root/drivers/tty/serial/meson_uart.c

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DEFINITIONS

This source file includes following definitions.
  1. meson_uart_set_mctrl
  2. meson_uart_get_mctrl
  3. meson_uart_tx_empty
  4. meson_uart_stop_tx
  5. meson_uart_stop_rx
  6. meson_uart_shutdown
  7. meson_uart_start_tx
  8. meson_receive_chars
  9. meson_uart_interrupt
  10. meson_uart_type
  11. meson_uart_reset
  12. meson_uart_startup
  13. meson_uart_change_speed
  14. meson_uart_set_termios
  15. meson_uart_verify_port
  16. meson_uart_release_port
  17. meson_uart_request_port
  18. meson_uart_config_port
  19. meson_uart_enable_tx_engine
  20. meson_console_putchar
  21. meson_serial_port_write
  22. meson_serial_console_write
  23. meson_serial_console_setup
  24. meson_serial_console_init
  25. meson_serial_early_console_write
  26. meson_serial_early_console_setup
  27. meson_uart_probe_clock
  28. meson_uart_probe_clocks_legacy
  29. meson_uart_probe_clocks
  30. meson_uart_probe
  31. meson_uart_remove
  32. meson_uart_init
  33. meson_uart_exit

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Based on meson_uart.c, by AMLOGIC, INC.
   4  *
   5  * Copyright (C) 2014 Carlo Caione <carlo@caione.org>
   6  */
   7 
   8 #if defined(CONFIG_SERIAL_MESON_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
   9 #define SUPPORT_SYSRQ
  10 #endif
  11 
  12 #include <linux/clk.h>
  13 #include <linux/console.h>
  14 #include <linux/delay.h>
  15 #include <linux/init.h>
  16 #include <linux/io.h>
  17 #include <linux/module.h>
  18 #include <linux/kernel.h>
  19 #include <linux/of.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/serial.h>
  22 #include <linux/serial_core.h>
  23 #include <linux/tty.h>
  24 #include <linux/tty_flip.h>
  25 
  26 /* Register offsets */
  27 #define AML_UART_WFIFO                  0x00
  28 #define AML_UART_RFIFO                  0x04
  29 #define AML_UART_CONTROL                0x08
  30 #define AML_UART_STATUS                 0x0c
  31 #define AML_UART_MISC                   0x10
  32 #define AML_UART_REG5                   0x14
  33 
  34 /* AML_UART_CONTROL bits */
  35 #define AML_UART_TX_EN                  BIT(12)
  36 #define AML_UART_RX_EN                  BIT(13)
  37 #define AML_UART_TWO_WIRE_EN            BIT(15)
  38 #define AML_UART_STOP_BIT_LEN_MASK      (0x03 << 16)
  39 #define AML_UART_STOP_BIT_1SB           (0x00 << 16)
  40 #define AML_UART_STOP_BIT_2SB           (0x01 << 16)
  41 #define AML_UART_PARITY_TYPE            BIT(18)
  42 #define AML_UART_PARITY_EN              BIT(19)
  43 #define AML_UART_TX_RST                 BIT(22)
  44 #define AML_UART_RX_RST                 BIT(23)
  45 #define AML_UART_CLEAR_ERR              BIT(24)
  46 #define AML_UART_RX_INT_EN              BIT(27)
  47 #define AML_UART_TX_INT_EN              BIT(28)
  48 #define AML_UART_DATA_LEN_MASK          (0x03 << 20)
  49 #define AML_UART_DATA_LEN_8BIT          (0x00 << 20)
  50 #define AML_UART_DATA_LEN_7BIT          (0x01 << 20)
  51 #define AML_UART_DATA_LEN_6BIT          (0x02 << 20)
  52 #define AML_UART_DATA_LEN_5BIT          (0x03 << 20)
  53 
  54 /* AML_UART_STATUS bits */
  55 #define AML_UART_PARITY_ERR             BIT(16)
  56 #define AML_UART_FRAME_ERR              BIT(17)
  57 #define AML_UART_TX_FIFO_WERR           BIT(18)
  58 #define AML_UART_RX_EMPTY               BIT(20)
  59 #define AML_UART_TX_FULL                BIT(21)
  60 #define AML_UART_TX_EMPTY               BIT(22)
  61 #define AML_UART_XMIT_BUSY              BIT(25)
  62 #define AML_UART_ERR                    (AML_UART_PARITY_ERR | \
  63                                          AML_UART_FRAME_ERR  | \
