/* * (C) Copyright 2002 * Gary Jennejohn, DENX Software Engineering, <garyj@denx.de> * * (C) Copyright 2008 * Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de> * * 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 <asm/arch/s3c6400.h> #ifdef CONFIG_SERIAL1 #define UART_NR S3C64XX_UART0 #elif defined(CONFIG_SERIAL2) #define UART_NR S3C64XX_UART1 #elif defined(CONFIG_SERIAL3) #define UART_NR S3C64XX_UART2 #else #error "Bad: you didn't configure serial ..." #endif #define barrier() asm volatile("" ::: "memory") /* * The coefficient, used to calculate the baudrate on S3C6400 UARTs is * calculated as * C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT * however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1, * 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants: */ static const int udivslot[] = { 0, 0x0080, 0x0808, 0x0888, 0x2222, 0x4924, 0x4a52, 0x54aa, 0x5555, 0xd555, 0xd5d5, 0xddd5, 0xdddd, 0xdfdd, 0xdfdf, 0xffdf, }; void serial_setbrg(void) { DECLARE_GLOBAL_DATA_PTR; s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR); u32 pclk = get_PCLK(); u32 baudrate = gd->baudrate; int i; i = (pclk / baudrate) % 16; uart->UBRDIV = pclk / baudrate / 16 - 1; uart->UDIVSLOT = udivslot[i]; for (i = 0; i < 100; i++) barrier(); } /* * Initialise the serial port with the given baudrate. The settings * are always 8 data bits, no parity, 1 stop bit, no start bits. */ int serial_init(void) { s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR); /* reset and enable FIFOs, set triggers to the maximum */ uart->UFCON = 0xff; uart->UMCON = 0; /* 8N1 */ uart->ULCON = 3; /* No interrupts, no DMA, pure polling */ uart->UCON = 5; serial_setbrg(); return 0; } /* * Read a single byte from the serial port. Returns 1 on success, 0 * otherwise. When the function is succesfull, the character read is * written into its argument c. */ int serial_getc(void) { s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR); /* wait for character to arrive */ while (!(uart->UTRSTAT & 0x1)); return uart->URXH & 0xff; } #ifdef CONFIG_MODEM_SUPPORT static int be_quiet; void disable_putc(void) { be_quiet = 1; } void enable_putc(void) { be_quiet = 0; } #endif /* * Output a single byte to the serial port. */ void serial_putc(const char c) { s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR); #ifdef CONFIG_MODEM_SUPPORT if (be_quiet) return; #endif /* wait for room in the tx FIFO */ while (!(uart->UTRSTAT & 0x2)); uart->UTXH = c; /* If \n, also do \r */ if (c == '\n') serial_putc('\r'); } /* * Test whether a character is in the RX buffer */ int serial_tstc(void) { s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR); return uart->UTRSTAT & 0x1; } void serial_puts(const char *s) { while (*s) serial_putc(*s++); }