drivers/tty/serial/rda-uart.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * RDA8810PL serial device driver
   4  *
   5  * Copyright RDA Microelectronics Company Limited
   6  * Copyright (c) 2017 Andreas Färber
   7  * Copyright (c) 2018 Manivannan Sadhasivam
   8  */
   9
  10 #include <linux/clk.h>
  11 #include <linux/console.h>
  12 #include <linux/delay.h>
  13 #include <linux/io.h>
  14 #include <linux/module.h>
  15 #include <linux/of.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/serial.h>
  18 #include <linux/serial_core.h>
  19 #include <linux/tty.h>
  20 #include <linux/tty_flip.h>
  21
  22 #define RDA_UART_PORT_NUM 3
  23 #define RDA_UART_DEV_NAME "ttyRDA"
  24
  25 #define RDA_UART_CTRL           0x00
  26 #define RDA_UART_STATUS         0x04
  27 #define RDA_UART_RXTX_BUFFER    0x08
  28 #define RDA_UART_IRQ_MASK       0x0c
  29 #define RDA_UART_IRQ_CAUSE      0x10
  30 #define RDA_UART_IRQ_TRIGGERS   0x14
  31 #define RDA_UART_CMD_SET        0x18
  32 #define RDA_UART_CMD_CLR        0x1c
  33
  34 /* UART_CTRL Bits */
  35 #define RDA_UART_ENABLE                 BIT(0)
  36 #define RDA_UART_DBITS_8                BIT(1)
  37 #define RDA_UART_TX_SBITS_2             BIT(2)
  38 #define RDA_UART_PARITY_EN              BIT(3)
  39 #define RDA_UART_PARITY(x)              (((x) & 0x3) << 4)
  40 #define RDA_UART_PARITY_ODD             RDA_UART_PARITY(0)
  41 #define RDA_UART_PARITY_EVEN            RDA_UART_PARITY(1)
  42 #define RDA_UART_PARITY_SPACE           RDA_UART_PARITY(2)
  43 #define RDA_UART_PARITY_MARK            RDA_UART_PARITY(3)
  44 #define RDA_UART_DIV_MODE               BIT(20)
  45 #define RDA_UART_IRDA_EN                BIT(21)
  46 #define RDA_UART_DMA_EN                 BIT(22)
  47 #define RDA_UART_FLOW_CNT_EN            BIT(23)
  48 #define RDA_UART_LOOP_BACK_EN           BIT(24)
  49 #define RDA_UART_RX_LOCK_ERR            BIT(25)
  50 #define RDA_UART_RX_BREAK_LEN(x)        (((x) & 0xf) << 28)
  51
  52 /* UART_STATUS Bits */
  53 #define RDA_UART_RX_FIFO(x)             (((x) & 0x7f) << 0)
  54 #define RDA_UART_RX_FIFO_MASK           (0x7f << 0)
  55 #define RDA_UART_TX_FIFO(x)             (((x) & 0x1f) << 8)
  56 #define RDA_UART_TX_FIFO_MASK           (0x1f << 8)
  57 #define RDA_UART_TX_ACTIVE              BIT(14)
  58 #define RDA_UART_RX_ACTIVE              BIT(15)
  59 #define RDA_UART_RX_OVERFLOW_ERR        BIT(16)
  60 #define RDA_UART_TX_OVERFLOW_ERR        BIT(17)
  61 #define RDA_UART_RX_PARITY_ERR          BIT(18)
  62 #define RDA_UART_RX_FRAMING_ERR         BIT(19)
  63 #define RDA_UART_RX_BREAK_INT           BIT(20)
  64 #define RDA_UART_DCTS                   BIT(24)
  65 #define RDA_UART_CTS                    BIT(25)
  66 #define RDA_UART_DTR                    BIT(28)
  67 #define RDA_UART_CLK_ENABLED            BIT(31)
  68
  69 /* UART_RXTX_BUFFER Bits */
  70 #define RDA_UART_RX_DATA(x)             (((x) & 0xff) << 0)
  71 #define RDA_UART_TX_DATA(x)             (((x) & 0xff) << 0)
  72
  73 /* UART_IRQ_MASK Bits */
  74 #define RDA_UART_TX_MODEM_STATUS        BIT(0)
  75 #define RDA_UART_RX_DATA_AVAILABLE      BIT(1)
  76 #define RDA_UART_TX_DATA_NEEDED         BIT(2)
  77 #define RDA_UART_RX_TIMEOUT             BIT(3)
  78 #define RDA_UART_RX_LINE_ERR            BIT(4)
  79 #define RDA_UART_TX_DMA_DONE            BIT(5)
  80 #define RDA_UART_RX_DMA_DONE            BIT(6)
  81 #define RDA_UART_RX_DMA_TIMEOUT         BIT(7)
  82 #define RDA_UART_DTR_RISE               BIT(8)
  83 #define RDA_UART_DTR_FALL               BIT(9)
  84
  85 /* UART_IRQ_CAUSE Bits */
  86 #define RDA_UART_TX_MODEM_STATUS_U      BIT(16)
