hwmon: (occ) Remove sequence numbering and checksum calculation

Checksumming of the request and sequence numbering is now done in the
OCC interface driver in order to keep unique sequence numbers. So
remove those in the hwmon driver. Also, add the command length to the
send_cmd function pointer, since the checksum must be placed in the
last two bytes of the command. The submit interface must receive the
exact size of the command - previously it could be rounded to the
nearest 8 bytes with no consequence.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20210721190231.117185-3-eajames@linux.ibm.com
Signed-off-by: Joel Stanley <joel@jms.id.au>

1 files changed, 12 insertions, 18 deletions

diff --git a/drivers/hwmon/occ/common.c b/drivers/hwmon/occ/common.c
index 0d68a78be980..fc298268c89e 100644
--- a/drivers/hwmon/occ/common.c
+++ b/drivers/hwmon/occ/common.c
@@ -132,22 +132,20 @@ struct extended_sensor {
 static int occ_poll(struct occ *occ)
 {
 	int rc;
-	u16 checksum = occ->poll_cmd_data + occ->seq_no + 1;
-	u8 cmd[8];
+	u8 cmd[7];
 	struct occ_poll_response_header *header;
 
 	/* big endian */
-	cmd[0] = occ->seq_no++;		/* sequence number */
+	cmd[0] = 0;			/* sequence number */
 	cmd[1] = 0;			/* cmd type */
 	cmd[2] = 0;			/* data length msb */
 	cmd[3] = 1;			/* data length lsb */
 	cmd[4] = occ->poll_cmd_data;	/* data */
-	cmd[5] = checksum >> 8;		/* checksum msb */
-	cmd[6] = checksum & 0xFF;	/* checksum lsb */
-	cmd[7] = 0;
+	cmd[5] = 0;			/* checksum msb */
+	cmd[6] = 0;			/* checksum lsb */
 
 	/* mutex should already be locked if necessary */
-	rc = occ->send_cmd(occ, cmd);
+	rc = occ->send_cmd(occ, cmd, sizeof(cmd));
 	if (rc) {
 		occ->last_error = rc;
 		if (occ->error_count++ > OCC_ERROR_COUNT_THRESHOLD)
@@ -184,25 +182,23 @@ static int occ_set_user_power_cap(struct occ *occ, u16 user_power_cap)
 {
 	int rc;
 	u8 cmd[8];
-	u16 checksum = 0x24;
 	__be16 user_power_cap_be = cpu_to_be16(user_power_cap);
 
-	cmd[0] = 0;
-	cmd[1] = 0x22;
-	cmd[2] = 0;
-	cmd[3] = 2;
+	cmd[0] = 0;	/* sequence number */
+	cmd[1] = 0x22;	/* cmd type */
+	cmd[2] = 0;	/* data length msb */
+	cmd[3] = 2;	/* data length lsb */
 
 	memcpy(&cmd[4], &user_power_cap_be, 2);
 
-	checksum += cmd[4] + cmd[5];
-	cmd[6] = checksum >> 8;
-	cmd[7] = checksum & 0xFF;
+	cmd[6] = 0;	/* checksum msb */
+	cmd[7] = 0;	/* checksum lsb */
 
 	rc = mutex_lock_interruptible(&occ->lock);
 	if (rc)
 		return rc;
 
-	rc = occ->send_cmd(occ, cmd);
+	rc = occ->send_cmd(occ, cmd, sizeof(cmd));
 
 	mutex_unlock(&occ->lock);
 
@@ -1151,8 +1147,6 @@ int occ_setup(struct occ *occ, const char *name)
 {
 	int rc;
 
-	/* start with 1 to avoid false match with zero-initialized SRAM buffer */
-	occ->seq_no = 1;
 	mutex_init(&occ->lock);
 	occ->groups[0] = &occ->group;