Re: [PATCH] mmc: sdhci: correct the tuning command handle for PIO mode

[Adrian Hunter <adrian.hunter@intel.com>]

On 13/08/21 3:34 pm, haibo.chen@nxp.com wrote:
> From: Haibo Chen <haibo.chen@nxp.com>
> 
> If sdhci use PIO mode, and use mmc_send_tuning() to send the
> tuning command, system will stuck because of the storm irq
> of sdhci. For PIO mode, use mmc_send_tuning(), it will trigger
> buffer_read_ready interrupt and data transfer complete interrupt.
> In current code logic, it will directly return in sdhci_data_irq,
> can not call the sdhci_transfer_pio(). So the buffer_read_ready
> interrupt storm happen. So for standard tuning method, need to
> excluse this case.
> 
> Signed-off-by: Haibo Chen <haibo.chen@nxp.com>

Acked-by: Adrian Hunter <adrian.hunter@intel.com>

> ---
>  drivers/mmc/host/sdhci.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index aba6e10b8605..acee54b368b0 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3278,8 +3278,14 @@ static void sdhci_data_irq(struct sdhci_host *host, u32 intmask)
>  {
>  	u32 command;
>  
> -	/* CMD19 generates _only_ Buffer Read Ready interrupt */
> -	if (intmask & SDHCI_INT_DATA_AVAIL) {
> +	/*
> +	 * CMD19 generates _only_ Buffer Read Ready interrupt if
> +	 * use sdhci_send_tuning.
> +	 * Need to exclude this case: PIO mode and use mmc_send_tuning,
> +	 * If not, sdhci_transfer_pio will never be called, make the
> +	 * SDHCI_INT_DATA_AVAIL always there, stuck in irq storm.
> +	 */
> +	if ((intmask & SDHCI_INT_DATA_AVAIL) && (!host->data)) {
>  		command = SDHCI_GET_CMD(sdhci_readw(host, SDHCI_COMMAND));
>  		if (command == MMC_SEND_TUNING_BLOCK ||
>  		    command == MMC_SEND_TUNING_BLOCK_HS200) {
>