  87 #define RDA_UART_RX_DATA_AVAILABLE_U    BIT(17)
  88 #define RDA_UART_TX_DATA_NEEDED_U       BIT(18)
  89 #define RDA_UART_RX_TIMEOUT_U           BIT(19)
  90 #define RDA_UART_RX_LINE_ERR_U          BIT(20)
  91 #define RDA_UART_TX_DMA_DONE_U          BIT(21)
  92 #define RDA_UART_RX_DMA_DONE_U          BIT(22)
  93 #define RDA_UART_RX_DMA_TIMEOUT_U       BIT(23)
  94 #define RDA_UART_DTR_RISE_U             BIT(24)
  95 #define RDA_UART_DTR_FALL_U             BIT(25)
  96
  97 /* UART_TRIGGERS Bits */
  98 #define RDA_UART_RX_TRIGGER(x)          (((x) & 0x1f) << 0)
  99 #define RDA_UART_TX_TRIGGER(x)          (((x) & 0xf) << 8)
 100 #define RDA_UART_AFC_LEVEL(x)           (((x) & 0x1f) << 16)
 101
 102 /* UART_CMD_SET Bits */
 103 #define RDA_UART_RI                     BIT(0)
 104 #define RDA_UART_DCD                    BIT(1)
 105 #define RDA_UART_DSR                    BIT(2)
 106 #define RDA_UART_TX_BREAK_CONTROL       BIT(3)
 107 #define RDA_UART_TX_FINISH_N_WAIT       BIT(4)
 108 #define RDA_UART_RTS                    BIT(5)
 109 #define RDA_UART_RX_FIFO_RESET          BIT(6)
 110 #define RDA_UART_TX_FIFO_RESET          BIT(7)
 111
 112 #define RDA_UART_TX_FIFO_SIZE   16
 113
 114 static struct uart_driver rda_uart_driver;
 115
 116 struct rda_uart_port {
 117         struct uart_port port;
 118         struct clk *clk;
 119 };
 120
 121 #define to_rda_uart_port(port) container_of(port, struct rda_uart_port, port)
 122
 123 static struct rda_uart_port *rda_uart_ports[RDA_UART_PORT_NUM];
 124
 125 static inline void rda_uart_write(struct uart_port *port, u32 val,
 126                                   unsigned int off)
 127 {
 128         writel(val, port->membase + off);
 129 }
 130
 131 static inline u32 rda_uart_read(struct uart_port *port, unsigned int off)
 132 {
 133         return readl(port->membase + off);
 134 }
 135
 136 static unsigned int rda_uart_tx_empty(struct uart_port *port)
 137 {
 138         unsigned long flags;
 139         unsigned int ret;
 140         u32 val;
 141
 142         uart_port_lock_irqsave(port, &flags);
 143
 144         val = rda_uart_read(port, RDA_UART_STATUS);
 145         ret = (val & RDA_UART_TX_FIFO_MASK) ? TIOCSER_TEMT : 0;
 146
 147         uart_port_unlock_irqrestore(port, flags);
 148
 149         return ret;
 150 }
 151
 152 static unsigned int rda_uart_get_mctrl(struct uart_port *port)
 153 {
 154         unsigned int mctrl = 0;
 155         u32 cmd_set, status;
 156
 157         cmd_set = rda_uart_read(port, RDA_UART_CMD_SET);
 158         status = rda_uart_read(port, RDA_UART_STATUS);
 159         if (cmd_set & RDA_UART_RTS)
 160                 mctrl |= TIOCM_RTS;
 161         if (!(status & RDA_UART_CTS))
 162                 mctrl |= TIOCM_CTS;
 163
 164         return mctrl;
 165 }
 166
 167 static void rda_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 168 {
 169         u32 val;
 170
 171         if (mctrl & TIOCM_RTS) {
 172                 val = rda_uart_read(port, RDA_UART_CMD_SET);
 173                 rda_uart_write(port, (val | RDA_UART_RTS), RDA_UART_CMD_SET);
 174         } else {
 175                 /* Clear RTS to stop to receive. */
 176                 val = rda_uart_read(port, RDA_UART_CMD_CLR);
 177                 rda_uart_write(port, (val | RDA_UART_RTS), RDA_UART_CMD_CLR);
 178         }
 179
 180         val = rda_uart_read(port, RDA_UART_CTRL);
 181
 182         if (mctrl & TIOCM_LOOP)
 183                 val |= RDA_UART_LOOP_BACK_EN;
 184         else
 185                 val &= ~RDA_UART_LOOP_BACK_EN;
 186
 187         rda_uart_write(port, val, RDA_UART_CTRL);
 188 }
 189
