/** * @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, * Nishanth Menon * * (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 #include #include #include #include #include #include "serial_ns16550.h" #include /*********** 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 = 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 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);