Commit aad53d4e authored by Brad Larson's avatar Brad Larson Committed by Ulf Hansson
Browse files

mmc: sdhci-cadence: Support mmc hardware reset 



Add support for mmc hardware reset using a reset-controller
that would need to be enabled in the device tree with
a supporting driver.  The default is disabled for all
existing designs.

Signed-off-by: default avatarBrad Larson <blarson@amd.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Reviewed-by: default avatarPhilipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20230410184526.15990-15-blarson@amd.com


Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
parent b5dbcf1f

drivers/mmc/host/sdhci-cadence.c

+27 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 
#include <linux/mmc/mmc.h>

#include <linux/of.h>

#include <linux/of_device.h>

#include <linux/reset.h>



#include "sdhci-pltfm.h"
@@ -70,6 +71,7 @@ struct sdhci_cdns_priv { 
	spinlock_t wrlock;	/* write lock */

	bool enhanced_strobe;

	void (*priv_writel)(struct sdhci_cdns_priv *priv, u32 val, void __iomem *reg);

	struct reset_control *rst_hw;

	unsigned int nr_phy_params;

	struct sdhci_cdns_phy_param phy_params[];

};
@@ -457,6 +459,22 @@ static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc, 
					 SDHCI_CDNS_HRS06_MODE_MMC_HS400);

}



static void sdhci_cdns_mmc_hw_reset(struct mmc_host *mmc)

{

	struct sdhci_host *host = mmc_priv(mmc);

	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);



	dev_dbg(mmc_dev(host->mmc), "emmc hardware reset\n");



	reset_control_assert(priv->rst_hw);

	/* For eMMC, minimum is 1us but give it 3us for good measure */

	udelay(3);



	reset_control_deassert(priv->rst_hw);

	/* For eMMC, minimum is 200us but give it 300us for good measure */

	usleep_range(300, 1000);

}



static int sdhci_cdns_probe(struct platform_device *pdev)

{

	struct sdhci_host *host;
@@ -520,6 +538,15 @@ static int sdhci_cdns_probe(struct platform_device *pdev) 
	if (ret)

		goto free;



	if (host->mmc->caps & MMC_CAP_HW_RESET) {

		priv->rst_hw = devm_reset_control_get_optional_exclusive(dev, NULL);

		if (IS_ERR(priv->rst_hw))

			return dev_err_probe(mmc_dev(host->mmc), PTR_ERR(priv->rst_hw),

					     "reset controller error\n");

		if (priv->rst_hw)

			host->mmc_host_ops.card_hw_reset = sdhci_cdns_mmc_hw_reset;

	}



	ret = sdhci_add_host(host);

	if (ret)

		goto free;