1 /* 2 * Copyright (C) 2004-2006 Atmel Corporation 3 * 4 * Modified to support C structur SoC access by 5 * Andreas Bießmann <biessmann@corscience.de> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 #include <common.h> 22 #include <watchdog.h> 23 #include <serial.h> 24 #include <linux/compiler.h> 25 26 #include <asm/io.h> 27 #include <asm/arch/clk.h> 28 #include <asm/arch/hardware.h> 29 30 #include "atmel_usart.h" 31 32 DECLARE_GLOBAL_DATA_PTR; 33 34 static void atmel_serial_setbrg(void) 35 { 36 atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; 37 unsigned long divisor; 38 unsigned long usart_hz; 39 40 /* 41 * Master Clock 42 * Baud Rate = -------------- 43 * 16 * CD 44 */ 45 usart_hz = get_usart_clk_rate(CONFIG_USART_ID); 46 divisor = (usart_hz / 16 + gd->baudrate / 2) / gd->baudrate; 47 writel(USART3_BF(CD, divisor), &usart->brgr); 48 } 49 50 static int atmel_serial_init(void) 51 { 52 atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; 53 54 /* 55 * Just in case: drain transmitter register 56 * 1000us is enough for baudrate >= 9600 57 */ 58 if (!(readl(&usart->csr) & USART3_BIT(TXEMPTY))) 59 __udelay(1000); 60 61 writel(USART3_BIT(RSTRX) | USART3_BIT(RSTTX), &usart->cr); 62 63 serial_setbrg(); 64 65 writel((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 &usart->mr); 71 writel(USART3_BIT(RXEN) | USART3_BIT(TXEN), &usart->cr); 72 /* 100us is enough for the new settings to be settled */ 73 __udelay(100); 74 75 return 0; 76 } 77 78 static void atmel_serial_putc(char c) 79 { 80 atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; 81 82 if (c == '\n') 83 serial_putc('\r'); 84 85 while (!(readl(&usart->csr) & USART3_BIT(TXRDY))); 86 writel(c, &usart->thr); 87 } 88 89 static void atmel_serial_puts(const char *s) 90 { 91 while (*s) 92 serial_putc(*s++); 93 } 94 95 static int atmel_serial_getc(void) 96 { 97 atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; 98 99 while (!(readl(&usart->csr) & USART3_BIT(RXRDY))) 100 WATCHDOG_RESET(); 101 return readl(&usart->rhr); 102 } 103 104 static int atmel_serial_tstc(void) 105 { 106 atmel_usart3_t *usart = (atmel_usart3_t *)CONFIG_USART_BASE; 107 return (readl(&usart->csr) & USART3_BIT(RXRDY)) != 0; 108 } 109 110 #ifdef CONFIG_SERIAL_MULTI 111 static struct serial_device atmel_serial_drv = { 112 .name = "atmel_serial", 113 .start = atmel_serial_init, 114 .stop = NULL, 115 .setbrg = atmel_serial_setbrg, 116 .putc = atmel_serial_putc, 117 .puts = atmel_serial_puts, 118 .getc = atmel_serial_getc, 119 .tstc = atmel_serial_tstc, 120 }; 121 122 void atmel_serial_initialize(void) 123 { 124 serial_register(&atmel_serial_drv); 125 } 126 127 __weak struct serial_device *default_serial_console(void) 128 { 129 return &atmel_serial_drv; 130 } 131 #else 132 int serial_init(void) 133 { 134 return atmel_serial_init(); 135 } 136 137 void serial_setbrg(void) 138 { 139 atmel_serial_setbrg(); 140 } 141 142 void serial_putc(const char c) 143 { 144 atmel_serial_putc(c); 145 } 146 147 void serial_puts(const char *s) 148 { 149 atmel_serial_puts(s); 150 } 151 152 int serial_getc(void) 153 { 154 return atmel_serial_getc(); 155 } 156 157 int serial_tstc(void) 158 { 159 return atmel_serial_tstc(); 160 } 161 #endif 162