serial: sh-sci: Add DMA support.

Support using DMA for sending and receiving data over SCI(F) interfaces of
various SH SoCs.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

drivers/serial/Kconfig

@@ -1009,6 +1009,10 @@ config SERIAL_SH_SCI_CONSOLE
 	depends on SERIAL_SH_SCI=y
 	select SERIAL_CORE_CONSOLE
 
+config SERIAL_SH_SCI_DMA
+	bool "DMA support"
+	depends on SERIAL_SH_SCI && SH_DMAE && EXPERIMENTAL
+
 config SERIAL_PNX8XXX
 	bool "Enable PNX8XXX SoCs' UART Support"
 	depends on MIPS && (SOC_PNX8550 || SOC_PNX833X)

include/linux/serial_sci.h

@@ -2,6 +2,7 @@
 #define __LINUX_SERIAL_SCI_H
 
 #include <linux/serial_core.h>
+#include <asm/dmaengine.h>
 
 /*
  * Generic header for SuperH SCI(F) (used by sh/sh64/h8300 and related parts)
@@ -16,6 +17,8 @@ enum {
 	SCIx_NR_IRQS,
 };
 
+struct device;
+
 /*
  * Platform device specific platform_data struct
  */
@@ -26,6 +29,9 @@ struct plat_sci_port {
 	unsigned int	type;			/* SCI / SCIF / IRDA */
 	upf_t		flags;			/* UPF_* flags */
 	char		*clk;			/* clock string */
+	struct device	*dma_dev;
+	enum sh_dmae_slave_chan_id dma_slave_tx;
+	enum sh_dmae_slave_chan_id dma_slave_rx;
 };
 
 #endif /* __LINUX_SERIAL_SCI_H */