Re: [PATCH] mmc: dwmmc: only clear handled interrupts

[Jaehoon Chung <jh80.chung@gmail.com>]

On 9/16/22 02:56, John Keeping wrote:
> Unconditionally clearing DTO when RXDR is set leads to spurious timeouts
> in FIFO mode transfers if events occur in the following order:
> 
> 	mask = dwmci_readl(host, DWMCI_RINTSTS);
> 
> 	// Hardware asserts DWMCI_INTMSK_DTO here
> 
> 	dwmci_writel(host, DWMCI_RINTSTS, DWMCI_INTMSK_DTO);
> 
> 	if (mask & DWMCI_INTMSK_DTO) {
> 		// Unreachable as DTO is cleared without being handled!
> 		return 0;
> 	}
> 
> Only clear interrupts that we have seen and are handling so that DTO is
> not missed.
> 
> Signed-off-by: John Keeping <john@metanate.com>

Reviewed-by: Jaehoon Chung <jh80.chung@samsung.com>

Best Regards,
Jaehoon Chung
> ---
>  drivers/mmc/dw_mmc.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
> index 4232c5eb8c..5085a3b491 100644
> --- a/drivers/mmc/dw_mmc.c
> +++ b/drivers/mmc/dw_mmc.c
> @@ -168,7 +168,8 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data)
>  			if (data->flags == MMC_DATA_READ &&
>  			    (mask & (DWMCI_INTMSK_RXDR | DWMCI_INTMSK_DTO))) {
>  				dwmci_writel(host, DWMCI_RINTSTS,
> -					     DWMCI_INTMSK_RXDR | DWMCI_INTMSK_DTO);
> +					     mask & (DWMCI_INTMSK_RXDR |
> +						     DWMCI_INTMSK_DTO));
>  				while (size) {
>  					ret = dwmci_fifo_ready(host,
>  							DWMCI_FIFO_EMPTY,