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/platform.h>
  23
  24 #include "atmel_usart.h"
  25
  26 DECLARE_GLOBAL_DATA_PTR;
  27
  28 void serial_setbrg(void)
  29 {
  30         unsigned long divisor;
  31         unsigned long usart_hz;
  32
  33         /*
  34          *              Master Clock
  35          * Baud Rate = --------------
  36          *                16 * CD
  37          */
  38         usart_hz = pm_get_clock_freq(gd->console_uart->resource[0].u.clock.id);
  39         divisor = (usart_hz / 16 + gd->baudrate / 2) / gd->baudrate;
  40         usart3_writel(gd->console_uart, BRGR, USART3_BF(CD, divisor));
  41 }
  42
  43 int serial_init(void)
  44 {
  45         usart3_writel(gd->console_uart, CR,
  46                       USART3_BIT(RSTRX) | USART3_BIT(RSTTX));
  47
  48         serial_setbrg();
  49
  50         usart3_writel(gd->console_uart, CR,
  51                       USART3_BIT(RXEN) | USART3_BIT(TXEN));
  52         usart3_writel(gd->console_uart, MR,
  53                       USART3_BF(USART_MODE, USART3_USART_MODE_NORMAL)
  54                       | USART3_BF(USCLKS, USART3_USCLKS_MCK)
  55                       | USART3_BF(CHRL, USART3_CHRL_8)
  56                       | USART3_BF(PAR, USART3_PAR_NONE)
  57                       | USART3_BF(NBSTOP, USART3_NBSTOP_1));
  58
  59         return 0;
  60 }
  61
  62 void serial_putc(char c)
  63 {
  64         if (c == '\n')
  65                 serial_putc('\r');
  66
  67         while (!(usart3_readl(gd->console_uart, CSR) & USART3_BIT(TXRDY))) ;
  68         usart3_writel(gd->console_uart, THR, c);
  69 }
  70
  71 void serial_puts(const char *s)
  72 {
  73         while (*s)
  74                 serial_putc(*s++);
  75 }
  76
  77 int serial_getc(void)
  78 {
  79         while (!(usart3_readl(gd->console_uart, CSR) & USART3_BIT(RXRDY))) ;
  80         return usart3_readl(gd->console_uart, RHR);
  81 }
  82
  83 int serial_tstc(void)
  84 {
  85         return (usart3_readl(gd->console_uart, CSR) & USART3_BIT(RXRDY)) != 0;
  86 }
  87
  88 #endif /* CONFIG_ATMEL_USART */