root/drivers/tty/serial/efm32-uart.c

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DEFINITIONS

This source file includes following definitions.
  1. efm32_uart_write32
  2. efm32_uart_read32
  3. efm32_uart_tx_empty
  4. efm32_uart_set_mctrl
  5. efm32_uart_get_mctrl
  6. efm32_uart_stop_tx
  7. efm32_uart_tx_chars
  8. efm32_uart_start_tx
  9. efm32_uart_stop_rx
  10. efm32_uart_break_ctl
  11. efm32_uart_rx_chars
  12. efm32_uart_rxirq
  13. efm32_uart_txirq
  14. efm32_uart_startup
  15. efm32_uart_shutdown
  16. efm32_uart_set_termios
  17. efm32_uart_type
  18. efm32_uart_release_port
  19. efm32_uart_request_port
  20. efm32_uart_config_port
  21. efm32_uart_verify_port
  22. efm32_uart_console_putchar
  23. efm32_uart_console_write
  24. efm32_uart_console_get_options
  25. efm32_uart_console_setup
  26. efm32_uart_probe_dt
  27. efm32_uart_probe
  28. efm32_uart_remove
  29. efm32_uart_init
  30. efm32_uart_exit

   1 // SPDX-License-Identifier: GPL-2.0
   2 #if defined(CONFIG_SERIAL_EFM32_UART_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
   3 #define SUPPORT_SYSRQ
   4 #endif
   5 
   6 #include <linux/kernel.h>
   7 #include <linux/module.h>
   8 #include <linux/io.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/console.h>
  11 #include <linux/sysrq.h>
  12 #include <linux/serial_core.h>
  13 #include <linux/tty_flip.h>
  14 #include <linux/slab.h>
  15 #include <linux/clk.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 
  19 #include <linux/platform_data/efm32-uart.h>
  20 
  21 #define DRIVER_NAME "efm32-uart"
  22 #define DEV_NAME "ttyefm"
  23 
  24 #define UARTn_CTRL              0x00
  25 #define UARTn_CTRL_SYNC         0x0001
  26 #define UARTn_CTRL_TXBIL                0x1000
  27 
  28 #define UARTn_FRAME             0x04
  29 #define UARTn_FRAME_DATABITS__MASK      0x000f
  30 #define UARTn_FRAME_DATABITS(n)         ((n) - 3)
  31 #define UARTn_FRAME_PARITY__MASK        0x0300
  32 #define UARTn_FRAME_PARITY_NONE         0x0000
  33 #define UARTn_FRAME_PARITY_EVEN         0x0200
  34 #define UARTn_FRAME_PARITY_ODD          0x0300
  35 #define UARTn_FRAME_STOPBITS_HALF       0x0000
  36 #define UARTn_FRAME_STOPBITS_ONE        0x1000
  37 #define UARTn_FRAME_STOPBITS_TWO        0x3000
  38 
  39 #define UARTn_CMD               0x0c
  40 #define UARTn_CMD_RXEN                  0x0001
  41 #define UARTn_CMD_RXDIS         0x0002
  42 #define UARTn_CMD_TXEN                  0x0004
  43 #define UARTn_CMD_TXDIS         0x0008
  44 
  45 #define UARTn_STATUS            0x10
  46 #define UARTn_STATUS_TXENS              0x0002
  47 #define UARTn_STATUS_TXC                0x0020
  48 #define UARTn_STATUS_TXBL               0x0040
  49 #define UARTn_STATUS_RXDATAV            0x0080
  50 
  51 #define UARTn_CLKDIV            0x14
  52 
  53 #define UARTn_RXDATAX           0x18
  54 #define UARTn_RXDATAX_RXDATA__MASK      0x01ff
  55 #define UARTn_RXDATAX_PERR              0x4000
  56 #define UARTn_RXDATAX_FERR              0x8000
  57 /*
  58  * This is a software only flag used for ignore_status_mask and
  59  * read_status_mask! It's used for breaks that the hardware doesn't report
  60  * explicitly.
