OCC: FSI and hwmon: Add sequence numbering

Sequence numbering of the commands submitted to the OCC is required by
the OCC interface specification. Add sequence numbering and check for
the correct sequence number on the response.

Signed-off-by: Eddie James <[e-mail]>
Acked-by: Guenter Roeck <[e-mail]>
Reviewed-by: Lei YU <[e-mail]>
Signed-off-by: Joel Stanley <[e-mail]>

drivers/fsi/fsi-occ.c

···
 		msecs_to_jiffies(OCC_CMD_IN_PRG_WAIT_MS);
 	struct occ *occ = dev_get_drvdata(dev);
 	struct occ_response *resp = response;
+	u8 seq_no;
 	u16 resp_data_length;
 	unsigned long start;
 	int rc;
···
 
 	mutex_lock(&occ->occ_lock);
 
+	/* Extract the seq_no from the command (first byte) */
+	seq_no = *(const u8 *)request;
 	rc = occ_putsram(occ, OCC_SRAM_CMD_ADDR, request, req_len);
 	if (rc)
 		goto done;
···
 		if (rc)
 			goto done;
 
-		if (resp->return_status == OCC_RESP_CMD_IN_PRG) {
+		if (resp->return_status == OCC_RESP_CMD_IN_PRG ||
+		    resp->seq_no != seq_no) {
 			rc = -ETIMEDOUT;
 
-			if (time_after(jiffies, start + timeout))
-				break;
+			if (time_after(jiffies, start + timeout)) {
+				dev_err(occ->dev, "resp timeout status=%02x "
+					"resp seq_no=%d our seq_no=%d\n",
+					resp->return_status, resp->seq_no,
+					seq_no);
+				goto done;
+			}
 
 			set_current_state(TASK_UNINTERRUPTIBLE);
 			schedule_timeout(wait_time);

drivers/hwmon/occ/common.c

···
 static int occ_poll(struct occ *occ)
 {
 	int rc;
-	u16 checksum = occ->poll_cmd_data + 1;
+	u16 checksum = occ->poll_cmd_data + occ->seq_no + 1;
 	u8 cmd[8];
 	struct occ_poll_response_header *header;
 
 	/* big endian */
-	cmd[0] = 0;			/* sequence number */
+	cmd[0] = occ->seq_no++;		/* sequence number */
 	cmd[1] = 0;			/* cmd type */
 	cmd[2] = 0;			/* data length msb */
 	cmd[3] = 1;			/* data length lsb */

drivers/hwmon/occ/common.h

···
 	struct occ_sensors sensors;
 
 	int powr_sample_time_us;	/* average power sample time */
+	u8 seq_no;
 	u8 poll_cmd_data;		/* to perform OCC poll command */
 	int (*send_cmd)(struct occ *occ, u8 *cmd);