  64                                          AML_UART_TX_FIFO_WERR)
  65 
  66 /* AML_UART_MISC bits */
  67 #define AML_UART_XMIT_IRQ(c)            (((c) & 0xff) << 8)
  68 #define AML_UART_RECV_IRQ(c)            ((c) & 0xff)
  69 
  70 /* AML_UART_REG5 bits */
  71 #define AML_UART_BAUD_MASK              0x7fffff
  72 #define AML_UART_BAUD_USE               BIT(23)
  73 #define AML_UART_BAUD_XTAL              BIT(24)
  74 
  75 #define AML_UART_PORT_NUM               12
  76 #define AML_UART_PORT_OFFSET            6
  77 #define AML_UART_DEV_NAME               "ttyAML"
  78 
  79 
  80 static struct uart_driver meson_uart_driver;
  81 
  82 static struct uart_port *meson_ports[AML_UART_PORT_NUM];
  83 
  84 static void meson_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
  85 {
  86 }
  87 
  88 static unsigned int meson_uart_get_mctrl(struct uart_port *port)
  89 {
  90         return TIOCM_CTS;
  91 }
  92 
  93 static unsigned int meson_uart_tx_empty(struct uart_port *port)
  94 {
  95         u32 val;
  96 
  97         val = readl(port->membase + AML_UART_STATUS);
  98         val &= (AML_UART_TX_EMPTY | AML_UART_XMIT_BUSY);
  99         return (val == AML_UART_TX_EMPTY) ? TIOCSER_TEMT : 0;
 100 }
 101 
 102 static void meson_uart_stop_tx(struct uart_port *port)
 103 {
 104         u32 val;
 105 
 106         val = readl(port->membase + AML_UART_CONTROL);
 107         val &= ~AML_UART_TX_INT_EN;
 108         writel(val, port->membase + AML_UART_CONTROL);
 109 }
 110 
 111 static void meson_uart_stop_rx(struct uart_port *port)
 112 {
 113         u32 val;
 114 
 115         val = readl(port->membase + AML_UART_CONTROL);
 116         val &= ~AML_UART_RX_EN;
 117         writel(val, port->membase + AML_UART_CONTROL);
 118 }
 119 
 120 static void meson_uart_shutdown(struct uart_port *port)
 121 {
 122         unsigned long flags;
 123         u32 val;
 124 
 125         free_irq(port->irq, port);
 126 
 127         spin_lock_irqsave(&port->lock, flags);
 128 
 129         val = readl(port->membase + AML_UART_CONTROL);
 130         val &= ~AML_UART_RX_EN;
 131         val &= ~(AML_UART_RX_INT_EN | AML_UART_TX_INT_EN);
 132         writel(val, port->membase + AML_UART_CONTROL);
 133 
 134         spin_unlock_irqrestore(&port->lock, flags);
 135 }
 136 
 137 static void meson_uart_start_tx(struct uart_port *port)
 138 {
 139         struct circ_buf *xmit = &port->state->xmit;
 140         unsigned int ch;
 141         u32 val;
 142 
 143         if (uart_tx_stopped(port)) {
 144                 meson_uart_stop_tx(port);
 145                 return;
 146         }
 147 
 148         while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) {
 149                 if (port->x_char) {
 150                         writel(port->x_char, port->membase + AML_UART_WFIFO);
 151                         port->icount.tx++;
 152                         port->x_char = 0;
 153                         continue;
 154                 }
 155 
 156                 if (uart_circ_empty(xmit))
 157                         break;
 158 
 159                 ch = xmit->buf[xmit->tail];
 160                 writel(ch, port->membase + AML_UART_WFIFO);
 161                 xmit->tail = (xmit->tail+1) & (SERIAL_XMIT_SIZE - 1);
 162                 port->icount.tx++;
 163         }
 164 
 165         if (!uart_circ_empty(xmit)) {
 166                 val = readl(port->membase + AML_UART_CONTROL);
 167                 val |= AML_UART_TX_INT_EN;
 168                 writel(val, port->membase + AML_UART_CONTROL);
 169         }
 170 
 171         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 172                 uart_write_wakeup(port);
