On Sun, Sep 24, 2023 at 4:02 AM William A. Kennington III
<william@xxxxxxxxxxxxxxx> wrote:
>
> Sometimes, our completions race with new master transfers and override
> the bus->operation and bus->master_or_slave variables. This causes
> transactions to timeout and kernel crashes less frequently.
>
> To remedy this, we re-order all completions to the very end of the
> function.
>
> Fixes: 56a1485b102e ("i2c: npcm7xx: Add Nuvoton NPCM I2C controller driver")
> Signed-off-by: William A. Kennington III <william@xxxxxxxxxxxxxxx>
> ---
> drivers/i2c/busses/i2c-npcm7xx.c | 17 +++++++----------
> 1 file changed, 7 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/i2c/busses/i2c-npcm7xx.c b/drivers/i2c/busses/i2c-npcm7xx.c
> index 495a8b5f6a2b..ae4bae63ad4f 100644
> --- a/drivers/i2c/busses/i2c-npcm7xx.c
> +++ b/drivers/i2c/busses/i2c-npcm7xx.c
> @@ -694,6 +694,7 @@ static void npcm_i2c_callback(struct npcm_i2c *bus,
> {
> struct i2c_msg *msgs;
> int msgs_num;
> + bool do_complete = false;
>
> msgs = bus->msgs;
> msgs_num = bus->msgs_num;
> @@ -722,23 +723,17 @@ static void npcm_i2c_callback(struct npcm_i2c *bus,
> msgs[1].flags & I2C_M_RD)
> msgs[1].len = info;
> }
> - if (completion_done(&bus->cmd_complete) == false)
> - complete(&bus->cmd_complete);
> - break;
> -
> + do_complete = true;
> + break;
> case I2C_NACK_IND:
> /* MASTER transmit got a NACK before tx all bytes */
> bus->cmd_err = -ENXIO;
> - if (bus->master_or_slave == I2C_MASTER)
> - complete(&bus->cmd_complete);
> -
> + do_complete = true;
> break;
> case I2C_BUS_ERR_IND:
> /* Bus error */
> bus->cmd_err = -EAGAIN;
> - if (bus->master_or_slave == I2C_MASTER)
> - complete(&bus->cmd_complete);
> -
> + do_complete = true;
> break;
> case I2C_WAKE_UP_IND:
> /* I2C wake up */
> @@ -752,6 +747,8 @@ static void npcm_i2c_callback(struct npcm_i2c *bus,
> if (bus->slave)
> bus->master_or_slave = I2C_SLAVE;
> #endif
> + if (do_complete)
> + complete(&bus->cmd_complete);
> }
>
> static u8 npcm_i2c_fifo_usage(struct npcm_i2c *bus)
> --
> 2.42.0.515.g380fc7ccd1-goog
>
Thanks William for the fix!
Reviewed-by: Tali Perry <tali.perry1@xxxxxxxxx>
