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 <gellert@raspberrypi.org>

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 <noralf@tronnes.org>

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 <noralf@tronnes.org>

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 <noralf@tronnes.org>

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 <noralf@tronnes.org>

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: https://github.com/raspberrypi/linux/issues/1327

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

bcm2835-mmc: New timer API

mmc: bcm2835-mmc: Support underclocking

Support underclocking of the SD bus using the max-frequency DT property
(which currently has no DT parameter). The sd_overclock parameter
already provides another way to achieve the same thing which should be
equivalent in end result, but it is a bug not to support max-frequency
as well.

See: https://github.com/raspberrypi/linux/issues/2350

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

mmc/bcm2835: Recover from MMC_SEND_EXT_CSD

If the user issues an "mmc extcsd read", the SD controller receives
what it thinks is a SEND_IF_COND command with an unexpected data block.
The resulting operations leave the FSM stuck in READWAIT, a state which
persists until the MMC framework resets the controller, by which point
the root filesystem is likely to have been unmounted.

A less heavyweight solution is to detect the condition and nudge the
FSM by asserting the (self-clearing) FORCE_DATA_MODE bit.

N.B. This workaround was essentially discovered by accident and without
a full understanding the inner workings of the controller, so it is
fortunate that the "fix" only modifies error paths.

See: https://github.com/raspberrypi/linux/issues/2728

Signed-off-by: Phil Elwell <phil@raspberrypi.org>

bcm2835-mmc: Fix DMA channel leak

The BCM2835 MMC host driver requests a DMA channel on probe but neglects
to release the channel in the probe error path and on driver unbind.

I'm seeing this happen on every boot of the Compute Module 3: On first
driver probe, DMA channel 2 is allocated and then leaked with a "could
not get clk, deferring probe" message. On second driver probe, channel 4
is allocated.

Fix it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>

bcm2835-mmc: Fix struct mmc_host leak on probe

The BCM2835 MMC host driver requests the bus address of the host's
register map on probe.  If that fails, the driver leaks the struct
mmc_host allocated earlier.

Fix it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>

bcm2835-mmc: Fix duplicate free_irq() on remove

The BCM2835 MMC host driver requests its interrupt as a device-managed
resource, so the interrupt is automatically freed after the driver is
unbound.

However on driver unbind, bcm2835_mmc_remove() frees the interrupt
explicitly to avoid invocation of the interrupt handler after driver
structures have been torn down.

The interrupt is thus freed twice, leading to a WARN splat in
__free_irq().  Fix by not requesting the interrupt as a device-managed
resource.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>

bcm2835-mmc: Handle mmc_add_host() errors

The BCM2835 MMC host driver calls mmc_add_host() but doesn't check its
return value.  Errors occurring in that function are therefore not
handled.  Fix it.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>

bcm2835-mmc: Deduplicate reset of driver data on remove

The BCM2835 MMC host driver sets the device's driver data pointer to
NULL on ->remove() even though the driver core subsequently does the
same in __device_release_driver().  Drop the duplicate assignment.

Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Frank Pavlic <f.pavlic@kunbus.de>

drivers/mmc/core/block.c

@@ -166,6 +166,13 @@ static DEFINE_MUTEX(open_lock);
 module_param(perdev_minors, int, 0444);
 MODULE_PARM_DESC(perdev_minors, "Minors numbers to allocate per device");
 
+/*
+ * Allow quirks to be overridden for the current card
+ */
+static char *card_quirks;
+module_param(card_quirks, charp, 0644);
+MODULE_PARM_DESC(card_quirks, "Force the use of the indicated quirks (a bitfield)");
+
 static inline int mmc_blk_part_switch(struct mmc_card *card,
 				      unsigned int part_type);
 
@@ -2904,6 +2911,7 @@ static int mmc_blk_probe(struct mmc_card *card)
 {
 	struct mmc_blk_data *md, *part_md;
 	char cap_str[10];
+	char quirk_str[24];
 
 	/*
 	 * Check that the card supports the command class(es) we need.
@@ -2911,7 +2919,16 @@ static int mmc_blk_probe(struct mmc_card *card)
 	if (!(card->csd.cmdclass & CCC_BLOCK_READ))
 		return -ENODEV;
 