  61  */
  62 #define SW_UARTn_RXDATAX_BERR           0x2000
  63 
  64 #define UARTn_TXDATA            0x34
  65 
  66 #define UARTn_IF                0x40
  67 #define UARTn_IF_TXC                    0x0001
  68 #define UARTn_IF_TXBL                   0x0002
  69 #define UARTn_IF_RXDATAV                0x0004
  70 #define UARTn_IF_RXOF                   0x0010
  71 
  72 #define UARTn_IFS               0x44
  73 #define UARTn_IFC               0x48
  74 #define UARTn_IEN               0x4c
  75 
  76 #define UARTn_ROUTE             0x54
  77 #define UARTn_ROUTE_LOCATION__MASK      0x0700
  78 #define UARTn_ROUTE_LOCATION(n)         (((n) << 8) & UARTn_ROUTE_LOCATION__MASK)
  79 #define UARTn_ROUTE_RXPEN               0x0001
  80 #define UARTn_ROUTE_TXPEN               0x0002
  81 
  82 struct efm32_uart_port {
  83         struct uart_port port;
  84         unsigned int txirq;
  85         struct clk *clk;
  86         struct efm32_uart_pdata pdata;
  87 };
  88 #define to_efm_port(_port) container_of(_port, struct efm32_uart_port, port)
  89 #define efm_debug(efm_port, format, arg...)                     \
  90         dev_dbg(efm_port->port.dev, format, ##arg)
  91 
  92 static void efm32_uart_write32(struct efm32_uart_port *efm_port,
  93                 u32 value, unsigned offset)
  94 {
  95         writel_relaxed(value, efm_port->port.membase + offset);
  96 }
  97 
  98 static u32 efm32_uart_read32(struct efm32_uart_port *efm_port,
  99                 unsigned offset)
 100 {
 101         return readl_relaxed(efm_port->port.membase + offset);
 102 }
 103 
 104 static unsigned int efm32_uart_tx_empty(struct uart_port *port)
 105 {
 106         struct efm32_uart_port *efm_port = to_efm_port(port);
 107         u32 status = efm32_uart_read32(efm_port, UARTn_STATUS);
 108 
 109         if (status & UARTn_STATUS_TXC)
 110                 return TIOCSER_TEMT;
 111         else
 112                 return 0;
 113 }
 114 
 115 static void efm32_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 116 {
 117         /* sorry, neither handshaking lines nor loop functionallity */
 118 }
 119 
 120 static unsigned int efm32_uart_get_mctrl(struct uart_port *port)
 121 {
 122         /* sorry, no handshaking lines available */
 123         return TIOCM_CAR | TIOCM_CTS | TIOCM_DSR;
 124 }
 125 
 126 static void efm32_uart_stop_tx(struct uart_port *port)
 127 {
 128         struct efm32_uart_port *efm_port = to_efm_port(port);
 129         u32 ien = efm32_uart_read32(efm_port,  UARTn_IEN);
 130 
 131         efm32_uart_write32(efm_port, UARTn_CMD_TXDIS, UARTn_CMD);
 132         ien &= ~(UARTn_IF_TXC | UARTn_IF_TXBL);
 133         efm32_uart_write32(efm_port, ien, UARTn_IEN);
 134 }
 135 
 136 static void efm32_uart_tx_chars(struct efm32_uart_port *efm_port)
 137 {
 138         struct uart_port *port = &efm_port->port;
 139         struct circ_buf *xmit = &port->state->xmit;
 140 
 141         while (efm32_uart_read32(efm_port, UARTn_STATUS) &
 142                         UARTn_STATUS_TXBL) {
 143                 if (port->x_char) {
 144                         port->icount.tx++;
 145                         efm32_uart_write32(efm_port, port->x_char,
 146                                         UARTn_TXDATA);
 147                         port->x_char = 0;
 148                         continue;
 149                 }
 150                 if (!uart_circ_empty(xmit) && !uart_tx_stopped(port)) {
 151                         port->icount.tx++;
 152                         efm32_uart_write32(efm_port, xmit->buf[xmit->tail],
 153                                         UARTn_TXDATA);
 154                         xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
 155                 } else
 156                         break;
 157         }
 158 
 159         if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
 160                 uart_write_wakeup(port);
 161 
 162         if (!port->x_char && uart_circ_empty(xmit) &&
 163                         efm32_uart_read32(efm_port, UARTn_STATUS) &
 164                                 UARTn_STATUS_TXC)
 165                 efm32_uart_stop_tx(port);
 166 }
 167 
 168 static void efm32_uart_start_tx(struct uart_port *port)
 169 {
 170         struct efm32_uart_port *efm_port = to_efm_port(port);
 171         u32 ien;
 172 
 173         efm32_uart_write32(efm_port,
 174                         UARTn_IF_TXBL | UARTn_IF_TXC, UARTn_IFC);
 175         ien = efm32_uart_read32(efm_port, UARTn_IEN);
 176         efm32_uart_write32(efm_port,
 177                         ien | UARTn_IF_TXBL | UARTn_IF_TXC, UARTn_IEN);
 178         efm32_uart_write32(efm_port, UARTn_CMD_TXEN, UARTn_CMD);
 179 
 180         efm32_uart_tx_chars(efm_port);
 181 }
 182 
 183 static void efm32_uart_stop_rx(struct uart_port *port)
 184 {
 185         struct efm32_uart_port *efm_port = to_efm_port(port);
 186 
 187         efm32_uart_write32(efm_port, UARTn_CMD_RXDIS, UARTn_CMD);
 188 }
 189 
 190 static void efm32_uart_break_ctl(struct uart_port *port, int ctl)
 191 {
 192         /* not possible without fiddling with gpios */
 193 }
 194 
 195 static void efm32_uart_rx_chars(struct efm32_uart_port *efm_port)
 196 {
 197         struct uart_port *port = &efm_port->port;
 198 
 199         while (efm32_uart_read32(efm_port, UARTn_STATUS) &
 200                         UARTn_STATUS_RXDATAV) {
 201                 u32 rxdata = efm32_uart_read32(efm_port, UARTn_RXDATAX);
 202                 int flag = 0;
 203 
 204                 /*
 205                  * This is a reserved bit and I only saw it read as 0. But to be
 206                  * sure not to be confused too much by new devices adhere to the
 207                  * warning in the reference manual that reserverd bits might
 208                  * read as 1 in the future.
