drivers/serial/serial_pl01x.c

   1 /*
   2  * (C) Copyright 2000
   3  * Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
   4  *
   5  * (C) Copyright 2004
   6  * ARM Ltd.
   7  * Philippe Robin, <philippe.robin@arm.com>
   8  *
   9  * SPDX-License-Identifier:     GPL-2.0+
  10  */
  11
  12 /* Simple U-Boot driver for the PrimeCell PL010/PL011 UARTs */
  13
  14 #include <common.h>
  15 #include <dm.h>
  16 #include <errno.h>
  17 #include <watchdog.h>
  18 #include <asm/io.h>
  19 #include <serial.h>
  20 #include <dm/platform_data/serial_pl01x.h>
  21 #include <linux/compiler.h>
  22 #include "serial_pl01x_internal.h"
  23
  24 #ifndef CONFIG_DM_SERIAL
  25
  26 static volatile unsigned char *const port[] = CONFIG_PL01x_PORTS;
  27 static enum pl01x_type pl01x_type __attribute__ ((section(".data")));
  28 static struct pl01x_regs *base_regs __attribute__ ((section(".data")));
  29 #define NUM_PORTS (sizeof(port)/sizeof(port[0]))
  30
  31 DECLARE_GLOBAL_DATA_PTR;
  32 #endif
  33
  34 static int pl01x_putc(struct pl01x_regs *regs, char c)
  35 {
  36         /* Wait until there is space in the FIFO */
  37         if (readl(&regs->fr) & UART_PL01x_FR_TXFF)
  38                 return -EAGAIN;
  39
  40         /* Send the character */
  41         writel(c, &regs->dr);
  42
  43         return 0;
  44 }
  45
  46 static int pl01x_getc(struct pl01x_regs *regs)
  47 {
  48         unsigned int data;
  49
  50         /* Wait until there is data in the FIFO */
  51         if (readl(&regs->fr) & UART_PL01x_FR_RXFE)
  52                 return -EAGAIN;
  53
  54         data = readl(&regs->dr);
  55
  56         /* Check for an error flag */
  57         if (data & 0xFFFFFF00) {
  58                 /* Clear the error */
  59                 writel(0xFFFFFFFF, &regs->ecr);
  60                 return -1;
  61         }
  62
  63         return (int) data;
  64 }
  65
  66 static int pl01x_tstc(struct pl01x_regs *regs)
  67 {
  68         WATCHDOG_RESET();
  69         return !(readl(&regs->fr) & UART_PL01x_FR_RXFE);
  70 }
  71
  72 static int pl01x_generic_serial_init(struct pl01x_regs *regs,
  73                                      enum pl01x_type type)
  74 {
  75 #ifdef CONFIG_PL011_SERIAL_FLUSH_ON_INIT
  76         if (type == TYPE_PL011) {
  77                 /* Empty RX fifo if necessary */
  78                 if (readl(&regs->pl011_cr) & UART_PL011_CR_UARTEN) {
  79                         while (!(readl(&regs->fr) & UART_PL01x_FR_RXFE))
  80                                 readl(&regs->dr);
  81                 }
  82         }
  83 #endif
  84
  85         /* First, disable everything */
  86         writel(0, &regs->pl010_cr);
  87
  88         switch (type) {
  89         case TYPE_PL010:
  90                 break;
  91         case TYPE_PL011:
  92                 break;
  93         default:
  94                 return -EINVAL;
  95         }
  96
  97         return 0;
  98 }
  99
 100 static int set_line_control(struct pl01x_regs *regs)
 101 {
 102         unsigned int lcr;
 103         /*
 104          * Internal update of baud rate register require line
 105          * control register write
 106          */
 107         lcr = UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN;
 108 #ifdef CONFIG_PL011_SERIAL_RLCR
 109         {
 110                 int i;
 111
 112                 /*
 113                  * Program receive line control register after waiting
 114                  * 10 bus cycles.  Delay be writing to readonly register
 115                  * 10 times
 116                  */
 117                 for (i = 0; i < 10; i++)