 190 static void rda_uart_stop_tx(struct uart_port *port)
 191 {
 192         u32 val;
 193
 194         val = rda_uart_read(port, RDA_UART_IRQ_MASK);
 195         val &= ~RDA_UART_TX_DATA_NEEDED;
 196         rda_uart_write(port, val, RDA_UART_IRQ_MASK);
 197
 198         val = rda_uart_read(port, RDA_UART_CMD_SET);
 199         val |= RDA_UART_TX_FIFO_RESET;
 200         rda_uart_write(port, val, RDA_UART_CMD_SET);
 201 }
 202
 203 static void rda_uart_stop_rx(struct uart_port *port)
 204 {
 205         u32 val;
 206
 207         val = rda_uart_read(port, RDA_UART_IRQ_MASK);
 208         val &= ~(RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT);
 209         rda_uart_write(port, val, RDA_UART_IRQ_MASK);
 210
 211         /* Read Rx buffer before reset to avoid Rx timeout interrupt */
 212         val = rda_uart_read(port, RDA_UART_RXTX_BUFFER);
 213
 214         val = rda_uart_read(port, RDA_UART_CMD_SET);
 215         val |= RDA_UART_RX_FIFO_RESET;
 216         rda_uart_write(port, val, RDA_UART_CMD_SET);
 217 }
 218
 219 static void rda_uart_start_tx(struct uart_port *port)
 220 {
 221         u32 val;
 222
 223         if (uart_tx_stopped(port)) {
 224                 rda_uart_stop_tx(port);
 225                 return;
 226         }
 227
 228         val = rda_uart_read(port, RDA_UART_IRQ_MASK);
 229         val |= RDA_UART_TX_DATA_NEEDED;
 230         rda_uart_write(port, val, RDA_UART_IRQ_MASK);
 231 }
 232
 233 static void rda_uart_change_baudrate(struct rda_uart_port *rda_port,
 234                                      unsigned long baud)
 235 {
 236         clk_set_rate(rda_port->clk, baud * 8);
 237 }
 238
 239 static void rda_uart_set_termios(struct uart_port *port,
 240                                  struct ktermios *termios,
 241                                  const struct ktermios *old)
 242 {
 243         struct rda_uart_port *rda_port = to_rda_uart_port(port);
 244         unsigned long flags;
 245         unsigned int ctrl, cmd_set, cmd_clr, triggers;
 246         unsigned int baud;
 247         u32 irq_mask;
 248
 249         uart_port_lock_irqsave(port, &flags);
 250
 251         baud = uart_get_baud_rate(port, termios, old, 9600, port->uartclk / 4);
 252         rda_uart_change_baudrate(rda_port, baud);
 253
 254         ctrl = rda_uart_read(port, RDA_UART_CTRL);
 255         cmd_set = rda_uart_read(port, RDA_UART_CMD_SET);
 256         cmd_clr = rda_uart_read(port, RDA_UART_CMD_CLR);
 257
 258         switch (termios->c_cflag & CSIZE) {
 259         case CS5:
 260         case CS6:
 261                 dev_warn(port->dev, "bit size not supported, using 7 bits\n");
 262                 fallthrough;
 263         case CS7:
 264                 ctrl &= ~RDA_UART_DBITS_8;
 265                 termios->c_cflag &= ~CSIZE;
 266                 termios->c_cflag |= CS7;
 267                 break;
 268         default:
 269                 ctrl |= RDA_UART_DBITS_8;
 270                 break;
 271         }
 272
 273         /* stop bits */
 274         if (termios->c_cflag & CSTOPB)
 275                 ctrl |= RDA_UART_TX_SBITS_2;
 276         else
 277                 ctrl &= ~RDA_UART_TX_SBITS_2;
 278
 279         /* parity check */
 280         if (termios->c_cflag & PARENB) {
 281                 ctrl |= RDA_UART_PARITY_EN;
 282
 283                 /* Mark or Space parity */
 284                 if (termios->c_cflag & CMSPAR) {
 285                         if (termios->c_cflag & PARODD)
 286                                 ctrl |= RDA_UART_PARITY_MARK;
 287                         else
 288                                 ctrl |= RDA_UART_PARITY_SPACE;