 209                  */
 210                 rxdata &= ~SW_UARTn_RXDATAX_BERR;
 211 
 212                 port->icount.rx++;
 213 
 214                 if ((rxdata & UARTn_RXDATAX_FERR) &&
 215                                 !(rxdata & UARTn_RXDATAX_RXDATA__MASK)) {
 216                         rxdata |= SW_UARTn_RXDATAX_BERR;
 217                         port->icount.brk++;
 218                         if (uart_handle_break(port))
 219                                 continue;
 220                 } else if (rxdata & UARTn_RXDATAX_PERR)
 221                         port->icount.parity++;
 222                 else if (rxdata & UARTn_RXDATAX_FERR)
 223                         port->icount.frame++;
 224 
 225                 rxdata &= port->read_status_mask;
 226 
 227                 if (rxdata & SW_UARTn_RXDATAX_BERR)
 228                         flag = TTY_BREAK;
 229                 else if (rxdata & UARTn_RXDATAX_PERR)
 230                         flag = TTY_PARITY;
 231                 else if (rxdata & UARTn_RXDATAX_FERR)
 232                         flag = TTY_FRAME;
 233                 else if (uart_handle_sysrq_char(port,
 234                                         rxdata & UARTn_RXDATAX_RXDATA__MASK))
 235                         continue;
 236 
 237                 if ((rxdata & port->ignore_status_mask) == 0)
 238                         tty_insert_flip_char(&port->state->port,
 239                                         rxdata & UARTn_RXDATAX_RXDATA__MASK, flag);
 240         }
 241 }
 242 
 243 static irqreturn_t efm32_uart_rxirq(int irq, void *data)
 244 {
 245         struct efm32_uart_port *efm_port = data;
 246         u32 irqflag = efm32_uart_read32(efm_port, UARTn_IF);
 247         int handled = IRQ_NONE;
 248         struct uart_port *port = &efm_port->port;
 249         struct tty_port *tport = &port->state->port;
 250 
 251         spin_lock(&port->lock);
 252 
 253         if (irqflag & UARTn_IF_RXDATAV) {
 254                 efm32_uart_write32(efm_port, UARTn_IF_RXDATAV, UARTn_IFC);
 255                 efm32_uart_rx_chars(efm_port);
 256 
 257                 handled = IRQ_HANDLED;
 258         }
 259 
 260         if (irqflag & UARTn_IF_RXOF) {
 261                 efm32_uart_write32(efm_port, UARTn_IF_RXOF, UARTn_IFC);
 262                 port->icount.overrun++;
 263                 tty_insert_flip_char(tport, 0, TTY_OVERRUN);
 264 
 265                 handled = IRQ_HANDLED;
 266         }
 267 
 268         spin_unlock(&port->lock);
 269 
 270         tty_flip_buffer_push(tport);
 271 
 272         return handled;
 273 }
 274 
 275 static irqreturn_t efm32_uart_txirq(int irq, void *data)
 276 {
 277         struct efm32_uart_port *efm_port = data;
 278         u32 irqflag = efm32_uart_read32(efm_port, UARTn_IF);
 279 
 280         /* TXBL doesn't need to be cleared */
 281         if (irqflag & UARTn_IF_TXC)
 282                 efm32_uart_write32(efm_port, UARTn_IF_TXC, UARTn_IFC);
 283 
 284         if (irqflag & (UARTn_IF_TXC | UARTn_IF_TXBL)) {
 285                 efm32_uart_tx_chars(efm_port);
 286                 return IRQ_HANDLED;
 287         } else
 288                 return IRQ_NONE;
 289 }
 290 
 291 static int efm32_uart_startup(struct uart_port *port)
 292 {
 293         struct efm32_uart_port *efm_port = to_efm_port(port);
 294         int ret;
 295 
 296         ret = clk_enable(efm_port->clk);
 297         if (ret) {
 298                 efm_debug(efm_port, "failed to enable clk\n");