 118                         writel(lcr, &regs->fr);
 119
 120                 writel(lcr, &regs->pl011_rlcr);
 121         }
 122 #endif
 123         writel(lcr, &regs->pl011_lcrh);
 124         return 0;
 125 }
 126
 127 static int pl01x_generic_setbrg(struct pl01x_regs *regs, enum pl01x_type type,
 128                                 int clock, int baudrate)
 129 {
 130         switch (type) {
 131         case TYPE_PL010: {
 132                 unsigned int divisor;
 133
 134                 switch (baudrate) {
 135                 case 9600:
 136                         divisor = UART_PL010_BAUD_9600;
 137                         break;
 138                 case 19200:
 139                         divisor = UART_PL010_BAUD_9600;
 140                         break;
 141                 case 38400:
 142                         divisor = UART_PL010_BAUD_38400;
 143                         break;
 144                 case 57600:
 145                         divisor = UART_PL010_BAUD_57600;
 146                         break;
 147                 case 115200:
 148                         divisor = UART_PL010_BAUD_115200;
 149                         break;
 150                 default:
 151                         divisor = UART_PL010_BAUD_38400;
 152                 }
 153
 154                 writel((divisor & 0xf00) >> 8, &regs->pl010_lcrm);
 155                 writel(divisor & 0xff, &regs->pl010_lcrl);
 156
 157                 /* Finally, enable the UART */
 158                 writel(UART_PL010_CR_UARTEN, &regs->pl010_cr);
 159                 break;
 160         }
 161         case TYPE_PL011: {
 162                 unsigned int temp;
 163                 unsigned int divider;
 164                 unsigned int remainder;
 165                 unsigned int fraction;
 166
 167                 /*
 168                 * Set baud rate
 169                 *
 170                 * IBRD = UART_CLK / (16 * BAUD_RATE)
 171                 * FBRD = RND((64 * MOD(UART_CLK,(16 * BAUD_RATE)))
 172                 *               / (16 * BAUD_RATE))
 173                 */
 174                 temp = 16 * baudrate;
 175                 divider = clock / temp;
 176                 remainder = clock % temp;
 177                 temp = (8 * remainder) / baudrate;
 178                 fraction = (temp >> 1) + (temp & 1);
 179
 180                 writel(divider, &regs->pl011_ibrd);
 181                 writel(fraction, &regs->pl011_fbrd);
 182
 183                 set_line_control(regs);
 184                 /* Finally, enable the UART */
 185                 writel(UART_PL011_CR_UARTEN | UART_PL011_CR_TXE |
 186                        UART_PL011_CR_RXE | UART_PL011_CR_RTS, &regs->pl011_cr);
 187                 break;
 188         }
 189         default:
 190                 return -EINVAL;
 191         }
 192
 193         return 0;
 194 }
 195
 196 #ifndef CONFIG_DM_SERIAL
 197 static void pl01x_serial_init_baud(int baudrate)
 198 {
 199         int clock = 0;
 200
 201 #if defined(CONFIG_PL010_SERIAL)
 202         pl01x_type = TYPE_PL010;
 203 #elif defined(CONFIG_PL011_SERIAL)
 204         pl01x_type = TYPE_PL011;
 205         clock = CONFIG_PL011_CLOCK;
 206 #endif
 207         base_regs = (struct pl01x_regs *)port[CONFIG_CONS_INDEX];
 208
 209         pl01x_generic_serial_init(base_regs, pl01x_type);
 210         pl01x_generic_setbrg(base_regs, pl01x_type, clock, baudrate);
 211 }
 212
 213 /*
 214  * Integrator AP has two UARTs, we use the first one, at 38400-8-N-1
 215  * Integrator CP has two UARTs, use the first one, at 38400-8-N-1
 216  * Versatile PB has four UARTs.
