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/**
* @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[in] cdev 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[in] cdev pointer to console device
* @param[in] c 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[in] cdev 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[in] cdev 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[in] cdev console device
* @param[in] baud_rate 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[in] dev 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,
};
/**
* @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);
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