 289                 } else if (termios->c_cflag & PARODD) {
 290                         ctrl |= RDA_UART_PARITY_ODD;
 291                 } else {
 292                         ctrl |= RDA_UART_PARITY_EVEN;
 293                 }
 294         } else {
 295                 ctrl &= ~RDA_UART_PARITY_EN;
 296         }
 297
 298         /* Hardware handshake (RTS/CTS) */
 299         if (termios->c_cflag & CRTSCTS) {
 300                 ctrl   |= RDA_UART_FLOW_CNT_EN;
 301                 cmd_set |= RDA_UART_RTS;
 302         } else {
 303                 ctrl   &= ~RDA_UART_FLOW_CNT_EN;
 304                 cmd_clr |= RDA_UART_RTS;
 305         }
 306
 307         ctrl |= RDA_UART_ENABLE;
 308         ctrl &= ~RDA_UART_DMA_EN;
 309
 310         triggers  = (RDA_UART_AFC_LEVEL(20) | RDA_UART_RX_TRIGGER(16));
 311         irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK);
 312         rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
 313
 314         rda_uart_write(port, triggers, RDA_UART_IRQ_TRIGGERS);
 315         rda_uart_write(port, ctrl, RDA_UART_CTRL);
 316         rda_uart_write(port, cmd_set, RDA_UART_CMD_SET);
 317         rda_uart_write(port, cmd_clr, RDA_UART_CMD_CLR);
 318
 319         rda_uart_write(port, irq_mask, RDA_UART_IRQ_MASK);
 320
 321         /* Don't rewrite B0 */
 322         if (tty_termios_baud_rate(termios))
 323                 tty_termios_encode_baud_rate(termios, baud, baud);
 324
 325         /* update the per-port timeout */
 326         uart_update_timeout(port, termios->c_cflag, baud);
 327
 328         uart_port_unlock_irqrestore(port, flags);
 329 }
 330
 331 static void rda_uart_send_chars(struct uart_port *port)
 332 {
 333         struct tty_port *tport = &port->state->port;
 334         unsigned char ch;
 335         u32 val;
 336
 337         if (uart_tx_stopped(port))
 338                 return;
 339
 340         if (port->x_char) {
 341                 while (!(rda_uart_read(port, RDA_UART_STATUS) &
 342                          RDA_UART_TX_FIFO_MASK))
 343                         cpu_relax();
 344
 345                 rda_uart_write(port, port->x_char, RDA_UART_RXTX_BUFFER);
 346                 port->icount.tx++;
 347                 port->x_char = 0;
 348         }
 349
 350         while ((rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_TX_FIFO_MASK) &&
 351                         uart_fifo_get(port, &ch))
 352                 rda_uart_write(port, ch, RDA_UART_RXTX_BUFFER);
 353
 354         if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS)
 355                 uart_write_wakeup(port);
 356
 357         if (!kfifo_is_empty(&tport->xmit_fifo)) {
 358                 /* Re-enable Tx FIFO interrupt */
 359                 val = rda_uart_read(port, RDA_UART_IRQ_MASK);
 360                 val |= RDA_UART_TX_DATA_NEEDED;
 361                 rda_uart_write(port, val, RDA_UART_IRQ_MASK);
 362         }
 363 }
 364
 365 static void rda_uart_receive_chars(struct uart_port *port)
 366 {
 367         u32 status, val;
 368
 369         status = rda_uart_read(port, RDA_UART_STATUS);
 370         while ((status & RDA_UART_RX_FIFO_MASK)) {
 371                 char flag = TTY_NORMAL;
 372
 373                 if (status & RDA_UART_RX_PARITY_ERR) {
 374                         port->icount.parity++;
 375                         flag = TTY_PARITY;
 376                 }
 377
 378                 if (status & RDA_UART_RX_FRAMING_ERR) {
 379                         port->icount.frame++;
 380                         flag = TTY_FRAME;
 381                 }
 382
 383                 if (status & RDA_UART_RX_OVERFLOW_ERR) {
 384                         port->icount.overrun++;
