[PATCH] mci: sdhci: don't hang indefinitely waiting for DMA completion

[Sascha Hauer]

On Thu, Aug 24, 2023 at 03:59:39PM +0200, Ahmad Fatoum wrote:
> barebox was observed to hang on an i.MX8MP while reading ext_csd from
> a broken eMMC that even bootROM refused to boot from. For PIO, we
> already have a maximum wait time of 10s. Do the same for DMA.
> 
> It's unlikely that in that state any further communication with the card
> will work, but at least, the system isn't stuck and the shell can be
> reached. The reset is done on the off-chance that the DMA would've completed
> after the 10s and corrupted memory if not disabled.
> 
> Signed-off-by: Ahmad Fatoum <a.fatoum at pengutronix.de>
> ---
>  drivers/mci/sdhci.c | 10 ++++++++++
>  1 file changed, 10 insertions(+)

Applied, thanks

Sascha

> 
> diff --git a/drivers/mci/sdhci.c b/drivers/mci/sdhci.c
> index b0b83bfaa9a7..9829a78cb6c5 100644
> --- a/drivers/mci/sdhci.c
> +++ b/drivers/mci/sdhci.c
> @@ -252,6 +252,7 @@ int sdhci_transfer_data_dma(struct sdhci *sdhci, struct mci_data *data,
>  			    dma_addr_t dma)
>  {
>  	struct device *dev = sdhci->mci->hw_dev;
> +	u64 start;
>  	int nbytes;
>  	u32 irqstat;
>  	int ret;
> @@ -261,6 +262,8 @@ int sdhci_transfer_data_dma(struct sdhci *sdhci, struct mci_data *data,
>  
>  	nbytes = data->blocks * data->blocksize;
>  
> +	start = get_time_ns();
> +
>  	do {
>  		irqstat = sdhci_read32(sdhci, SDHCI_INT_STATUS);
>  
> @@ -304,6 +307,13 @@ int sdhci_transfer_data_dma(struct sdhci *sdhci, struct mci_data *data,
>  
>  		if (irqstat & SDHCI_INT_XFER_COMPLETE)
>  			break;
> +
> +		if (is_timeout(start, 10 * SECOND)) {
> +			dev_alert(dev, "DMA wait timed out. Resetting, but recovery unlikely\n");
> +			sdhci_reset(sdhci, SDHCI_RESET_ALL);
> +			ret = -ETIMEDOUT;
> +			goto out;
> +		}
>  	} while (1);
>  
>  	ret = 0;
> -- 
> 2.39.2
> 
> 
> 

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