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Message-ID: <0100f37b-3bbb-bd0c-2a11-5a45d1d7b199@intel.com>
Date:   Tue, 15 Nov 2022 15:09:39 -0700
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Subject: Re: [PATCH 03/11] cxl/mem: Implement Clear Event Records command
Content-Language: en-US
To:     ira.weiny@intel.com, Dan Williams <dan.j.williams@intel.com>
Cc:     Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Alison Schofield <alison.schofield@intel.com>,
        Vishal Verma <vishal.l.verma@intel.com>,
        Ben Widawsky <bwidawsk@kernel.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Davidlohr Bueso <dave@stgolabs.net>,
        linux-kernel@vger.kernel.org, linux-cxl@vger.kernel.org
References: <20221110185758.879472-1-ira.weiny@intel.com>
 <20221110185758.879472-4-ira.weiny@intel.com>
From:   Dave Jiang <dave.jiang@intel.com>
In-Reply-To: <20221110185758.879472-4-ira.weiny@intel.com>
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On 11/10/2022 10:57 AM, ira.weiny@intel.com wrote:
> 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() 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@huawei.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>

Reviewed-by: Dave Jiang <dave.jiang@intel.com>

> 
> ---
> 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      | 46 ++++++++++++++++++++++++++++++------
>   drivers/cxl/cxlmem.h         | 15 ++++++++++++
>   include/uapi/linux/cxl_mem.h |  1 +
>   3 files changed, 55 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/cxl/core/mbox.c b/drivers/cxl/core/mbox.c
> index a908b95a7de4..f46558e09f08 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 +709,27 @@ 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 nr)
> +{
> +	struct cxl_mbox_clear_event_payload payload = {
> +		.event_log = log,
> +		.nr_recs = nr,
> +	};
> +	int i;
> +
> +	for (i = 0; i < nr; i++) {
> +		payload.handle[i] = get_pl->record[i].hdr.handle;
> +		dev_dbg(cxlds->dev, "Event log '%s': Clearning %u\n",
> +			cxl_event_log_type_str(log),
> +			le16_to_cpu(payload.handle[i]));
> +	}
> +
> +	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)
>   {
> @@ -728,14 +750,23 @@ static void cxl_mem_get_records_log(struct cxl_dev_state *cxlds,
>   		}
>   
>   		pl_nr = le16_to_cpu(payload.record_count);
> -		if (trace_cxl_generic_event_enabled()) {
> +		if (pl_nr > 0) {
>   			u16 nr_rec = min_t(u16, pl_nr, CXL_GET_EVENT_NR_RECORDS);
>   			int i;
>   
> -			for (i = 0; i < nr_rec; i++)
> -				trace_cxl_generic_event(dev_name(cxlds->dev),
> -							type,
> -							&payload.record[i]);
> +			if (trace_cxl_generic_event_enabled()) {
> +				for (i = 0; i < nr_rec; i++)
> +					trace_cxl_generic_event(dev_name(cxlds->dev),
> +								type,
> +								&payload.record[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() &&
> @@ -750,10 +781,11 @@ 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 da64ba0f156b..28a114c7cf69 100644
> --- a/drivers/cxl/cxlmem.h
> +++ b/drivers/cxl/cxlmem.h
> @@ -258,6 +258,7 @@ 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,
> @@ -397,6 +398,20 @@ 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[CXL_GET_EVENT_NR_RECORDS];
> +};
> +
>   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"),                          \