22.04.2022 20:09, Sebastian Reichel пишет:
> From: Yifeng Zhao <yifeng.zhao@xxxxxxxxxxxxxx>
>
> The reset function build in the SDHCI will not reset the logic
> circuit related to the tuning function, which may cause data
> reading errors. Resetting the complete SDHCI controller through
> the reset controller fixes the issue.
>
> Signed-off-by: Yifeng Zhao <yifeng.zhao@xxxxxxxxxxxxxx>
> [rebase]
> Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
> ---
> drivers/mmc/host/sdhci-of-dwcmshc.c | 28 +++++++++++++++++++++++++++-
> 1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-of-dwcmshc.c b/drivers/mmc/host/sdhci-of-dwcmshc.c
> index bac874ab0b33..d95ae6ca1256 100644
> --- a/drivers/mmc/host/sdhci-of-dwcmshc.c
> +++ b/drivers/mmc/host/sdhci-of-dwcmshc.c
> @@ -15,6 +15,7 @@
> #include <linux/module.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> +#include <linux/reset.h>
> #include <linux/sizes.h>
>
> #include "sdhci-pltfm.h"
> @@ -63,6 +64,7 @@
> struct rk3568_priv {
> /* Rockchip specified optional clocks */
> struct clk_bulk_data rockchip_clks[RK3568_MAX_CLKS];
> + struct reset_control *reset;
> u8 txclk_tapnum;
> };
>
> @@ -255,6 +257,23 @@ static void dwcmshc_rk3568_set_clock(struct sdhci_host *host, unsigned int clock
> sdhci_writel(host, extra, DWCMSHC_EMMC_DLL_STRBIN);
> }
>
> +static void rk35xx_sdhci_reset(struct sdhci_host *host, u8 mask)
> +{
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct dwcmshc_priv *dwc_priv = sdhci_pltfm_priv(pltfm_host);
> + struct rk35xx_priv *priv = dwc_priv->priv;
> +
> + if (mask & SDHCI_RESET_ALL) {
> + if (!IS_ERR_OR_NULL(priv->reset)) {
priv->reset can't be a error ptr since probe fails on error.
> + reset_control_assert(priv->reset);
> + udelay(1);
> + reset_control_deassert(priv->reset);
> + }
> + }
> +
> + sdhci_reset(host, mask);
> +}
> +
> static const struct sdhci_ops sdhci_dwcmshc_ops = {
> .set_clock = sdhci_set_clock,
> .set_bus_width = sdhci_set_bus_width,
> @@ -269,7 +288,7 @@ static const struct sdhci_ops sdhci_dwcmshc_rk3568_ops = {
> .set_bus_width = sdhci_set_bus_width,
> .set_uhs_signaling = dwcmshc_set_uhs_signaling,
> .get_max_clock = sdhci_pltfm_clk_get_max_clock,
> - .reset = sdhci_reset,
> + .reset = rk35xx_sdhci_reset,
> .adma_write_desc = dwcmshc_adma_write_desc,
> };
>
> @@ -292,6 +311,13 @@ static int dwcmshc_rk3568_init(struct sdhci_host *host, struct dwcmshc_priv *dwc
> int err;
> struct rk3568_priv *priv = dwc_priv->priv;
>
> + priv->reset = devm_reset_control_array_get_exclusive(mmc_dev(host->mmc));
The devm_reset_control_array_get_exclusive() never returns NULL.
The devm_reset_control_array_get_optional_exclusive(() may return NULL
if reset is missing in DT, perhaps that's what you actually want?
> + if (IS_ERR_OR_NULL(priv->reset)) {
> + err = PTR_ERR(priv->reset);
NULL isn't a error
> + dev_err(mmc_dev(host->mmc), "failed to get reset control %d\n", err);
dev_err_probe()?
