrs = NULL;
+	xa_for_each(&doe_mb->feats, i, entry) {
+		if (attrs[i].show)
+			sysfs_remove_file_from_group(&dev->kobj, &attrs[i].attr,
+						     pci_doe_sysfs_group.name);
+		kfree(attrs[i].attr.name);
+	}
+	kfree(attrs);
+}
+
+static int pci_doe_sysfs_feature_populate(struct pci_dev *pdev,
+					  struct pci_doe_mb *doe_mb)
+{
+	struct device *dev = &pdev->dev;
+	struct device_attribute *attrs;
+	unsigned long num_features = 0;
+	unsigned long vid, type;
+	unsigned long i;
+	void *entry;
+	int ret;
+
+	xa_for_each(&doe_mb->feats, i, entry)
+		num_features++;
+
+	attrs = kcalloc(num_features, sizeof(*attrs), GFP_KERNEL);
+	if (!attrs) {
+		pci_warn(pdev, "Failed allocating the device_attribute array\n");
+		return -ENOMEM;
+	}
+
+	doe_mb->sysfs_attrs = attrs;
+	xa_for_each(&doe_mb->feats, i, entry) {
+		sysfs_attr_init(&attrs[i].attr);
+		vid = xa_to_value(entry) >> 8;
+		type = xa_to_value(entry) & 0xFF;
+
+		if (vid == PCI_VENDOR_ID_PCI_SIG && type == PCI_DOE_FEATURE_DISCOVERY) {
+			/* DOE Discovery, manually displayed by `dev_attr_doe_discovery` */
+			continue;
+		}
+
+		attrs[i].attr.name = kasprintf(GFP_KERNEL,
+					       "%04lx:%02lx", vid, type);
+		if (!attrs[i].attr.name) {
+			ret = -ENOMEM;
+			pci_warn(pdev, "Failed allocating the attribute name\n");
+			goto fail;
+		}
+
+		attrs[i].attr.mode = 0444;
+		attrs[i].show = pci_doe_sysfs_feature_show;
+
+		ret = sysfs_add_file_to_group(&dev->kobj, &attrs[i].attr,
+					      pci_doe_sysfs_group.name);
+		if (ret) {
+			attrs[i].show = NULL;
+			if (ret != -EEXIST) {
+				pci_warn(pdev, "Failed adding %s to sysfs group\n",
+					 attrs[i].attr.name);
+				goto fail;
+			} else
+				kfree(attrs[i].attr.name);
+		}
+	}
+
+	return 0;
+
+fail:
+	pci_doe_sysfs_feature_remove(pdev, doe_mb);
+	return ret;
+}
+
+void pci_doe_sysfs_teardown(struct pci_dev *pdev)
+{
+	struct pci_doe_mb *doe_mb;
+	unsigned long index;
+
+	xa_for_each(&pdev->doe_mbs, index, doe_mb)
+		pci_doe_sysfs_feature_remove(pdev, doe_mb);
+}
+
+void pci_doe_sysfs_init(struct pci_dev *pdev)
+{
+	struct pci_doe_mb *doe_mb;
+	unsigned long index;
+	int ret;
+
+	xa_for_each(&pdev->doe_mbs, index, doe_mb) {
+		ret = pci_doe_sysfs_feature_populate(pdev, doe_mb);
+		if (ret)
+			return;
+	}
+}
+#endif
+
 static int pci_doe_wait(struct pci_doe_mb *doe_mb, unsigned long timeout)
 {
 	if (wait_event_timeout(doe_mb->wq,
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index b46ce1a2c554..5e3874eaa3c1 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -1804,6 +1804,9 @@ const struct attribute_group *pci_dev_attr_groups[] = {
 #endif
 #ifdef CONFIG_PCIEASPM
 	&aspm_ctrl_attr_group,
+#endif
+#ifdef CONFIG_PCI_DOE
+	&pci_doe_sysfs_group,
 #endif
 	NULL,
 };
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 01e51db8d285..476d33c82058 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -253,6 +253,7 @@ extern const struct attribute_group *pci_dev_groups[];
 extern const struct attribute_group *pci_dev_attr_groups[];
 extern const struct attribute_group *pcibus_groups[];
 extern const struct attribute_group *pci_bus_groups[];
+extern const struct attribute_group pci_doe_sysfs_group;
 #else
 static inline int pci_create_sysfs_dev_files(struct pci_dev *pdev) { return 0; }
 static inline void pci_remove_sysfs_dev_files(struct pci_dev *pdev) { }
@@ -456,6 +457,14 @@ static inline void pci_npem_create(struct pci_dev *dev) { }
 static inline void pci_npem_remove(struct pci_dev *dev) { }
 #endif
 
