Re: [PATCH v5 4/4] hw/ssi/pnv_spi: Put a limit to RDR match failures

["Nicholas Piggin" <npiggin@gmail.com>]

On Sat Jan 4, 2025 at 2:18 AM AEST, Chalapathi V wrote:
> There is a possibility that SPI controller can get into loop due to indefinite
> RDR match failures. Hence put a limit to failures and stop the sequencer.
>
> Signed-off-by: Chalapathi V <chalapathi.v@linux.ibm.com>
> ---
>  hw/ssi/pnv_spi.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/hw/ssi/pnv_spi.c b/hw/ssi/pnv_spi.c
> index 41beb559c6..d605fa8b46 100644
> --- a/hw/ssi/pnv_spi.c
> +++ b/hw/ssi/pnv_spi.c
> @@ -20,6 +20,7 @@
>  #define PNV_SPI_OPCODE_LO_NIBBLE(x) (x & 0x0F)
>  #define PNV_SPI_MASKED_OPCODE(x) (x & 0xF0)
>  #define PNV_SPI_FIFO_SIZE 16
> +#define RDR_MATCH_FAILURE_LIMIT 16
>  
>  /*
>   * Macro from include/hw/ppc/fdt.h
> @@ -838,21 +839,31 @@ static void operation_sequencer(PnvSpi *s)
>               */
>              if (GETFIELD(SPI_STS_RDR_FULL, s->status) == 1) {
>                  bool rdr_matched = false;
> +                static int fail_count;

This will be shared by SPI instances, is that okay or should it be
in PnvSpi?

Other than that, looks good.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>