drivers/serial/serial_s5p.c

   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 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 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 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 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 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 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 int s5p_serial##port##_init(void) { return serial_init_dev(port); } \
 203 void s5p_serial##port##_setbrg(void) { serial_setbrg_dev(port); } \
 204 int s5p_serial##port##_getc(void) { return serial_getc_dev(port); } \
 205 int s5p_serial##port##_tstc(void) { return serial_tstc_dev(port); } \
 206 void s5p_serial##port##_putc(const char c) { serial_putc_dev(c, port); } \
 207 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 }