linux/drivers/tty/serial/efm32-uart.c
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   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
  82struct 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
  92static 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
  98static 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
 104static 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
 115static void efm32_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
 116{
 117        /* sorry, neither handshaking lines nor loop functionallity */
 118}
 119
 120static 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
 126static 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
 136static 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
 168static 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
 183static 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
 190static void efm32_uart_break_ctl(struct uart_port *port, int ctl)
 191{
 192        /* not possible without fiddling with gpios */
 193}
 194
 195static 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
 243static 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
 275static 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
 291static 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);
 324err_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
 333err_clk_enable:
 334        return ret;
 335}
 336
 337static 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
 347static 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
 429static const char *efm32_uart_type(struct uart_port *port)
 430{
 431        return port->type == PORT_EFMUART ? "efm32-uart" : NULL;
 432}
 433
 434static 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
 443static 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);
 465err_clk_get:
 466
 467                iounmap(port->membase);
 468err_ioremap:
 469                return ret;
 470        }
 471        return 0;
 472}
 473
 474static 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
 481static 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
 492static 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
 510static struct efm32_uart_port *efm32_uart_ports[5];
 511
 512#ifdef CONFIG_SERIAL_EFM32_UART_CONSOLE
 513static 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
 530static 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
 556static 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
 595static 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
 640static struct uart_driver efm32_uart_reg;
 641
 642static 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
 656static 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
 664static 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
 706static 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;
 777err_probe_dt:
 778err_get_rxirq:
 779err_too_small:
 780err_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
 790static 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
 805static 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};
 815MODULE_DEVICE_TABLE(of, efm32_uart_dt_ids);
 816
 817static 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
 827static 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}
 843module_init(efm32_uart_init);
 844
 845static void __exit efm32_uart_exit(void)
 846{
 847        platform_driver_unregister(&efm32_uart_driver);
 848        uart_unregister_driver(&efm32_uart_reg);
 849}
 850module_exit(efm32_uart_exit);
 851
 852MODULE_AUTHOR("Uwe Kleine-Koenig <u.kleine-koenig@pengutronix.de>");
 853MODULE_DESCRIPTION("EFM32 UART/USART driver");
 854MODULE_LICENSE("GPL v2");
 855MODULE_ALIAS("platform:" DRIVER_NAME);
 856