[PATCH v2 02/10] cxl/mbox: Add GET_FEATURE mailbox command

[shiju.jose]

From: Shiju Jose <shiju.jose@xxxxxxxxxx>

Add support for GET_FEATURE mailbox command.

CXL spec 3.0 section 8.2.9.6 describes optional device specific features.
The settings of a feature can be retrieved using Get Feature command.

Signed-off-by: Shiju Jose <shiju.jose@xxxxxxxxxx>
---
 drivers/cxl/core/mbox.c      | 23 +++++++++++++++++++++++
 drivers/cxl/cxlmem.h         | 23 +++++++++++++++++++++++
 include/uapi/linux/cxl_mem.h |  1 +
 3 files changed, 47 insertions(+)

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 06ec9ef50e7f..2675c616caec 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -64,6 +64,7 @@ static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
 	CXL_CMD(SET_SHUTDOWN_STATE, 0x1, 0, 0),
 	CXL_CMD(GET_SCAN_MEDIA_CAPS, 0x10, 0x4, 0),
 	CXL_CMD(GET_SUPPORTED_FEATURES, 0x8, CXL_VARIABLE_PAYLOAD, 0),
+	CXL_CMD(GET_FEATURE, 0x15, CXL_VARIABLE_PAYLOAD, 0),
 };
 
 /*
@@ -1327,6 +1328,28 @@ int cxl_get_supported_features(struct cxl_memdev_state *mds,
 }
 EXPORT_SYMBOL_NS_GPL(cxl_get_supported_features, CXL);
 
+int cxl_get_feature(struct cxl_memdev_state *mds,
+		    struct cxl_mbox_get_feat_in *pi, void *feat_out)
+{
+	struct cxl_mbox_cmd mbox_cmd;
+	int rc;
+
+	mbox_cmd = (struct cxl_mbox_cmd) {
+		.opcode = CXL_MBOX_OP_GET_FEATURE,
+		.size_in = sizeof(*pi),
+		.payload_in = pi,
+		.size_out = pi->count,
+		.payload_out = feat_out,
+		.min_out = pi->count,
+	};
+	rc = cxl_internal_send_cmd(mds, &mbox_cmd);
+	if (rc < 0)
+		return rc;
+
+	return 0;
+}
+EXPORT_SYMBOL_NS_GPL(cxl_get_feature, CXL);
+
 int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
 		       struct cxl_region *cxlr)
 {
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index d831dad748f5..92c1f2a44713 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -507,6 +507,7 @@ enum cxl_opcode {
 	CXL_MBOX_OP_GET_SUPPORTED_LOGS	= 0x0400,
 	CXL_MBOX_OP_GET_LOG		= 0x0401,
 	CXL_MBOX_OP_GET_SUPPORTED_FEATURES	= 0x0500,
+	CXL_MBOX_OP_GET_FEATURE		= 0x0501,
 	CXL_MBOX_OP_IDENTIFY		= 0x4000,
 	CXL_MBOX_OP_GET_PARTITION_INFO	= 0x4100,
 	CXL_MBOX_OP_SET_PARTITION_INFO	= 0x4101,
@@ -796,6 +797,26 @@ struct cxl_mbox_get_supp_feats_out {
 	struct cxl_mbox_supp_feat_entry feat_entries[];
 } __packed;
 
+/* Get Feature CXL 3.0 Spec 8.2.9.6.2 */
+/*
+ * Get Feature input payload
+ * CXL rev 3.0 section 8.2.9.6.2; Table 8-79
+ */
+/* Get Feature : Payload in selection */
+enum cxl_get_feat_selection {
+	CXL_GET_FEAT_SEL_CURRENT_VALUE = 0x0,
+	CXL_GET_FEAT_SEL_DEFAULT_VALUE = 0x1,
+	CXL_GET_FEAT_SEL_SAVED_VALUE = 0x2,
+	CXL_GET_FEAT_SEL_MAX
+};
+
+struct cxl_mbox_get_feat_in {
+	uuid_t uuid;
+	__le16 offset;
+	__le16 count;
+	u8 selection;
+}  __packed;
+
 /* Get Poison List  CXL 3.0 Spec 8.2.9.8.4.1 */
 struct cxl_mbox_poison_in {
 	__le64 offset;
@@ -926,6 +947,8 @@ int cxl_set_timestamp(struct cxl_memdev_state *mds);
 int cxl_get_supported_features(struct cxl_memdev_state *mds,
 			       struct cxl_mbox_get_supp_feats_in *pi,
 			       void *feats_out);
+int cxl_get_feature(struct cxl_memdev_state *mds,
+		    struct cxl_mbox_get_feat_in *pi, void *feat_out);
 int cxl_poison_state_init(struct cxl_memdev_state *mds);
 int cxl_mem_get_poison(struct cxl_memdev *cxlmd, u64 offset, u64 len,
 		       struct cxl_region *cxlr);
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index 656450274001..b20de60bfc71 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -47,6 +47,7 @@
 	___DEPRECATED(SCAN_MEDIA, "Scan Media"),                          \
 	___DEPRECATED(GET_SCAN_MEDIA, "Get Scan Media Results"),          \
 	___C(GET_SUPPORTED_FEATURES, "Get Supported Features"),           \
+	___C(GET_FEATURE, "Get Feature"),                                 \
 	___C(MAX, "invalid / last command")
 
 #define ___C(a, b) CXL_MEM_COMMAND_ID_##a
-- 
2.34.1