+#if defined(CONFIG_PCI_DOE) && defined(CONFIG_SYSFS)
+void pci_doe_sysfs_init(struct pci_dev *pci_dev);
+void pci_doe_sysfs_teardown(struct pci_dev *pdev);
+#else
+static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
+static inline void pci_doe_sysfs_teardown(struct pci_dev *pdev) { }
+#endif
+
 /**
  * pci_dev_set_io_state - Set the new error state if possible.
  *
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 246744d8d268..9b21e9379dae 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2662,6 +2662,8 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
 	WARN_ON(ret < 0);
 
 	pci_npem_create(dev);
+
+	pci_doe_sysfs_init(dev);
 }
 
 struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn)
diff --git a/drivers/pci/remove.c b/drivers/pci/remove.c
index efc37fcb73e2..5813726214e6 100644
--- a/drivers/pci/remove.c
+++ b/drivers/pci/remove.c
@@ -53,6 +53,7 @@ static void pci_destroy_dev(struct pci_dev *dev)
 	if (pci_dev_test_and_set_removed(dev))
 		return;
 
+	pci_doe_sysfs_teardown(dev);
 	pci_npem_remove(dev);
 
 	device_del(&dev->dev);
-- 
2.48.1

[PATCH v17 4/4] PCI/DOE: Allow enabling DOE without CXL

[Alistair Francis]

PCIe devices (not CXL) can support DOE as well, so allow DOE to be
enabled even if CXL isn't.

Signed-off-by: Alistair Francis <alistair@alistair23.me>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
v17:
 - No changes
v16:
 - No changes

 drivers/pci/Kconfig | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig
index 2fbd379923fd..fff4f3c6f6d3 100644
--- a/drivers/pci/Kconfig
+++ b/drivers/pci/Kconfig
@@ -122,7 +122,10 @@ config PCI_ATS
 	bool
 
 config PCI_DOE
-	bool
+	bool "Enable PCI Data Object Exchange (DOE) support"
+	help
+	  Say Y here if you want be able to communicate with PCIe DOE
+	  mailboxes.
 
 config PCI_ECAM
 	bool
-- 
2.48.1

Re: [PATCH v17 1/4] PCI/DOE: Rename DOE protocol to feature

[Bjorn Helgaas]

On Thu, Mar 06, 2025 at 05:52:08PM +1000, Alistair Francis wrote:
> DOE r1.1 replaced all occurrences of "protocol" with the term "feature"
> or "Data Object Type".
> 
> PCIe r6.1 (which was published July 24) incorporated that change.
> 
> Rename the existing terms protocol with feature.
> 
> Signed-off-by: Alistair Francis <alistair@alistair23.me>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> Reviewed-by: Lukas Wunner <lukas@wunner.de>

All four patches applied to pci/doe for v6.15, thanks!

  [PATCH v17 1/4] PCI/DOE: Rename DOE protocol to feature
  [PATCH v17 2/4] PCI/DOE: Rename Discovery Response Data Object Contents to type
  [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs
  [PATCH v17 4/4] PCI/DOE: Allow enabling DOE without CXL

Re: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs

[kernel test robot]

Hi Alistair,

kernel test robot noticed the following build errors:

[auto build test ERROR on pci/next]
[also build test ERROR on pci/for-linus linus/master v6.14-rc5 next-20250306]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Alistair-Francis/PCI-DOE-Rename-Discovery-Response-Data-Object-Contents-to-type/20250306-155550
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20250306075211.1855177-3-alistair%40alistair23.me
patch subject: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs
config: powerpc-icon_defconfig (https://download.01.org/0day-ci/archive/20250307/202503071950.vvsA3SXV-lkp@intel.com/config)
compiler: powerpc-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250307/202503071950.vvsA3SXV-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202503071950.vvsA3SXV-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/powerpc/kernel/pci-common.c:44:
   arch/powerpc/kernel/../../../drivers/pci/pci.h: In function 'pci_doe_sysfs_init':
>> arch/powerpc/kernel/../../../drivers/pci/pci.h:488:70: error: 'return' with a value, in function returning void [-Wreturn-mismatch]
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                                                                      ^
   arch/powerpc/kernel/../../../drivers/pci/pci.h:488:20: note: declared here
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                    ^~~~~~~~~~~~~~~~~~


vim +/return +488 arch/powerpc/kernel/../../../drivers/pci/pci.h

   483	
   484	#if defined(CONFIG_PCI_DOE) && defined(CONFIG_SYSFS)
   485	void pci_doe_sysfs_init(struct pci_dev *pci_dev);
   486	void pci_doe_sysfs_teardown(struct pci_dev *pdev);
   487	#else
 > 488	static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
   489	static inline void pci_doe_sysfs_teardown(struct pci_dev *pdev) { }
   490	#endif
   491	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs

[kernel test robot]

Hi Alistair,

kernel test robot noticed the following build warnings:

