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mmc: sdhci-cadence: Support mmc hardware reset

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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: Brad Larson <blarson@amd.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Link: https://lore.kernel.org/r/20230410184526.15990-15-blarson@amd.com
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
This commit is contained in:
Brad Larson 2023-04-10 11:45:25 -07:00 committed by Ulf Hansson
parent b5dbcf1f1d
commit aad53d4ee7
1 changed files with 27 additions and 0 deletions
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27
drivers/mmc/host/sdhci-cadence.c
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@ -12,6 +12,7 @@
#include <linux/mmc/mmc.h> #include <linux/mmc/mmc.h>
#include <linux/of.h> #include <linux/of.h>
#include <linux/of_device.h> #include <linux/of_device.h>
#include <linux/reset.h>
#include "sdhci-pltfm.h" #include "sdhci-pltfm.h"
@ -70,6 +71,7 @@ struct sdhci_cdns_priv {
spinlock_t wrlock; /* write lock */ spinlock_t wrlock; /* write lock */
bool enhanced_strobe; bool enhanced_strobe;
void (*priv_writel)(struct sdhci_cdns_priv *priv, u32 val, void __iomem *reg); void (*priv_writel)(struct sdhci_cdns_priv *priv, u32 val, void __iomem *reg);
struct reset_control *rst_hw;
unsigned int nr_phy_params; unsigned int nr_phy_params;
struct sdhci_cdns_phy_param 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); 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) static int sdhci_cdns_probe(struct platform_device *pdev)
{ {
struct sdhci_host *host; struct sdhci_host *host;
@ -520,6 +538,15 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
if (ret) if (ret)
goto free; 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); ret = sdhci_add_host(host);
if (ret) if (ret)
goto free; goto free;