[PATCH 1/8] soundwire: amd: fix SDW command timeout return value handling

[Vijendar Mukunda]

amd_sdw_send_cmd_get_resp() returned u64 but was returning -ETIMEDOUT
(a negative int) on readl_poll_timeout() failures, which silently
widens to a large u64 value.

Change the return type to int and pass the raw u64 response through an
out-parameter. Timeout is detected directly from readl_poll_timeout()
return value.

Update all callers: amd_program_scp_addr(), _amd_sdw_xfer_msg(),
amd_sdw_read_and_process_ping_status(), and amd_sdw_read_ping_status()
to check the return value and handle timeout explicitly. In
amd_sdw_read_and_process_ping_status(), the mutex unlock is also moved
to after amd_sdw_process_ping_status() so the lock is held across the
full status processing step.

Fixes: d8f48fbdfd9a ("soundwire: amd: Add support for AMD Manager driver")
Signed-off-by: Vijendar Mukunda <Vijendar.Mukunda@xxxxxxx>
---
 drivers/soundwire/amd_manager.c | 56 +++++++++++++++++++--------------
 1 file changed, 33 insertions(+), 23 deletions(-)

diff --git a/drivers/soundwire/amd_manager.c b/drivers/soundwire/amd_manager.c
index a3316efdf8ac..fa3f4e797edd 100644
--- a/drivers/soundwire/amd_manager.c
+++ b/drivers/soundwire/amd_manager.c
@@ -250,10 +250,9 @@ static void amd_sdw_ctl_word_prep(u32 *lower_word, u32 *upper_word, struct sdw_m
 	*lower_word = lower_data;
 }
 
-static u64 amd_sdw_send_cmd_get_resp(struct amd_sdw_manager *amd_manager, u32 lower_data,
-				     u32 upper_data)
+static int amd_sdw_send_cmd_get_resp(struct amd_sdw_manager *amd_manager, u32 lower_data,
+				     u32 upper_data, u64 *response)
 {
-	u64 resp;
 	u32 lower_resp, upper_resp;
 	u32 sts;
 	int ret;
@@ -291,9 +290,8 @@ static u64 amd_sdw_send_cmd_get_resp(struct amd_sdw_manager *amd_manager, u32 lo
 			amd_manager->instance);
 		return ret;
 	}
-	resp = upper_resp;
-	resp = (resp << 32) | lower_resp;
-	return resp;
+	*response = ((u64)upper_resp << 32) | lower_resp;
+	return 0;
 }
 
 static enum sdw_command_response
@@ -309,19 +307,22 @@ amd_program_scp_addr(struct amd_sdw_manager *amd_manager, struct sdw_msg *msg)
 	scp_msg.buf = &msg->addr_page1;
 	scp_msg.flags = SDW_MSG_FLAG_WRITE;
 	amd_sdw_ctl_word_prep(&lower_data, &upper_data, &scp_msg, 0);
-	response_buf[0] = amd_sdw_send_cmd_get_resp(amd_manager, lower_data, upper_data);
+	if (amd_sdw_send_cmd_get_resp(amd_manager, lower_data, upper_data, &response_buf[0])) {
+		dev_err_ratelimited(amd_manager->dev,
+				    "SCP_addrpage command timeout for Slave %d\n", msg->dev_num);
+		return SDW_CMD_TIMEOUT;
+	}
 	scp_msg.addr = SDW_SCP_ADDRPAGE2;
 	scp_msg.buf = &msg->addr_page2;
 	amd_sdw_ctl_word_prep(&lower_data, &upper_data, &scp_msg, 0);
-	response_buf[1] = amd_sdw_send_cmd_get_resp(amd_manager, lower_data, upper_data);
+	if (amd_sdw_send_cmd_get_resp(amd_manager, lower_data, upper_data, &response_buf[1])) {
+		dev_err_ratelimited(amd_manager->dev,
+				    "SCP_addrpage command timeout for Slave %d\n", msg->dev_num);
+		return SDW_CMD_TIMEOUT;
+	}
 
