diff mbox

[1/1] mmc: implemented eMMC4.4 hardware reset feature

Message ID 20101025141820.GA28000@intel.com (mailing list archive)
State New, archived
Headers show

Commit Message

Chuanxiao.Dong Oct. 25, 2010, 2:18 p.m. UTC
None
diff mbox

Patch

diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 8f86d70..75615ce 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -209,6 +209,8 @@  static void mmc_wait_done(struct mmc_request *mrq)
  */
 void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
 {
+	struct mmc_card *card = host->card;
+
 	DECLARE_COMPLETION_ONSTACK(complete);
 
 	mrq->done_data = &complete;
@@ -217,6 +219,30 @@  void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
 	mmc_start_request(host, mrq);
 
 	wait_for_completion(&complete);
+	/* as MMC4.4 standard says, when some data timeout conditions
+	 * occur, HC need to do a hardware reset for eMMC4.4 card.
+	 * If the card is eMMC4.4 card && data error is timeout,
+	 * do the following things:
+	 * 1. let host controller do a specific hardware reset for eMMC
+	 *    card (trigger RST_n signal).
+	 * 2. after reset done, reinit eMMC4.4 card.
+	 * */
+	if (mrq->data && card &&
+		mrq->data->error == -ETIMEDOUT &&
+		card->ext_csd.rst == 1) {
+		int err = 1;
+		if (host->ops->hardware_reset &&
+				host->bus_ops->reinit) {
+			err = host->ops->hardware_reset(host);
+			if (err)
+				pr_warn("MMC card reset failed, no reinit\n");
+			else
+				err = host->bus_ops->reinit(host);
+		}
+
+		if (err)
+			pr_warn("cannot reset and reinit eMMC4.4 card\n");
+	}
 }
 
 EXPORT_SYMBOL(mmc_wait_for_req);
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 77240cd..232a3d9 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -24,6 +24,7 @@  struct mmc_bus_ops {
 	int (*resume)(struct mmc_host *);
 	int (*power_save)(struct mmc_host *);
 	int (*power_restore)(struct mmc_host *);
+	int (*reinit)(struct mmc_host *);
 };
 
 void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 995261f..e015e55 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -237,6 +237,8 @@  static int mmc_read_ext_csd(struct mmc_card *card)
 		}
 	}
 
+	card->ext_csd.rst = ext_csd[EXT_CSD_RST];
+
 	card->ext_csd.rev = ext_csd[EXT_CSD_REV];
 	if (card->ext_csd.rev > 5) {
 		printk(KERN_ERR "%s: unrecognised EXT_CSD revision %d\n",
@@ -484,6 +486,32 @@  static int mmc_init_card(struct mmc_host *host, u32 ocr,
 	}
 
 	/*
+	 * eMMC4.4 version card has HW reset capbility.
+	 * Enable this feature here:
+	 * RST_N_FUNCTION register is W/R, one time programmable
+	 * or readable.
+	 * So need to enable this register only once after power on
+	 * */
+	if (card->csd.mmca_vsn >= CSD_SPEC_VER_4 &&
+			card->ext_csd.rev >= 4 &&
+			card->ext_csd.rst != 1) {
+		/* FIXME should driver set this register? */
+		err = mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
+				EXT_CSD_RST, 1);
+
+		if (err && err != -EBADMSG)
+			goto free_card;
+
+		if (err) {
+			printk(KERN_WARNING "%s: switch to rst enable "
+				   "failed %d\n",
+				   mmc_hostname(card->host), err);
+			err = 0;
+		} else
+			card->ext_csd.rst = 1;
+	}
+
+	/*
 	 * Activate high speed (if supported)
 	 */
 	if ((card->ext_csd.hs_max_dtr != 0) &&
@@ -699,6 +727,23 @@  static int mmc_awake(struct mmc_host *host)
 	return err;
 }
 