-	mmc_fixup_device(card, mmc_blk_fixups);
+	if (card_quirks) {
+		unsigned long quirks;
+		if (kstrtoul(card_quirks, 0, &quirks) == 0)
+			card->quirks = (unsigned int)quirks;
+		else
+			pr_err("mmc_block: Invalid card_quirks parameter '%s'\n",
+			       card_quirks);
+	}
+	else
+		mmc_fixup_device(card, mmc_blk_fixups);
 
 	card->complete_wq = alloc_workqueue("mmc_complete",
 					WQ_MEM_RECLAIM | WQ_HIGHPRI, 0);
@@ -2926,9 +2943,14 @@ static int mmc_blk_probe(struct mmc_card *card)
 
 	string_get_size((u64)get_capacity(md->disk), 512, STRING_UNITS_2,
 			cap_str, sizeof(cap_str));
-	pr_info("%s: %s %s %s %s\n",
+	if (card->quirks)
+		snprintf(quirk_str, sizeof(quirk_str),
+			 " (quirks 0x%08x)", card->quirks);
+	else
+		quirk_str[0] = '\0';
+	pr_info("%s: %s %s %s%s%s\n",
 		md->disk->disk_name, mmc_card_id(card), mmc_card_name(card),
-		cap_str, md->read_only ? "(ro)" : "");
+		cap_str, md->read_only ? " (ro)" : "", quirk_str);
 
 	if (mmc_blk_alloc_parts(card, md))
 		goto out;

drivers/mmc/core/core.c

@@ -1920,7 +1920,8 @@ EXPORT_SYMBOL(mmc_erase);
 int mmc_can_erase(struct mmc_card *card)
 {
 	if ((card->host->caps & MMC_CAP_ERASE) &&
-	    (card->csd.cmdclass & CCC_ERASE) && card->erase_size)
+	    (card->csd.cmdclass & CCC_ERASE) && card->erase_size &&
+	    !(card->quirks & MMC_QUIRK_ERASE_BROKEN))
 		return 1;
 	return 0;
 }

drivers/mmc/core/host.c

@@ -400,15 +400,30 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 {
 	int err;
 	struct mmc_host *host;
+	int id;
 
 	host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
 	if (!host)
 		return NULL;
 
+	/* If OF aliases exist, start dynamic assignment after highest */
+	id = of_alias_get_highest_id("mmc");
+	id = (id < 0) ? 0 : id + 1;
+
+	/* If this devices has OF node, maybe it has an alias */
+	if (dev->of_node) {
+		int of_id = of_alias_get_id(dev->of_node, "mmc");
+
+		if (of_id < 0)
+			dev_warn(dev, "/aliases ID not available\n");
+		else
+			id = of_id;
+	}
+
 	/* scanning will be enabled when we're ready */
 	host->rescan_disable = 1;
 
-	err = ida_simple_get(&mmc_host_ida, 0, 0, GFP_KERNEL);
+	err = ida_simple_get(&mmc_host_ida, id, 0, GFP_KERNEL);
 	if (err < 0) {
 		kfree(host);
 		return NULL;

drivers/mmc/core/quirks.h

@@ -99,6 +99,14 @@ static const struct mmc_fixup mmc_blk_fixups[] = {
 	MMC_FIXUP("V10016", CID_MANFID_KINGSTON, CID_OEMID_ANY, add_quirk_mmc,
 		  MMC_QUIRK_TRIM_BROKEN),
 
+	/*
+	 *  On some Kingston SD cards, multiple erases of less than 64
+	 *  sectors can cause corruption.
+	 */
+	MMC_FIXUP("SD16G", 0x41, 0x3432, add_quirk, MMC_QUIRK_ERASE_BROKEN),
+	MMC_FIXUP("SD32G", 0x41, 0x3432, add_quirk, MMC_QUIRK_ERASE_BROKEN),
+	MMC_FIXUP("SD64G", 0x41, 0x3432, add_quirk, MMC_QUIRK_ERASE_BROKEN),
+
 	END_FIXUP
 };
 

drivers/mmc/host/Kconfig

@@ -5,6 +5,35 @@
 
 comment "MMC/SD/SDIO Host Controller Drivers"
 
+config MMC_BCM2835_MMC
+	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_MMC
+	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 && 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_DEBUG
 	bool "MMC host drivers debugging"
 	depends on MMC != n

drivers/mmc/host/Makefile

@@ -23,6 +23,7 @@ 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_SDHCI_AM654)	+= sdhci_am654.o
+obj-$(CONFIG_MMC_BCM2835_MMC)	+= bcm2835-mmc.o
 obj-$(CONFIG_MMC_WBSD)		+= wbsd.o
 obj-$(CONFIG_MMC_AU1X)		+= au1xmmc.o
 obj-$(CONFIG_MMC_ALCOR)	+= alcor.o

include/linux/mmc/card.h

@@ -270,6 +270,8 @@ struct mmc_card {
 #define MMC_QUIRK_TRIM_BROKEN	(1<<12)		/* Skip trim */
 #define MMC_QUIRK_BROKEN_HPI	(1<<13)		/* Disable broken HPI support */
 
+#define MMC_QUIRK_ERASE_BROKEN	(1<<31)		/* Skip erase */
+
 	bool			reenable_cmdq;	/* Re-enable Command Queue */
 
 	unsigned int		erase_size;	/* erase size in sectors */