serial: samsung: add struct s3c24xx_uart_dma

This struct contains DMA configuration for each serial port.
It will be used in next commits adding DMA support in driver.

Based on previous work of Sylwester Nawrocki and Lukasz Czerwinski.
Signed-off-by: Robert Baldyga <r.baldyga@samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/tty/serial/samsung.h

@@ -12,6 +12,8 @@
  * published by the Free Software Foundation.
 */
 
+#include <linux/dmaengine.h>
+
 struct s3c24xx_uart_info {
 	char			*name;
 	unsigned int		type;
@@ -41,6 +43,40 @@ struct s3c24xx_serial_drv_data {
 	unsigned int			fifosize[CONFIG_SERIAL_SAMSUNG_UARTS];
 };
 
+struct s3c24xx_uart_dma {
+	dma_filter_fn			fn;
+	void				*rx_param;
+	void				*tx_param;
+
+	unsigned int			rx_chan_id;
+	unsigned int			tx_chan_id;
+
+	struct dma_slave_config		rx_conf;
+	struct dma_slave_config		tx_conf;
+
+	struct dma_chan			*rx_chan;
+	struct dma_chan			*tx_chan;
+
+	dma_addr_t			rx_addr;
+	dma_addr_t			tx_addr;
+
+	dma_cookie_t			rx_cookie;
+	dma_cookie_t			tx_cookie;
+
+	char				*rx_buf;
+
+	dma_addr_t			tx_transfer_addr;
+
+	size_t				rx_size;
+	size_t				tx_size;
+
+	struct dma_async_tx_descriptor	*tx_desc;
+	struct dma_async_tx_descriptor	*rx_desc;
+
+	int				tx_bytes_requested;
+	int				rx_bytes_requested;
+};
+
 struct s3c24xx_uart_port {
 	unsigned char			rx_claimed;
 	unsigned char			tx_claimed;
@@ -59,6 +95,8 @@ struct s3c24xx_uart_port {
 	/* reference to platform data */
 	struct s3c2410_uartcfg		*cfg;
 
+	struct s3c24xx_uart_dma		*dma;
+
 #ifdef CONFIG_CPU_FREQ
 	struct notifier_block		freq_transition;
 #endif