 385                         flag = TTY_OVERRUN;
 386                 }
 387
 388                 val = rda_uart_read(port, RDA_UART_RXTX_BUFFER);
 389                 val &= 0xff;
 390
 391                 port->icount.rx++;
 392                 if (!uart_prepare_sysrq_char(port, val))
 393                         tty_insert_flip_char(&port->state->port, val, flag);
 394
 395                 status = rda_uart_read(port, RDA_UART_STATUS);
 396         }
 397
 398         tty_flip_buffer_push(&port->state->port);
 399 }
 400
 401 static irqreturn_t rda_interrupt(int irq, void *dev_id)
 402 {
 403         struct uart_port *port = dev_id;
 404         u32 val, irq_mask;
 405
 406         uart_port_lock(port);
 407
 408         /* Clear IRQ cause */
 409         val = rda_uart_read(port, RDA_UART_IRQ_CAUSE);
 410         rda_uart_write(port, val, RDA_UART_IRQ_CAUSE);
 411
 412         if (val & (RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT))
 413                 rda_uart_receive_chars(port);
 414
 415         if (val & (RDA_UART_TX_DATA_NEEDED)) {
 416                 irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK);
 417                 irq_mask &= ~RDA_UART_TX_DATA_NEEDED;
 418                 rda_uart_write(port, irq_mask, RDA_UART_IRQ_MASK);
 419
 420                 rda_uart_send_chars(port);
 421         }
 422
 423         uart_unlock_and_check_sysrq(port);
 424
 425         return IRQ_HANDLED;
 426 }
 427
 428 static int rda_uart_startup(struct uart_port *port)
 429 {
 430         unsigned long flags;
 431         int ret;
 432         u32 val;
 433
 434         uart_port_lock_irqsave(port, &flags);
 435         rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
 436         uart_port_unlock_irqrestore(port, flags);
 437
 438         ret = request_irq(port->irq, rda_interrupt, IRQF_NO_SUSPEND,
 439                           "rda-uart", port);
 440         if (ret)
 441                 return ret;
 442
 443         uart_port_lock_irqsave(port, &flags);
 444
 445         val = rda_uart_read(port, RDA_UART_CTRL);
 446         val |= RDA_UART_ENABLE;
 447         rda_uart_write(port, val, RDA_UART_CTRL);
 448
 449         /* enable rx interrupt */
 450         val = rda_uart_read(port, RDA_UART_IRQ_MASK);
 451         val |= (RDA_UART_RX_DATA_AVAILABLE | RDA_UART_RX_TIMEOUT);
 452         rda_uart_write(port, val, RDA_UART_IRQ_MASK);
 453
 454         uart_port_unlock_irqrestore(port, flags);
 455
 456         return 0;
 457 }
 458
 459 static void rda_uart_shutdown(struct uart_port *port)
 460 {
 461         unsigned long flags;
 462         u32 val;
 463
 464         uart_port_lock_irqsave(port, &flags);
 465
 466         rda_uart_stop_tx(port);
 467         rda_uart_stop_rx(port);
 468
 469         val = rda_uart_read(port, RDA_UART_CTRL);
 470         val &= ~RDA_UART_ENABLE;
 471         rda_uart_write(port, val, RDA_UART_CTRL);
 472
 473         uart_port_unlock_irqrestore(port, flags);
 474 }
 475
 476 static const char *rda_uart_type(struct uart_port *port)
 477 {
 478         return (port->type == PORT_RDA) ? "rda-uart" : NULL;
 479 }
 480
 481 static int rda_uart_request_port(struct uart_port *port)
 482 {
 483         struct platform_device *pdev = to_platform_device(port->dev);
 484         struct resource *res;
 485
 486         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 487         if (!res)
 488                 return -ENXIO;
 489
 490         if (!devm_request_mem_region(port->dev, port->mapbase,
 491                                      resource_size(res), dev_name(port->dev)))
 492                 return -EBUSY;
 493
