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         switch (type) {
  76         case TYPE_PL010:
  77                 /* disable everything */
  78                 writel(0, &regs->pl010_cr);
  79                 break;
  80         case TYPE_PL011:
  81 #ifdef CONFIG_PL011_SERIAL_FLUSH_ON_INIT
  82                 /* Empty RX fifo if necessary */
  83                 if (readl(&regs->pl011_cr) & UART_PL011_CR_UARTEN) {
  84                         while (!(readl(&regs->fr) & UART_PL01x_FR_RXFE))
  85                                 readl(&regs->dr);
  86                 }
  87 #endif
  88                 /* disable everything */
  89                 writel(0, &regs->pl011_cr);
  90                 break;
  91         default:
  92                 return -EINVAL;
  93         }
  94
  95         return 0;
  96 }
  97
  98 static int set_line_control(struct pl01x_regs *regs)
  99 {
 100         unsigned int lcr;
 101         /*
 102          * Internal update of baud rate register require line
 103          * control register write
 104          */
 105         lcr = UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN;
 106 #ifdef CONFIG_PL011_SERIAL_RLCR
 107         {
 108                 int i;
 109
 110                 /*
 111                  * Program receive line control register after waiting
 112                  * 10 bus cycles.  Delay be writing to readonly register
 113                  * 10 times
 114                  */
 115                 for (i = 0; i < 10; i++)
 116                         writel(lcr, &regs->fr);
 117
 118                 writel(lcr, &regs->pl011_rlcr);
 119         }
 120 #endif
 121         writel(lcr, &regs->pl011_lcrh);
 122         return 0;
 123 }
 124
 125 static int pl01x_generic_setbrg(struct pl01x_regs *regs, enum pl01x_type type,
 126                                 int clock, int baudrate)
 127 {
 128         switch (type) {
 129         case TYPE_PL010: {
 130                 unsigned int divisor;
 131
 132                 switch (baudrate) {
 133                 case 9600:
 134                         divisor = UART_PL010_BAUD_9600;
 135                         break;
 136                 case 19200:
 137                         divisor = UART_PL010_BAUD_9600;
 138                         break;
 139                 case 38400:
 140                         divisor = UART_PL010_BAUD_38400;
 141                         break;
 142                 case 57600:
 143                         divisor = UART_PL010_BAUD_57600;
 144                         break;
 145                 case 115200:
 146                         divisor = UART_PL010_BAUD_115200;
 147                         break;
 148                 default:
 149                         divisor = UART_PL010_BAUD_38400;
 150                 }
 151
 152                 writel((divisor & 0xf00) >> 8, &regs->pl010_lcrm);
 153                 writel(divisor & 0xff, &regs->pl010_lcrl);
 154
 155                 /* Finally, enable the UART */
 156                 writel(UART_PL010_CR_UARTEN, &regs->pl010_cr);
 157                 break;
 158         }
 159         case TYPE_PL011: {
 160                 unsigned int temp;
 161                 unsigned int divider;
 162                 unsigned int remainder;
 163                 unsigned int fraction;
 164
 165                 /*
 166                 * Set baud rate
 167                 *
 168                 * IBRD = UART_CLK / (16 * BAUD_RATE)
 169                 * FBRD = RND((64 * MOD(UART_CLK,(16 * BAUD_RATE)))
 170                 *               / (16 * BAUD_RATE))
 171                 */
 172                 temp = 16 * baudrate;
 173                 divider = clock / temp;
 174                 remainder = clock % temp;
 175                 temp = (8 * remainder) / baudrate;
 176                 fraction = (temp >> 1) + (temp & 1);
 177
 178                 writel(divider, &regs->pl011_ibrd);
 179                 writel(fraction, &regs->pl011_fbrd);
 180
 181                 set_line_control(regs);
 182                 /* Finally, enable the UART */
 183                 writel(UART_PL011_CR_UARTEN | UART_PL011_CR_TXE |
 184                        UART_PL011_CR_RXE | UART_PL011_CR_RTS, &regs->pl011_cr);
 185                 break;
 186         }
 187         default:
 188                 return -EINVAL;
 189         }
 190
 191         return 0;
 192 }
 193
 194 #ifndef CONFIG_DM_SERIAL
 195 static void pl01x_serial_init_baud(int baudrate)
 196 {
 197         int clock = 0;
 198
 199 #if defined(CONFIG_PL010_SERIAL)
 200         pl01x_type = TYPE_PL010;
 201 #elif defined(CONFIG_PL011_SERIAL)
 202         pl01x_type = TYPE_PL011;
 203         clock = CONFIG_PL011_CLOCK;
 204 #endif
 205         base_regs = (struct pl01x_regs *)port[CONFIG_CONS_INDEX];
 206
 207         pl01x_generic_serial_init(base_regs, pl01x_type);
 208         pl01x_generic_setbrg(base_regs, pl01x_type, clock, baudrate);
 209 }
 210
 211 /*
 212  * Integrator AP has two UARTs, we use the first one, at 38400-8-N-1
 213  * Integrator CP has two UARTs, use the first one, at 38400-8-N-1
 214  * Versatile PB has four UARTs.
