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