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

ira.weiny
2022-12-01T00:27:45Z

From: Ira Weiny <ira.weiny@intel.com>

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() to clear all record retrieved from
the device.

Each record is cleared explicitly. A clear all bit is specified but
events could arrive between a get and any final clear all operation.
This means events would be missed.
Therefore each event is cleared specifically.

Signed-off-by: Ira Weiny <ira.weiny@intel.com>

---
Changes from V1:
Clear Event Record allows for u8 handles while Get Event Record
allows for u16 records to be returned. Based on Jonathan's
feedback; allow for all event records to be handled in this
clear. Which means a double loop with potentially multiple
Clear Event payloads being sent to clear all events sent.

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 | 61 +++++++++++++++++++++++++++++++-----
drivers/cxl/cxlmem.h | 14 +++++++++
include/uapi/linux/cxl_mem.h | 1 +
3 files changed, 69 insertions(+), 7 deletions(-)

diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
index 70b681027a3d..076a3df0ba38 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 +709,42 @@ 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,
+ struct cxl_get_event_payload *get_pl,
+ u16 total)
+{
+ struct cxl_mbox_clear_event_payload payload = {
+ .event_log = log,
+ };
+ int cnt;
+
+ /*
+ * Clear Event Records uses u8 for the handle cnt while Get Event
+ * Record can return up to 0xffff records.
+ */
+ for (cnt = 0; cnt < total; /* cnt incremented internally */) {
+ u8 nr_recs = min_t(u8, (total - cnt),
+ CXL_CLEAR_EVENT_MAX_HANDLES);
+ int i, rc;
+
+ for (i = 0; i < nr_recs; i++, cnt++) {
+ payload.handle[i] = get_pl->records[cnt].hdr.handle;
+ dev_dbg(cxlds->dev, "Event log '%s': Clearning %u\n",
+ cxl_event_log_type_str(log),
+ le16_to_cpu(payload.handle[i]));
+ }
+ payload.nr_recs = nr_recs;
+
+ rc = cxl_mbox_send_cmd(cxlds, CXL_MBOX_OP_CLEAR_EVENT_RECORD,
+ &payload, sizeof(payload), NULL, 0);
+ if (rc)
+ return rc;
+ }
+
+ return 0;
+}
+
static void cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
enum cxl_event_log_type type)
{
@@ -732,13 +769,22 @@ static void cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
}

nr_rec = le16_to_cpu(payload->record_count);
- if (trace_cxl_generic_event_enabled()) {
+ if (nr_rec > 0) {
int i;

- for (i = 0; i < nr_rec; i++)
- trace_cxl_generic_event(dev_name(cxlds->dev),
- type,
- &payload->records[i]);
+ if (trace_cxl_generic_event_enabled()) {
+ for (i = 0; i < nr_rec; i++)
+ trace_cxl_generic_event(dev_name(cxlds->dev),
+ type,
+ &payload->records[i]);
+ }
+
+ rc = cxl_clear_event_record(cxlds, type, payload, nr_rec);
+ if (rc) {
+ dev_err(cxlds->dev, "Event log '%s': Failed to clear events : %d",
+ cxl_event_log_type_str(type), rc);
+ return;
+ }
}

if (trace_cxl_overflow_enabled() &&
@@ -780,10 +826,11 @@ static struct cxl_get_event_payload *alloc_event_buf(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 55d57f5a64bc..1ae9962c5a06 100644
--- a/drivers/cxl/cxlmem.h
+++ b/drivers/cxl/cxlmem.h
@@ -261,6 +261,7 @@ 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 +397,19 @@ 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
+ */
+#define CXL_CLEAR_EVENT_MAX_HANDLES (0xff)
+struct cxl_mbox_clear_event_payload {
+ u8 event_log; /* enum cxl_event_log_type */
+ u8 clear_flags;
+ u8 nr_recs;
+ u8 reserved[3];
+ __le16 handle[CXL_CLEAR_EVENT_MAX_HANDLES];
+};
+
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