Re: [PATCH 5.15 96/98] hwmon: (occ) Remove sequence numbering and checksum calculation

Joel Stanley
2022-07-06T06:44:05Z

On Tue, 5 Jul 2022 at 12:14, Greg Kroah-Hartman
<gregkh@linuxfoundation.org> wrote:
>
> From: Eddie James <eajames@linux.ibm.com>
>
> [ Upstream commit 908dbf0242e21dd95c69a1b0935814cd1abfc134 ]
>
> 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>
> Signed-off-by: Sasha Levin <sashal@kernel.org>

If this patch is being backported then we must also backport:

62f79f3d0eb9 ("fsi: occ: Force sequence numbering per OCC")

I was only cc'd on this one so I assume that means 62f79f3d0eb9 is not
already in the queue.

> ---
> 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 ae664613289c..0cb4a0a6cbc1 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);
>
> @@ -1144,8 +1140,6 @@ 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..9e61e1fb5142 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_t(size_t, len, 4));
> + if (len > 4) {
> + len -= 4;
> + memcpy(&data1, data + 4, min_t(size_t, len, 4));
> + }
>
> 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;
>
> --
> 2.35.1
>
>
>