[PATCH] fsi: scom: Reset the FSI2PIB engine for any error

[Joel Stanley]

On Mon, 29 Mar 2021 at 15:13, Eddie James <eajames at linux.ibm.com> wrote:
>
> The error bits in the FSI2PIB status are only cleared by a reset. So
> the driver needs to perform a reset after seeing any of the FSI2PIB
> errors, otherwise subsequent operations will also look like failures.
>
> Fixes: 6b293258cded ("fsi: scom: Major overhaul")
> Signed-off-by: Eddie James <eajames at linux.ibm.com>

Reviewed-by: Joel Stanley <joel at jms.id.au>

I've got some other FSI fixes that I will send out shortly. I will
include this one in that series to ensure it gets applied.

> ---
>  drivers/fsi/fsi-scom.c | 16 +++++++++-------
>  1 file changed, 9 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/fsi/fsi-scom.c b/drivers/fsi/fsi-scom.c
> index b45bfab7b7f5..75d1389e2626 100644
> --- a/drivers/fsi/fsi-scom.c
> +++ b/drivers/fsi/fsi-scom.c
> @@ -38,9 +38,10 @@
>  #define SCOM_STATUS_PIB_RESP_MASK      0x00007000
>  #define SCOM_STATUS_PIB_RESP_SHIFT     12
>
> -#define SCOM_STATUS_ANY_ERR            (SCOM_STATUS_PROTECTION | \
> -                                        SCOM_STATUS_PARITY |     \
> -                                        SCOM_STATUS_PIB_ABORT | \
> +#define SCOM_STATUS_FSI2PIB_ERROR      (SCOM_STATUS_PROTECTION |       \
> +                                        SCOM_STATUS_PARITY |           \
> +                                        SCOM_STATUS_PIB_ABORT)
> +#define SCOM_STATUS_ANY_ERR            (SCOM_STATUS_FSI2PIB_ERROR |    \
>                                          SCOM_STATUS_PIB_RESP_MASK)
>  /* SCOM address encodings */
>  #define XSCOM_ADDR_IND_FLAG            BIT_ULL(63)
> @@ -240,13 +241,14 @@ static int handle_fsi2pib_status(struct scom_device *scom, uint32_t status)
>  {
>         uint32_t dummy = -1;
>
> -       if (status & SCOM_STATUS_PROTECTION)
> -               return -EPERM;
> -       if (status & SCOM_STATUS_PARITY) {
> +       if (status & SCOM_STATUS_FSI2PIB_ERROR)
>                 fsi_device_write(scom->fsi_dev, SCOM_FSI2PIB_RESET_REG, &dummy,
>                                  sizeof(uint32_t));
> +
> +       if (status & SCOM_STATUS_PROTECTION)
> +               return -EPERM;
> +       if (status & SCOM_STATUS_PARITY)
>                 return -EIO;
> -       }
>         /* Return -EBUSY on PIB abort to force a retry */
>         if (status & SCOM_STATUS_PIB_ABORT)
>                 return -EBUSY;
> --
> 2.27.0
>