mmc: add DMA support to tmio_mmc driver, when used on SuperH

SDHI controllers on SuperH, served by the tmio_mmc driver, can use slave DMA
for data transfer. This patch adds support for the dmaengine API to the
tmio_mmc driver.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: Ian Molton <ian@mnementh.co.uk>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

drivers/mfd/Kconfig

@@ -49,6 +49,7 @@ config MFD_SH_MOBILE_SDHI
 	bool "Support for SuperH Mobile SDHI"
 	depends on SUPERH || ARCH_SHMOBILE
 	select MFD_CORE
+	select TMIO_MMC_DMA
 	 ---help---
 	  This driver supports the SDHI hardware block found in many
 	  SuperH Mobile SoCs.
@@ -162,6 +163,11 @@ config MFD_TMIO
 	bool
 	default n
 
+config TMIO_MMC_DMA
+	bool
+	select DMA_ENGINE
+	select DMADEVICES
+
 config MFD_T7L66XB
 	bool "Support Toshiba T7L66XB"
 	depends on ARM && HAVE_CLK

drivers/mmc/host/tmio_mmc.h

@@ -10,6 +10,8 @@
  */
 
 #include <linux/highmem.h>
+#include <linux/interrupt.h>
+#include <linux/dmaengine.h>
 
 #define CTL_SD_CMD 0x00
 #define CTL_ARG_REG 0x04
@@ -106,6 +108,17 @@ struct tmio_mmc_host {
 	unsigned int            sg_off;
 
 	struct platform_device *pdev;
+
+	/* DMA support */
+	struct dma_chan		*chan_rx;
+	struct dma_chan		*chan_tx;
+	struct tasklet_struct	dma_complete;
+	struct tasklet_struct	dma_issue;
+#ifdef CONFIG_TMIO_MMC_DMA
+	struct dma_async_tx_descriptor *desc;
+	unsigned int            dma_sglen;
+	dma_cookie_t		cookie;
+#endif
 };
 
 #include <linux/io.h>