drivers/atmel_usart.c

   1 /*
   2  * Copyright (C) 2004-2006 Atmel Corporation
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  */
  18 #include <common.h>
  19
  20 #ifdef CONFIG_ATMEL_USART
  21 #include <asm/io.h>
  22 #include <asm/arch/clk.h>
  23 #include <asm/arch/memory-map.h>
  24
  25 #if defined(CONFIG_USART0)
  26 # define USART_ID       0
  27 # define USART_BASE     USART0_BASE
  28 #elif defined(CONFIG_USART1)
  29 # define USART_ID       1
  30 # define USART_BASE     USART1_BASE
  31 #elif defined(CONFIG_USART2)
  32 # define USART_ID       2
  33 # define USART_BASE     USART2_BASE
  34 #elif defined(CONFIG_USART3)
  35 # define USART_ID       3
  36 # define USART_BASE     USART3_BASE
  37 #endif
  38
  39 #include "atmel_usart.h"
  40
  41 DECLARE_GLOBAL_DATA_PTR;
  42
  43 void serial_setbrg(void)
  44 {
  45         unsigned long divisor;
  46         unsigned long usart_hz;
  47
  48         /*
  49          *              Master Clock
  50          * Baud Rate = --------------
  51          *                16 * CD
  52          */
  53         usart_hz = get_usart_clk_rate(USART_ID);
  54         divisor = (usart_hz / 16 + gd->baudrate / 2) / gd->baudrate;
  55         usart3_writel(BRGR, USART3_BF(CD, divisor));
  56 }
  57
  58 int serial_init(void)
  59 {
  60         usart3_writel(CR, USART3_BIT(RSTRX) | USART3_BIT(RSTTX));
  61
  62         serial_setbrg();
  63
  64         usart3_writel(CR, USART3_BIT(RXEN) | USART3_BIT(TXEN));
  65         usart3_writel(MR, (USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL)
  66                            | USART3_BF(USCLKS, USART3_USCLKS_MCK)
  67                            | USART3_BF(CHRL, USART3_CHRL_8)
  68                            | USART3_BF(PAR, USART3_PAR_NONE)
  69                            | USART3_BF(NBSTOP, USART3_NBSTOP_1)));
  70
  71         return 0;
  72 }
  73
  74 void serial_putc(char c)
  75 {
  76         if (c == '\n')
  77                 serial_putc('\r');
  78
  79         while (!(usart3_readl(CSR) & USART3_BIT(TXRDY))) ;
  80         usart3_writel(THR, c);
  81 }
  82
  83 void serial_puts(const char *s)
  84 {
  85         while (*s)
  86                 serial_putc(*s++);
  87 }
  88
  89 int serial_getc(void)
  90 {
  91         while (!(usart3_readl(CSR) & USART3_BIT(RXRDY))) ;
  92         return usart3_readl(RHR);
  93 }
  94
  95 int serial_tstc(void)
  96 {
  97         return (usart3_readl(CSR) & USART3_BIT(RXRDY)) != 0;
  98 }
  99
 100 #endif /* CONFIG_ATMEL_USART */