+static int mmc_reinit_card(struct mmc_host *host)
+{
+	int err;
+
+	BUG_ON(!host);
+	BUG_ON(!host->card);
+
+	host->ios.clock = host->f_min;
+	mmc_set_clock(host, host->ios.clock);
+
+	err = mmc_init_card(host, host->ocr, host->card);
+	if (err)
+		printk(KERN_ERR "%s: err %d\n", __func__, err);
+
+	return err;
+}
+
 static const struct mmc_bus_ops mmc_ops = {
 	.awake = mmc_awake,
 	.sleep = mmc_sleep,
@@ -707,6 +752,7 @@  static const struct mmc_bus_ops mmc_ops = {
 	.suspend = NULL,
 	.resume = NULL,
 	.power_restore = mmc_power_restore,
+	.reinit = mmc_reinit_card,
 };
 
 static const struct mmc_bus_ops mmc_ops_unsafe = {
@@ -717,6 +763,7 @@  static const struct mmc_bus_ops mmc_ops_unsafe = {
 	.suspend = mmc_suspend,
 	.resume = mmc_resume,
 	.power_restore = mmc_power_restore,
+	.reinit = mmc_reinit_card,
 };
 
 static void mmc_attach_bus_ops(struct mmc_host *host)
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 782c0ee..ac789d9 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1266,11 +1266,34 @@  out:
 	spin_unlock_irqrestore(&host->lock, flags);
 }
 
+/*
+ *  HW reset callback for eMMC4.4 card
+ *  In this function, HC will do the real HW reset
+ *  for eMMC4.4 card
+ *
+ *  RETURN VALUE:
+ *  0: reset emmc successfully
+ *  1: reset emmc failed
+ * */
+static int sdhci_hardware_reset(struct mmc_host *mmc)
+{
+	int err = 1;
+	struct sdhci_host *host;
+
+	host = mmc_priv(mmc);
+
+	if (host->ops && host->ops->reset_emmc)
+		err = host->ops->reset_emmc(host);
+
+	return err;
+}
+
 static const struct mmc_host_ops sdhci_ops = {
 	.request	= sdhci_request,
 	.set_ios	= sdhci_set_ios,
 	.get_ro		= sdhci_get_ro,
 	.enable_sdio_irq = sdhci_enable_sdio_irq,
+	.hardware_reset = sdhci_hardware_reset,
 };
 
 /*****************************************************************************\
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index b7b8a3b..c4cb360 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -215,6 +215,7 @@  struct sdhci_ops {
 	void (*platform_send_init_74_clocks)(struct sdhci_host *host,
 					     u8 power_mode);
 	unsigned int    (*get_ro)(struct sdhci_host *host);
+	int		(*reset_emmc)(struct sdhci_host *host);
 };
 
 #ifdef CONFIG_MMC_SDHCI_IO_ACCESSORS
diff --git a/include/linux/mmc/card.h b/include/linux/mmc/card.h
index 8ce0827..3d17867 100644
--- a/include/linux/mmc/card.h
+++ b/include/linux/mmc/card.h
@@ -54,6 +54,7 @@  struct mmc_ext_csd {
 	unsigned int		sec_trim_mult;	/* Secure trim multiplier  */
 	unsigned int		sec_erase_mult;	/* Secure erase multiplier */
 	unsigned int		trim_timeout;		/* In milliseconds */
+	unsigned int		rst;
 };
 
 struct sd_scr {
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 6d87f68..6e9eba8 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -117,6 +117,11 @@  struct mmc_host_ops {
 
 	/* optional callback for HC quirks */
 	void	(*init_card)(struct mmc_host *host, struct mmc_card *card);
+
+	/* HW reset callback, used for eMMC 4.4 new feature.
+	 * when occurs data timeout, HC will need to reset eMMC4.4 card
+	 * */
+	int (*hardware_reset)(struct mmc_host *host);
 };
 
 struct mmc_card;
diff --git a/include/linux/mmc/mmc.h b/include/linux/mmc/mmc.h
index 956fbd8..9edc643 100644
--- a/include/linux/mmc/mmc.h
+++ b/include/linux/mmc/mmc.h
@@ -251,6 +251,7 @@  struct _mmc_csd {
  * EXT_CSD fields
  */
 
+#define EXT_CSD_RST					162	/* R/W */
 #define EXT_CSD_ERASE_GROUP_DEF		175	/* R/W */
 #define EXT_CSD_ERASED_MEM_CONT		181	/* RO */
 #define EXT_CSD_BUS_WIDTH		183	/* R/W */