009-add-NS16550

[Patch 09/17] U-Boot-V2:Serial: Add support for NS16550 Driver.

This introduces support for NS16550 and related OMAP support. This driver is a port from Uboot v1 driver from OMAP's Uboot tree.
OMAP U-Boot V1 source is available here: http://linux.omap.com/pub/bootloader/3430sdp/u-boot-v1.tar.gz

Signed-off-by: Nishanth Menon<x0nishan@ti.com>

4 files changed, 363 insertions, 0 deletions

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 154600672e..5d7604de4d 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -24,4 +24,17 @@ config DRIVER_SERIAL_BLACKFIN
 	depends on BLACKFIN
 	default y
 	bool "Blackfin serial driver"
+
+config DRIVER_SERIAL_NS16550
+	default n
+	bool "NS16550 serial driver"
+	help
+	  Enable this to get support for NS16550 based serial devices
+
+config DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
+	bool "OMAP Extensions for NS16550"
+	depends on DRIVER_SERIAL_NS16550
+	depends on ARCH_OMAP
+	help
+	  Say Y here if you are using OMAP extensions to NS16550
 endmenu
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 088d03dfc5..1a72e9b9f7 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_DRIVER_SERIAL_NETX)		+= serial_netx.o
 obj-$(CONFIG_DRIVER_SERIAL_LINUX_COMSOLE)	+= linux_console.o
 obj-$(CONFIG_DRIVER_SERIAL_MPC5XXX)		+= serial_mpc5xxx.o
 obj-$(CONFIG_DRIVER_SERIAL_BLACKFIN)		+= serial_blackfin.o
+obj-$(CONFIG_DRIVER_SERIAL_NS16550)		+= serial_ns16550.o
diff --git a/drivers/serial/serial_ns16550.c b/drivers/serial/serial_ns16550.c
new file mode 100644
index 0000000000..077429be8f
--- /dev/null
+++ b/drivers/serial/serial_ns16550.c
@@ -0,0 +1,251 @@
+/**
+ * @file
+ * @brief NS16550 Driver implementation
+ *
+ * FileName: drivers/serial/serial_ns16550.c
+ *
+ * NS16550 support
+ * Modified from U-Boot V1 drivers/serial.c and drivers/ns16550.c
+ * originally from linux source (arch/ppc/boot/ns16550.c)
+ * modified to use CFG_ISA_MEM and new defines
+ */
+/*
+ * (C) Copyright 2008
+ * Texas Instruments, <www.ti.com>
+ * Nishanth Menon <x0nishan@ti.com>
+ *
+ * (C) Copyright 2000
+ * Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
+ * MA 02111-1307 USA
+ */
+
+#include <common.h>
+#include <driver.h>
+#include <init.h>
+#include <errno.h>
+#include <malloc.h>
+#include <asm/io.h>
+
+#include "serial_ns16550.h"
+#include <ns16550.h>
+
+/*********** Private Functions **********************************/
+
+/**
+ * @brief ns16550_calc_divisor - compute the divisor for a baud rate
+ *
+ * @param[in] cdev - pointer to console device
+ * @param[in] baudrate - baud rate
+ *
+ * @return divisor to be set
+ */
+static unsigned int ns16550_calc_divisor(struct console_device *cdev,
+					 unsigned int baudrate)
+{
+	struct NS16550_plat *plat = (struct NS16550_plat *)
+	    cdev->dev->platform_data;
+	unsigned int clk = plat->clock;
+#ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
+	/* FIXME: Legacy Code copied from U-Boot V1 implementation
+	 */
+#ifdef CONFIG_ARCH_OMAP1510
+	unsigned long base = cdev->dev->map_base;
+	/* If can't cleanly clock 115200 set div to 1 */
+	if ((clk == 12000000) && (baudrate == 115200)) {
+		/* enable 6.5 * divisor */
+		plat->reg_write(OSC_12M_SEL, base, osc_12m_sel);
+		return 1;	/* return 1 for base divisor */
+	}
+	/* clear if previously set */
+	plat->reg_write(0, base, osc_12m_sel);
+#elif defined(CONFIG_ARCH_OMAP1610)
+	/* If can't cleanly clock 115200 set div to 1 */
+	if ((clk == 48000000) && (baudrate == 115200))
+		return 26;	/* return 26 for base divisor */
+#endif
+
+#endif				/* End of OMAP specific handling */
+	return (clk / MODE_X_DIV / baudrate);
+
+}
+
+/**
+ * @brief ns16550_serial_init_port - initialize the device
+ *
+ * @param cdev[in] - pointer to console device
+ */
+static void ns16550_serial_init_port(struct console_device *cdev)
