[PATCH 22/22] mmc: omap_hsmmc: add a hardware reset before initialization

Adrian Hunter
2011-05-05T11:52:53Z

After a warm restart, an eMMC which cannot be powered off is
in an unknown state, so reset it to be sure it will initialize.

Signed-off-by: Adrian Hunter <adrian.hunter@nokia.com>
---
drivers/mmc/host/omap_hsmmc.c | 38 +++++++++++++++++++++++++++++++++++++-
1 files changed, 37 insertions(+), 1 deletions(-)

diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 8c5e7d3..c791230 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -542,10 +542,25 @@ static int omap_hsmmc_gpio_init(struct omap_mmc_platform_data *pdata)
} else
pdata->slots[0].gpio_wp = -EINVAL;

+ if (gpio_is_valid(pdata->slots[0].gpio_hw_reset)) {
+ ret = gpio_request(pdata->slots[0].gpio_hw_reset,
+ "mmc_hw_reset");
+ if (ret)
+ goto err_free_wp;
+ ret = gpio_direction_output(pdata->slots[0].gpio_hw_reset, 1);
+ if (ret)
+ goto err_free_hw_reset;
+ } else
+ pdata->slots[0].gpio_hw_reset = -EINVAL;
+
return 0;

+
+err_free_hw_reset:
+ gpio_free(pdata->slots[0].gpio_hw_reset);
err_free_wp:
- gpio_free(pdata->slots[0].gpio_wp);
+ if (gpio_is_valid(pdata->slots[0].gpio_wp))
+ gpio_free(pdata->slots[0].gpio_wp);
err_free_cd:
if (gpio_is_valid(pdata->slots[0].switch_pin))
err_free_sp:
@@ -555,6 +570,8 @@ err_free_sp:

static void omap_hsmmc_gpio_free(struct omap_mmc_platform_data *pdata)
{
+ if (gpio_is_valid(pdata->slots[0].gpio_hw_reset))
+ gpio_free(pdata->slots[0].gpio_hw_reset);
if (gpio_is_valid(pdata->slots[0].gpio_wp))
gpio_free(pdata->slots[0].gpio_wp);
if (gpio_is_valid(pdata->slots[0].switch_pin))
@@ -815,6 +832,18 @@ static void omap_hsmmc_context_save(struct omap_hsmmc_host *host)

#endif

+static void omap_hsmmc_do_hw_reset(struct omap_hsmmc_host *host)
+{
+ if (!gpio_is_valid(mmc_slot(host).gpio_hw_reset))
+ return;
+
+ gpio_set_value_cansleep(mmc_slot(host).gpio_hw_reset, 0);
+ udelay(9);
+ gpio_set_value_cansleep(mmc_slot(host).gpio_hw_reset, 1);
+ usleep_range(1000, 2000);
+ printk(KERN_INFO "%s: hardware reset done\n", mmc_hostname(host->mmc));
+}
+
/*
* Send init stream sequence to card
* before sending IDLE command
@@ -827,6 +856,13 @@ static void send_init_stream(struct omap_hsmmc_host *host)
if (host->protect_card)
return;

+ /*
+ * After a warm restart, an eMMC which cannot be powered off is in an
+ * unknown state so reset it to be sure it will initialize.
+ */
+ if (mmc_slot(host).no_off)
+ omap_hsmmc_do_hw_reset(host);
+
disable_irq(host->irq);

OMAP_HSMMC_WRITE(host->base, IE, INT_EN_MASK);
--
1.7.0.4