173 lines
3.5 KiB
C
173 lines
3.5 KiB
C
/*
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* (C) Copyright 2002
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* Gary Jennejohn, DENX Software Engineering, <garyj@denx.de>
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*
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* (C) Copyright 2008
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* Guennadi Liakhovetki, DENX Software Engineering, <lg@denx.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*/
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#include <common.h>
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#include <s3c6400.h>
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#ifdef CONFIG_SERIAL1
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#define UART_NR S3C64XX_UART0
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#elif defined(CONFIG_SERIAL2)
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#define UART_NR S3C64XX_UART1
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#elif defined(CONFIG_SERIAL3)
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#define UART_NR S3C64XX_UART2
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#else
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#error "Bad: you didn't configure serial ..."
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#endif
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#define barrier() asm volatile("" ::: "memory")
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/*
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* The coefficient, used to calculate the baudrate on S3C6400 UARTs is
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* calculated as
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* C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT
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* however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1,
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* 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants:
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*/
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static const int udivslot[] = {
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0,
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0x0080,
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0x0808,
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0x0888,
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0x2222,
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0x4924,
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0x4a52,
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0x54aa,
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0x5555,
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0xd555,
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0xd5d5,
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0xddd5,
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0xdddd,
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0xdfdd,
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0xdfdf,
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0xffdf,
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};
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void serial_setbrg(void)
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{
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DECLARE_GLOBAL_DATA_PTR;
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s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
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u32 pclk = get_PCLK();
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u32 baudrate = gd->baudrate;
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int i;
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i = (pclk / baudrate) % 16;
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uart->UBRDIV = pclk / baudrate / 16 - 1;
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uart->UDIVSLOT = udivslot[i];
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for (i = 0; i < 100; i++)
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barrier();
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}
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/*
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* Initialise the serial port with the given baudrate. The settings
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* are always 8 data bits, no parity, 1 stop bit, no start bits.
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*/
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int serial_init(void)
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{
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s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
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/* reset and enable FIFOs, set triggers to the maximum */
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uart->UFCON = 0xff;
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uart->UMCON = 0;
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/* 8N1 */
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uart->ULCON = 3;
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/* No interrupts, no DMA, pure polling */
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uart->UCON = 5;
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serial_setbrg();
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return 0;
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}
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/*
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* Read a single byte from the serial port. Returns 1 on success, 0
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* otherwise. When the function is succesfull, the character read is
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* written into its argument c.
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*/
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int serial_getc(void)
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{
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s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
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/* wait for character to arrive */
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while (!(uart->UTRSTAT & 0x1));
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return uart->URXH & 0xff;
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}
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#ifdef CONFIG_MODEM_SUPPORT
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static int be_quiet;
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void disable_putc(void)
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{
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be_quiet = 1;
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}
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void enable_putc(void)
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{
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be_quiet = 0;
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}
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#endif
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/*
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* Output a single byte to the serial port.
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*/
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void serial_putc(const char c)
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{
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s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
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#ifdef CONFIG_MODEM_SUPPORT
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if (be_quiet)
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return;
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#endif
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/* wait for room in the tx FIFO */
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while (!(uart->UTRSTAT & 0x2));
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uart->UTXH = c;
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/* If \n, also do \r */
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if (c == '\n')
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serial_putc('\r');
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}
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/*
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* Test whether a character is in the RX buffer
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*/
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int serial_tstc(void)
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{
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s3c64xx_uart *const uart = s3c64xx_get_base_uart(UART_NR);
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return uart->UTRSTAT & 0x1;
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}
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void serial_puts(const char *s)
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{
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while (*s)
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serial_putc(*s++);
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}
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