4.19-stable review patch. If anyone has any objections, please let me know.
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From: Heiner Kallweit hkallweit1@gmail.com
commit f78ca48a8ba9cdec96e8839351e49eec3233b177 upstream.
Currently we set SMBHSTCNT_LAST_BYTE only after the host has started receiving the last byte. If we get e.g. preempted before setting SMBHSTCNT_LAST_BYTE, the host may be finished with receiving the byte before SMBHSTCNT_LAST_BYTE is set. Therefore change the code to set SMBHSTCNT_LAST_BYTE before writing SMBHSTSTS_BYTE_DONE for the byte before the last byte. Now the code is also consistent with what we do in i801_isr_byte_done().
Reported-by: Jean Delvare jdelvare@suse.com Closes: https://lore.kernel.org/linux-i2c/20230828152747.09444625@endymion.delvare/ Cc: stable@vger.kernel.org Acked-by: Andi Shyti andi.shyti@kernel.org Signed-off-by: Heiner Kallweit hkallweit1@gmail.com Reviewed-by: Jean Delvare jdelvare@suse.de Signed-off-by: Wolfram Sang wsa@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/i2c/busses/i2c-i801.c | 19 +++++++++---------- 1 file changed, 9 insertions(+), 10 deletions(-)
--- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -712,15 +712,11 @@ static int i801_block_transaction_byte_b return i801_check_post(priv, status); }
- for (i = 1; i <= len; i++) { - if (i == len && read_write == I2C_SMBUS_READ) - smbcmd |= SMBHSTCNT_LAST_BYTE; - outb_p(smbcmd, SMBHSTCNT(priv)); - - if (i == 1) - outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START, - SMBHSTCNT(priv)); + if (len == 1 && read_write == I2C_SMBUS_READ) + smbcmd |= SMBHSTCNT_LAST_BYTE; + outb_p(smbcmd | SMBHSTCNT_START, SMBHSTCNT(priv));
+ for (i = 1; i <= len; i++) { status = i801_wait_byte_done(priv); if (status) goto exit; @@ -743,9 +739,12 @@ static int i801_block_transaction_byte_b data->block[0] = len; }
- /* Retrieve/store value in SMBBLKDAT */ - if (read_write == I2C_SMBUS_READ) + if (read_write == I2C_SMBUS_READ) { data->block[i] = inb_p(SMBBLKDAT(priv)); + if (i == len - 1) + outb_p(smbcmd | SMBHSTCNT_LAST_BYTE, SMBHSTCNT(priv)); + } + if (read_write == I2C_SMBUS_WRITE && i+1 <= len) outb_p(data->block[i+1], SMBBLKDAT(priv));