| /** |
| * @file |
| * @brief NS16550 Driver implementation |
| * |
| * FileName: drivers/serial/serial_ns16550.c |
| * |
| * NS16550 support |
| * Modified from u-boot 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 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 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 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 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 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 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 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 = xzalloc(sizeof(*cdev)); |
| |
| 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 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); |