add alternative MMC driver and support scatter/gather transfers in dmaengine

arch/arm/configs/bcmrpi_defconfig

@@ -896,6 +896,9 @@ CONFIG_USB_ISIGHTFW=m
 CONFIG_USB_YUREX=m
 CONFIG_MMC=y
 CONFIG_MMC_BLOCK_MINORS=32
+CONFIG_MMC_BCM2835=y
+CONFIG_MMC_BCM2835_DMA=y
+CONFIG_MMC_BCM2835_PIO_DMA_BARRIER=2
 CONFIG_MMC_SDHCI=y
 CONFIG_MMC_SDHCI_PLTFM=y
 CONFIG_MMC_SDHCI_BCM2708=y
@@ -945,7 +948,7 @@ CONFIG_RTC_DRV_DS3234=m
 CONFIG_RTC_DRV_PCF2123=m
 CONFIG_RTC_DRV_RX4581=m
 CONFIG_DMADEVICES=y
-CONFIG_DMA_BCM2708=m
+CONFIG_DMA_BCM2708=y
 CONFIG_UIO=m
 CONFIG_UIO_PDRV_GENIRQ=m
 CONFIG_STAGING=y

arch/arm/mach-bcm2708/bcm2708.c

@@ -90,6 +90,7 @@ static unsigned disk_led_active_low = 1;
 static unsigned reboot_part = 0;
 static unsigned w1_gpio_pin = W1_GPIO;
 static unsigned w1_gpio_pullup = W1_PULLUP;
+static unsigned bcm2835_mmc = 0;
 
 static void __init bcm2708_init_led(void);
 
@@ -452,6 +453,34 @@ struct platform_device bcm2708_emmc_device = {
 };
 #endif /* CONFIG_MMC_SDHCI_BCM2708 */
 
+#ifdef CONFIG_MMC_BCM2835	/* Arasan emmc SD (new) */
+static struct resource bcm2835_emmc_resources[] = {
+	[0] = {
+	       .start = EMMC_BASE,
+	       .end = EMMC_BASE + SZ_256 - 1,	/* we only need this area */
+	       /* the memory map actually makes SZ_4K available  */
+	       .flags = IORESOURCE_MEM,
+	       },
+	[1] = {
+	       .start = IRQ_ARASANSDIO,
+	       .end = IRQ_ARASANSDIO,
+	       .flags = IORESOURCE_IRQ,
+	       },
+};
+
+static u64 bcm2835_emmc_dmamask = 0xffffffffUL;
+
+struct platform_device bcm2835_emmc_device = {
+	.name = "mmc-bcm2835",
+	.id = 0,
+	.num_resources = ARRAY_SIZE(bcm2835_emmc_resources),
+	.resource = bcm2835_emmc_resources,
+	.dev = {
+		.dma_mask = &bcm2835_emmc_dmamask,
+		.coherent_dma_mask = 0xffffffffUL},
+};
+#endif /* CONFIG_MMC_BCM2835 */
+
 static struct resource bcm2708_powerman_resources[] = {
 	[0] = {
 	       .start = PM_BASE,
@@ -806,7 +835,12 @@ void __init bcm2708_init(void)
 	bcm_register_device(&bcm2708_powerman_device);
 
 #ifdef CONFIG_MMC_SDHCI_BCM2708
-	bcm_register_device(&bcm2708_emmc_device);
+	if (!bcm2835_mmc)
+		bcm_register_device(&bcm2708_emmc_device);
+#endif
+#ifdef CONFIG_MMC_BCM2835
+	if (bcm2835_mmc)
+		bcm_register_device(&bcm2835_emmc_device);
 #endif
 	bcm2708_init_led();
 	for (i = 0; i < ARRAY_SIZE(bcm2708_alsa_devices); i++)
@@ -1030,3 +1064,4 @@ module_param(disk_led_active_low, uint, 0644);
 module_param(reboot_part, uint, 0644);
 module_param(w1_gpio_pin, uint, 0644);
 module_param(w1_gpio_pullup, uint, 0644);
+module_param(bcm2835_mmc, uint, 0644);

arch/arm/mach-bcm2708/dma.c

@@ -156,6 +156,8 @@ static void vc_dmaman_init(struct vc_dmaman *dmaman, void __iomem *dma_base,
 	dmaman->chan_available = chans_available;
 	dmaman->has_feature[BCM_DMA_FEATURE_FAST_ORD] = 0x0c;  /* chans 2 & 3 */
 	dmaman->has_feature[BCM_DMA_FEATURE_BULK_ORD] = 0x01;  /* chan 0 */
+	dmaman->has_feature[BCM_DMA_FEATURE_NORMAL_ORD] = 0xfe;  /* chans 1 to 7 */
+	dmaman->has_feature[BCM_DMA_FEATURE_LITE_ORD] = 0x7f00;  /* chans 8 to 14 */
 }
 
 static int vc_dmaman_chan_alloc(struct vc_dmaman *dmaman,

arch/arm/mach-bcm2708/include/mach/dma.h

@@ -77,9 +77,13 @@ extern int /*rc*/ bcm_dma_abort(void __iomem *dma_chan_base);
    those with higher priority smaller ordinal numbers */
 #define BCM_DMA_FEATURE_FAST_ORD 0
 #define BCM_DMA_FEATURE_BULK_ORD 1
+#define BCM_DMA_FEATURE_NORMAL_ORD 2
+#define BCM_DMA_FEATURE_LITE_ORD 3
 #define BCM_DMA_FEATURE_FAST	 (1<<BCM_DMA_FEATURE_FAST_ORD)
 #define BCM_DMA_FEATURE_BULK	 (1<<BCM_DMA_FEATURE_BULK_ORD)
-#define BCM_DMA_FEATURE_COUNT	 2
+#define BCM_DMA_FEATURE_NORMAL	 (1<<BCM_DMA_FEATURE_NORMAL_ORD)
+#define BCM_DMA_FEATURE_LITE	 (1<<BCM_DMA_FEATURE_LITE_ORD)
+#define BCM_DMA_FEATURE_COUNT	 4
 
 /* return channel no or -ve error */
 extern int bcm_dma_chan_alloc(unsigned preferred_feature_set,