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 #define RX_FIFO_COUNT_MASK 0xff 34 #define RX_FIFO_FULL_MASK (1 << 8) 35 #define TX_FIFO_FULL_MASK (1 << 24) 36 37 static inline struct s5p_uart *s5p_get_base_uart(int dev_index) 38 { 39 u32 offset = dev_index * sizeof(struct s5p_uart); 40 return (struct s5p_uart *)(samsung_get_base_uart() + offset); 41 } 42 43 /* 44 * The coefficient, used to calculate the baudrate on S5P UARTs is 45 * calculated as 46 * C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT 47 * however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1, 48 * 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants: 49 */ 50 static const int udivslot[] = { 51 0, 52 0x0080, 53 0x0808, 54 0x0888, 55 0x2222, 56 0x4924, 57 0x4a52, 58 0x54aa, 59 0x5555, 60 0xd555, 61 0xd5d5, 62 0xddd5, 63 0xdddd, 64 0xdfdd, 65 0xdfdf, 66 0xffdf, 67 }; 68 69 void serial_setbrg_dev(const int dev_index) 70 { 71 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 72 u32 uclk = get_uart_clk(dev_index); 73 u32 baudrate = gd->baudrate; 74 u32 val; 75 76 val = uclk / baudrate; 77 78 writel(val / 16 - 1, &uart->ubrdiv); 79 80 if (s5p_uart_divslot()) 81 writew(udivslot[val % 16], &uart->rest.slot); 82 else 83 writeb(val % 16, &uart->rest.value); 84 } 85 86 /* 87 * Initialise the serial port with the given baudrate. The settings 88 * are always 8 data bits, no parity, 1 stop bit, no start bits. 89 */ 90 int serial_init_dev(const int dev_index) 91 { 92 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 93 94 /* enable FIFOs */ 95 writel(0x1, &uart->ufcon); 96 writel(0, &uart->umcon); 97 /* 8N1 */ 98 writel(0x3, &uart->ulcon); 99 /* No interrupts, no DMA, pure polling */ 100 writel(0x245, &uart->ucon); 101 102 serial_setbrg_dev(dev_index); 103 104 return 0; 105 } 106 107 static int serial_err_check(const int dev_index, int op) 108 { 109 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 110 unsigned int mask; 111 112 /* 113 * UERSTAT 114 * Break Detect [3] 115 * Frame Err [2] : receive operation 116 * Parity Err [1] : receive operation 117 * Overrun Err [0] : receive operation 118 */ 119 if (op) 120 mask = 0x8; 121 else 122 mask = 0xf; 123 124 return readl(&uart->uerstat) & mask; 125 } 126 127 /* 128 * Read a single byte from the serial port. Returns 1 on success, 0 129 * otherwise. When the function is succesfull, the character read is 130 * written into its argument c. 131 */ 132 int serial_getc_dev(const int dev_index) 133 { 134 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 135 136 /* wait for character to arrive */ 137 while (!(readl(&uart->ufstat) & (RX_FIFO_COUNT_MASK | 138 RX_FIFO_FULL_MASK))) { 139 if (serial_err_check(dev_index, 0)) 140 return 0; 141 } 142 143 return (int)(readb(&uart->urxh) & 0xff); 144 } 145 146 /* 147 * Output a single byte to the serial port. 148 */ 149 void serial_putc_dev(const char c, const int dev_index) 150 { 151 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 152 153 /* wait for room in the tx FIFO */ 154 while ((readl(&uart->ufstat) & TX_FIFO_FULL_MASK)) { 155 if (serial_err_check(dev_index, 1)) 156 return; 157 } 158 159 writeb(c, &uart->utxh); 160 161 /* If \n, also do \r */ 162 if (c == '\n') 163 serial_putc('\r'); 164 } 165 166 /* 167 * Test whether a character is in the RX buffer 168 */ 169 int serial_tstc_dev(const int dev_index) 170 { 171 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 172 173 return (int)(readl(&uart->utrstat) & 0x1); 174 } 175 176 void serial_puts_dev(const char *s, const int dev_index) 177 { 178 while (*s) 179 serial_putc_dev(*s++, dev_index); 180 } 181 182 /* Multi serial device functions */ 183 #define DECLARE_S5P_SERIAL_FUNCTIONS(port) \ 184 int s5p_serial##port##_init(void) { return serial_init_dev(port); } \ 185 void s5p_serial##port##_setbrg(void) { serial_setbrg_dev(port); } \ 186 int s5p_serial##port##_getc(void) { return serial_getc_dev(port); } \ 187 int s5p_serial##port##_tstc(void) { return serial_tstc_dev(port); } \ 188 void s5p_serial##port##_putc(const char c) { serial_putc_dev(c, port); } \ 189 void s5p_serial##port##_puts(const char *s) { serial_puts_dev(s, port); } 190 191 #define INIT_S5P_SERIAL_STRUCTURE(port, __name) { \ 192 .name = __name, \ 193 .start = s5p_serial##port##_init, \ 194 .stop = NULL, \ 195 .setbrg = s5p_serial##port##_setbrg, \ 196 .getc = s5p_serial##port##_getc, \ 197 .tstc = s5p_serial##port##_tstc, \ 198 .putc = s5p_serial##port##_putc, \ 199 .puts = s5p_serial##port##_puts, \ 200 } 201 202 DECLARE_S5P_SERIAL_FUNCTIONS(0); 203 struct serial_device s5p_serial0_device = 204 INIT_S5P_SERIAL_STRUCTURE(0, "s5pser0"); 205 DECLARE_S5P_SERIAL_FUNCTIONS(1); 206 struct serial_device s5p_serial1_device = 207 INIT_S5P_SERIAL_STRUCTURE(1, "s5pser1"); 208 DECLARE_S5P_SERIAL_FUNCTIONS(2); 209 struct serial_device s5p_serial2_device = 210 INIT_S5P_SERIAL_STRUCTURE(2, "s5pser2"); 211 DECLARE_S5P_SERIAL_FUNCTIONS(3); 212 struct serial_device s5p_serial3_device = 213 INIT_S5P_SERIAL_STRUCTURE(3, "s5pser3"); 214 215 __weak struct serial_device *default_serial_console(void) 216 { 217 #if defined(CONFIG_SERIAL0) 218 return &s5p_serial0_device; 219 #elif defined(CONFIG_SERIAL1) 220 return &s5p_serial1_device; 221 #elif defined(CONFIG_SERIAL2) 222 return &s5p_serial2_device; 223 #elif defined(CONFIG_SERIAL3) 224 return &s5p_serial3_device; 225 #else 226 #error "CONFIG_SERIAL? missing." 227 #endif 228 } 229 230 void s5p_serial_initialize(void) 231 { 232 serial_register(&s5p_serial0_device); 233 serial_register(&s5p_serial1_device); 234 serial_register(&s5p_serial2_device); 235 serial_register(&s5p_serial3_device); 236 } 237