1 /* 2 * (C) Copyright 2009 SAMSUNG Electronics 3 * Minkyu Kang <mk7.kang@samsung.com> 4 * Heungjun Kim <riverful.kim@samsung.com> 5 * 6 * based on drivers/serial/s3c64xx.c 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License as published by 10 * the Free Software Foundation; either version 2 of the License, or 11 * (at your option) any later version. 12 * 13 * This program is distributed in the hope that it will be useful, 14 * but WITHOUT ANY WARRANTY; without even the implied warranty of 15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 * GNU General Public License for more details. 17 * 18 * You should have received a copy of the GNU General Public License 19 * along with this program; if not, write to the Free Software 20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21 * 22 */ 23 24 #include <common.h> 25 #include <linux/compiler.h> 26 #include <asm/io.h> 27 #include <asm/arch/uart.h> 28 #include <asm/arch/clk.h> 29 #include <serial.h> 30 31 DECLARE_GLOBAL_DATA_PTR; 32 33 static inline struct s5p_uart *s5p_get_base_uart(int dev_index) 34 { 35 u32 offset = dev_index * sizeof(struct s5p_uart); 36 return (struct s5p_uart *)(samsung_get_base_uart() + offset); 37 } 38 39 /* 40 * The coefficient, used to calculate the baudrate on S5P UARTs is 41 * calculated as 42 * C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT 43 * however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1, 44 * 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants: 45 */ 46 static const int udivslot[] = { 47 0, 48 0x0080, 49 0x0808, 50 0x0888, 51 0x2222, 52 0x4924, 53 0x4a52, 54 0x54aa, 55 0x5555, 56 0xd555, 57 0xd5d5, 58 0xddd5, 59 0xdddd, 60 0xdfdd, 61 0xdfdf, 62 0xffdf, 63 }; 64 65 void serial_setbrg_dev(const int dev_index) 66 { 67 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 68 u32 uclk = get_uart_clk(dev_index); 69 u32 baudrate = gd->baudrate; 70 u32 val; 71 72 val = uclk / baudrate; 73 74 writel(val / 16 - 1, &uart->ubrdiv); 75 76 if (s5p_uart_divslot()) 77 writew(udivslot[val % 16], &uart->rest.slot); 78 else 79 writeb(val % 16, &uart->rest.value); 80 } 81 82 /* 83 * Initialise the serial port with the given baudrate. The settings 84 * are always 8 data bits, no parity, 1 stop bit, no start bits. 85 */ 86 int serial_init_dev(const int dev_index) 87 { 88 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 89 90 /* reset and enable FIFOs, set triggers to the maximum */ 91 writel(0, &uart->ufcon); 92 writel(0, &uart->umcon); 93 /* 8N1 */ 94 writel(0x3, &uart->ulcon); 95 /* No interrupts, no DMA, pure polling */ 96 writel(0x245, &uart->ucon); 97 98 serial_setbrg_dev(dev_index); 99 100 return 0; 101 } 102 103 static int serial_err_check(const int dev_index, int op) 104 { 105 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 106 unsigned int mask; 107 108 /* 109 * UERSTAT 110 * Break Detect [3] 111 * Frame Err [2] : receive operation 112 * Parity Err [1] : receive operation 113 * Overrun Err [0] : receive operation 114 */ 115 if (op) 116 mask = 0x8; 117 else 118 mask = 0xf; 119 120 return readl(&uart->uerstat) & mask; 121 } 122 123 /* 124 * Read a single byte from the serial port. Returns 1 on success, 0 125 * otherwise. When the function is succesfull, the character read is 126 * written into its argument c. 127 */ 128 int serial_getc_dev(const int dev_index) 129 { 130 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 131 132 /* wait for character to arrive */ 133 while (!(readl(&uart->utrstat) & 0x1)) { 134 if (serial_err_check(dev_index, 0)) 135 return 0; 136 } 137 138 return (int)(readb(&uart->urxh) & 0xff); 139 } 140 141 /* 142 * Output a single byte to the serial port. 143 */ 144 void serial_putc_dev(const char c, const int dev_index) 145 { 146 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 147 148 /* wait for room in the tx FIFO */ 149 while (!(readl(&uart->utrstat) & 0x2)) { 150 if (serial_err_check(dev_index, 1)) 151 return; 152 } 153 154 writeb(c, &uart->utxh); 155 156 /* If \n, also do \r */ 157 if (c == '\n') 158 serial_putc('\r'); 159 } 160 161 /* 162 * Test whether a character is in the RX buffer 163 */ 164 int serial_tstc_dev(const int dev_index) 165 { 166 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 167 168 return (int)(readl(&uart->utrstat) & 0x1); 169 } 170 171 void serial_puts_dev(const char *s, const int dev_index) 172 { 173 while (*s) 174 serial_putc_dev(*s++, dev_index); 175 } 176 177 /* Multi serial device functions */ 178 #define DECLARE_S5P_SERIAL_FUNCTIONS(port) \ 179 int s5p_serial##port##_init(void) { return serial_init_dev(port); } \ 180 void s5p_serial##port##_setbrg(void) { serial_setbrg_dev(port); } \ 181 int s5p_serial##port##_getc(void) { return serial_getc_dev(port); } \ 182 int s5p_serial##port##_tstc(void) { return serial_tstc_dev(port); } \ 183 void s5p_serial##port##_putc(const char c) { serial_putc_dev(c, port); } \ 184 void s5p_serial##port##_puts(const char *s) { serial_puts_dev(s, port); } 185 186 #define INIT_S5P_SERIAL_STRUCTURE(port, name) { \ 187 name, \ 188 s5p_serial##port##_init, \ 189 NULL, \ 190 s5p_serial##port##_setbrg, \ 191 s5p_serial##port##_getc, \ 192 s5p_serial##port##_tstc, \ 193 s5p_serial##port##_putc, \ 194 s5p_serial##port##_puts, } 195 196 DECLARE_S5P_SERIAL_FUNCTIONS(0); 197 struct serial_device s5p_serial0_device = 198 INIT_S5P_SERIAL_STRUCTURE(0, "s5pser0"); 199 DECLARE_S5P_SERIAL_FUNCTIONS(1); 200 struct serial_device s5p_serial1_device = 201 INIT_S5P_SERIAL_STRUCTURE(1, "s5pser1"); 202 DECLARE_S5P_SERIAL_FUNCTIONS(2); 203 struct serial_device s5p_serial2_device = 204 INIT_S5P_SERIAL_STRUCTURE(2, "s5pser2"); 205 DECLARE_S5P_SERIAL_FUNCTIONS(3); 206 struct serial_device s5p_serial3_device = 207 INIT_S5P_SERIAL_STRUCTURE(3, "s5pser3"); 208 209 __weak struct serial_device *default_serial_console(void) 210 { 211 #if defined(CONFIG_SERIAL0) 212 return &s5p_serial0_device; 213 #elif defined(CONFIG_SERIAL1) 214 return &s5p_serial1_device; 215 #elif defined(CONFIG_SERIAL2) 216 return &s5p_serial2_device; 217 #elif defined(CONFIG_SERIAL3) 218 return &s5p_serial3_device; 219 #else 220 #error "CONFIG_SERIAL? missing." 221 #endif 222 } 223