 494         if (port->flags & UPF_IOREMAP) {
 495                 port->membase = devm_ioremap(port->dev, port->mapbase,
 496                                                      resource_size(res));
 497                 if (!port->membase)
 498                         return -EBUSY;
 499         }
 500
 501         return 0;
 502 }
 503
 504 static void rda_uart_config_port(struct uart_port *port, int flags)
 505 {
 506         unsigned long irq_flags;
 507
 508         if (flags & UART_CONFIG_TYPE) {
 509                 port->type = PORT_RDA;
 510                 rda_uart_request_port(port);
 511         }
 512
 513         uart_port_lock_irqsave(port, &irq_flags);
 514
 515         /* Clear mask, so no surprise interrupts. */
 516         rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
 517
 518         /* Clear status register */
 519         rda_uart_write(port, 0, RDA_UART_STATUS);
 520
 521         uart_port_unlock_irqrestore(port, irq_flags);
 522 }
 523
 524 static void rda_uart_release_port(struct uart_port *port)
 525 {
 526         struct platform_device *pdev = to_platform_device(port->dev);
 527         struct resource *res;
 528
 529         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 530         if (!res)
 531                 return;
 532
 533         if (port->flags & UPF_IOREMAP) {
 534                 devm_release_mem_region(port->dev, port->mapbase,
 535                                         resource_size(res));
 536                 devm_iounmap(port->dev, port->membase);
 537                 port->membase = NULL;
 538         }
 539 }
 540
 541 static int rda_uart_verify_port(struct uart_port *port,
 542                                 struct serial_struct *ser)
 543 {
 544         if (port->type != PORT_RDA)
 545                 return -EINVAL;
 546
 547         if (port->irq != ser->irq)
 548                 return -EINVAL;
 549
 550         return 0;
 551 }
 552
 553 static const struct uart_ops rda_uart_ops = {
 554         .tx_empty       = rda_uart_tx_empty,
 555         .get_mctrl      = rda_uart_get_mctrl,
 556         .set_mctrl      = rda_uart_set_mctrl,
 557         .start_tx       = rda_uart_start_tx,
 558         .stop_tx        = rda_uart_stop_tx,
 559         .stop_rx        = rda_uart_stop_rx,
 560         .startup        = rda_uart_startup,
 561         .shutdown       = rda_uart_shutdown,
 562         .set_termios    = rda_uart_set_termios,
 563         .type           = rda_uart_type,
 564         .request_port   = rda_uart_request_port,
 565         .release_port   = rda_uart_release_port,
 566         .config_port    = rda_uart_config_port,
 567         .verify_port    = rda_uart_verify_port,
 568 };
 569
 570 #ifdef CONFIG_SERIAL_RDA_CONSOLE
 571
 572 static void rda_console_putchar(struct uart_port *port, unsigned char ch)
 573 {
 574         if (!port->membase)
 575                 return;
 576
 577         while (!(rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_TX_FIFO_MASK))
 578                 cpu_relax();
 579
 580         rda_uart_write(port, ch, RDA_UART_RXTX_BUFFER);
 581 }
 582
 583 static void rda_uart_port_write(struct uart_port *port, const char *s,
 584                                 u_int count)
 585 {
 586         u32 old_irq_mask;
 587         unsigned long flags;
 588         int locked = 1;
 589
 590         if (oops_in_progress)
 591                 locked = uart_port_trylock_irqsave(port, &flags);
 592         else
 593                 uart_port_lock_irqsave(port, &flags);
 594
 595         old_irq_mask = rda_uart_read(port, RDA_UART_IRQ_MASK);
 596         rda_uart_write(port, 0, RDA_UART_IRQ_MASK);
