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 static inline struct s5p_uart *s5p_get_base_uart(int dev_index) 31 { 32 u32 offset = dev_index * sizeof(struct s5p_uart); 33 return (struct s5p_uart *)(samsung_get_base_uart() + offset); 34 } 35 36 /* 37 * The coefficient, used to calculate the baudrate on S5P UARTs is 38 * calculated as 39 * C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT 40 * however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1, 41 * 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants: 42 */ 43 static const int udivslot[] = { 44 0, 45 0x0080, 46 0x0808, 47 0x0888, 48 0x2222, 49 0x4924, 50 0x4a52, 51 0x54aa, 52 0x5555, 53 0xd555, 54 0xd5d5, 55 0xddd5, 56 0xdddd, 57 0xdfdd, 58 0xdfdf, 59 0xffdf, 60 }; 61 62 void serial_setbrg_dev(const int dev_index) 63 { 64 DECLARE_GLOBAL_DATA_PTR; 65 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 66 u32 uclk = get_uart_clk(dev_index); 67 u32 baudrate = gd->baudrate; 68 u32 val; 69 70 val = uclk / baudrate; 71 72 writel(val / 16 - 1, &uart->ubrdiv); 73 writew(udivslot[val % 16], &uart->udivslot); 74 } 75 76 /* 77 * Initialise the serial port with the given baudrate. The settings 78 * are always 8 data bits, no parity, 1 stop bit, no start bits. 79 */ 80 int serial_init_dev(const int dev_index) 81 { 82 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 83 84 /* reset and enable FIFOs, set triggers to the maximum */ 85 writel(0, &uart->ufcon); 86 writel(0, &uart->umcon); 87 /* 8N1 */ 88 writel(0x3, &uart->ulcon); 89 /* No interrupts, no DMA, pure polling */ 90 writel(0x245, &uart->ucon); 91 92 serial_setbrg_dev(dev_index); 93 94 return 0; 95 } 96 97 static int serial_err_check(const int dev_index, int op) 98 { 99 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 100 unsigned int mask; 101 102 /* 103 * UERSTAT 104 * Break Detect [3] 105 * Frame Err [2] : receive operation 106 * Parity Err [1] : receive operation 107 * Overrun Err [0] : receive operation 108 */ 109 if (op) 110 mask = 0x8; 111 else 112 mask = 0xf; 113 114 return readl(&uart->uerstat) & mask; 115 } 116 117 /* 118 * Read a single byte from the serial port. Returns 1 on success, 0 119 * otherwise. When the function is succesfull, the character read is 120 * written into its argument c. 121 */ 122 int serial_getc_dev(const int dev_index) 123 { 124 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 125 126 /* wait for character to arrive */ 127 while (!(readl(&uart->utrstat) & 0x1)) { 128 if (serial_err_check(dev_index, 0)) 129 return 0; 130 } 131 132 return (int)(readb(&uart->urxh) & 0xff); 133 } 134 135 /* 136 * Output a single byte to the serial port. 137 */ 138 void serial_putc_dev(const char c, const int dev_index) 139 { 140 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 141 142 /* wait for room in the tx FIFO */ 143 while (!(readl(&uart->utrstat) & 0x2)) { 144 if (serial_err_check(dev_index, 1)) 145 return; 146 } 147 148 writeb(c, &uart->utxh); 149 150 /* If \n, also do \r */ 151 if (c == '\n') 152 serial_putc('\r'); 153 } 154 155 /* 156 * Test whether a character is in the RX buffer 157 */ 158 int serial_tstc_dev(const int dev_index) 159 { 160 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 161 162 return (int)(readl(&uart->utrstat) & 0x1); 163 } 164 165 void serial_puts_dev(const char *s, const int dev_index) 166 { 167 while (*s) 168 serial_putc_dev(*s++, dev_index); 169 } 170 171 /* Multi serial device functions */ 172 #define DECLARE_S5P_SERIAL_FUNCTIONS(port) \ 173 int s5p_serial##port##_init(void) { return serial_init_dev(port); } \ 174 void s5p_serial##port##_setbrg(void) { serial_setbrg_dev(port); } \ 175 int s5p_serial##port##_getc(void) { return serial_getc_dev(port); } \ 176 int s5p_serial##port##_tstc(void) { return serial_tstc_dev(port); } \ 177 void s5p_serial##port##_putc(const char c) { serial_putc_dev(c, port); } \ 178 void s5p_serial##port##_puts(const char *s) { serial_puts_dev(s, port); } 179 180 #define INIT_S5P_SERIAL_STRUCTURE(port, name, bus) { \ 181 name, \ 182 bus, \ 183 s5p_serial##port##_init, \ 184 NULL, \ 185 s5p_serial##port##_setbrg, \ 186 s5p_serial##port##_getc, \ 187 s5p_serial##port##_tstc, \ 188 s5p_serial##port##_putc, \ 189 s5p_serial##port##_puts, } 190 191 DECLARE_S5P_SERIAL_FUNCTIONS(0); 192 struct serial_device s5p_serial0_device = 193 INIT_S5P_SERIAL_STRUCTURE(0, "s5pser0", "S5PUART0"); 194 DECLARE_S5P_SERIAL_FUNCTIONS(1); 195 struct serial_device s5p_serial1_device = 196 INIT_S5P_SERIAL_STRUCTURE(1, "s5pser1", "S5PUART1"); 197 DECLARE_S5P_SERIAL_FUNCTIONS(2); 198 struct serial_device s5p_serial2_device = 199 INIT_S5P_SERIAL_STRUCTURE(2, "s5pser2", "S5PUART2"); 200 DECLARE_S5P_SERIAL_FUNCTIONS(3); 201 struct serial_device s5p_serial3_device = 202 INIT_S5P_SERIAL_STRUCTURE(3, "s5pser3", "S5PUART3"); 203