 173 }
 174 
 175 static void meson_receive_chars(struct uart_port *port)
 176 {
 177         struct tty_port *tport = &port->state->port;
 178         char flag;
 179         u32 ostatus, status, ch, mode;
 180 
 181         do {
 182                 flag = TTY_NORMAL;
 183                 port->icount.rx++;
 184                 ostatus = status = readl(port->membase + AML_UART_STATUS);
 185 
 186                 if (status & AML_UART_ERR) {
 187                         if (status & AML_UART_TX_FIFO_WERR)
 188                                 port->icount.overrun++;
 189                         else if (status & AML_UART_FRAME_ERR)
 190                                 port->icount.frame++;
 191                         else if (status & AML_UART_PARITY_ERR)
 192                                 port->icount.frame++;
 193 
 194                         mode = readl(port->membase + AML_UART_CONTROL);
 195                         mode |= AML_UART_CLEAR_ERR;
 196                         writel(mode, port->membase + AML_UART_CONTROL);
 197 
 198                         /* It doesn't clear to 0 automatically */
 199                         mode &= ~AML_UART_CLEAR_ERR;
 200                         writel(mode, port->membase + AML_UART_CONTROL);
 201 
 202                         status &= port->read_status_mask;
 203                         if (status & AML_UART_FRAME_ERR)
 204                                 flag = TTY_FRAME;
 205                         else if (status & AML_UART_PARITY_ERR)
 206                                 flag = TTY_PARITY;
 207                 }
 208 
 209                 ch = readl(port->membase + AML_UART_RFIFO);
 210                 ch &= 0xff;
 211 
 212                 if ((ostatus & AML_UART_FRAME_ERR) && (ch == 0)) {
 213                         port->icount.brk++;
 214                         flag = TTY_BREAK;
 215                         if (uart_handle_break(port))
 216                                 continue;
 217                 }
 218 
 219                 if (uart_handle_sysrq_char(port, ch))
 220                         continue;
 221 
 222                 if ((status & port->ignore_status_mask) == 0)
 223                         tty_insert_flip_char(tport, ch, flag);
 224 
 225                 if (status & AML_UART_TX_FIFO_WERR)
 226                         tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 227 
 228         } while (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY));
 229 
 230         spin_unlock(&port->lock);
 231         tty_flip_buffer_push(tport);
 232         spin_lock(&port->lock);
 233 }
 234 
 235 static irqreturn_t meson_uart_interrupt(int irq, void *dev_id)
 236 {
 237         struct uart_port *port = (struct uart_port *)dev_id;
 238 
 239         spin_lock(&port->lock);
 240 
 241         if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_RX_EMPTY))
 242                 meson_receive_chars(port);
 243 
 244         if (!(readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)) {
 245                 if (readl(port->membase + AML_UART_CONTROL) & AML_UART_TX_INT_EN)
 246                         meson_uart_start_tx(port);
 247         }
 248 
 249         spin_unlock(&port->lock);
 250 
 251         return IRQ_HANDLED;
 252 }
 253 
 254 static const char *meson_uart_type(struct uart_port *port)
 255 {
 256         return (port->type == PORT_MESON) ? "meson_uart" : NULL;
 257 }
 258 
 259 static void meson_uart_reset(struct uart_port *port)
 260 {
 261         u32 val;
 262 
 263         val = readl(port->membase + AML_UART_CONTROL);
 264         val |= (AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLEAR_ERR);