 299                 goto err_clk_enable;
 300         }
 301         port->uartclk = clk_get_rate(efm_port->clk);
 302 
 303         /* Enable pins at configured location */
 304         efm32_uart_write32(efm_port,
 305                         UARTn_ROUTE_LOCATION(efm_port->pdata.location) |
 306                         UARTn_ROUTE_RXPEN | UARTn_ROUTE_TXPEN,
 307                         UARTn_ROUTE);
 308 
 309         ret = request_irq(port->irq, efm32_uart_rxirq, 0,
 310                         DRIVER_NAME, efm_port);
 311         if (ret) {
 312                 efm_debug(efm_port, "failed to register rxirq\n");
 313                 goto err_request_irq_rx;
 314         }
 315 
 316         /* disable all irqs */
 317         efm32_uart_write32(efm_port, 0, UARTn_IEN);
 318 
 319         ret = request_irq(efm_port->txirq, efm32_uart_txirq, 0,
 320                         DRIVER_NAME, efm_port);
 321         if (ret) {
 322                 efm_debug(efm_port, "failed to register txirq\n");
 323                 free_irq(port->irq, efm_port);
 324 err_request_irq_rx:
 325 
 326                 clk_disable(efm_port->clk);
 327         } else {
 328                 efm32_uart_write32(efm_port,
 329                                 UARTn_IF_RXDATAV | UARTn_IF_RXOF, UARTn_IEN);
 330                 efm32_uart_write32(efm_port, UARTn_CMD_RXEN, UARTn_CMD);
 331         }
 332 
 333 err_clk_enable:
 334         return ret;
 335 }
 336 
 337 static void efm32_uart_shutdown(struct uart_port *port)
 338 {
 339         struct efm32_uart_port *efm_port = to_efm_port(port);
 340 
 341         efm32_uart_write32(efm_port, 0, UARTn_IEN);
 342         free_irq(port->irq, efm_port);
 343 
 344         clk_disable(efm_port->clk);
 345 }
 346 
 347 static void efm32_uart_set_termios(struct uart_port *port,
 348                 struct ktermios *new, struct ktermios *old)
 349 {
 350         struct efm32_uart_port *efm_port = to_efm_port(port);
 351         unsigned long flags;
 352         unsigned baud;
 353         u32 clkdiv;
 354         u32 frame = 0;
 355 
 356         /* no modem control lines */
 357         new->c_cflag &= ~(CRTSCTS | CMSPAR);
 358 
 359         baud = uart_get_baud_rate(port, new, old,
 360                         DIV_ROUND_CLOSEST(port->uartclk, 16 * 8192),
 361                         DIV_ROUND_CLOSEST(port->uartclk, 16));
 362 
 363         switch (new->c_cflag & CSIZE) {
 364         case CS5:
 365                 frame |= UARTn_FRAME_DATABITS(5);
 366                 break;
 367         case CS6:
 368                 frame |= UARTn_FRAME_DATABITS(6);
 369                 break;
 370         case CS7:
 371                 frame |= UARTn_FRAME_DATABITS(7);
 372                 break;
 373         case CS8:
 374                 frame |= UARTn_FRAME_DATABITS(8);
 375                 break;
 376         }
 377 
 378         if (new->c_cflag & CSTOPB)
 379                 /* the receiver only verifies the first stop bit */
 380                 frame |= UARTn_FRAME_STOPBITS_TWO;
 381         else
 382                 frame |= UARTn_FRAME_STOPBITS_ONE;
 383 
 384         if (new->c_cflag & PARENB) {
 385                 if (new->c_cflag & PARODD)
 386                         frame |= UARTn_FRAME_PARITY_ODD;
 387                 else
 388                         frame |= UARTn_FRAME_PARITY_EVEN;
 389         } else
 390                 frame |= UARTn_FRAME_PARITY_NONE;
 391 
 392         /*
 393          * the 6 lowest bits of CLKDIV are dc, bit 6 has value 0.25.