[auto build test WARNING on pci/next]
[also build test WARNING on pci/for-linus linus/master v6.14-rc5 next-20250307]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Alistair-Francis/PCI-DOE-Rename-Discovery-Response-Data-Object-Contents-to-type/20250306-155550
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20250306075211.1855177-3-alistair%40alistair23.me
patch subject: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs
config: microblaze-randconfig-r111-20250307 (https://download.01.org/0day-ci/archive/20250307/202503072119.bmT7zRPN-lkp@intel.com/config)
compiler: microblaze-linux-gcc (GCC) 14.2.0
reproduce: (https://download.01.org/0day-ci/archive/20250307/202503072119.bmT7zRPN-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202503072119.bmT7zRPN-lkp@intel.com/

sparse warnings: (new ones prefixed by >>)
>> drivers/pci/doe.c:109:1: sparse: sparse: symbol 'dev_attr_doe_discovery' was not declared. Should it be static?

vim +/dev_attr_doe_discovery +109 drivers/pci/doe.c

   101	
   102	#ifdef CONFIG_SYSFS
   103	static ssize_t doe_discovery_show(struct device *dev,
   104					  struct device_attribute *attr,
   105					  char *buf)
   106	{
   107		return sysfs_emit(buf, "0001:00\n");
   108	}
 > 109	DEVICE_ATTR_RO(doe_discovery);
   110	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs

[kernel test robot]

Hi Alistair,

kernel test robot noticed the following build errors:

[auto build test ERROR on pci/next]
[also build test ERROR on pci/for-linus linus/master v6.14-rc5 next-20250307]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Alistair-Francis/PCI-DOE-Rename-Discovery-Response-Data-Object-Contents-to-type/20250306-155550
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20250306075211.1855177-3-alistair%40alistair23.me
patch subject: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs
config: powerpc64-randconfig-003-20250307 (https://download.01.org/0day-ci/archive/20250307/202503072251.DHy2O6b1-lkp@intel.com/config)
compiler: powerpc64-linux-gcc (GCC) 14.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250307/202503072251.DHy2O6b1-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202503072251.DHy2O6b1-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from arch/powerpc/platforms/powernv/pci-ioda.c:46:
   arch/powerpc/platforms/powernv/../../../../drivers/pci/pci.h: In function 'pci_doe_sysfs_init':
>> arch/powerpc/platforms/powernv/../../../../drivers/pci/pci.h:488:70: error: 'return' with a value, in function returning void [-Wreturn-mismatch]
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                                                                      ^
   arch/powerpc/platforms/powernv/../../../../drivers/pci/pci.h:488:20: note: declared here
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                    ^~~~~~~~~~~~~~~~~~


vim +/return +488 arch/powerpc/platforms/powernv/../../../../drivers/pci/pci.h

   483	
   484	#if defined(CONFIG_PCI_DOE) && defined(CONFIG_SYSFS)
   485	void pci_doe_sysfs_init(struct pci_dev *pci_dev);
   486	void pci_doe_sysfs_teardown(struct pci_dev *pdev);
   487	#else
 > 488	static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
   489	static inline void pci_doe_sysfs_teardown(struct pci_dev *pdev) { }
   490	#endif
   491	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

Re: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs

[kernel test robot]

Hi Alistair,

kernel test robot noticed the following build warnings:

[auto build test WARNING on pci/next]
[also build test WARNING on pci/for-linus linus/master v6.14-rc5 next-20250307]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Alistair-Francis/PCI-DOE-Rename-Discovery-Response-Data-Object-Contents-to-type/20250306-155550
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git next
patch link:    https://lore.kernel.org/r/20250306075211.1855177-3-alistair%40alistair23.me
patch subject: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs
config: um-randconfig-r063-20250307 (https://download.01.org/0day-ci/archive/20250307/202503072302.i9H71Jqv-lkp@intel.com/config)
compiler: gcc-12 (Debian 12.2.0-14) 12.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250307/202503072302.i9H71Jqv-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202503072302.i9H71Jqv-lkp@intel.com/

All warnings (new ones prefixed by >>):