 265         writel(val, port->membase + AML_UART_CONTROL);
 266 
 267         val &= ~(AML_UART_RX_RST | AML_UART_TX_RST | AML_UART_CLEAR_ERR);
 268         writel(val, port->membase + AML_UART_CONTROL);
 269 }
 270 
 271 static int meson_uart_startup(struct uart_port *port)
 272 {
 273         u32 val;
 274         int ret = 0;
 275 
 276         val = readl(port->membase + AML_UART_CONTROL);
 277         val |= AML_UART_CLEAR_ERR;
 278         writel(val, port->membase + AML_UART_CONTROL);
 279         val &= ~AML_UART_CLEAR_ERR;
 280         writel(val, port->membase + AML_UART_CONTROL);
 281 
 282         val |= (AML_UART_RX_EN | AML_UART_TX_EN);
 283         writel(val, port->membase + AML_UART_CONTROL);
 284 
 285         val |= (AML_UART_RX_INT_EN | AML_UART_TX_INT_EN);
 286         writel(val, port->membase + AML_UART_CONTROL);
 287 
 288         val = (AML_UART_RECV_IRQ(1) | AML_UART_XMIT_IRQ(port->fifosize / 2));
 289         writel(val, port->membase + AML_UART_MISC);
 290 
 291         ret = request_irq(port->irq, meson_uart_interrupt, 0,
 292                           port->name, port);
 293 
 294         return ret;
 295 }
 296 
 297 static void meson_uart_change_speed(struct uart_port *port, unsigned long baud)
 298 {
 299         u32 val;
 300 
 301         while (!meson_uart_tx_empty(port))
 302                 cpu_relax();
 303 
 304         if (port->uartclk == 24000000) {
 305                 val = ((port->uartclk / 3) / baud) - 1;
 306                 val |= AML_UART_BAUD_XTAL;
 307         } else {
 308                 val = ((port->uartclk * 10 / (baud * 4) + 5) / 10) - 1;
 309         }
 310         val |= AML_UART_BAUD_USE;
 311         writel(val, port->membase + AML_UART_REG5);
 312 }
 313 
 314 static void meson_uart_set_termios(struct uart_port *port,
 315                                    struct ktermios *termios,
 316                                    struct ktermios *old)
 317 {
 318         unsigned int cflags, iflags, baud;
 319         unsigned long flags;
 320         u32 val;
 321 
 322         spin_lock_irqsave(&port->lock, flags);
 323 
 324         cflags = termios->c_cflag;
 325         iflags = termios->c_iflag;
 326 
 327         val = readl(port->membase + AML_UART_CONTROL);
 328 
 329         val &= ~AML_UART_DATA_LEN_MASK;
 330         switch (cflags & CSIZE) {
 331         case CS8:
 332                 val |= AML_UART_DATA_LEN_8BIT;
 333                 break;
 334         case CS7:
 335                 val |= AML_UART_DATA_LEN_7BIT;
 336                 break;
 337         case CS6:
 338                 val |= AML_UART_DATA_LEN_6BIT;
 339                 break;
 340         case CS5:
 341                 val |= AML_UART_DATA_LEN_5BIT;
 342                 break;
 343         }
 344 
 345         if (cflags & PARENB)
 346                 val |= AML_UART_PARITY_EN;
 347         else
 348                 val &= ~AML_UART_PARITY_EN;
 349 
 350         if (cflags & PARODD)
 351                 val |= AML_UART_PARITY_TYPE;
 352         else
 353                 val &= ~AML_UART_PARITY_TYPE;
 354 
 355         val &= ~AML_UART_STOP_BIT_LEN_MASK;
 356         if (cflags & CSTOPB)
 357                 val |= AML_UART_STOP_BIT_2SB;
 358         else
 359                 val |= AML_UART_STOP_BIT_1SB;
 360 
 361         if (cflags & CRTSCTS)
 362                 val &= ~AML_UART_TWO_WIRE_EN;
 363         else
 364                 val |= AML_UART_TWO_WIRE_EN;
 365 
 366         writel(val, port->membase + AML_UART_CONTROL);
 367 
 368         baud = uart_get_baud_rate(port, termios, old, 50, 4000000);
 369         meson_uart_change_speed(port, baud);
 370 
