platform/chrome: cros_ec_proto: Add response tracing

Add the ability to view response codes as well.

I dropped the EVENT_CLASS since there is only one event per class.

cros_ec_cmd has now been renamed to cros_ec_request_start.

Example:
$ echo 1 > /sys/kernel/debug/tracing/events/cros_ec/enable
$ cat /sys/kernel/debug/tracing/trace

369.416372: cros_ec_request_start: version: 0, command: EC_CMD_USB_PD_POWER_INFO
369.420528: cros_ec_request_done: version: 0, command: EC_CMD_USB_PD_POWER_INFO, ec result: EC_RES_SUCCESS, retval: 16
369.420529: cros_ec_request_start: version: 0, command: EC_CMD_USB_PD_DISCOVERY
369.421383: cros_ec_request_done: version: 0, command: EC_CMD_USB_PD_DISCOVERY, ec result: EC_RES_SUCCESS, retval: 5

Signed-off-by: Raul E Rangel <rrangel@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>

drivers/platform/chrome/cros_ec_proto.c

@@ -54,8 +54,6 @@ static int send_command(struct cros_ec_device *ec_dev,
 	int ret;
 	int (*xfer_fxn)(struct cros_ec_device *ec, struct cros_ec_command *msg);
 
-	trace_cros_ec_cmd(msg);
-
 	if (ec_dev->proto_version > 2)
 		xfer_fxn = ec_dev->pkt_xfer;
 	else
@@ -72,7 +70,9 @@ static int send_command(struct cros_ec_device *ec_dev,
 		return -EIO;
 	}
 
+	trace_cros_ec_request_start(msg);
 	ret = (*xfer_fxn)(ec_dev, msg);
+	trace_cros_ec_request_done(msg, ret);
 	if (msg->result == EC_RES_IN_PROGRESS) {
 		int i;
 		struct cros_ec_command *status_msg;
@@ -95,7 +95,9 @@ static int send_command(struct cros_ec_device *ec_dev,
 		for (i = 0; i < EC_COMMAND_RETRIES; i++) {
 			usleep_range(10000, 11000);
 
+			trace_cros_ec_request_start(status_msg);
 			ret = (*xfer_fxn)(ec_dev, status_msg);
+			trace_cros_ec_request_done(status_msg, ret);
 			if (ret == -EAGAIN)
 				continue;
 			if (ret < 0)

drivers/platform/chrome/cros_ec_trace.c

@@ -182,5 +182,29 @@
 	TRACE_SYMBOL(EC_CMD_BOARD_SPECIFIC_BASE), \
 	TRACE_SYMBOL(EC_CMD_BOARD_SPECIFIC_LAST)
 
+/* See the enum ec_status in include/linux/platform_data/cros_ec_commands.h */
+#define EC_RESULT \
+	TRACE_SYMBOL(EC_RES_SUCCESS), \
+	TRACE_SYMBOL(EC_RES_INVALID_COMMAND), \
+	TRACE_SYMBOL(EC_RES_ERROR), \
+	TRACE_SYMBOL(EC_RES_INVALID_PARAM), \
+	TRACE_SYMBOL(EC_RES_ACCESS_DENIED), \
+	TRACE_SYMBOL(EC_RES_INVALID_RESPONSE), \
+	TRACE_SYMBOL(EC_RES_INVALID_VERSION), \
+	TRACE_SYMBOL(EC_RES_INVALID_CHECKSUM), \
+	TRACE_SYMBOL(EC_RES_IN_PROGRESS), \
+	TRACE_SYMBOL(EC_RES_UNAVAILABLE), \
+	TRACE_SYMBOL(EC_RES_TIMEOUT), \
+	TRACE_SYMBOL(EC_RES_OVERFLOW), \
+	TRACE_SYMBOL(EC_RES_INVALID_HEADER), \
+	TRACE_SYMBOL(EC_RES_REQUEST_TRUNCATED), \
+	TRACE_SYMBOL(EC_RES_RESPONSE_TOO_BIG), \
+	TRACE_SYMBOL(EC_RES_BUS_ERROR), \
+	TRACE_SYMBOL(EC_RES_BUSY), \
+	TRACE_SYMBOL(EC_RES_INVALID_HEADER_VERSION), \
+	TRACE_SYMBOL(EC_RES_INVALID_HEADER_CRC), \
+	TRACE_SYMBOL(EC_RES_INVALID_DATA_CRC), \
+	TRACE_SYMBOL(EC_RES_DUP_UNAVAILABLE)
+
 #define CREATE_TRACE_POINTS
 #include "cros_ec_trace.h"

drivers/platform/chrome/cros_ec_trace.h

@@ -18,7 +18,7 @@
 
 #include <linux/tracepoint.h>
 
-DECLARE_EVENT_CLASS(cros_ec_cmd_class,
+TRACE_EVENT(cros_ec_request_start,
 	TP_PROTO(struct cros_ec_command *cmd),
 	TP_ARGS(cmd),
 	TP_STRUCT__entry(
@@ -33,10 +33,26 @@ DECLARE_EVENT_CLASS(cros_ec_cmd_class,
 		  __print_symbolic(__entry->command, EC_CMDS))
 );
 
-
-DEFINE_EVENT(cros_ec_cmd_class, cros_ec_cmd,
-	TP_PROTO(struct cros_ec_command *cmd),
-	TP_ARGS(cmd)
+TRACE_EVENT(cros_ec_request_done,
+	TP_PROTO(struct cros_ec_command *cmd, int retval),
+	TP_ARGS(cmd, retval),
+	TP_STRUCT__entry(
+		__field(uint32_t, version)
+		__field(uint32_t, command)
+		__field(uint32_t, result)
+		__field(int, retval)
+	),
+	TP_fast_assign(
+		__entry->version = cmd->version;
+		__entry->command = cmd->command;
+		__entry->result = cmd->result;
+		__entry->retval = retval;
+	),
+	TP_printk("version: %u, command: %s, ec result: %s, retval: %d",
+		  __entry->version,
+		  __print_symbolic(__entry->command, EC_CMDS),
+		  __print_symbolic(__entry->result, EC_RESULT),
+		  __entry->retval)
 );