 215  */
 216 int pl01x_serial_init(void)
 217 {
 218         pl01x_serial_init_baud(CONFIG_BAUDRATE);
 219
 220         return 0;
 221 }
 222
 223 static void pl01x_serial_putc(const char c)
 224 {
 225         if (c == '\n')
 226                 while (pl01x_putc(base_regs, '\r') == -EAGAIN);
 227
 228         while (pl01x_putc(base_regs, c) == -EAGAIN);
 229 }
 230
 231 static int pl01x_serial_getc(void)
 232 {
 233         while (1) {
 234                 int ch = pl01x_getc(base_regs);
 235
 236                 if (ch == -EAGAIN) {
 237                         WATCHDOG_RESET();
 238                         continue;
 239                 }
 240
 241                 return ch;
 242         }
 243 }
 244
 245 static int pl01x_serial_tstc(void)
 246 {
 247         return pl01x_tstc(base_regs);
 248 }
 249
 250 static void pl01x_serial_setbrg(void)
 251 {
 252         /*
 253          * Flush FIFO and wait for non-busy before changing baudrate to avoid
 254          * crap in console
 255          */
 256         while (!(readl(&base_regs->fr) & UART_PL01x_FR_TXFE))
 257                 WATCHDOG_RESET();
 258         while (readl(&base_regs->fr) & UART_PL01x_FR_BUSY)
 259                 WATCHDOG_RESET();
 260         pl01x_serial_init_baud(gd->baudrate);
 261 }
 262
 263 static struct serial_device pl01x_serial_drv = {
 264         .name   = "pl01x_serial",
 265         .start  = pl01x_serial_init,
 266         .stop   = NULL,
 267         .setbrg = pl01x_serial_setbrg,
 268         .putc   = pl01x_serial_putc,
 269         .puts   = default_serial_puts,
 270         .getc   = pl01x_serial_getc,
 271         .tstc   = pl01x_serial_tstc,
 272 };
 273
 274 void pl01x_serial_initialize(void)
 275 {
 276         serial_register(&pl01x_serial_drv);
 277 }
 278
 279 __weak struct serial_device *default_serial_console(void)
 280 {
 281         return &pl01x_serial_drv;
 282 }
 283
 284 #endif /* nCONFIG_DM_SERIAL */
 285
 286 #ifdef CONFIG_DM_SERIAL
 287
 288 struct pl01x_priv {
 289         struct pl01x_regs *regs;
 290         enum pl01x_type type;
 291 };
 292
 293 static int pl01x_serial_setbrg(struct udevice *dev, int baudrate)
 294 {
 295         struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
 296         struct pl01x_priv *priv = dev_get_priv(dev);
 297
 298         pl01x_generic_setbrg(priv->regs, priv->type, plat->clock, baudrate);
 299
 300         return 0;
 301 }
 302
 303 static int pl01x_serial_probe(struct udevice *dev)
 304 {
 305         struct pl01x_serial_platdata *plat = dev_get_platdata(dev);
 306         struct pl01x_priv *priv = dev_get_priv(dev);
 307
 308         priv->regs = (struct pl01x_regs *)plat->base;
 309         priv->type = plat->type;
 310         return pl01x_generic_serial_init(priv->regs, priv->type);
 311 }
 312
 313 static int pl01x_serial_getc(struct udevice *dev)
 314 {
 315         struct pl01x_priv *priv = dev_get_priv(dev);
 316
 317         return pl01x_getc(priv->regs);
 318 }
 319
 320 static int pl01x_serial_putc(struct udevice *dev, const char ch)
 321 {
 322         struct pl01x_priv *priv = dev_get_priv(dev);
 323
 324         return pl01x_putc(priv->regs, ch);
 325 }
 326
 327 static int pl01x_serial_pending(struct udevice *dev, bool input)
 328 {
 329         struct pl01x_priv *priv = dev_get_priv(dev);
 330         unsigned int fr = readl(&priv->regs->fr);
 331
 332         if (input)
 333                 return pl01x_tstc(priv->regs);
 334         else
 335                 return fr & UART_PL01x_FR_TXFF ? 0 : 1;
 336 }
 337
 338 static const struct dm_serial_ops pl01x_serial_ops = {
 339         .putc = pl01x_serial_putc,
 340         .pending = pl01x_serial_pending,
 341         .getc = pl01x_serial_getc,
 342         .setbrg = pl01x_serial_setbrg,
 343 };
 344
 345 U_BOOT_DRIVER(serial_pl01x) = {
 346         .name   = "serial_pl01x",
 347         .id     = UCLASS_SERIAL,
 348         .probe = pl01x_serial_probe,
 349         .ops    = &pl01x_serial_ops,
 350         .flags = DM_FLAG_PRE_RELOC,
 351 };
 352
 353 #endif