 394          * port->uartclk <= 14e6, so 4 * port->uartclk doesn't overflow.
 395          */
 396         clkdiv = (DIV_ROUND_CLOSEST(4 * port->uartclk, 16 * baud) - 4) << 6;
 397 
 398         spin_lock_irqsave(&port->lock, flags);
 399 
 400         efm32_uart_write32(efm_port,
 401                         UARTn_CMD_TXDIS | UARTn_CMD_RXDIS, UARTn_CMD);
 402 
 403         port->read_status_mask = UARTn_RXDATAX_RXDATA__MASK;
 404         if (new->c_iflag & INPCK)
 405                 port->read_status_mask |=
 406                         UARTn_RXDATAX_FERR | UARTn_RXDATAX_PERR;
 407         if (new->c_iflag & (IGNBRK | BRKINT | PARMRK))
 408                 port->read_status_mask |= SW_UARTn_RXDATAX_BERR;
 409 
 410         port->ignore_status_mask = 0;
 411         if (new->c_iflag & IGNPAR)
 412                 port->ignore_status_mask |=
 413                         UARTn_RXDATAX_FERR | UARTn_RXDATAX_PERR;
 414         if (new->c_iflag & IGNBRK)
 415                 port->ignore_status_mask |= SW_UARTn_RXDATAX_BERR;
 416 
 417         uart_update_timeout(port, new->c_cflag, baud);
 418 
 419         efm32_uart_write32(efm_port, UARTn_CTRL_TXBIL, UARTn_CTRL);
 420         efm32_uart_write32(efm_port, frame, UARTn_FRAME);
 421         efm32_uart_write32(efm_port, clkdiv, UARTn_CLKDIV);
 422 
 423         efm32_uart_write32(efm_port, UARTn_CMD_TXEN | UARTn_CMD_RXEN,
 424                         UARTn_CMD);
 425 
 426         spin_unlock_irqrestore(&port->lock, flags);
 427 }
 428 
 429 static const char *efm32_uart_type(struct uart_port *port)
 430 {
 431         return port->type == PORT_EFMUART ? "efm32-uart" : NULL;
 432 }
 433 
 434 static void efm32_uart_release_port(struct uart_port *port)
 435 {
 436         struct efm32_uart_port *efm_port = to_efm_port(port);
 437 
 438         clk_unprepare(efm_port->clk);
 439         clk_put(efm_port->clk);
 440         iounmap(port->membase);
 441 }
 442 
 443 static int efm32_uart_request_port(struct uart_port *port)
 444 {
 445         struct efm32_uart_port *efm_port = to_efm_port(port);
 446         int ret;
 447 
 448         port->membase = ioremap(port->mapbase, 60);
 449         if (!efm_port->port.membase) {
 450                 ret = -ENOMEM;
 451                 efm_debug(efm_port, "failed to remap\n");
 452                 goto err_ioremap;
 453         }
 454 
 455         efm_port->clk = clk_get(port->dev, NULL);
 456         if (IS_ERR(efm_port->clk)) {
 457                 ret = PTR_ERR(efm_port->clk);
 458                 efm_debug(efm_port, "failed to get clock\n");
 459                 goto err_clk_get;
 460         }
 461 
 462         ret = clk_prepare(efm_port->clk);
 463         if (ret) {
 464                 clk_put(efm_port->clk);
 465 err_clk_get:
 466 
 467                 iounmap(port->membase);
 468 err_ioremap:
 469                 return ret;
 470         }
 471         return 0;
 472 }
 473 
 474 static void efm32_uart_config_port(struct uart_port *port, int type)
 475 {
 476         if (type & UART_CONFIG_TYPE &&
 477                         !efm32_uart_request_port(port))
 478                 port->type = PORT_EFMUART;
 479 }
 480 
 481 static int efm32_uart_verify_port(struct uart_port *port,
 482                 struct serial_struct *serinfo)
 483 {
 484         int ret = 0;
 485 
 486         if (serinfo->type != PORT_UNKNOWN && serinfo->type != PORT_EFMUART)
 487                 ret = -EINVAL;
 488 
 489         return ret;
 490 }
 491 
 492 static const struct uart_ops efm32_uart_pops = {
 493         .tx_empty = efm32_uart_tx_empty,
 494         .set_mctrl = efm32_uart_set_mctrl,
 495         .get_mctrl = efm32_uart_get_mctrl,
 496         .stop_tx = efm32_uart_stop_tx,
 497         .start_tx = efm32_uart_start_tx,
 498         .stop_rx = efm32_uart_stop_rx,
 499         .break_ctl = efm32_uart_break_ctl,
 500         .startup = efm32_uart_startup,
 501         .shutdown = efm32_uart_shutdown,
 502         .set_termios = efm32_uart_set_termios,
 503         .type = efm32_uart_type,
 504         .release_port = efm32_uart_release_port,
 505         .request_port = efm32_uart_request_port,