 371         port->read_status_mask = AML_UART_TX_FIFO_WERR;
 372         if (iflags & INPCK)
 373                 port->read_status_mask |= AML_UART_PARITY_ERR |
 374                                           AML_UART_FRAME_ERR;
 375 
 376         port->ignore_status_mask = 0;
 377         if (iflags & IGNPAR)
 378                 port->ignore_status_mask |= AML_UART_PARITY_ERR |
 379                                             AML_UART_FRAME_ERR;
 380 
 381         uart_update_timeout(port, termios->c_cflag, baud);
 382         spin_unlock_irqrestore(&port->lock, flags);
 383 }
 384 
 385 static int meson_uart_verify_port(struct uart_port *port,
 386                                   struct serial_struct *ser)
 387 {
 388         int ret = 0;
 389 
 390         if (port->type != PORT_MESON)
 391                 ret = -EINVAL;
 392         if (port->irq != ser->irq)
 393                 ret = -EINVAL;
 394         if (ser->baud_base < 9600)
 395                 ret = -EINVAL;
 396         return ret;
 397 }
 398 
 399 static void meson_uart_release_port(struct uart_port *port)
 400 {
 401         devm_iounmap(port->dev, port->membase);
 402         port->membase = NULL;
 403         devm_release_mem_region(port->dev, port->mapbase, port->mapsize);
 404 }
 405 
 406 static int meson_uart_request_port(struct uart_port *port)
 407 {
 408         if (!devm_request_mem_region(port->dev, port->mapbase, port->mapsize,
 409                                      dev_name(port->dev))) {
 410                 dev_err(port->dev, "Memory region busy\n");
 411                 return -EBUSY;
 412         }
 413 
 414         port->membase = devm_ioremap_nocache(port->dev, port->mapbase,
 415                                              port->mapsize);
 416         if (!port->membase)
 417                 return -ENOMEM;
 418 
 419         return 0;
 420 }
 421 
 422 static void meson_uart_config_port(struct uart_port *port, int flags)
 423 {
 424         if (flags & UART_CONFIG_TYPE) {
 425                 port->type = PORT_MESON;
 426                 meson_uart_request_port(port);
 427         }
 428 }
 429 
 430 static const struct uart_ops meson_uart_ops = {
 431         .set_mctrl      = meson_uart_set_mctrl,
 432         .get_mctrl      = meson_uart_get_mctrl,
 433         .tx_empty       = meson_uart_tx_empty,
 434         .start_tx       = meson_uart_start_tx,
 435         .stop_tx        = meson_uart_stop_tx,
 436         .stop_rx        = meson_uart_stop_rx,
 437         .startup        = meson_uart_startup,
 438         .shutdown       = meson_uart_shutdown,
 439         .set_termios    = meson_uart_set_termios,
 440         .type           = meson_uart_type,
 441         .config_port    = meson_uart_config_port,
 442         .request_port   = meson_uart_request_port,
 443         .release_port   = meson_uart_release_port,
 444         .verify_port    = meson_uart_verify_port,
 445 };
 446 
 447 #ifdef CONFIG_SERIAL_MESON_CONSOLE
 448 static void meson_uart_enable_tx_engine(struct uart_port *port)
 449 {
 450         u32 val;
 451 
 452         val = readl(port->membase + AML_UART_CONTROL);
 453         val |= AML_UART_TX_EN;
 454         writel(val, port->membase + AML_UART_CONTROL);
 455 }
 456 
 457 static void meson_console_putchar(struct uart_port *port, int ch)
 458 {
 459         if (!port->membase)
 460                 return;
 461 
 462         while (readl(port->membase + AML_UART_STATUS) & AML_UART_TX_FULL)
 463                 cpu_relax();
 464         writel(ch, port->membase + AML_UART_WFIFO);
 465 }
 466 
 467 static void meson_serial_port_write(struct uart_port *port, const char *s,
 468                                     u_int count)