 597
 598         uart_console_write(port, s, count, rda_console_putchar);
 599
 600         /* wait until all contents have been sent out */
 601         while (!(rda_uart_read(port, RDA_UART_STATUS) & RDA_UART_TX_FIFO_MASK))
 602                 cpu_relax();
 603
 604         rda_uart_write(port, old_irq_mask, RDA_UART_IRQ_MASK);
 605
 606         if (locked)
 607                 uart_port_unlock_irqrestore(port, flags);
 608 }
 609
 610 static void rda_uart_console_write(struct console *co, const char *s,
 611                                    u_int count)
 612 {
 613         struct rda_uart_port *rda_port;
 614
 615         rda_port = rda_uart_ports[co->index];
 616         if (!rda_port)
 617                 return;
 618
 619         rda_uart_port_write(&rda_port->port, s, count);
 620 }
 621
 622 static int rda_uart_console_setup(struct console *co, char *options)
 623 {
 624         struct rda_uart_port *rda_port;
 625         int baud = 921600;
 626         int bits = 8;
 627         int parity = 'n';
 628         int flow = 'n';
 629
 630         if (co->index < 0 || co->index >= RDA_UART_PORT_NUM)
 631                 return -EINVAL;
 632
 633         rda_port = rda_uart_ports[co->index];
 634         if (!rda_port || !rda_port->port.membase)
 635                 return -ENODEV;
 636
 637         if (options)
 638                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 639
 640         return uart_set_options(&rda_port->port, co, baud, parity, bits, flow);
 641 }
 642
 643 static struct console rda_uart_console = {
 644         .name = RDA_UART_DEV_NAME,
 645         .write = rda_uart_console_write,
 646         .device = uart_console_device,
 647         .setup = rda_uart_console_setup,
 648         .flags = CON_PRINTBUFFER,
 649         .index = -1,
 650         .data = &rda_uart_driver,
 651 };
 652
 653 static int __init rda_uart_console_init(void)
 654 {
 655         register_console(&rda_uart_console);
 656
 657         return 0;
 658 }
 659 console_initcall(rda_uart_console_init);
 660
 661 static void rda_uart_early_console_write(struct console *co,
 662                                          const char *s,
 663                                          u_int count)
 664 {
 665         struct earlycon_device *dev = co->data;
 666
 667         rda_uart_port_write(&dev->port, s, count);
 668 }
 669
 670 static int __init
 671 rda_uart_early_console_setup(struct earlycon_device *device, const char *opt)
 672 {
 673         if (!device->port.membase)
 674                 return -ENODEV;
 675
 676         device->con->write = rda_uart_early_console_write;
 677
 678         return 0;
 679 }
 680
 681 OF_EARLYCON_DECLARE(rda, "rda,8810pl-uart",
 682                     rda_uart_early_console_setup);
 683
 684 #define RDA_UART_CONSOLE (&rda_uart_console)
 685 #else
 686 #define RDA_UART_CONSOLE NULL
 687 #endif /* CONFIG_SERIAL_RDA_CONSOLE */
 688
 689 static struct uart_driver rda_uart_driver = {
 690         .owner = THIS_MODULE,
 691         .driver_name = "rda-uart",
 692         .dev_name = RDA_UART_DEV_NAME,
 693         .nr = RDA_UART_PORT_NUM,
 694         .cons = RDA_UART_CONSOLE,
 695 };
 696
 697 static const struct of_device_id rda_uart_dt_matches[] = {
 698         { .compatible = "rda,8810pl-uart" },
 699         { }
 700 };
 701 MODULE_DEVICE_TABLE(of, rda_uart_dt_matches);
 702
 703 static int rda_uart_probe(struct platform_device *pdev)
 704 {
 705         struct resource *res_mem;
 706         struct rda_uart_port *rda_port;
 707         int ret, irq;
 708
 709         if (pdev->dev.of_node)
 710                 pdev->id = of_alias_get_id(pdev->dev.of_node, "serial");
