[U-Boot] [PATCH v2] mmc: fsl_esdhc: Poll until card is not busy anymore

[Dirk Behme]

This patch imports parts of two patches from the Freescale U-Boot with the following
commit messages:

ENGR00156405 ESDHC: Add workaround for auto-clock gate errata ENGcm03648
http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/commit/drivers/mmc/imx_esdhc.c?h=imx_v2009.08_12.01.01&id=e436525a70fe47623d346bc7d9f08f12ff8ad787
The errata, not applicable to USDHC, causes ESDHC to shut off clock to the card
when auto-clock gating is enabled for commands with busy signalling and no data
phase. The card might require the clock to exit the busy state, so the workaround
is to disable the auto-clock gate bits in SYSCTL register for such commands. The
workaround also entails polling on DAT0 bit in the PRSSTAT register to learn when
busy state is complete. Auto-clock gating is re-enabled at the end of busy state.

ENGR00156670-1 ESDHC/USDHC: Remove delay before each cmd and some bug fixes
http://git.freescale.com/git/cgit.cgi/imx/uboot-imx.git/commit/drivers/mmc/imx_esdhc.c?h=imx_v2009.08_12.01.01&id=a77c6fec8596891be96b2cdbc742c9824844b92a
Removed delay of 10 ms before each command. There should not be a need to have this
delay after the ENGR00156405 patch that polls until card is not busy anymore before
proceeding to next cmd.

This patch imports the polling part of both patches. The auto-clock gating code
don't apply for i.MX6 as implemented in these two patches. 

SYSCTL_RSTA was defined twice. Remove one definition.

Signed-off-by: Dirk Behme <dirk.behme at de.bosch.com>
CC: Andy Fleming <afleming at freescale.com>
CC: Fabio Estevam <fabio.estevam at freescale.com>
CC: Stefano Babic <sbabic at denx.de>
---
Changes in v2:

* Drop the removal of the udelay(). It's not sure if the PowerPC would be
  ok with this removal.
* Drop touching the sysctl register. Reviewing the iMX6 spec shows that this
  was an NOP.

 drivers/mmc/fsl_esdhc.c |   39 ++++++++++++++++++++++++++++++++++++++-
 include/fsl_esdhc.h     |    4 +++-
 2 files changed, 41 insertions(+), 2 deletions(-)

Index: freescale-u-boot-imx.git/drivers/mmc/fsl_esdhc.c
===================================================================
--- freescale-u-boot-imx.git.orig/drivers/mmc/fsl_esdhc.c
+++ freescale-u-boot-imx.git/drivers/mmc/fsl_esdhc.c
@@ -307,19 +307,56 @@ esdhc_send_cmd(struct mmc *mmc, struct m
 #else
 	esdhc_write32(&regs->xfertyp, xfertyp);
 #endif
+
+	/* Mask all irqs */
+	esdhc_write32(&regs->irqsigen, 0);
+
 	/* Wait for the command to complete */
-	while (!(esdhc_read32(&regs->irqstat) & IRQSTAT_CC))
+	while (!(esdhc_read32(&regs->irqstat) & (IRQSTAT_CC | IRQSTAT_CTOE)))
 		;
 
 	irqstat = esdhc_read32(&regs->irqstat);
 	esdhc_write32(&regs->irqstat, irqstat);
 
+	/* Reset CMD and DATA portions on error */
+	if (irqstat & (CMD_ERR | IRQSTAT_CTOE)) {
+		esdhc_write32(&regs->sysctl, esdhc_read32(&regs->sysctl) |
+			      SYSCTL_RSTC);
+		while (esdhc_read32(&regs->sysctl) & SYSCTL_RSTC)
+			;
+
+		if (data) {
+			esdhc_write32(&regs->sysctl,
+				      esdhc_read32(&regs->sysctl) |
+				      SYSCTL_RSTD);
+			while ((esdhc_read32(&regs->sysctl) & SYSCTL_RSTD))
+				;
+		}
+	}
+
 	if (irqstat & CMD_ERR)
 		return COMM_ERR;
 
 	if (irqstat & IRQSTAT_CTOE)
 		return TIMEOUT;
 
+	/* Workaround for ESDHC errata ENGcm03648 */
+	if (!data && (cmd->resp_type & MMC_RSP_BUSY)) {
+		int timeout = 2500;
+
+		/* Poll on DATA0 line for cmd with busy signal for 250 ms */
+		while (timeout > 0 && !(esdhc_read32(&regs->prsstat) &
+					PRSSTAT_DAT0)) {
+			udelay(100);
+			timeout--;
+		}
+
+		if (timeout <= 0) {
+			printf("Timeout waiting for DAT0 to go high!\n");
+			return TIMEOUT;
+		}
+	}
+
 	/* Copy the response to the response buffer */
 	if (cmd->resp_type & MMC_RSP_136) {
 		u32 cmdrsp3, cmdrsp2, cmdrsp1, cmdrsp0;
Index: freescale-u-boot-imx.git/include/fsl_esdhc.h
===================================================================
--- freescale-u-boot-imx.git.orig/include/fsl_esdhc.h
+++ freescale-u-boot-imx.git/include/fsl_esdhc.h
@@ -34,12 +34,13 @@
 #define SYSCTL_INITA		0x08000000
 #define SYSCTL_TIMEOUT_MASK	0x000f0000
 #define SYSCTL_CLOCK_MASK	0x0000fff0
-#define SYSCTL_RSTA		0x01000000
 #define SYSCTL_CKEN		0x00000008
 #define SYSCTL_PEREN		0x00000004
 #define SYSCTL_HCKEN		0x00000002
 #define SYSCTL_IPGEN		0x00000001
 #define SYSCTL_RSTA		0x01000000
+#define SYSCTL_RSTC		0x02000000
+#define SYSCTL_RSTD		0x04000000
 
 #define IRQSTAT			0x0002e030
 #define IRQSTAT_DMAE		(0x10000000)
@@ -85,6 +86,7 @@
 #define IRQSTATEN_CC		(0x00000001)
 
 #define PRSSTAT			0x0002e024
+#define PRSSTAT_DAT0		(0x01000000)
 #define PRSSTAT_CLSL		(0x00800000)
 #define PRSSTAT_WPSPL		(0x00080000)
 #define PRSSTAT_CDPL		(0x00040000)