+{
+	struct NS16550_plat *plat = (struct NS16550_plat *)
+	    cdev->dev->platform_data;
+	unsigned long base = cdev->dev->map_base;
+	unsigned int baud_divisor;
+
+	/* Setup the serial port with the defaults first */
+	baud_divisor = ns16550_calc_divisor(cdev, CONFIG_BAUDRATE);
+
+	/* initializing the device for the first time */
+	plat->reg_write(0x00, base, ier);
+#ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
+	plat->reg_write(0x07, base, mdr1);	/* Disable */
+#endif
+	plat->reg_write(LCR_BKSE | LCRVAL, base, lcr);
+	plat->reg_write(baud_divisor & 0xFF, base, dll);
+	plat->reg_write((baud_divisor >> 8) & 0xff, base, dlm);
+	plat->reg_write(LCRVAL, base, lcr);
+	plat->reg_write(MCRVAL, base, mcr);
+	plat->reg_write(FCRVAL, base, fcr);
+#ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
+	plat->reg_write(0x00, base, mdr1);
+#endif
+}
+
+/*********** Exposed Functions **********************************/
+
+/**
+ * @brief ns16550_putc- put a character to the serial port
+ *
+ * @param cdev[in] - pointer to console device
+ * @param c[in] - character to put
+ */
+static void ns16550_putc(struct console_device *cdev, char c)
+{
+	struct NS16550_plat *plat = (struct NS16550_plat *)
+	    cdev->dev->platform_data;
+	unsigned long base = cdev->dev->map_base;
+	/* Loop Doing Nothing */
+	while ((plat->reg_read(base, lsr) & LSR_THRE) == 0) ;
+	plat->reg_write(c, base, thr);
+}
+
+/**
+ * @brief ns16550_getc - retrieve a character from serial port
+ *
+ * @param cdev[in] - pointer to console device
+ *
+ * @return return the character read
+ */
+static int ns16550_getc(struct console_device *cdev)
+{
+	struct NS16550_plat *plat = (struct NS16550_plat *)
+	    cdev->dev->platform_data;
+	unsigned long base = cdev->dev->map_base;
+	/* Loop Doing Nothing */
+	while ((plat->reg_read(base, lsr) & LSR_DR) == 0) ;
+	return plat->reg_read(base, rbr);
+}
+
+/**
+ * @brief ns16550_tstc - test if character is available
+ *
+ * @param cdev[in] -pointer to console device
+ *
+ * @return  - status based on data availability
+ */
+static int ns16550_tstc(struct console_device *cdev)
+{
+	struct NS16550_plat *plat = (struct NS16550_plat *)
+	    cdev->dev->platform_data;
+	unsigned long base = cdev->dev->map_base;
+	return ((plat->reg_read(base, lsr) & LSR_DR) != 0);
+}
+
+/**
+ * @brief ns16550_setbaudrate - set the baudrate for the uart port
+ *
+ * @param cdev[in] - console device
+ * @param baud_rate[in] - baud rate to set
+ *
+ * @return  0-implied to support the baudrate
+ */
+static int ns16550_setbaudrate(struct console_device *cdev, int baud_rate)
+{
+	struct NS16550_plat *plat = (struct NS16550_plat *)
+	    cdev->dev->platform_data;
+	unsigned long base = cdev->dev->map_base;
+	unsigned int baud_divisor = ns16550_calc_divisor(cdev, baud_rate);
+	plat->reg_write(0x00, base, ier);
+	plat->reg_write(LCR_BKSE, base, lcr);
+	plat->reg_write(baud_divisor & 0xff, base, dll);
+	plat->reg_write((baud_divisor >> 8) & 0xff, base, dlm);
+	plat->reg_write(LCRVAL, base, lcr);
+	plat->reg_write(MCRVAL, base, mcr);
+	plat->reg_write(FCRVAL, base, fcr);
+	return 0;
+}
+
+/**
+ * @brief ns16550_probe - Probe entry point -called on the first
+ *			  match for device
+ *
+ * @param dev[in]  - matched device
+ *
+ * @return EINVAL if platform_data is not populated,
+ *	   ENOMEM if calloc failed
+ *	   else return result of console_register
+ */
+static int ns16550_probe(struct device_d *dev)
+{
+	struct console_device *cdev;
+	struct NS16550_plat *plat = (struct NS16550_plat *)dev->platform_data;
+
+	/* we do expect platform specific data */
+	if (plat == NULL)
+		return -EINVAL;
+	if ((plat->reg_read == NULL) || (plat->reg_write == NULL))
+		return -EINVAL;
+
+	cdev = calloc(1, sizeof(struct console_device));
+	if (cdev == NULL)