 	for (index = 0; index < 2; index++) {
-		if (response_buf[index] == -ETIMEDOUT) {
-			dev_err_ratelimited(amd_manager->dev,
-					    "SCP_addrpage command timeout for Slave %d\n",
-					    msg->dev_num);
-			return SDW_CMD_TIMEOUT;
-		} else if (!(response_buf[index] & AMD_SDW_MCP_RESP_ACK)) {
+		if (!(response_buf[index] & AMD_SDW_MCP_RESP_ACK)) {
 			if (response_buf[index] & AMD_SDW_MCP_RESP_NACK) {
 				dev_err_ratelimited(amd_manager->dev,
 						    "SCP_addrpage NACKed for Slave %d\n",
@@ -366,11 +367,7 @@ static enum sdw_command_response amd_sdw_fill_msg_resp(struct amd_sdw_manager *a
 		if (msg->flags == SDW_MSG_FLAG_READ)
 			msg->buf[offset] = FIELD_GET(AMD_SDW_MCP_RESP_RDATA, response);
 	} else {
-		if (response == -ETIMEDOUT) {
-			dev_err_ratelimited(amd_manager->dev, "command timeout for Slave %d\n",
-					    msg->dev_num);
-			return SDW_CMD_TIMEOUT;
-		} else if (response & AMD_SDW_MCP_RESP_NACK) {
+		if (response & AMD_SDW_MCP_RESP_NACK) {
 			dev_err_ratelimited(amd_manager->dev,
 					    "command response NACK received for Slave %d\n",
 					    msg->dev_num);
@@ -390,7 +387,11 @@ static unsigned int _amd_sdw_xfer_msg(struct amd_sdw_manager *amd_manager, struc
 	u32 upper_data = 0, lower_data = 0;
 
 	amd_sdw_ctl_word_prep(&lower_data, &upper_data, msg, cmd_offset);
-	response = amd_sdw_send_cmd_get_resp(amd_manager, lower_data, upper_data);
+	if (amd_sdw_send_cmd_get_resp(amd_manager, lower_data, upper_data, &response)) {
+		dev_err_ratelimited(amd_manager->dev, "command timeout for Slave %d\n",
+				    msg->dev_num);
+		return SDW_CMD_TIMEOUT;
+	}
 	return amd_sdw_fill_msg_resp(amd_manager, msg, response, cmd_offset);
 }
 
@@ -446,9 +447,14 @@ static void amd_sdw_read_and_process_ping_status(struct amd_sdw_manager *amd_man
 	u64 response;
 
 	mutex_lock(&amd_manager->bus.msg_lock);
-	response = amd_sdw_send_cmd_get_resp(amd_manager, 0, 0);
-	mutex_unlock(&amd_manager->bus.msg_lock);
+	if (amd_sdw_send_cmd_get_resp(amd_manager, 0, 0, &response)) {
+		mutex_unlock(&amd_manager->bus.msg_lock);
+		dev_err_ratelimited(amd_manager->dev, "SDW%x ping status timeout\n",
+				    amd_manager->instance);
+		return;
+	}
 	amd_sdw_process_ping_status(response, amd_manager);
+	mutex_unlock(&amd_manager->bus.msg_lock);
 }
 
 static u32 amd_sdw_read_ping_status(struct sdw_bus *bus)
@@ -457,7 +463,11 @@ static u32 amd_sdw_read_ping_status(struct sdw_bus *bus)
 	u64 response;
 	u32 slave_stat;
 
-	response = amd_sdw_send_cmd_get_resp(amd_manager, 0, 0);
+	if (amd_sdw_send_cmd_get_resp(amd_manager, 0, 0, &response)) {
+		dev_err_ratelimited(amd_manager->dev, "SDW%x ping status timeout\n",
+				    amd_manager->instance);
+		return 0;
+	}
 	/* slave status from ping response */
 	slave_stat = FIELD_GET(AMD_SDW_MCP_SLAVE_STAT_0_3, response);
 	slave_stat |= FIELD_GET(AMD_SDW_MCP_SLAVE_STAT_4_11, response) << 8;
-- 
2.48.1