[PATCH v2] mmc: dw_mmc: reset controller after data error

[Kever Yang]

On 2023/4/3 18:44, Eugen Hristev wrote:
> From: Ziyuan Xu <xzy.xu at rock-chips.com>
>
> Per dw_mmc databook, it's recommended to reset the host controller if
> some data-related error occurred.
> Implement a reset mechanism.
>
> Signed-off-by: Ziyuan Xu <xzy.xu at rock-chips.com>
> Co-developed-by: Jason Zhu <jason.zhu at rock-chips.com>
> Signed-off-by: Jason Zhu <jason.zhu at rock-chips.com>
> [eugen.hristev at collabora.com: modified a bit the variables initialization]
> Signed-off-by: Eugen Hristev <eugen.hristev at collabora.com>
Reviewed-by: Kever Yang <kever.yang at rock-chips.com>

Thanks,
- Kever
> ---
> Changes in v2:
> - actually decrement the reset timeout timer
>
>   drivers/mmc/dw_mmc.c | 20 +++++++++++++++++++-
>   1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
> index 5085a3b491da..d6cad998b0cd 100644
> --- a/drivers/mmc/dw_mmc.c
> +++ b/drivers/mmc/dw_mmc.c
> @@ -138,7 +138,7 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data)
>   {
>   	struct mmc *mmc = host->mmc;
>   	int ret = 0;
> -	u32 timeout, mask, size, i, len = 0;
> +	u32 timeout, reset_timeout = 100, status, ctrl, mask, size, i, len = 0;
>   	u32 *buf = NULL;
>   	ulong start = get_timer(0);
>   	u32 fifo_depth = (((host->fifoth_val & RX_WMARK_MASK) >>
> @@ -159,6 +159,24 @@ static int dwmci_data_transfer(struct dwmci_host *host, struct mmc_data *data)
>   		/* Error during data transfer. */
>   		if (mask & (DWMCI_DATA_ERR | DWMCI_DATA_TOUT)) {
>   			debug("%s: DATA ERROR!\n", __func__);
> +
> +			dwmci_wait_reset(host, DWMCI_RESET_ALL);
> +			dwmci_writel(host, DWMCI_CMD, DWMCI_CMD_PRV_DAT_WAIT |
> +				     DWMCI_CMD_UPD_CLK | DWMCI_CMD_START);
> +
> +			do {
> +				status = dwmci_readl(host, DWMCI_CMD);
> +				if (!reset_timeout--)
> +					break;
> +				udelay(100);
> +			} while (status & DWMCI_CMD_START);
> +
> +			if (!host->fifo_mode) {
> +				ctrl = dwmci_readl(host, DWMCI_BMOD);
> +				ctrl |= DWMCI_BMOD_IDMAC_RESET;
> +				dwmci_writel(host, DWMCI_BMOD, ctrl);
> +			}
> +
>   			ret = -EINVAL;
>   			break;
>   		}