MMC: added alternative MMC driver

mmc: Disable CMD23 transfers on all cards

Pending wire-level investigation of these types of transfers
and associated errors on bcm2835-mmc, disable for now. Fallback of
CMD18/CMD25 transfers will be used automatically by the MMC layer.

Reported/Tested-by: Gellert Weisz <[email protected]>

mmc: bcm2835-mmc: enable DT support for all architectures

Both ARCH_BCM2835 and ARCH_BCM270x are built with OF now.
Enable Device Tree support for all architectures.

Signed-off-by: Noralf Trønnes <[email protected]>

mmc: bcm2835-mmc: fix probe error handling

Probe error handling is broken in several places.
Simplify error handling by using device managed functions.
Replace pr_{err,info} with dev_{err,info}.

Signed-off-by: Noralf Trønnes <[email protected]>

bcm2835-mmc: Add locks when accessing sdhost registers

bcm2835-mmc: Add range of debug options for slowing things down

bcm2835-mmc: Add option to disable some delays

bcm2835-mmc: Add option to disable MMC_QUIRK_BLK_NO_CMD23

bcm2835-mmc: Default to disabling MMC_QUIRK_BLK_NO_CMD23

bcm2835-mmc: Adding overclocking option

Allow a different clock speed to be substitued for a requested 50MHz.
This option is exposed using the "overclock_50" DT parameter.
Note that the mmc interface is restricted to EVEN integer divisions of
250MHz, and the highest sensible option is 63 (250/4 = 62.5), the
next being 125 (250/2) which is much too high.

Use at your own risk.

bcm2835-mmc: Round up the overclock, so 62 works for 62.5Mhz

Also only warn once for each overclock setting.

mmc: bcm2835-mmc: Make available on ARCH_BCM2835

Make the bcm2835-mmc driver available for use on ARCH_BCM2835.

Signed-off-by: Noralf Trønnes <[email protected]>

BCM270x_DT: add bcm2835-mmc entry

Add Device Tree entry for bcm2835-mmc.
In non-DT mode, don't add the device in the board file.

Signed-off-by: Noralf Trønnes <[email protected]>

bcm2835-mmc: Don't overwrite MMC capabilities from DT

bcm2835-mmc: Don't override bus width capabilities from devicetree

Take out the force setting of the MMC_CAP_4_BIT_DATA host capability
so that the result read from devicetree via mmc_of_parse() is
preserved.

bcm2835-mmc: Only claim one DMA channel

With both MMC controllers enabled there are few DMA channels left. The
bcm2835-mmc driver only uses DMA in one direction at a time, so it
doesn't need to claim two channels.

See: #1327

Signed-off-by: Phil Elwell <[email protected]>

Author: weiszg

drivers/mmc/core/quirks.c

@@ -53,6 +53,9 @@ static const struct mmc_fixup mmc_fixup_methods[] = {
 
 void mmc_fixup_device(struct mmc_card *card, const struct mmc_fixup *table)
 {
+#ifdef CONFIG_MMC_BCM2835
+	extern unsigned mmc_debug;
+#endif
 	const struct mmc_fixup *f;
 	u64 rev = cid_rev_card(card);
 
@@ -79,5 +82,12 @@ void mmc_fixup_device(struct mmc_card *card, const struct mmc_fixup *table)
 			f->vendor_fixup(card, f->data);
 		}
 	}
+	/* SDHCI on BCM2708 - bug causes a certain sequence of CMD23 operations to fail.
+	 * Disable this flag for all cards (fall-back to CMD25/CMD18 multi-block transfers).
+	 */
+#ifdef CONFIG_MMC_BCM2835
+	if (mmc_debug & (1<<13))
+	card->quirks |= MMC_QUIRK_BLK_NO_CMD23;
+#endif
 }
 EXPORT_SYMBOL(mmc_fixup_device);

drivers/mmc/host/Kconfig

@@ -4,6 +4,35 @@
 
 comment "MMC/SD/SDIO Host Controller Drivers"
 
+config MMC_BCM2835
+	tristate "MMC support on BCM2835"
+	depends on MACH_BCM2708 || MACH_BCM2709 || ARCH_BCM2835
+	help
+	  This selects the MMC Interface on BCM2835.
+
+	  If you have a controller with this interface, say Y or M here.
+
+	  If unsure, say N.
+
+config MMC_BCM2835_DMA
+	bool "DMA support on BCM2835 Arasan controller"
+	depends on MMC_BCM2835
+	help
+	  Enable DMA support on the Arasan SDHCI controller in Broadcom 2708
+	  based chips.
+
+	  If unsure, say N.
+
+config MMC_BCM2835_PIO_DMA_BARRIER
+	int "Block count limit for PIO transfers"
+	depends on MMC_BCM2835 && MMC_BCM2835_DMA
+	range 0 256
+	default 2
+	help
+	  The inclusive limit in bytes under which PIO will be used instead of DMA
+
+	  If unsure, say 2 here.
+
 config MMC_ARMMMCI
 	tristate "ARM AMBA Multimedia Card Interface support"
 	depends on ARM_AMBA

drivers/mmc/host/Makefile

@@ -18,6 +18,7 @@ obj-$(CONFIG_MMC_SDHCI_S3C)	+= sdhci-s3c.o
 obj-$(CONFIG_MMC_SDHCI_SIRF)   	+= sdhci-sirf.o
 obj-$(CONFIG_MMC_SDHCI_F_SDH30)	+= sdhci_f_sdh30.o
 obj-$(CONFIG_MMC_SDHCI_SPEAR)	+= sdhci-spear.o
+obj-$(CONFIG_MMC_BCM2835)	+= bcm2835-mmc.o
 obj-$(CONFIG_MMC_WBSD)		+= wbsd.o
 obj-$(CONFIG_MMC_AU1X)		+= au1xmmc.o
 obj-$(CONFIG_MMC_MTK)		+= mtk-sd.o