[Skiboot] [PATCH] lpc: Clear sync no-response field prior to device probe

[Artem Senichev]

On 18/10/2018 10:56, Andrew Jeffery wrote:
> Artem Senichev reported[1] his P8 platform was failing to boot from
> a43e9a66aae9 ("astbmc: Fail SFC init if SIO is unavailable") with the
> following error:
> 
> [  110.097168975,3] PLAT: Failed to open PNOR flash controller
> 
> I reproduced this behaviour on a Palmetto; we need to ensure the state
> of the no-response error bit is clear before proceding with the presence
> test.
> 
> The fix appears to resolve the failure to open the PNOR flash controller
> on Palmetto and doesn't change the expected behaviour on Witherspoon.
> 
> [1] https://github.com/open-power/skiboot/issues/197
> 
> Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
> ---
>   hw/lpc.c | 7 ++++++-
>   1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/lpc.c b/hw/lpc.c
> index c55d47638ee9..20e54c99cd73 100644
> --- a/hw/lpc.c
> +++ b/hw/lpc.c
> @@ -473,6 +473,7 @@ static const struct lpc_error_entry lpc_error_table[] = {
>   static int64_t lpc_probe_prepare(struct lpcm *lpc)
>   {
>   	const uint32_t irqmask_addr = lpc_reg_opb_base + LPC_HC_IRQMASK;
> +	const uint32_t irqstat_addr = lpc_reg_opb_base + LPC_HC_IRQSTAT;
>   	uint32_t irqmask;
>   	int rc;
>   
> @@ -481,7 +482,11 @@ static int64_t lpc_probe_prepare(struct lpcm *lpc)
>   		return rc;
>   
>   	irqmask &= ~LPC_HC_IRQ_SYNC_NORESP_ERR;
> -	return opb_write(lpc, irqmask_addr, irqmask, 4);
> +	rc = opb_write(lpc, irqmask_addr, irqmask, 4);
> +	if (rc)
> +		return rc;
> +
> +	return opb_write(lpc, irqstat_addr, LPC_HC_IRQ_SYNC_NORESP_ERR, 4);
>   }
>   
>   static int64_t lpc_probe_test(struct lpcm *lpc)
> 
Tested-by: Artem Senichev <a.senichev at yadro.com>