 506         .config_port = efm32_uart_config_port,
 507         .verify_port = efm32_uart_verify_port,
 508 };
 509 
 510 static struct efm32_uart_port *efm32_uart_ports[5];
 511 
 512 #ifdef CONFIG_SERIAL_EFM32_UART_CONSOLE
 513 static void efm32_uart_console_putchar(struct uart_port *port, int ch)
 514 {
 515         struct efm32_uart_port *efm_port = to_efm_port(port);
 516         unsigned int timeout = 0x400;
 517         u32 status;
 518 
 519         while (1) {
 520                 status = efm32_uart_read32(efm_port, UARTn_STATUS);
 521 
 522                 if (status & UARTn_STATUS_TXBL)
 523                         break;
 524                 if (!timeout--)
 525                         return;
 526         }
 527         efm32_uart_write32(efm_port, ch, UARTn_TXDATA);
 528 }
 529 
 530 static void efm32_uart_console_write(struct console *co, const char *s,
 531                 unsigned int count)
 532 {
 533         struct efm32_uart_port *efm_port = efm32_uart_ports[co->index];
 534         u32 status = efm32_uart_read32(efm_port, UARTn_STATUS);
 535         unsigned int timeout = 0x400;
 536 
 537         if (!(status & UARTn_STATUS_TXENS))
 538                 efm32_uart_write32(efm_port, UARTn_CMD_TXEN, UARTn_CMD);
 539 
 540         uart_console_write(&efm_port->port, s, count,
 541                         efm32_uart_console_putchar);
 542 
 543         /* Wait for the transmitter to become empty */
 544         while (1) {
 545                 u32 status = efm32_uart_read32(efm_port, UARTn_STATUS);
 546                 if (status & UARTn_STATUS_TXC)
 547                         break;
 548                 if (!timeout--)
 549                         break;
 550         }
 551 
 552         if (!(status & UARTn_STATUS_TXENS))
 553                 efm32_uart_write32(efm_port, UARTn_CMD_TXDIS, UARTn_CMD);
 554 }
 555 
 556 static void efm32_uart_console_get_options(struct efm32_uart_port *efm_port,
 557                 int *baud, int *parity, int *bits)
 558 {
 559         u32 ctrl = efm32_uart_read32(efm_port, UARTn_CTRL);
 560         u32 route, clkdiv, frame;
 561 
 562         if (ctrl & UARTn_CTRL_SYNC)
 563                 /* not operating in async mode */
 564                 return;
 565 
 566         route = efm32_uart_read32(efm_port, UARTn_ROUTE);
 567         if (!(route & UARTn_ROUTE_TXPEN))
 568                 /* tx pin not routed */
 569                 return;
 570 
 571         clkdiv = efm32_uart_read32(efm_port, UARTn_CLKDIV);
 572 
 573         *baud = DIV_ROUND_CLOSEST(4 * efm_port->port.uartclk,
 574                         16 * (4 + (clkdiv >> 6)));
 575 
 576         frame = efm32_uart_read32(efm_port, UARTn_FRAME);
 577         switch (frame & UARTn_FRAME_PARITY__MASK) {
 578         case UARTn_FRAME_PARITY_ODD:
 579                 *parity = 'o';
 580                 break;
 581         case UARTn_FRAME_PARITY_EVEN:
 582                 *parity = 'e';
 583                 break;
 584         default:
 585                 *parity = 'n';
 586         }
 587 
 588         *bits = (frame & UARTn_FRAME_DATABITS__MASK) -
 589                         UARTn_FRAME_DATABITS(4) + 4;
 590 
 591         efm_debug(efm_port, "get_opts: options=%d%c%d\n",
 592                         *baud, *parity, *bits);
 593 }
 594 
 595 static int efm32_uart_console_setup(struct console *co, char *options)
 596 {
 597         struct efm32_uart_port *efm_port;
 598         int baud = 115200;
 599         int bits = 8;
 600         int parity = 'n';
 601         int flow = 'n';
 602         int ret;
 603 
 604         if (co->index < 0 || co->index >= ARRAY_SIZE(efm32_uart_ports)) {
 605                 unsigned i;
 606                 for (i = 0; i < ARRAY_SIZE(efm32_uart_ports); ++i) {
 607                         if (efm32_uart_ports[i]) {
 608                                 pr_warn("efm32-console: fall back to console index %u (from %hhi)\n",
 609                                                 i, co->index);
 610                                 co->index = i;
 611                                 break;
 612                         }
 613                 }
 614         }
