[PATCH v1 2/2] scsi: ufs: Add trace event for UIC commands

[Stanley Chu <stanley.chu@xxxxxxxxxxxx>]

Use the ftrace infrastructure to conditionally trace UFS UIC command
events.

New trace event "ufshcd_uic_command" is created, which samples the
following UFS UIC command data:
- Device name
- Optional identification string
- UIC command opcode
- UIC command argument1
- UIC command argument2
- UIC command argement3
- UIC command execution result

Usage:
	echo 1 > /sys/kernel/debug/tracing/events/ufs/enable
	cat /sys/kernel/debug/tracing/trace_pipe

Signed-off-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>
---
 drivers/scsi/ufs/ufshcd.c  | 29 +++++++++++++++++++++++++++++
 include/trace/events/ufs.h | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c197a3315d21..181617966658 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -339,6 +339,27 @@ static void ufshcd_add_tm_upiu_trace(struct ufs_hba *hba, unsigned int tag,
 			&descp->input_param1);
 }
 
+static void ufshcd_add_uic_command_trace(struct ufs_hba *hba,
+					 struct uic_command *ucmd,
+					 const char *str)
+{
+	u32 cmd;
+
+	if (!trace_ufshcd_uic_command_enabled())
+		return;
+
+	if (!strcmp(str, "uic_send"))
+		cmd = ucmd->command;
+	else
+		cmd = ufshcd_readl(hba, REG_UIC_COMMAND);
+
+	trace_ufshcd_uic_command(dev_name(hba->dev), str, cmd,
+				 ucmd->result,
+				 ufshcd_readl(hba, REG_UIC_COMMAND_ARG_1),
+				 ufshcd_readl(hba, REG_UIC_COMMAND_ARG_2),
+				 ufshcd_readl(hba, REG_UIC_COMMAND_ARG_3));
+}
+
 static void ufshcd_add_command_trace(struct ufs_hba *hba,
 		unsigned int tag, const char *str)
 {
@@ -2054,6 +2075,8 @@ ufshcd_dispatch_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	/* Write UIC Cmd */
 	ufshcd_writel(hba, uic_cmd->command & COMMAND_OPCODE_MASK,
 		      REG_UIC_COMMAND);
+
+	ufshcd_add_uic_command_trace(hba, uic_cmd, "uic_send");
 }
 
 /**
@@ -2080,6 +2103,9 @@ ufshcd_wait_for_uic_cmd(struct ufs_hba *hba, struct uic_command *uic_cmd)
 	hba->active_uic_cmd = NULL;
 	spin_unlock_irqrestore(hba->host->host_lock, flags);
 
+	uic_cmd->result = ret;
+	ufshcd_add_uic_command_trace(hba, uic_cmd, "uic_complete");
+
 	return ret;
 }
 
@@ -3760,6 +3786,9 @@ static int ufshcd_uic_pwr_ctrl(struct ufs_hba *hba, struct uic_command *cmd)
 		ret = (status != PWR_OK) ? status : -1;
 	}
 out:
+	cmd->result = ret;
+	ufshcd_add_uic_command_trace(hba, cmd, "uic_complete");
+
 	if (ret) {
 		ufshcd_print_host_state(hba);
 		ufshcd_print_pwr_info(hba);
diff --git a/include/trace/events/ufs.h b/include/trace/events/ufs.h
index 5f300739240d..cf8d568d5a13 100644
--- a/include/trace/events/ufs.h
+++ b/include/trace/events/ufs.h
@@ -249,6 +249,39 @@ TRACE_EVENT(ufshcd_command,
 	)
 );
 
+TRACE_EVENT(ufshcd_uic_command,
+	TP_PROTO(const char *dev_name, const char *str, u32 cmd, int result,
+		 u32 arg1, u32 arg2, u32 arg3),
+
+	TP_ARGS(dev_name, str, cmd, result, arg1, arg2, arg3),
+
+	TP_STRUCT__entry(
+		__string(dev_name, dev_name)
+		__string(str, str)
+		__field(u32, cmd)
+		__field(int, result)
+		__field(u32, arg1)
+		__field(u32, arg2)
+		__field(u32, arg3)
+	),
+
+	TP_fast_assign(
+		__assign_str(dev_name, dev_name);
+		__assign_str(str, str);
+		__entry->cmd = cmd;
+		__entry->result = result;
+		__entry->arg1 = arg1;
+		__entry->arg2 = arg2;
+		__entry->arg3 = arg3;
+	),
+
+	TP_printk(
+		"%s: %s: cmd: 0x%x, arg1: 0x%x, arg2: 0x%x, arg3: 0x%x, result: %d",
+		__get_str(str), __get_str(dev_name), __entry->cmd,
+		__entry->arg1, __entry->arg2, __entry->arg3, __entry->result
+	)
+);
+
 TRACE_EVENT(ufshcd_upiu,
 	TP_PROTO(const char *dev_name, const char *str, void *hdr, void *tsf),
 
-- 
2.18.0