 711
 712         if (pdev->id < 0 || pdev->id >= RDA_UART_PORT_NUM) {
 713                 dev_err(&pdev->dev, "id %d out of range\n", pdev->id);
 714                 return -EINVAL;
 715         }
 716
 717         res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 718         if (!res_mem) {
 719                 dev_err(&pdev->dev, "could not get mem\n");
 720                 return -ENODEV;
 721         }
 722
 723         irq = platform_get_irq(pdev, 0);
 724         if (irq < 0)
 725                 return irq;
 726
 727         if (rda_uart_ports[pdev->id]) {
 728                 dev_err(&pdev->dev, "port %d already allocated\n", pdev->id);
 729                 return -EBUSY;
 730         }
 731
 732         rda_port = devm_kzalloc(&pdev->dev, sizeof(*rda_port), GFP_KERNEL);
 733         if (!rda_port)
 734                 return -ENOMEM;
 735
 736         rda_port->clk = devm_clk_get(&pdev->dev, NULL);
 737         if (IS_ERR(rda_port->clk)) {
 738                 dev_err(&pdev->dev, "could not get clk\n");
 739                 return PTR_ERR(rda_port->clk);
 740         }
 741
 742         rda_port->port.dev = &pdev->dev;
 743         rda_port->port.regshift = 0;
 744         rda_port->port.line = pdev->id;
 745         rda_port->port.type = PORT_RDA;
 746         rda_port->port.iotype = UPIO_MEM;
 747         rda_port->port.mapbase = res_mem->start;
 748         rda_port->port.irq = irq;
 749         rda_port->port.uartclk = clk_get_rate(rda_port->clk);
 750         if (rda_port->port.uartclk == 0) {
 751                 dev_err(&pdev->dev, "clock rate is zero\n");
 752                 return -EINVAL;
 753         }
 754         rda_port->port.flags = UPF_BOOT_AUTOCONF | UPF_IOREMAP |
 755                                UPF_LOW_LATENCY;
 756         rda_port->port.x_char = 0;
 757         rda_port->port.fifosize = RDA_UART_TX_FIFO_SIZE;
 758         rda_port->port.ops = &rda_uart_ops;
 759
 760         rda_uart_ports[pdev->id] = rda_port;
 761         platform_set_drvdata(pdev, rda_port);
 762
 763         ret = uart_add_one_port(&rda_uart_driver, &rda_port->port);
 764         if (ret)
 765                 rda_uart_ports[pdev->id] = NULL;
 766
 767         return ret;
 768 }
 769
 770 static void rda_uart_remove(struct platform_device *pdev)
 771 {
 772         struct rda_uart_port *rda_port = platform_get_drvdata(pdev);
 773
 774         uart_remove_one_port(&rda_uart_driver, &rda_port->port);
 775         rda_uart_ports[pdev->id] = NULL;
 776 }
 777
 778 static struct platform_driver rda_uart_platform_driver = {
 779         .probe = rda_uart_probe,
 780         .remove = rda_uart_remove,
 781         .driver = {
 782                 .name = "rda-uart",
 783                 .of_match_table = rda_uart_dt_matches,
 784         },
 785 };
 786
 787 static int __init rda_uart_init(void)
 788 {
 789         int ret;
 790
 791         ret = uart_register_driver(&rda_uart_driver);
 792         if (ret)
 793                 return ret;
 794
 795         ret = platform_driver_register(&rda_uart_platform_driver);
 796         if (ret)
 797                 uart_unregister_driver(&rda_uart_driver);
 798
 799         return ret;
 800 }
 801
 802 static void __exit rda_uart_exit(void)
 803 {
 804         platform_driver_unregister(&rda_uart_platform_driver);
 805         uart_unregister_driver(&rda_uart_driver);
 806 }
 807
 808 module_init(rda_uart_init);
 809 module_exit(rda_uart_exit);
 810
 811 MODULE_AUTHOR("Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>");
 812 MODULE_DESCRIPTION("RDA8810PL serial device driver");
 813 MODULE_LICENSE("GPL");