[RFC V2 PATCH 03/11] cxl/mem: Implement Clear Event Records command

From: ira . weiny
Date: Mon Oct 10 2022 - 18:43:14 EST


From: Ira Weiny <ira.weiny@xxxxxxxxx>

CXL rev 3.0 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.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@xxxxxxxxxx>
Signed-off-by: Ira Weiny <ira.weiny@xxxxxxxxx>

---
Changes from RFC:
Jonathan
Clean up init of payload and use return code.
Also report any error to clear the event.
s/v3.0/rev 3.0
---
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 5f258c3f2190..bc4e42b3e01b 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),
@@ -711,6 +712,20 @@ 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 = {
+ .event_log = log,
+ .nr_recs = 1,
+ .handle = handle,
+ };
+
+ return cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_CLEAR_EVENT_RECORD,
+ &payload, sizeof(payload), NULL, 0);
+}
+
static void cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
enum cxl_event_log_type type)
{
@@ -729,9 +744,18 @@ static void cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
return;
}

- if (le16_to_cpu(payload.record_count) == 1)
+ if (le16_to_cpu(payload.record_count) == 1) {
trace_generic_event(dev_name(cxlds->dev), type,
&payload.record);
+ rc = cxl_clear_event_record(cxlds, type,
+ payload.record.hdr.handle);
+ if (rc) {
+ dev_err(cxlds->dev, "Event log '%s': Failed to clear event (%u) : %d",
+ cxl_event_log_type_str(type),
+ payload.record.hdr.handle, rc);
+ return;
+ }
+ }

if (payload.flags & CXL_GET_EVENT_FLAG_OVERFLOW)
trace_overflow(dev_name(cxlds->dev), type, &payload);
@@ -743,10 +767,11 @@ static void 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 rev 3.0 @8.2.9.2.2 Get Event Records
+ * See CXL rev 3.0 @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 fa8d248fb299..75aea34f3ffb 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,
@@ -396,6 +397,20 @@ static inline const char *cxl_event_log_type_str(enum cxl_event_log_type type)
return "<unknown>";
}

+/*
+ * Clear Event Records input payload
+ * CXL rev 3.0 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"), \
--
2.37.2