jz4740/jz_serial.c

   1 /*
   2  * Jz47xx UART support
   3  *
   4  * Options hardcoded to 8N1
   5  *
   6  *  Copyright (c) 2009, yajin <yajin@vm-kernel.org>
   7  *  Copyright (c) 2005 - 2008, Ingenic Semiconductor Inc.
   8  *  Ingenic Semiconductor, <jlwei@ingenic.cn>
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of
  13  * the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  23  * MA 02111-1307 USA
  24  */
  25
  26
  27 #include <jz4740.h>
  28 #include <board.h>
  29
  30 #undef UART_BASE
  31 #ifndef CFG_UART_BASE
  32 #define UART_BASE  UART0_BASE
  33 #else
  34 #define UART_BASE  CFG_UART_BASE
  35 #endif
  36
  37 /******************************************************************************
  38 *
  39 * serial_init - initialize a channel
  40 *
  41 * This routine initializes the number of data bits, parity
  42 * and set the selected baud rate. Interrupts are disabled.
  43 * Set the modem control signals if the option is selected.
  44 *
  45 * RETURNS: N/A
  46 */
  47
  48 static void serial_setbrg(void)
  49 {
  50     volatile u8 *uart_lcr = (volatile u8 *) (UART_BASE + OFF_LCR);
  51     volatile u8 *uart_dlhr = (volatile u8 *) (UART_BASE + OFF_DLHR);
  52     volatile u8 *uart_dllr = (volatile u8 *) (UART_BASE + OFF_DLLR);
  53     u32 baud_div, tmp;
  54
  55     baud_div = CFG_EXTAL / 16 / CONFIG_BAUDRATE;
  56     tmp = *uart_lcr;
  57     tmp |= UART_LCR_DLAB;
  58     *uart_lcr = tmp;
  59
  60     *uart_dlhr = (baud_div >> 8) & 0xff;
  61     *uart_dllr = baud_div & 0xff;
  62
  63     tmp &= ~UART_LCR_DLAB;
  64     *uart_lcr = tmp;
  65 }
  66
  67 int serial_init(void)
  68 {
  69     volatile u8 *uart_fcr = (volatile u8 *) (UART_BASE + OFF_FCR);
  70     volatile u8 *uart_lcr = (volatile u8 *) (UART_BASE + OFF_LCR);
  71     volatile u8 *uart_ier = (volatile u8 *) (UART_BASE + OFF_IER);
  72     volatile u8 *uart_sircr = (volatile u8 *) (UART_BASE + OFF_SIRCR);
  73
  74     /* Disable port interrupts while changing hardware */
  75     *uart_ier = 0;
  76
  77     /* Disable UART unit function */
  78     *uart_fcr = ~UART_FCR_UUE;
  79
  80     /* Set both receiver and transmitter in UART mode (not SIR) */
  81     *uart_sircr = ~(SIRCR_RSIRE | SIRCR_TSIRE);
  82
  83     /* Set databits, stopbits and parity. (8-bit data, 1 stopbit, no parity) */
  84     *uart_lcr = UART_LCR_WLEN_8 | UART_LCR_STOP_1;
  85
  86     /* Set baud rate */
  87     serial_setbrg();
  88
  89     /* Enable UART unit, enable and clear FIFO */
  90     *uart_fcr = UART_FCR_UUE | UART_FCR_FE | UART_FCR_TFLS | UART_FCR_RFLS;
  91
  92     return 0;
  93 }
  94
  95 void serial_putc(const char c)
  96 {
  97     volatile u8 *uart_lsr = (volatile u8 *) (UART_BASE + OFF_LSR);
  98     volatile u8 *uart_tdr = (volatile u8 *) (UART_BASE + OFF_TDR);
  99
 100     if (c == '\n')
 101         serial_putc('\r');
 102
 103     /* Wait for fifo to shift out some bytes */
 104     while (!((*uart_lsr & (UART_LSR_TDRQ | UART_LSR_TEMT)) == 0x60));
 105
 106     *uart_tdr = (u8) c;
 107 }
 108
 109 void serial_puts(const char *s)
 110 {
 111     while (*s)
 112     {
 113         serial_putc(*s++);
 114     }
 115 }