[RFC PATCH 2/9] cxl/mem: Implement Clear Event Records command

[ira . weiny]

From: Ira Weiny <ira.weiny@xxxxxxxxx>

CXL v3.0 section 8.2.9.2.3 defines the Clear Event Records mailbox
command.  After an event record is read it needs to be cleared from the
event log.

Implement cxl_clear_event_record() and call it for each record retrieved
from the device.

Each record is cleared individually.  A clear all bit is specified but
events could arrive between a get and the final clear all operation.
Therefore each event is cleared specifically.

Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>
---
 drivers/cxl/core/mbox.c      | 31 ++++++++++++++++++++++++++++---
 drivers/cxl/cxlmem.h         | 15 +++++++++++++++
 include/uapi/linux/cxl_mem.h |  1 +
 3 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 2cceed8608dc..493f5ceb5d1c 100644
--- a/drivers/cxl/core/mbox.c
+++ b/drivers/cxl/core/mbox.c
@@ -52,6 +52,7 @@ static struct cxl_mem_command cxl_mem_commands[CXL_MEM_COMMAND_ID_MAX] = {
 #endif
 	CXL_CMD(GET_SUPPORTED_LOGS, 0, CXL_VARIABLE_PAYLOAD, CXL_CMD_FLAG_FORCE_ENABLE),
 	CXL_CMD(GET_EVENT_RECORD, 1, CXL_VARIABLE_PAYLOAD, 0),
+	CXL_CMD(CLEAR_EVENT_RECORD, CXL_VARIABLE_PAYLOAD, 0, 0),
 	CXL_CMD(GET_FW_INFO, 0, 0x50, 0),
 	CXL_CMD(GET_PARTITION_INFO, 0, 0x20, 0),
 	CXL_CMD(GET_LSA, 0x8, CXL_VARIABLE_PAYLOAD, 0),
@@ -708,6 +709,26 @@ int cxl_enumerate_cmds(struct cxl_dev_state *cxlds)
 }
 EXPORT_SYMBOL_NS_GPL(cxl_enumerate_cmds, CXL);
 
+static int cxl_clear_event_record(struct cxl_dev_state *cxlds,
+				  enum cxl_event_log_type log,
+				  __le16 handle)
+{
+	struct cxl_mbox_clear_event_payload payload;
+	int rc;
+
+	memset(&payload, 0, sizeof(payload));
+	payload.event_log = log;
+	payload.nr_recs = 1;
+	payload.handle = handle;
+
+	rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_CLEAR_EVENT_RECORD,
+			       &payload, sizeof(payload), NULL, 0);
+	if (rc)
+		return rc;
+
+	return 0;
+}
+
 static int cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
 				   enum cxl_event_log_type type)
 {
@@ -725,9 +746,12 @@ static int cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
 			return rc;
 
 		record_count = le16_to_cpu(payload.record_count);
-		if (record_count > 0)
+		if (record_count > 0) {
 			trace_cxl_event(dev_name(cxlds->dev), type,
 					&payload.record);
+			cxl_clear_event_record(cxlds, type,
+					       payload.record.hdr.handle);
+		}
 
 		if (payload.flags & CXL_GET_EVENT_FLAG_OVERFLOW)
 			trace_cxl_event_overflow(dev_name(cxlds->dev), type,
@@ -742,10 +766,11 @@ static int cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
  * cxl_mem_get_event_records - Get Event Records from the device
  * @cxlds: The device data for the operation
  *
- * Retrieve all event records available on the device and report them as trace
- * events.
+ * Retrieve all event records available on the device, report them as trace
+ * events, and clear them.
  *
  * See CXL v3.0 @8.2.9.2.2 Get Event Records
+ * See CXL v3.0 @8.2.9.2.3 Clear Event Records
  */
 void cxl_mem_get_event_records(struct cxl_dev_state *cxlds)
 {
diff --git a/drivers/cxl/cxlmem.h b/drivers/cxl/cxlmem.h
index f83634f3bc8d..5506e7210cf6 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -255,6 +255,7 @@ enum cxl_opcode {
 	CXL_MBOX_OP_INVALID		= 0x0000,
 	CXL_MBOX_OP_RAW			= CXL_MBOX_OP_INVALID,
 	CXL_MBOX_OP_GET_EVENT_RECORD	= 0x0100,
+	CXL_MBOX_OP_CLEAR_EVENT_RECORD	= 0x0101,
 	CXL_MBOX_OP_GET_FW_INFO		= 0x0200,
 	CXL_MBOX_OP_ACTIVATE_FW		= 0x0202,
 	CXL_MBOX_OP_GET_SUPPORTED_LOGS	= 0x0400,
@@ -387,6 +388,20 @@ static inline char *cxl_event_log_type_str(enum cxl_event_log_type type)
 	return "<unknown>";
 }
 
+/*
+ * Clear Event Records input payload
+ * CXL v3.0 section 8.2.9.2.3; Table 8-51
+ *
+ * Space given for 1 record
+ */
+struct cxl_mbox_clear_event_payload {
+	u8 event_log;		/* enum cxl_event_log_type */
+	u8 clear_flags;
+	u8 nr_recs;		/* 1 for this struct */
+	u8 reserved[3];
+	__le16 handle;
+};
+
 struct cxl_mbox_get_partition_info {
 	__le64 active_volatile_cap;
 	__le64 active_persistent_cap;
diff --git a/include/uapi/linux/cxl_mem.h b/include/uapi/linux/cxl_mem.h
index 70459be5bdd4..7c1ad8062792 100644
--- a/include/uapi/linux/cxl_mem.h
+++ b/include/uapi/linux/cxl_mem.h
@@ -25,6 +25,7 @@
 	___C(RAW, "Raw device command"),                                  \
 	___C(GET_SUPPORTED_LOGS, "Get Supported Logs"),                   \
 	___C(GET_EVENT_RECORD, "Get Event Record"),                       \
+	___C(CLEAR_EVENT_RECORD, "Clear Event Record"),                   \
 	___C(GET_FW_INFO, "Get FW Info"),                                 \
 	___C(GET_PARTITION_INFO, "Get Partition Information"),            \
 	___C(GET_LSA, "Get Label Storage Area"),                          \
-- 
2.35.3