 469 {
 470         unsigned long flags;
 471         int locked;
 472         u32 val, tmp;
 473 
 474         local_irq_save(flags);
 475         if (port->sysrq) {
 476                 locked = 0;
 477         } else if (oops_in_progress) {
 478                 locked = spin_trylock(&port->lock);
 479         } else {
 480                 spin_lock(&port->lock);
 481                 locked = 1;
 482         }
 483 
 484         val = readl(port->membase + AML_UART_CONTROL);
 485         tmp = val & ~(AML_UART_TX_INT_EN | AML_UART_RX_INT_EN);
 486         writel(tmp, port->membase + AML_UART_CONTROL);
 487 
 488         uart_console_write(port, s, count, meson_console_putchar);
 489         writel(val, port->membase + AML_UART_CONTROL);
 490 
 491         if (locked)
 492                 spin_unlock(&port->lock);
 493         local_irq_restore(flags);
 494 }
 495 
 496 static void meson_serial_console_write(struct console *co, const char *s,
 497                                        u_int count)
 498 {
 499         struct uart_port *port;
 500 
 501         port = meson_ports[co->index];
 502         if (!port)
 503                 return;
 504 
 505         meson_serial_port_write(port, s, count);
 506 }
 507 
 508 static int meson_serial_console_setup(struct console *co, char *options)
 509 {
 510         struct uart_port *port;
 511         int baud = 115200;
 512         int bits = 8;
 513         int parity = 'n';
 514         int flow = 'n';
 515 
 516         if (co->index < 0 || co->index >= AML_UART_PORT_NUM)
 517                 return -EINVAL;
 518 
 519         port = meson_ports[co->index];
 520         if (!port || !port->membase)
 521                 return -ENODEV;
 522 
 523         meson_uart_enable_tx_engine(port);
 524 
 525         if (options)
 526                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 527 
 528         return uart_set_options(port, co, baud, parity, bits, flow);
 529 }
 530 
 531 static struct console meson_serial_console = {
 532         .name           = AML_UART_DEV_NAME,
 533         .write          = meson_serial_console_write,
 534         .device         = uart_console_device,
 535         .setup          = meson_serial_console_setup,
 536         .flags          = CON_PRINTBUFFER,
 537         .index          = -1,
 538         .data           = &meson_uart_driver,
 539 };
 540 
 541 static int __init meson_serial_console_init(void)
 542 {
 543         register_console(&meson_serial_console);
 544         return 0;
 545 }
 546 console_initcall(meson_serial_console_init);
 547 
 548 static void meson_serial_early_console_write(struct console *co,
 549                                              const char *s,
 550                                              u_int count)
 551 {
 552         struct earlycon_device *dev = co->data;
 553 
 554         meson_serial_port_write(&dev->port, s, count);
 555 }
 556 
 557 static int __init
 558 meson_serial_early_console_setup(struct earlycon_device *device, const char *opt)
 559 {
 560         if (!device->port.membase)
 561                 return -ENODEV;
 562 
 563         meson_uart_enable_tx_engine(&device->port);
 564         device->con->write = meson_serial_early_console_write;
 565         return 0;
 566 }
 567 /* Legacy bindings, should be removed when no more used */
 568 OF_EARLYCON_DECLARE(meson, "amlogic,meson-uart",
 569                     meson_serial_early_console_setup);
 570 /* Stable bindings */
 571 OF_EARLYCON_DECLARE(meson, "amlogic,meson-ao-uart",
 572                     meson_serial_early_console_setup);
 573 
 574 #define MESON_SERIAL_CONSOLE    (&meson_serial_console)