 217  */
 218 int pl01x_serial_init(void)
 219 {
 220         pl01x_serial_init_baud(CONFIG_BAUDRATE);
 221
 222         return 0;
 223 }
 224
 225 static void pl01x_serial_putc(const char c)
 226 {
 227         if (c == '\n')
 228                 while (pl01x_putc(base_regs, '\r') == -EAGAIN);
 229
 230         while (pl01x_putc(base_regs, c) == -EAGAIN);
 231 }
 232
 233 static int pl01x_serial_getc(void)
 234 {
 235         while (1) {
 236                 int ch = pl01x_getc(base_regs);
 237
 238                 if (ch == -EAGAIN) {
 239                         WATCHDOG_RESET();
 240                         continue;
 241                 }
 242
 243                 return ch;
 244         }
 245 }
 246
 247 static int pl01x_serial_tstc(void)
 248 {
 249         return pl01x_tstc(base_regs);
 250 }
 251
 252 static void pl01x_serial_setbrg(void)
 253 {
 254         /*
 255          * Flush FIFO and wait for non-busy before changing baudrate to avoid
 256          * crap in console
 257          */
 258         while (!(readl(&base_regs->fr) & UART_PL01x_FR_TXFE))
 259                 WATCHDOG_RESET();
 260         while (readl(&base_regs->fr) & UART_PL01x_FR_BUSY)
 261                 WATCHDOG_RESET();
 262         pl01x_serial_init_baud(gd->baudrate);
 263 }
 264
 265 static struct serial_device pl01x_serial_drv = {
 266         .name   = "pl01x_serial",
 267         .start  = pl01x_serial_init,
 268         .stop   = NULL,
 269         .setbrg = pl01x_serial_setbrg,
 270         .putc   = pl01x_serial_putc,
 271         .puts   = default_serial_puts,
 272         .getc   = pl01x_serial_getc,
 273         .tstc   = pl01x_serial_tstc,
 274 };
 275
 276 void pl01x_serial_initialize(void)
 277 {
 278         serial_register(&pl01x_serial_drv);
 279 }
 280
 281 __weak struct serial_device *default_serial_console(void)
 282 {
 283         return &pl01x_serial_drv;
 284 }
 285
 286 #endif /* nCONFIG_DM_SERIAL */
 287
 288 #ifdef CONFIG_DM_SERIAL
 289
 290 struct pl01x_priv {
 291         struct pl01x_regs *regs;
 292         enum pl01x_type type;
 293 };
 294
 295 static int pl01x_serial_setbrg(struct udevice *dev, int baudrate)
 296 {
 297         struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
 298         struct pl01x_priv *priv = dev_get_priv(dev);
 299
 300         pl01x_generic_setbrg(priv->regs, priv->type, plat->clock, baudrate);
 301
 302         return 0;
 303 }
 304
 305 static int pl01x_serial_probe(struct udevice *dev)
 306 {
 307         struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
 308         struct pl01x_priv *priv = dev_get_priv(dev);
 309
 310         priv->regs = (struct pl01x_regs *)plat->base;
 311         priv->type = plat->type;
 312         return pl01x_generic_serial_init(priv->regs, priv->type);
 313 }
 314
 315 static int pl01x_serial_getc(struct udevice *dev)
 316 {
 317         struct pl01x_priv *priv = dev_get_priv(dev);
 318
 319         return pl01x_getc(priv->regs);
 320 }
 321
 322 static int pl01x_serial_putc(struct udevice *dev, const char ch)
 323 {
 324         struct pl01x_priv *priv = dev_get_priv(dev);
 325
 326         return pl01x_putc(priv->regs, ch);
 327 }
 328
 329 static int pl01x_serial_pending(struct udevice *dev, bool input)
 330 {
 331         struct pl01x_priv *priv = dev_get_priv(dev);
 332         unsigned int fr = readl(&priv->regs->fr);
 333
 334         if (input)
 335                 return pl01x_tstc(priv->regs);
 336         else
 337                 return fr & UART_PL01x_FR_TXFF ? 0 : 1;
 338 }
 339
 340 static const struct dm_serial_ops pl01x_serial_ops = {
 341         .putc = pl01x_serial_putc,
 342         .pending = pl01x_serial_pending,
 343         .getc = pl01x_serial_getc,
 344         .setbrg = pl01x_serial_setbrg,
 345 };
 346
 347 U_BOOT_DRIVER(serial_pl01x) = {
 348         .name   = "serial_pl01x",
 349         .id     = UCLASS_SERIAL,
 350         .probe = pl01x_serial_probe,
 351         .ops    = &pl01x_serial_ops,
 352         .flags = DM_FLAG_PRE_RELOC,
 353 };
 354
 355 #endif