 615 
 616         efm_port = efm32_uart_ports[co->index];
 617         if (!efm_port) {
 618                 pr_warn("efm32-console: No port at %d\n", co->index);
 619                 return -ENODEV;
 620         }
 621 
 622         ret = clk_prepare(efm_port->clk);
 623         if (ret) {
 624                 dev_warn(efm_port->port.dev,
 625                                 "console: clk_prepare failed: %d\n", ret);
 626                 return ret;
 627         }
 628 
 629         efm_port->port.uartclk = clk_get_rate(efm_port->clk);
 630 
 631         if (options)
 632                 uart_parse_options(options, &baud, &parity, &bits, &flow);
 633         else
 634                 efm32_uart_console_get_options(efm_port,
 635                                 &baud, &parity, &bits);
 636 
 637         return uart_set_options(&efm_port->port, co, baud, parity, bits, flow);
 638 }
 639 
 640 static struct uart_driver efm32_uart_reg;
 641 
 642 static struct console efm32_uart_console = {
 643         .name = DEV_NAME,
 644         .write = efm32_uart_console_write,
 645         .device = uart_console_device,
 646         .setup = efm32_uart_console_setup,
 647         .flags = CON_PRINTBUFFER,
 648         .index = -1,
 649         .data = &efm32_uart_reg,
 650 };
 651 
 652 #else
 653 #define efm32_uart_console (*(struct console *)NULL)
 654 #endif /* ifdef CONFIG_SERIAL_EFM32_UART_CONSOLE / else */
 655 
 656 static struct uart_driver efm32_uart_reg = {
 657         .owner = THIS_MODULE,
 658         .driver_name = DRIVER_NAME,
 659         .dev_name = DEV_NAME,
 660         .nr = ARRAY_SIZE(efm32_uart_ports),
 661         .cons = &efm32_uart_console,
 662 };
 663 
 664 static int efm32_uart_probe_dt(struct platform_device *pdev,
 665                 struct efm32_uart_port *efm_port)
 666 {
 667         struct device_node *np = pdev->dev.of_node;
 668         u32 location;
 669         int ret;
 670 
 671         if (!np)
 672                 return 1;
 673 
 674         ret = of_property_read_u32(np, "energymicro,location", &location);
 675 
 676         if (ret)
 677                 /* fall back to wrongly namespaced property */
 678                 ret = of_property_read_u32(np, "efm32,location", &location);
 679 
 680         if (ret)
 681                 /* fall back to old and (wrongly) generic property "location" */
 682                 ret = of_property_read_u32(np, "location", &location);
 683 
 684         if (!ret) {
 685                 if (location > 5) {
 686                         dev_err(&pdev->dev, "invalid location\n");
 687                         return -EINVAL;
 688                 }
 689                 efm_debug(efm_port, "using location %u\n", location);
 690                 efm_port->pdata.location = location;
 691         } else {
 692                 efm_debug(efm_port, "fall back to location 0\n");
 693         }
 694 
 695         ret = of_alias_get_id(np, "serial");
 696         if (ret < 0) {
 697                 dev_err(&pdev->dev, "failed to get alias id: %d\n", ret);
 698                 return ret;
 699         } else {
 700                 efm_port->port.line = ret;
 701                 return 0;
 702         }
 703 
 704 }
 705 
 706 static int efm32_uart_probe(struct platform_device *pdev)
 707 {
 708         struct efm32_uart_port *efm_port;
 709         struct resource *res;
 710         unsigned int line;
 711         int ret;
 712 
 713         efm_port = kzalloc(sizeof(*efm_port), GFP_KERNEL);
 714         if (!efm_port) {
 715                 dev_dbg(&pdev->dev, "failed to allocate private data\n");
 716                 return -ENOMEM;
 717         }
 718 
 719         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 720         if (!res) {
 721                 ret = -ENODEV;
 722                 dev_dbg(&pdev->dev, "failed to determine base address\n");
 723                 goto err_get_base;
 724         }
 725 
 726         if (resource_size(res) < 60) {
 727                 ret = -EINVAL;
 728                 dev_dbg(&pdev->dev, "memory resource too small\n");
 729                 goto err_too_small;
 730         }
 731 