 575 #else
 576 #define MESON_SERIAL_CONSOLE    NULL
 577 #endif
 578 
 579 static struct uart_driver meson_uart_driver = {
 580         .owner          = THIS_MODULE,
 581         .driver_name    = "meson_uart",
 582         .dev_name       = AML_UART_DEV_NAME,
 583         .nr             = AML_UART_PORT_NUM,
 584         .cons           = MESON_SERIAL_CONSOLE,
 585 };
 586 
 587 static inline struct clk *meson_uart_probe_clock(struct device *dev,
 588                                                  const char *id)
 589 {
 590         struct clk *clk = NULL;
 591         int ret;
 592 
 593         clk = devm_clk_get(dev, id);
 594         if (IS_ERR(clk))
 595                 return clk;
 596 
 597         ret = clk_prepare_enable(clk);
 598         if (ret) {
 599                 dev_err(dev, "couldn't enable clk\n");
 600                 return ERR_PTR(ret);
 601         }
 602 
 603         devm_add_action_or_reset(dev,
 604                         (void(*)(void *))clk_disable_unprepare,
 605                         clk);
 606 
 607         return clk;
 608 }
 609 
 610 /*
 611  * This function gets clocks in the legacy non-stable DT bindings.
 612  * This code will be remove once all the platforms switch to the
 613  * new DT bindings.
 614  */
 615 static int meson_uart_probe_clocks_legacy(struct platform_device *pdev,
 616                                           struct uart_port *port)
 617 {
 618         struct clk *clk = NULL;
 619 
 620         clk = meson_uart_probe_clock(&pdev->dev, NULL);
 621         if (IS_ERR(clk))
 622                 return PTR_ERR(clk);
 623 
 624         port->uartclk = clk_get_rate(clk);
 625 
 626         return 0;
 627 }
 628 
 629 static int meson_uart_probe_clocks(struct platform_device *pdev,
 630                                    struct uart_port *port)
 631 {
 632         struct clk *clk_xtal = NULL;
 633         struct clk *clk_pclk = NULL;
 634         struct clk *clk_baud = NULL;
 635 
 636         clk_pclk = meson_uart_probe_clock(&pdev->dev, "pclk");
 637         if (IS_ERR(clk_pclk))
 638                 return PTR_ERR(clk_pclk);
 639 
 640         clk_xtal = meson_uart_probe_clock(&pdev->dev, "xtal");
 641         if (IS_ERR(clk_xtal))
 642                 return PTR_ERR(clk_xtal);
 643 
 644         clk_baud = meson_uart_probe_clock(&pdev->dev, "baud");
 645         if (IS_ERR(clk_baud))
 646                 return PTR_ERR(clk_baud);
 647 
 648         port->uartclk = clk_get_rate(clk_baud);
 649 
 650         return 0;
 651 }
 652 
 653 static int meson_uart_probe(struct platform_device *pdev)
 654 {
 655         struct resource *res_mem, *res_irq;
 656         struct uart_port *port;
 657         int ret = 0;
 658         int id = -1;
 659 
 660         if (pdev->dev.of_node)
 661                 pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
 662 
 663         if (pdev->id < 0) {
 664                 for (id = AML_UART_PORT_OFFSET; id < AML_UART_PORT_NUM; id++) {
 665                         if (!meson_ports[id]) {
 666                                 pdev->id = id;
 667                                 break;
 668                         }
 669                 }
 670         }
 671 
 672         if (pdev->id < 0 || pdev->id >= AML_UART_PORT_NUM)
 673                 return -EINVAL;
 674 
 675         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 676         if (!res_mem)
 677                 return -ENODEV;
 678 
 679         res_irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 680         if (!res_irq)
 681                 return -ENODEV;
 682 
 683         if (meson_ports[pdev->id]) {
 684                 dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
