There are boards (like Hardkernel's Odroid boards) on which eMMC card's
reset line is connected to SoC GPIO line instead of the hardware reset
logic. In case of such boards, before performing system reboot,
additional reset of eMMC card is required to boot again properly.
This patch adds code for handling such cases.
Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
.../devicetree/bindings/mmc/exynos-dw-mshc.txt | 6 +++
drivers/mmc/host/dw_mmc-exynos.c | 43 +++++++++++++++++++++-
2 files changed, 48 insertions(+), 1 deletion(-)
diff --git a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
index ee4fc0576c7d..fc53d335e7db 100644
--- a/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
+++ b/Documentation/devicetree/bindings/mmc/exynos-dw-mshc.txt
@@ -50,6 +50,12 @@ Required Properties:
- if CIU clock divider value is 0 (that is divide by 1), both tx and rx
phase shift clocks should be 0.
+Optional properties:
+
+* dw-mshc-reset-gpios: optional property specifying gpio for the eMMC nreset
+ line, it will be triggered on system reboot to properly reset eMMC card for
+ next system boot.
+
Required properties for a slot (Deprecated - Recommend to use one slot per host):
* gpios: specifies a list of gpios used for command, clock and data bus. The
diff --git a/drivers/mmc/host/dw_mmc-exynos.c b/drivers/mmc/host/dw_mmc-exynos.c
index 509365cb22c6..2add5a93859d 100644
--- a/drivers/mmc/host/dw_mmc-exynos.c
+++ b/drivers/mmc/host/dw_mmc-exynos.c
@@ -12,12 +12,14 @@
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/clk.h>
+#include <linux/delay.h>
#include <linux/mmc/host.h>
#include <linux/mmc/dw_mmc.h>
#include <linux/mmc/mmc.h>
#include <linux/of.h>
#include <linux/of_gpio.h>
#include <linux/slab.h>
+#include <linux/reboot.h>
#include "dw_mmc.h"
#include "dw_mmc-pltfm.h"
@@ -77,8 +79,23 @@ struct dw_mci_exynos_priv_data {
u32 sdr_timing;
u32 ddr_timing;
u32 cur_speed;
+ struct gpio_desc *reset_gpio;
+ struct notifier_block reset_nb;
};
+static int dw_mci_restart_handler(struct notifier_block *this,
+ unsigned long mode, void *cmd)
+{
+ struct dw_mci_exynos_priv_data *data;
+ data = container_of(this, struct dw_mci_exynos_priv_data, reset_nb);
+
+ gpiod_direction_output(data->reset_gpio, 0);
+ mdelay(150);
+ gpiod_direction_output(data->reset_gpio, 1);
+
+ return NOTIFY_DONE;
+}
+
static struct dw_mci_exynos_compatible {
char *compatible;
enum dw_mci_exynos_type ctrl_type;
@@ -295,7 +312,20 @@ static int dw_mci_exynos_parse_dt(struct dw_mci *host)
return ret;
priv->ddr_timing = SDMMC_CLKSEL_TIMING(timing[0], timing[1], div);
+
+ priv->reset_gpio = devm_gpiod_get_optional(host->dev,
+ "samsung,dw-mshc-reset",
+ GPIOD_OUT_HIGH);
+ if (!IS_ERR_OR_NULL(priv->reset_gpio)) {
+ priv->reset_nb.notifier_call = dw_mci_restart_handler;
+ priv->reset_nb.priority = 255;
+ ret = register_restart_handler(&priv->reset_nb);
+ if (ret)
+ dev_err(host->dev, "cannot register restart handler\n");
+ }
+
host->priv = priv;
+
return 0;
}
@@ -490,6 +520,17 @@ static int dw_mci_exynos_probe(struct platform_device *pdev)
return dw_mci_pltfm_register(pdev, drv_data);
}
+static int dw_mci_exynos_remove(struct platform_device *pdev)
+{
+ struct dw_mci *host = platform_get_drvdata(pdev);
+ struct dw_mci_exynos_priv_data *priv = host->priv;
+
+ if (priv->reset_gpio)
+ unregister_restart_handler(&priv->reset_nb);
+
+ return dw_mci_pltfm_remove(pdev);
+}
+
static const struct dev_pm_ops dw_mci_exynos_pmops = {
SET_SYSTEM_SLEEP_PM_OPS(dw_mci_exynos_suspend, dw_mci_exynos_resume)
.resume_noirq = dw_mci_exynos_resume_noirq,
@@ -499,7 +540,7 @@ static const struct dev_pm_ops dw_mci_exynos_pmops = {
static struct platform_driver dw_mci_exynos_pltfm_driver = {
.probe = dw_mci_exynos_probe,
- .remove = __exit_p(dw_mci_pltfm_remove),
+ .remove = dw_mci_exynos_remove,
.driver = {
.name = "dwmmc_exynos",
.of_match_table = dw_mci_exynos_match,
--
1.9.2
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