serial: Add OMAP high-speed UART driver

This patch adds driver support for OMAP2/3/4 high speed UART.

The driver is made separate from 8250 driver as we cannot
over load 8250 driver with omap platform specific configuration for
features like DMA, it makes easier to implement features like DMA and
hardware flow control and software flow control configuration with
this driver as required for the omap-platform.
This patch involves only the core driver and its dependent.

Cc: Tony Lindgren <tony@atomide.com>
Signed-off-by: Govindraj.R <govindraj.raja@ti.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

arch/arm/plat-omap/include/plat/omap-serial.h

@@ -0,0 +1,129 @@
+/*
+ * Driver for OMAP-UART controller.
+ * Based on drivers/serial/8250.c
+ *
+ * Copyright (C) 2010 Texas Instruments.
+ *
+ * Authors:
+ *	Govindraj R	<govindraj.raja@ti.com>
+ *	Thara Gopinath	<thara@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#ifndef __OMAP_SERIAL_H__
+#define __OMAP_SERIAL_H__
+
+#include <linux/serial_core.h>
+#include <linux/platform_device.h>
+
+#include <plat/control.h>
+#include <plat/mux.h>
+
+#define DRIVER_NAME	"omap-hsuart"
+
+/*
+ * Use tty device name as ttyO, [O -> OMAP]
+ * in bootargs we specify as console=ttyO0 if uart1
+ * is used as console uart.
+ */
+#define OMAP_SERIAL_NAME	"ttyO"
+
+#define OMAP_MDR1_DISABLE	0x07
+#define OMAP_MDR1_MODE13X	0x03
+#define OMAP_MDR1_MODE16X	0x00
+#define OMAP_MODE13X_SPEED	230400
+
+/*
+ * LCR = 0XBF: Switch to Configuration Mode B.
+ * In configuration mode b allow access
+ * to EFR,DLL,DLH.
+ * Reference OMAP TRM Chapter 17
+ * Section: 1.4.3 Mode Selection
+ */
+#define OMAP_UART_LCR_CONF_MDB	0XBF
+
+/* WER = 0x7F
+ * Enable module level wakeup in WER reg
+ */
+#define OMAP_UART_WER_MOD_WKUP	0X7F
+
+/* Enable XON/XOFF flow control on output */
+#define OMAP_UART_SW_TX		0x04
+
+/* Enable XON/XOFF flow control on input */
+#define OMAP_UART_SW_RX		0x04
+
+#define OMAP_UART_SYSC_RESET	0X07
+#define OMAP_UART_TCR_TRIG	0X0F
+#define OMAP_UART_SW_CLR	0XF0
+#define OMAP_UART_FIFO_CLR	0X06
+
+#define OMAP_UART_DMA_CH_FREE	-1
+
+#define RX_TIMEOUT		(3 * HZ)
+#define OMAP_MAX_HSUART_PORTS	4
+
+#define MSR_SAVE_FLAGS		UART_MSR_ANY_DELTA
+
+struct omap_uart_port_info {
+	bool			dma_enabled;	/* To specify DMA Mode */
+	unsigned int		uartclk;	/* UART clock rate */
+	void __iomem		*membase;	/* ioremap cookie or NULL */
+	resource_size_t		mapbase;	/* resource base */
+	unsigned long		irqflags;	/* request_irq flags */
+	upf_t			flags;		/* UPF_* flags */
+};
+
+struct uart_omap_dma {
+	u8			uart_dma_tx;
+	u8			uart_dma_rx;
+	int			rx_dma_channel;
+	int			tx_dma_channel;
+	dma_addr_t		rx_buf_dma_phys;
+	dma_addr_t		tx_buf_dma_phys;
+	unsigned int		uart_base;
+	/*
+	 * Buffer for rx dma.It is not required for tx because the buffer
+	 * comes from port structure.
+	 */
+	unsigned char		*rx_buf;
+	unsigned int		prev_rx_dma_pos;
+	int			tx_buf_size;
+	int			tx_dma_used;
+	int			rx_dma_used;
+	spinlock_t		tx_lock;
+	spinlock_t		rx_lock;
+	/* timer to poll activity on rx dma */
+	struct timer_list	rx_timer;
+	int			rx_buf_size;
+	int			rx_timeout;
+};
+
+struct uart_omap_port {
+	struct uart_port	port;
+	struct uart_omap_dma	uart_dma;
+	struct platform_device	*pdev;
+
+	unsigned char		ier;
+	unsigned char		lcr;
+	unsigned char		mcr;
+	unsigned char		fcr;
+	unsigned char		efr;
+
+	int			use_dma;
+	/*
+	 * Some bits in registers are cleared on a read, so they must
+	 * be saved whenever the register is read but the bits will not
+	 * be immediately processed.
+	 */
+	unsigned int		lsr_break_flag;
+	unsigned char		msr_saved_flags;
+	char			name[20];
+	unsigned long		port_activity;
+};
+
+#endif /* __OMAP_SERIAL_H__ */

drivers/serial/Kconfig

@@ -1416,6 +1416,33 @@ config SERIAL_OF_PLATFORM
 	  Currently, only 8250 compatible ports are supported, but
 	  others can easily be added.
 
+config SERIAL_OMAP
+	tristate "OMAP serial port support"
+	depends on ARCH_OMAP2 || ARCH_OMAP3 || ARCH_OMAP4
+	select SERIAL_CORE
+	help
+	  If you have a machine based on an Texas Instruments OMAP CPU you
+	  can enable its onboard serial ports by enabling this option.
+
+	  By enabling this option you take advantage of dma feature available
+	  with the omap-serial driver. DMA support can be enabled from platform
+	  data.
+
+config SERIAL_OMAP_CONSOLE
+	bool "Console on OMAP serial port"
+	depends on SERIAL_OMAP
+	select SERIAL_CORE_CONSOLE
+	help
+	  Select this option if you would like to use omap serial port as
+	  console.
+
+	  Even if you say Y here, the currently visible virtual console
+	  (/dev/tty0) will still be used as the system console by default, but
+	  you can alter that using a kernel command line option such as
+	  "console=ttyOx". (Try "man bootparam" or see the documentation of
+	  your boot loader about how to pass options to the kernel at
+	  boot time.)
+
 config SERIAL_OF_PLATFORM_NWPSERIAL
 	tristate "NWP serial port driver"
 	depends on PPC_OF && PPC_DCR

drivers/serial/Makefile

@@ -88,3 +88,4 @@ obj-$(CONFIG_SERIAL_ALTERA_JTAGUART) += altera_jtaguart.o
 obj-$(CONFIG_SERIAL_ALTERA_UART) += altera_uart.o
 obj-$(CONFIG_SERIAL_MRST_MAX3110)	+= mrst_max3110.o
 obj-$(CONFIG_SERIAL_MFD_HSU)	+= mfd.o
+obj-$(CONFIG_SERIAL_OMAP) += omap-serial.o

include/linux/serial_core.h

@@ -196,6 +196,9 @@
 /* High Speed UART for Medfield */
 #define PORT_MFD	95
 
+/* TI OMAP-UART */
+#define PORT_OMAP	96
+
 #ifdef __KERNEL__
 
 #include <linux/compiler.h>