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 <asm/io.h> 26 #include <asm/arch/uart.h> 27 #include <asm/arch/clk.h> 28 #include <serial.h> 29 30 DECLARE_GLOBAL_DATA_PTR; 31 32 static inline struct s5p_uart *s5p_get_base_uart(int dev_index) 33 { 34 u32 offset = dev_index * sizeof(struct s5p_uart); 35 return (struct s5p_uart *)(samsung_get_base_uart() + offset); 36 } 37 38 /* 39 * The coefficient, used to calculate the baudrate on S5P UARTs is 40 * calculated as 41 * C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT 42 * however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1, 43 * 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants: 44 */ 45 static const int udivslot[] = { 46 0, 47 0x0080, 48 0x0808, 49 0x0888, 50 0x2222, 51 0x4924, 52 0x4a52, 53 0x54aa, 54 0x5555, 55 0xd555, 56 0xd5d5, 57 0xddd5, 58 0xdddd, 59 0xdfdd, 60 0xdfdf, 61 0xffdf, 62 }; 63 64 void serial_setbrg_dev(const int dev_index) 65 { 66 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 67 u32 uclk = get_uart_clk(dev_index); 68 u32 baudrate = gd->baudrate; 69 u32 val; 70 71 val = uclk / baudrate; 72 73 writel(val / 16 - 1, &uart->ubrdiv); 74 75 if (s5p_uart_divslot()) 76 writew(udivslot[val % 16], &uart->rest.slot); 77 else 78 writeb(val % 16, &uart->rest.value); 79 } 80 81 /* 82 * Initialise the serial port with the given baudrate. The settings 83 * are always 8 data bits, no parity, 1 stop bit, no start bits. 84 */ 85 int serial_init_dev(const int dev_index) 86 { 87 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 88 89 /* reset and enable FIFOs, set triggers to the maximum */ 90 writel(0, &uart->ufcon); 91 writel(0, &uart->umcon); 92 /* 8N1 */ 93 writel(0x3, &uart->ulcon); 94 /* No interrupts, no DMA, pure polling */ 95 writel(0x245, &uart->ucon); 96 97 serial_setbrg_dev(dev_index); 98 99 return 0; 100 } 101 102 static int serial_err_check(const int dev_index, int op) 103 { 104 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 105 unsigned int mask; 106 107 /* 108 * UERSTAT 109 * Break Detect [3] 110 * Frame Err [2] : receive operation 111 * Parity Err [1] : receive operation 112 * Overrun Err [0] : receive operation 113 */ 114 if (op) 115 mask = 0x8; 116 else 117 mask = 0xf; 118 119 return readl(&uart->uerstat) & mask; 120 } 121 122 /* 123 * Read a single byte from the serial port. Returns 1 on success, 0 124 * otherwise. When the function is succesfull, the character read is 125 * written into its argument c. 126 */ 127 int serial_getc_dev(const int dev_index) 128 { 129 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 130 131 /* wait for character to arrive */ 132 while (!(readl(&uart->utrstat) & 0x1)) { 133 if (serial_err_check(dev_index, 0)) 134 return 0; 135 } 136 137 return (int)(readb(&uart->urxh) & 0xff); 138 } 139 140 /* 141 * Output a single byte to the serial port. 142 */ 143 void serial_putc_dev(const char c, const int dev_index) 144 { 145 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 146 147 /* wait for room in the tx FIFO */ 148 while (!(readl(&uart->utrstat) & 0x2)) { 149 if (serial_err_check(dev_index, 1)) 150 return; 151 } 152 153 writeb(c, &uart->utxh); 154 155 /* If \n, also do \r */ 156 if (c == '\n') 157 serial_putc('\r'); 158 } 159 160 /* 161 * Test whether a character is in the RX buffer 162 */ 163 int serial_tstc_dev(const int dev_index) 164 { 165 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 166 167 return (int)(readl(&uart->utrstat) & 0x1); 168 } 169 170 void serial_puts_dev(const char *s, const int dev_index) 171 { 172 while (*s) 173 serial_putc_dev(*s++, dev_index); 174 } 175 176 /* Multi serial device functions */ 177 #define DECLARE_S5P_SERIAL_FUNCTIONS(port) \ 178 int s5p_serial##port##_init(void) { return serial_init_dev(port); } \ 179 void s5p_serial##port##_setbrg(void) { serial_setbrg_dev(port); } \ 180 int s5p_serial##port##_getc(void) { return serial_getc_dev(port); } \ 181 int s5p_serial##port##_tstc(void) { return serial_tstc_dev(port); } \ 182 void s5p_serial##port##_putc(const char c) { serial_putc_dev(c, port); } \ 183 void s5p_serial##port##_puts(const char *s) { serial_puts_dev(s, port); } 184 185 #define INIT_S5P_SERIAL_STRUCTURE(port, name, bus) { \ 186 name, \ 187 bus, \ 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", "S5PUART0"); 199 DECLARE_S5P_SERIAL_FUNCTIONS(1); 200 struct serial_device s5p_serial1_device = 201 INIT_S5P_SERIAL_STRUCTURE(1, "s5pser1", "S5PUART1"); 202 DECLARE_S5P_SERIAL_FUNCTIONS(2); 203 struct serial_device s5p_serial2_device = 204 INIT_S5P_SERIAL_STRUCTURE(2, "s5pser2", "S5PUART2"); 205 DECLARE_S5P_SERIAL_FUNCTIONS(3); 206 struct serial_device s5p_serial3_device = 207 INIT_S5P_SERIAL_STRUCTURE(3, "s5pser3", "S5PUART3"); 208