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From:   Eddie James <eajames@linux.ibm.com>
To:     linux-kernel@vger.kernel.org
Cc:     linux-hwmon@vger.kernel.org, linux-fsi@lists.ozlabs.org,
        linux@roeck-us.net, jdelvare@suse.com, jk@ozlabs.org,
        joel@jms.id.au, alistair@popple.id.au, openbmc@lists.ozlabs.org,
        Eddie James <eajames@linux.ibm.com>
Subject: [PATCH 2/3] hwmon: (occ) Remove sequence numbering and checksum calculation
Date:   Fri, 16 Jul 2021 10:18:49 -0500
Message-Id: <20210716151850.28973-3-eajames@linux.ibm.com>
In-Reply-To: <20210716151850.28973-1-eajames@linux.ibm.com>
References: <20210716151850.28973-1-eajames@linux.ibm.com>
MIME-Version: 1.0
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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.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
 drivers/hwmon/occ/common.c | 30 ++++++++++++------------------
 drivers/hwmon/occ/common.h |  3 +--
 drivers/hwmon/occ/p8_i2c.c | 15 +++++++++------
 drivers/hwmon/occ/p9_sbe.c |  4 ++--
 4 files changed, 24 insertions(+), 28 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;
 
diff --git a/drivers/hwmon/occ/common.h b/drivers/hwmon/occ/common.h
index e6df719770e8..5020117be740 100644
--- a/drivers/hwmon/occ/common.h
+++ b/drivers/hwmon/occ/common.h
@@ -95,9 +95,8 @@ struct occ {
 	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);
+	int (*send_cmd)(struct occ *occ, u8 *cmd, size_t len);
 
 	unsigned long next_update;
 	struct mutex lock;		/* lock OCC access */
diff --git a/drivers/hwmon/occ/p8_i2c.c b/drivers/hwmon/occ/p8_i2c.c
index 0cf8588be35a..22af189eafa6 100644
--- a/drivers/hwmon/occ/p8_i2c.c
+++ b/drivers/hwmon/occ/p8_i2c.c
@@ -97,18 +97,21 @@ static int p8_i2c_occ_putscom_u32(struct i2c_client *client, u32 address,
 }
 
 static int p8_i2c_occ_putscom_be(struct i2c_client *client, u32 address,
-				 u8 *data)
+				 u8 *data, size_t len)
 {
-	__be32 data0, data1;
+	__be32 data0 = 0, data1 = 0;
 
-	memcpy(&data0, data, 4);
-	memcpy(&data1, data + 4, 4);
+	memcpy(&data0, data, min(len, 4UL));
+	if (len > 4UL) {
+		len -= 4;
+		memcpy(&data1, data + 4, min(len, 4UL));
+	}
 
 	return p8_i2c_occ_putscom_u32(client, address, be32_to_cpu(data0),
 				      be32_to_cpu(data1));
 }
 
-static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd)
+static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd, size_t len)
 {
 	int i, rc;
 	unsigned long start;
@@ -127,7 +130,7 @@ static int p8_i2c_occ_send_cmd(struct occ *occ, u8 *cmd)
 		return rc;
 
 	/* write command (expected to already be BE), we need bus-endian... */
-	rc = p8_i2c_occ_putscom_be(client, OCB_DATA3, cmd);
+	rc = p8_i2c_occ_putscom_be(client, OCB_DATA3, cmd, len);
 	if (rc)
 		return rc;
 
diff --git a/drivers/hwmon/occ/p9_sbe.c b/drivers/hwmon/occ/p9_sbe.c
index f6387cc0b754..9709f2b9c052 100644
--- a/drivers/hwmon/occ/p9_sbe.c
+++ b/drivers/hwmon/occ/p9_sbe.c
@@ -16,14 +16,14 @@ struct p9_sbe_occ {
 
 #define to_p9_sbe_occ(x)	container_of((x), struct p9_sbe_occ, occ)
 
-static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd)
+static int p9_sbe_occ_send_cmd(struct occ *occ, u8 *cmd, size_t len)
 {
 	struct occ_response *resp = &occ->resp;
 	struct p9_sbe_occ *ctx = to_p9_sbe_occ(occ);
 	size_t resp_len = sizeof(*resp);
 	int rc;
 
-	rc = fsi_occ_submit(ctx->sbe, cmd, 8, resp, &resp_len);
+	rc = fsi_occ_submit(ctx->sbe, cmd, len, resp, &resp_len);
 	if (rc < 0)
 		return rc;
 
-- 
2.27.0