   In file included from drivers/pci/msi/pcidev_msi.c:5:
   drivers/pci/msi/../pci.h: In function 'pci_doe_sysfs_init':
>> drivers/pci/msi/../pci.h:488:70: warning: 'return' with a value, in function returning void [-Wreturn-type]
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                                                                      ^
   drivers/pci/msi/../pci.h:488:20: note: declared here
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                    ^~~~~~~~~~~~~~~~~~
--
   In file included from drivers/pci/pcie/aspm.c:27:
   drivers/pci/pcie/../pci.h: In function 'pci_doe_sysfs_init':
>> drivers/pci/pcie/../pci.h:488:70: warning: 'return' with a value, in function returning void [-Wreturn-type]
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                                                                      ^
   drivers/pci/pcie/../pci.h:488:20: note: declared here
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                    ^~~~~~~~~~~~~~~~~~
--
   In file included from drivers/pci/hotplug/pci_hotplug_core.c:32:
   drivers/pci/hotplug/../pci.h: In function 'pci_doe_sysfs_init':
>> drivers/pci/hotplug/../pci.h:488:70: warning: 'return' with a value, in function returning void [-Wreturn-type]
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                                                                      ^
   drivers/pci/hotplug/../pci.h:488:20: note: declared here
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                    ^~~~~~~~~~~~~~~~~~
--
   In file included from drivers/pci/controller/dwc/pcie-designware.c:24:
   drivers/pci/controller/dwc/../../pci.h: In function 'pci_doe_sysfs_init':
>> drivers/pci/controller/dwc/../../pci.h:488:70: warning: 'return' with a value, in function returning void [-Wreturn-type]
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                                                                      ^
   drivers/pci/controller/dwc/../../pci.h:488:20: note: declared here
     488 | static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
         |                    ^~~~~~~~~~~~~~~~~~


vim +/return +488 drivers/pci/msi/../pci.h

   483	
   484	#if defined(CONFIG_PCI_DOE) && defined(CONFIG_SYSFS)
   485	void pci_doe_sysfs_init(struct pci_dev *pci_dev);
   486	void pci_doe_sysfs_teardown(struct pci_dev *pdev);
   487	#else
 > 488	static inline void pci_doe_sysfs_init(struct pci_dev *pdev) { return 0; }
   489	static inline void pci_doe_sysfs_teardown(struct pci_dev *pdev) { }
   490	#endif
   491	

-- 
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https://github.com/intel/lkp-tests/wiki

Re: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs

[Bjorn Helgaas]

On Thu, Mar 06, 2025 at 05:52:10PM +1000, Alistair Francis wrote:
> The PCIe 6 specification added support for the Data Object
> Exchange (DOE).
> When DOE is supported the DOE Discovery Feature must be implemented per
> PCIe r6.1 sec 6.30.1.1. DOE allows a requester to obtain
> information about the other DOE features supported by the device.

> +#ifdef CONFIG_SYSFS
> +static ssize_t doe_discovery_show(struct device *dev,
> +				  struct device_attribute *attr,
> +				  char *buf)
> +{
> +	return sysfs_emit(buf, "0001:00\n");
> +}
> +DEVICE_ATTR_RO(doe_discovery);

I think this needs:

  static DEVICE_ATTR_RO(doe_discovery);

Otherwise sparse complains:

  $ make C=2 drivers/pci/doe.o
    CHECK   scripts/mod/empty.c
    CALL    scripts/checksyscalls.sh
    DESCEND objtool
    INSTALL libsubcmd_headers
    CHECK   drivers/pci/doe.c
  drivers/pci/doe.c:109:1: warning: symbol 'dev_attr_doe_discovery' was not declared. Should it be static?


Right?  I added this in, so we're all set unless you think that's
wrong.

Bjorn

Re: [PATCH v17 3/4] PCI/DOE: Expose the DOE features via sysfs

[Alistair Francis]

On Sat, Mar 22, 2025 at 7:42 AM Bjorn Helgaas <helgaas@kernel.org> wrote:
>
> On Thu, Mar 06, 2025 at 05:52:10PM +1000, Alistair Francis wrote:
> > The PCIe 6 specification added support for the Data Object
> > Exchange (DOE).
> > When DOE is supported the DOE Discovery Feature must be implemented per
> > PCIe r6.1 sec 6.30.1.1. DOE allows a requester to obtain
> > information about the other DOE features supported by the device.
>
> > +#ifdef CONFIG_SYSFS
> > +static ssize_t doe_discovery_show(struct device *dev,
> > +                               struct device_attribute *attr,
> > +                               char *buf)
> > +{
> > +     return sysfs_emit(buf, "0001:00\n");
> > +}
> > +DEVICE_ATTR_RO(doe_discovery);
>
> I think this needs:
>
>   static DEVICE_ATTR_RO(doe_discovery);
>
> Otherwise sparse complains:
>
>   $ make C=2 drivers/pci/doe.o
>     CHECK   scripts/mod/empty.c
>     CALL    scripts/checksyscalls.sh
>     DESCEND objtool
>     INSTALL libsubcmd_headers
>     CHECK   drivers/pci/doe.c
>   drivers/pci/doe.c:109:1: warning: symbol 'dev_attr_doe_discovery' was not declared. Should it be static?
>
>
> Right?  I added this in, so we're all set unless you think that's
> wrong.

Yeah, I think it's missing a `static`. Thanks for adding it, sorry
that I missed this in the first place

Alistair

>
> Bjorn