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 * SPDX-License-Identifier: GPL-2.0+ 9 */ 10 11 #include <common.h> 12 #include <fdtdec.h> 13 #include <linux/compiler.h> 14 #include <asm/io.h> 15 #include <asm/arch/uart.h> 16 #include <asm/arch/clk.h> 17 #include <serial.h> 18 19 DECLARE_GLOBAL_DATA_PTR; 20 21 #define RX_FIFO_COUNT_MASK 0xff 22 #define RX_FIFO_FULL_MASK (1 << 8) 23 #define TX_FIFO_FULL_MASK (1 << 24) 24 25 /* Information about a serial port */ 26 struct fdt_serial { 27 u32 base_addr; /* address of registers in physical memory */ 28 u8 port_id; /* uart port number */ 29 u8 enabled; /* 1 if enabled, 0 if disabled */ 30 } config __attribute__ ((section(".data"))); 31 32 static inline struct s5p_uart *s5p_get_base_uart(int dev_index) 33 { 34 #ifdef CONFIG_OF_CONTROL 35 return (struct s5p_uart *)(config.base_addr); 36 #else 37 u32 offset = dev_index * sizeof(struct s5p_uart); 38 return (struct s5p_uart *)(samsung_get_base_uart() + offset); 39 #endif 40 } 41 42 /* 43 * The coefficient, used to calculate the baudrate on S5P UARTs is 44 * calculated as 45 * C = UBRDIV * 16 + number_of_set_bits_in_UDIVSLOT 46 * however, section 31.6.11 of the datasheet doesn't recomment using 1 for 1, 47 * 3 for 2, ... (2^n - 1) for n, instead, they suggest using these constants: 48 */ 49 static const int udivslot[] = { 50 0, 51 0x0080, 52 0x0808, 53 0x0888, 54 0x2222, 55 0x4924, 56 0x4a52, 57 0x54aa, 58 0x5555, 59 0xd555, 60 0xd5d5, 61 0xddd5, 62 0xdddd, 63 0xdfdd, 64 0xdfdf, 65 0xffdf, 66 }; 67 68 static void serial_setbrg_dev(const int dev_index) 69 { 70 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 71 u32 uclk = get_uart_clk(dev_index); 72 u32 baudrate = gd->baudrate; 73 u32 val; 74 75 #if defined(CONFIG_SILENT_CONSOLE) && \ 76 defined(CONFIG_OF_CONTROL) && \ 77 !defined(CONFIG_SPL_BUILD) 78 if (fdtdec_get_config_int(gd->fdt_blob, "silent_console", 0)) 79 gd->flags |= GD_FLG_SILENT; 80 #endif 81 82 if (!config.enabled) 83 return; 84 85 val = uclk / baudrate; 86 87 writel(val / 16 - 1, &uart->ubrdiv); 88 89 if (s5p_uart_divslot()) 90 writew(udivslot[val % 16], &uart->rest.slot); 91 else 92 writeb(val % 16, &uart->rest.value); 93 } 94 95 /* 96 * Initialise the serial port with the given baudrate. The settings 97 * are always 8 data bits, no parity, 1 stop bit, no start bits. 98 */ 99 static int serial_init_dev(const int dev_index) 100 { 101 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 102 103 /* enable FIFOs */ 104 writel(0x1, &uart->ufcon); 105 writel(0, &uart->umcon); 106 /* 8N1 */ 107 writel(0x3, &uart->ulcon); 108 /* No interrupts, no DMA, pure polling */ 109 writel(0x245, &uart->ucon); 110 111 serial_setbrg_dev(dev_index); 112 113 return 0; 114 } 115 116 static int serial_err_check(const int dev_index, int op) 117 { 118 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 119 unsigned int mask; 120 121 /* 122 * UERSTAT 123 * Break Detect [3] 124 * Frame Err [2] : receive operation 125 * Parity Err [1] : receive operation 126 * Overrun Err [0] : receive operation 127 */ 128 if (op) 129 mask = 0x8; 130 else 131 mask = 0xf; 132 133 return readl(&uart->uerstat) & mask; 134 } 135 136 /* 137 * Read a single byte from the serial port. Returns 1 on success, 0 138 * otherwise. When the function is succesfull, the character read is 139 * written into its argument c. 140 */ 141 static int serial_getc_dev(const int dev_index) 142 { 143 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 144 145 if (!config.enabled) 146 return 0; 147 148 /* wait for character to arrive */ 149 while (!