 685                 return -EBUSY;
 686         }
 687 
 688         port = devm_kzalloc(&pdev->dev, sizeof(struct uart_port), GFP_KERNEL);
 689         if (!port)
 690                 return -ENOMEM;
 691 
 692         /* Use legacy way until all platforms switch to new bindings */
 693         if (of_device_is_compatible(pdev->dev.of_node, "amlogic,meson-uart"))
 694                 ret = meson_uart_probe_clocks_legacy(pdev, port);
 695         else
 696                 ret = meson_uart_probe_clocks(pdev, port);
 697 
 698         if (ret)
 699                 return ret;
 700 
 701         port->iotype = UPIO_MEM;
 702         port->mapbase = res_mem->start;
 703         port->mapsize = resource_size(res_mem);
 704         port->irq = res_irq->start;
 705         port->flags = UPF_BOOT_AUTOCONF | UPF_LOW_LATENCY;
 706         port->dev = &pdev->dev;
 707         port->line = pdev->id;
 708         port->type = PORT_MESON;
 709         port->x_char = 0;
 710         port->ops = &meson_uart_ops;
 711         port->fifosize = 64;
 712 
 713         meson_ports[pdev->id] = port;
 714         platform_set_drvdata(pdev, port);
 715 
 716         /* reset port before registering (and possibly registering console) */
 717         if (meson_uart_request_port(port) >= 0) {
 718                 meson_uart_reset(port);
 719                 meson_uart_release_port(port);
 720         }
 721 
 722         ret = uart_add_one_port(&meson_uart_driver, port);
 723         if (ret)
 724                 meson_ports[pdev->id] = NULL;
 725 
 726         return ret;
 727 }
 728 
 729 static int meson_uart_remove(struct platform_device *pdev)
 730 {
 731         struct uart_port *port;
 732 
 733         port = platform_get_drvdata(pdev);
 734         uart_remove_one_port(&meson_uart_driver, port);
 735         meson_ports[pdev->id] = NULL;
 736 
 737         return 0;
 738 }
 739 
 740 static const struct of_device_id meson_uart_dt_match[] = {
 741         /* Legacy bindings, should be removed when no more used */
 742         { .compatible = "amlogic,meson-uart" },
 743         /* Stable bindings */
 744         { .compatible = "amlogic,meson6-uart" },
 745         { .compatible = "amlogic,meson8-uart" },
 746         { .compatible = "amlogic,meson8b-uart" },
 747         { .compatible = "amlogic,meson-gx-uart" },
 748         { /* sentinel */ },
 749 };
 750 MODULE_DEVICE_TABLE(of, meson_uart_dt_match);
 751 
 752 static  struct platform_driver meson_uart_platform_driver = {
 753         .probe          = meson_uart_probe,
 754         .remove         = meson_uart_remove,
 755         .driver         = {
 756                 .name           = "meson_uart",
 757                 .of_match_table = meson_uart_dt_match,
 758         },
 759 };
 760 
 761 static int __init meson_uart_init(void)
 762 {
 763         int ret;
 764 
 765         ret = uart_register_driver(&meson_uart_driver);
 766         if (ret)
 767                 return ret;
 768 
 769         ret = platform_driver_register(&meson_uart_platform_driver);
 770         if (ret)
 771                 uart_unregister_driver(&meson_uart_driver);
 772 
 773         return ret;
 774 }
 775 
 776 static void __exit meson_uart_exit(void)
 777 {
 778         platform_driver_unregister(&meson_uart_platform_driver);
 779         uart_unregister_driver(&meson_uart_driver);
 780 }
 781 
 782 module_init(meson_uart_init);
 783 module_exit(meson_uart_exit);
 784 
 785 MODULE_AUTHOR("Carlo Caione <carlo@caione.org>");
 786 MODULE_DESCRIPTION("Amlogic Meson serial port driver");
 787 MODULE_LICENSE("GPL v2");

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