 732         ret = platform_get_irq(pdev, 0);
 733         if (ret <= 0) {
 734                 dev_dbg(&pdev->dev, "failed to get rx irq\n");
 735                 goto err_get_rxirq;
 736         }
 737 
 738         efm_port->port.irq = ret;
 739 
 740         ret = platform_get_irq(pdev, 1);
 741         if (ret <= 0)
 742                 ret = efm_port->port.irq + 1;
 743 
 744         efm_port->txirq = ret;
 745 
 746         efm_port->port.dev = &pdev->dev;
 747         efm_port->port.mapbase = res->start;
 748         efm_port->port.type = PORT_EFMUART;
 749         efm_port->port.iotype = UPIO_MEM32;
 750         efm_port->port.fifosize = 2;
 751         efm_port->port.ops = &efm32_uart_pops;
 752         efm_port->port.flags = UPF_BOOT_AUTOCONF;
 753 
 754         ret = efm32_uart_probe_dt(pdev, efm_port);
 755         if (ret > 0) {
 756                 /* not created by device tree */
 757                 const struct efm32_uart_pdata *pdata = dev_get_platdata(&pdev->dev);
 758 
 759                 efm_port->port.line = pdev->id;
 760 
 761                 if (pdata)
 762                         efm_port->pdata = *pdata;
 763         } else if (ret < 0)
 764                 goto err_probe_dt;
 765 
 766         line = efm_port->port.line;
 767 
 768         if (line >= 0 && line < ARRAY_SIZE(efm32_uart_ports))
 769                 efm32_uart_ports[line] = efm_port;
 770 
 771         ret = uart_add_one_port(&efm32_uart_reg, &efm_port->port);
 772         if (ret) {
 773                 dev_dbg(&pdev->dev, "failed to add port: %d\n", ret);
 774 
 775                 if (line >= 0 && line < ARRAY_SIZE(efm32_uart_ports))
 776                         efm32_uart_ports[line] = NULL;
 777 err_probe_dt:
 778 err_get_rxirq:
 779 err_too_small:
 780 err_get_base:
 781                 kfree(efm_port);
 782         } else {
 783                 platform_set_drvdata(pdev, efm_port);
 784                 dev_dbg(&pdev->dev, "\\o/\n");
 785         }
 786 
 787         return ret;
 788 }
 789 
 790 static int efm32_uart_remove(struct platform_device *pdev)
 791 {
 792         struct efm32_uart_port *efm_port = platform_get_drvdata(pdev);
 793         unsigned int line = efm_port->port.line;
 794 
 795         uart_remove_one_port(&efm32_uart_reg, &efm_port->port);
 796 
 797         if (line >= 0 && line < ARRAY_SIZE(efm32_uart_ports))
 798                 efm32_uart_ports[line] = NULL;
 799 
 800         kfree(efm_port);
 801 
 802         return 0;
 803 }
 804 
 805 static const struct of_device_id efm32_uart_dt_ids[] = {
 806         {
 807                 .compatible = "energymicro,efm32-uart",
 808         }, {
 809                 /* doesn't follow the "vendor,device" scheme, don't use */
 810                 .compatible = "efm32,uart",
 811         }, {
 812                 /* sentinel */
 813         }
 814 };
 815 MODULE_DEVICE_TABLE(of, efm32_uart_dt_ids);
 816 
 817 static struct platform_driver efm32_uart_driver = {
 818         .probe = efm32_uart_probe,
 819         .remove = efm32_uart_remove,
 820 
 821         .driver = {
 822                 .name = DRIVER_NAME,
 823                 .of_match_table = efm32_uart_dt_ids,
 824         },
 825 };
 826 
 827 static int __init efm32_uart_init(void)
 828 {
 829         int ret;
 830 
 831         ret = uart_register_driver(&efm32_uart_reg);
 832         if (ret)
 833                 return ret;
 834 
 835         ret = platform_driver_register(&efm32_uart_driver);
 836         if (ret)
 837                 uart_unregister_driver(&efm32_uart_reg);
 838 
 839         pr_info("EFM32 UART/USART driver\n");
 840 
 841         return ret;
 842 }
 843 module_init(efm32_uart_init);
 844 
 845 static void __exit efm32_uart_exit(void)
 846 {
 847         platform_driver_unregister(&efm32_uart_driver);
 848         uart_unregister_driver(&efm32_uart_reg);
 849 }
 850 module_exit(efm32_uart_exit);
 851 
 852 MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
 853 MODULE_DESCRIPTION("EFM32 UART/USART driver");
 854 MODULE_LICENSE("GPL v2");
 855 MODULE_ALIAS("platform:" DRIVER_NAME);

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