[RFC PATCH v8 03/10] cxl/mbox: Add GET_FEATURE mailbox command

From: shiju.jose
Date: Fri Apr 19 2024 - 12:48:17 EST


From: Shiju Jose <shiju.jose@xxxxxxxxxx>

Add support for GET_FEATURE mailbox command.

CXL spec 3.1 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 | 53 +++++++++++++++++++++++++++++++++++++++++
drivers/cxl/cxlmem.h | 28 ++++++++++++++++++++++
2 files changed, 81 insertions(+)

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 82e279b821e2..999965871048 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -1318,6 +1318,59 @@ int cxl_get_supported_features(struct cxl_memdev_state *mds,
}
EXPORT_SYMBOL_NS_GPL(cxl_get_supported_features, CXL);

+size_t cxl_get_feature(struct cxl_memdev_state *mds,
+ const uuid_t feat_uuid, void *feat_out,
+ size_t feat_out_size,
+ size_t feat_out_min_size,
+ enum cxl_get_feat_selection selection)
+{
+ struct cxl_dev_state *cxlds = &mds->cxlds;
+ struct cxl_mbox_get_feat_in pi;
+ struct cxl_mbox_cmd mbox_cmd;
+ size_t data_rcvd_size = 0;
+ size_t data_to_rd_size, size_out;
+ int rc;
+
+ if (feat_out_size < feat_out_min_size) {
+ dev_err(cxlds->dev,
+ "%s: feature out buffer size(%lu) is not big enough\n",
+ __func__, feat_out_size);
+ return 0;
+ }
+
+ if (feat_out_size <= mds->payload_size)
+ size_out = feat_out_size;
+ else
+ size_out = mds->payload_size;
+ pi.uuid = feat_uuid;
+ pi.selection = selection;
+ do {
+ if ((feat_out_min_size - data_rcvd_size) <= mds->payload_size)
+ data_to_rd_size = feat_out_min_size - data_rcvd_size;
+ else
+ data_to_rd_size = mds->payload_size;
+
+ pi.offset = cpu_to_le16(data_rcvd_size);
+ pi.count = cpu_to_le16(data_to_rd_size);
+
+ mbox_cmd = (struct cxl_mbox_cmd) {
+ .opcode = CXL_MBOX_OP_GET_FEATURE,
+ .size_in = sizeof(pi),
+ .payload_in = &pi,
+ .size_out = size_out,
+ .payload_out = feat_out + data_rcvd_size,
+ .min_out = data_to_rd_size,
+ };
+ rc = cxl_internal_send_cmd(mds, &mbox_cmd);
+ if (rc < 0 || mbox_cmd.size_out == 0)
+ return 0;
+ data_rcvd_size += mbox_cmd.size_out;
+ } while (data_rcvd_size < feat_out_min_size);
+
+ return data_rcvd_size;
+}
+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 06231e63373e..c822eb30e6d1 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -528,6 +528,7 @@ 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,
@@ -754,6 +755,28 @@ struct cxl_mbox_get_supp_feats_out {
struct cxl_mbox_supp_feat_entry feat_entries[];
} __packed;

+/*
+ * Get Feature CXL 3.1 Spec 8.2.9.6.2
+ */
+
+/*
+ * Get Feature input payload
+ * CXL rev 3.1 section 8.2.9.6.2 Table 8-99
+ */
+enum cxl_get_feat_selection {
+ CXL_GET_FEAT_SEL_CURRENT_VALUE,
+ CXL_GET_FEAT_SEL_DEFAULT_VALUE,
+ CXL_GET_FEAT_SEL_SAVED_VALUE,
+ 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;
@@ -888,6 +911,11 @@ int cxl_set_timestamp(struct cxl_memdev_state *mds);
int cxl_get_supported_features(struct cxl_memdev_state *mds,
u32 count, u16 start_index,
struct cxl_mbox_get_supp_feats_out *feats_out);
+size_t cxl_get_feature(struct cxl_memdev_state *mds,
+ const uuid_t feat_uuid, void *feat_out,
+ size_t feat_out_size,
+ size_t feat_out_min_size,
+ enum cxl_get_feat_selection selection);
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);
--
2.34.1