On Sat, 02 Sep 2023 22:10:52 +0200, Heiner Kallweit wrote: > 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@xxxxxxxx> Note for Wolfram: checkpatch says we should insert here: Closes: https://lore.kernel.org/linux-i2c/20230828152747.09444625@endymion.delvare/ > Reviewed-by: Jean Delvare <jdelvare@xxxxxxx> > Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx> > --- > v2: > - remove incorrect Fixes tag > --- > drivers/i2c/busses/i2c-i801.c | 19 +++++++++---------- > 1 file changed, 9 insertions(+), 10 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c > index 7a0ccc584..8acf09539 100644 > --- a/drivers/i2c/busses/i2c-i801.c > +++ b/drivers/i2c/busses/i2c-i801.c > @@ -679,15 +679,11 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, > return result ? priv->status : -ETIMEDOUT; > } > > - 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) > return status; > @@ -710,9 +706,12 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, > 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)); > -- Jean Delvare SUSE L3 Support