+		return -ENOMEM;
+
+	dev->type_data = cdev;
+	cdev->dev = dev;
+	cdev->f_caps = plat->f_caps;
+	cdev->tstc = ns16550_tstc;
+	cdev->putc = ns16550_putc;
+	cdev->getc = ns16550_getc;
+	cdev->setbrg = ns16550_setbaudrate;
+
+	ns16550_serial_init_port(cdev);
+
+	return console_register(cdev);
+}
+
+/**
+ * @brief Driver registration structure
+ */
+static struct driver_d ns16550_serial_driver = {
+	.name = "serial_ns16550",
+	.probe = ns16550_probe,
+	.type = DEVICE_TYPE_CONSOLE,
+};
+
+/**
+ * @brief ns16550_serial_init - driver initialization function
+ *
+ * @return result of register_driver
+ */
+static int ns16550_serial_init(void)
+{
+	return register_driver(&ns16550_serial_driver);
+}
+
+console_initcall(ns16550_serial_init);
diff --git a/drivers/serial/serial_ns16550.h b/drivers/serial/serial_ns16550.h
new file mode 100644
index 0000000000..eb2fd1080f
--- /dev/null
+++ b/drivers/serial/serial_ns16550.h
@@ -0,0 +1,98 @@
+/**
+ * @file
+ * @brief Serial NS16550 header
+ *
+ * FileName: drivers/serial/serial_ns16550.h
+ *
+ * @code struct NS16550 @endcode
+ * Register definitions for NS16550 device
+ */
+/*
+ * This file is licensed under
+ * the terms of the GNU General Public License version 2.  This program
+ * is licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ *
+ * NS16550 Serial Port
+ * originally from linux source (arch/ppc/boot/ns16550.h)
+ * modified slightly to
+ * have addresses as offsets from CFG_ISA_BASE
+ * added a few more definitions
+ * added prototypes for ns16550.c
+ * reduced no of com ports to 2
+ * modifications (c) Rob Taylor, Flying Pig Systems. 2000.
+ *
+ * added support for port on 64-bit bus
+ * by Richard Danter (richard.danter@windriver.com), (C) 2005 Wind River Systems
+ */
+
+#ifndef __SERIAL_NS16550__H
+#define  __SERIAL_NS16550__H
+
+/** Register offset definitions
+ * platform implementation needs to translate this
+ */
+#define rbr		0
+#define ier		1
+#define fcr		2
+#define lcr		3
+#define mcr		4
+#define lsr		5
+#define msr		6
+#define scr		7
+#ifdef CONFIG_DRIVER_SERIAL_NS16550_OMAP_EXTENSIONS
+#define mdr1		8
+#define osc_12m_sel	9
+#endif
+
+#define thr		rbr
+#define iir		fcr
+#define dll		rbr
+#define dlm		ier
+
+#define FCR_FIFO_EN     0x01	/* Fifo enable */
+#define FCR_RXSR        0x02	/* Receiver soft reset */
+#define FCR_TXSR        0x04	/* Transmitter soft reset */
+
+#define MCR_DTR         0x01
+#define MCR_RTS         0x02
+#define MCR_DMA_EN      0x04
+#define MCR_TX_DFR      0x08
+
+#define LCR_WLS_MSK	0x03	/* character length select mask */
+#define LCR_WLS_5	0x00	/* 5 bit character length */
+#define LCR_WLS_6	0x01	/* 6 bit character length */
+#define LCR_WLS_7	0x02	/* 7 bit character length */
+#define LCR_WLS_8	0x03	/* 8 bit character length */
+/* Number of stop Bits, off = 1, on = 1.5 or 2) */
+#define LCR_STB		0x04
+#define LCR_PEN		0x08	/* Parity eneble */
+#define LCR_EPS		0x10	/* Even Parity Select */
+#define LCR_STKP	0x20	/* Stick Parity */
+#define LCR_SBRK	0x40	/* Set Break */
+#define LCR_BKSE	0x80	/* Bank select enable */
+
+#define LSR_DR		0x01	/* Data ready */
+#define LSR_OE		0x02	/* Overrun */
+#define LSR_PE		0x04	/* Parity error */
+#define LSR_FE		0x08	/* Framing error */
+#define LSR_BI		0x10	/* Break */
+#define LSR_THRE	0x20	/* Xmit holding register empty */
+#define LSR_TEMT	0x40	/* Xmitter empty */
+#define LSR_ERR		0x80	/* Error */
+
+#ifdef CONFIG_ARCH_OMAP1510
+#define OSC_12M_SEL	0x01	/* selects 6.5 * current clk div */
+#endif
+
+/* useful defaults for LCR */
+#define LCR_8N1		0x03
+
+#define LCRVAL		LCR_8N1	/* 8 data, 1 stop, no parity */
+#define MCRVAL		(MCR_DTR | MCR_RTS) /* RTS/DTR */
+/* Clear & enable FIFOs */
+#define FCRVAL		(FCR_FIFO_EN | FCR_RXSR | FCR_TXSR)
+
+#define MODE_X_DIV	16
+
+#endif				/*  __SERIAL_NS16550__H */