(readl(&uart->ufstat) & (RX_FIFO_COUNT_MASK | 150 RX_FIFO_FULL_MASK))) { 151 if (serial_err_check(dev_index, 0)) 152 return 0; 153 } 154 155 return (int)(readb(&uart->urxh) & 0xff); 156 } 157 158 /* 159 * Output a single byte to the serial port. 160 */ 161 static void serial_putc_dev(const char c, const int dev_index) 162 { 163 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 164 165 if (!config.enabled) 166 return; 167 168 /* wait for room in the tx FIFO */ 169 while ((readl(&uart->ufstat) & TX_FIFO_FULL_MASK)) { 170 if (serial_err_check(dev_index, 1)) 171 return; 172 } 173 174 writeb(c, &uart->utxh); 175 176 /* If \n, also do \r */ 177 if (c == '\n') 178 serial_putc('\r'); 179 } 180 181 /* 182 * Test whether a character is in the RX buffer 183 */ 184 static int serial_tstc_dev(const int dev_index) 185 { 186 struct s5p_uart *const uart = s5p_get_base_uart(dev_index); 187 188 if (!config.enabled) 189 return 0; 190 191 return (int)(readl(&uart->utrstat) & 0x1); 192 } 193 194 static void serial_puts_dev(const char *s, const int dev_index) 195 { 196 while (*s) 197 serial_putc_dev(*s++, dev_index); 198 } 199 200 /* Multi serial device functions */ 201 #define DECLARE_S5P_SERIAL_FUNCTIONS(port) \ 202 static int s5p_serial##port##_init(void) { return serial_init_dev(port); } \ 203 static void s5p_serial##port##_setbrg(void) { serial_setbrg_dev(port); } \ 204 static int s5p_serial##port##_getc(void) { return serial_getc_dev(port); } \ 205 static int s5p_serial##port##_tstc(void) { return serial_tstc_dev(port); } \ 206 static void s5p_serial##port##_putc(const char c) { serial_putc_dev(c, port); } \ 207 static void s5p_serial##port##_puts(const char *s) { serial_puts_dev(s, port); } 208 209 #define INIT_S5P_SERIAL_STRUCTURE(port, __name) { \ 210 .name = __name, \ 211 .start = s5p_serial##port##_init, \ 212 .stop = NULL, \ 213 .setbrg = s5p_serial##port##_setbrg, \ 214 .getc = s5p_serial##port##_getc, \ 215 .tstc = s5p_serial##port##_tstc, \ 216 .putc = s5p_serial##port##_putc, \ 217 .puts = s5p_serial##port##_puts, \ 218 } 219 220 DECLARE_S5P_SERIAL_FUNCTIONS(0); 221 struct serial_device s5p_serial0_device = 222 INIT_S5P_SERIAL_STRUCTURE(0, "s5pser0"); 223 DECLARE_S5P_SERIAL_FUNCTIONS(1); 224 struct serial_device s5p_serial1_device = 225 INIT_S5P_SERIAL_STRUCTURE(1, "s5pser1"); 226 DECLARE_S5P_SERIAL_FUNCTIONS(2); 227 struct serial_device s5p_serial2_device = 228 INIT_S5P_SERIAL_STRUCTURE(2, "s5pser2"); 229 DECLARE_S5P_SERIAL_FUNCTIONS(3); 230 struct serial_device s5p_serial3_device = 231 INIT_S5P_SERIAL_STRUCTURE(3, "s5pser3"); 232 233 #ifdef CONFIG_OF_CONTROL 234 int fdtdec_decode_console(int *index, struct fdt_serial *uart) 235 { 236 const void *blob = gd->fdt_blob; 237 int node; 238 239 node = fdt_path_offset(blob, "console"); 240 if (node < 0) 241 return node; 242 243 uart->base_addr = fdtdec_get_addr(blob, node, "reg"); 244 if (uart->base_addr == FDT_ADDR_T_NONE) 245 return -FDT_ERR_NOTFOUND; 246 247 uart->port_id = fdtdec_get_int(blob, node, "id", -1); 248 uart->enabled = fdtdec_get_is_enabled(blob, node); 249 250 return 0; 251 } 252 #endif 253 254 __weak struct serial_device *default_serial_console(void) 255 { 256 #ifdef CONFIG_OF_CONTROL 257 int index = 0; 258 259 if ((!config.base_addr) && (fdtdec_decode_console(&index, &config))) { 260 debug("Cannot decode default console node\n"); 261 return NULL; 262 } 263 264 switch (config.port_id) { 265 case 0: 266 return &s5p_serial0_device; 267 case 1: 268 return &s5p_serial1_device; 269 case 2: 270 return &s5p_serial2_device; 271 case 3: 272 return &s5p_serial3_device; 273 default: 274 debug("Unknown config.port_id: %d", config.port_id); 275 break; 276 } 277 278 return NULL; 279 #else 280 config.enabled = 1; 281 #if defined(CONFIG_SERIAL0) 282 return &s5p_serial0_device; 283 #elif defined(CONFIG_SERIAL1) 284 return &s5p_serial1_device; 285 #elif defined(CONFIG_SERIAL2) 286 return &s5p_serial2_device; 287 #elif defined(CONFIG_SERIAL3) 288 return &s5p_serial3_device; 289 #else 290 #error "CONFIG_SERIAL? missing." 291 #endif 292 #endif 293 } 294 295 void s5p_serial_initialize(void) 296 { 297 serial_register(&s5p_serial0_device); 298 serial_register(&s5p_serial1_device); 299 serial_register(&s5p_serial2_device); 300 serial_register(&s5p_serial3_device); 301 } 302