The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/mips/mediatek/uart_dev_mtk.c

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    1 /* $NetBSD: uart.c,v 1.2 2007/03/23 20:05:47 dogcow Exp $ */
    2 
    3 /*-
    4  * Copyright (c) 2013, Alexander A. Mityaev <sansan@adm.ua>
    5  * Copyright (c) 2010 Aleksandr Rybalko.
    6  * Copyright (c) 2007 Ruslan Ermilov and Vsevolod Lobko.
    7  * Copyright (c) 2007 Oleksandr Tymoshenko.
    8  * All rights reserved.
    9  *
   10  * Redistribution and use in source and binary forms, with or
   11  * without modification, are permitted provided that the following
   12  * conditions are met:
   13  * 1. Redistributions of source code must retain the above copyright
   14  *    notice, this list of conditions and the following disclaimer.
   15  * 2. Redistributions in binary form must reproduce the above
   16  *    copyright notice, this list of conditions and the following
   17  *    disclaimer in the documentation and/or other materials provided
   18  *    with the distribution.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS ``AS IS'' AND ANY
   21  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   22  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   23  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS
   24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
   25  * OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   26  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA,
   27  * OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
   29  * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
   30  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
   31  * OF SUCH DAMAGE.
   32  */
   33 
   34 #include <sys/cdefs.h>
   35 __FBSDID("$FreeBSD: releng/11.1/sys/mips/mediatek/uart_dev_mtk.c 297669 2016-04-07 11:16:32Z sgalabov $");
   36 
   37 #include "opt_ddb.h"
   38 
   39 #include <sys/param.h>
   40 #include <sys/systm.h>
   41 #include <sys/bus.h>
   42 #include <sys/conf.h>
   43 #include <sys/kdb.h>
   44 #include <sys/reboot.h>
   45 #include <sys/sysctl.h>
   46 #include <sys/kernel.h>
   47 #include <machine/bus.h>
   48 #include <machine/fdt.h>
   49 
   50 #include <dev/uart/uart.h>
   51 #include <dev/uart/uart_cpu.h>
   52 #include <dev/uart/uart_cpu_fdt.h>
   53 #include <dev/uart/uart_bus.h>
   54 
   55 #include <mips/mediatek/uart_dev_mtk.h>
   56 #include <mips/mediatek/mtk_soc.h>
   57 #include <mips/mediatek/mtk_sysctl.h>
   58 
   59 #include "uart_if.h"
   60 
   61 /* Set some reference clock value. Real value will be taken from FDT */
   62 #define DEFAULT_RCLK            (120 * 1000 * 1000)
   63 
   64 /*
   65  * Low-level UART interface.
   66  */
   67 static int mtk_uart_probe(struct uart_bas *bas);
   68 static void mtk_uart_init(struct uart_bas *bas, int, int, int, int);
   69 static void mtk_uart_term(struct uart_bas *bas);
   70 static void mtk_uart_putc(struct uart_bas *bas, int);
   71 static int mtk_uart_rxready(struct uart_bas *bas);
   72 static int mtk_uart_getc(struct uart_bas *bas, struct mtx *);
   73 
   74 static struct uart_ops uart_mtk_ops = {
   75         .probe = mtk_uart_probe,
   76         .init = mtk_uart_init,
   77         .term = mtk_uart_term,
   78         .putc = mtk_uart_putc,
   79         .rxready = mtk_uart_rxready,
   80         .getc = mtk_uart_getc,
   81 };
   82 
   83 static int      uart_output = 1;
   84 TUNABLE_INT("kern.uart_output", &uart_output);
   85 SYSCTL_INT(_kern, OID_AUTO, uart_output, CTLFLAG_RW,
   86     &uart_output, 0, "UART output enabled.");
   87 
   88 static int
   89 mtk_uart_probe(struct uart_bas *bas)
   90 {
   91         return (0);
   92 }
   93 
   94 static void
   95 mtk_uart_init(struct uart_bas *bas, int baudrate, int databits,
   96     int stopbits, int parity)
   97 {
   98         /* CLKDIV  = 384000000/ 3/ 16/ br */
   99         /* for 384MHz CLKDIV = 8000000 / baudrate; */
  100         switch (databits) {
  101         case 5:
  102                 databits = UART_LCR_5B;
  103                 break;
  104         case 6:
  105                 databits = UART_LCR_6B;
  106                 break;
  107         case 7:
  108                 databits = UART_LCR_7B;
  109                 break;
  110         case 8:
  111                 databits = UART_LCR_8B;
  112                 break;
  113         default:
  114                 /* Unsupported */
  115                 return;
  116         }
  117         switch (parity) {
  118         case UART_PARITY_EVEN:  parity = (UART_LCR_PEN|UART_LCR_EVEN); break;
  119         case UART_PARITY_ODD:   parity = (UART_LCR_PEN); break;
  120         case UART_PARITY_NONE:  parity = 0; break;
  121         /* Unsupported */
  122         default:                return;
  123         }
  124 
  125         if (bas->rclk && baudrate) {
  126                 uart_setreg(bas, UART_CDDL_REG, bas->rclk/16/baudrate);
  127                 uart_barrier(bas);
  128         }
  129 
  130         uart_setreg(bas, UART_LCR_REG, databits |
  131                                 (stopbits==1?0:UART_LCR_STB_15) |
  132                                 parity);
  133         uart_barrier(bas);
  134 }
  135 
  136 static void
  137 mtk_uart_term(struct uart_bas *bas)
  138 {
  139         uart_setreg(bas, UART_MCR_REG, 0);
  140         uart_barrier(bas);
  141 }
  142 
  143 static void
  144 mtk_uart_putc(struct uart_bas *bas, int c)
  145 {
  146         char chr;
  147         if (!uart_output) return;
  148         chr = c;
  149         while (!(uart_getreg(bas, UART_LSR_REG) & UART_LSR_THRE));
  150         uart_setreg(bas, UART_TX_REG, c);
  151         uart_barrier(bas);
  152         while (!(uart_getreg(bas, UART_LSR_REG) & UART_LSR_THRE));
  153 }
  154 
  155 static int
  156 mtk_uart_rxready(struct uart_bas *bas)
  157 {
  158         if (uart_getreg(bas, UART_LSR_REG) & UART_LSR_DR)
  159                 return (1);
  160         return (0);
  161 }
  162 
  163 static int
  164 mtk_uart_getc(struct uart_bas *bas, struct mtx *hwmtx)
  165 {
  166         int c;
  167 
  168         uart_lock(hwmtx);
  169 
  170         while (!(uart_getreg(bas, UART_LSR_REG) & UART_LSR_DR)) {
  171                 uart_unlock(hwmtx);
  172                 DELAY(10);
  173                 uart_lock(hwmtx);
  174         }
  175 
  176         c = uart_getreg(bas, UART_RX_REG);
  177 
  178         uart_unlock(hwmtx);
  179 
  180         return (c);
  181 }
  182 
  183 /*
  184  * High-level UART interface.
  185  */
  186 struct uart_mtk_softc {
  187         struct uart_softc base;
  188         uint8_t ier_mask;
  189         uint8_t ier;
  190 };
  191 
  192 static int mtk_uart_bus_attach(struct uart_softc *);
  193 static int mtk_uart_bus_detach(struct uart_softc *);
  194 static int mtk_uart_bus_flush(struct uart_softc *, int);
  195 static int mtk_uart_bus_getsig(struct uart_softc *);
  196 static int mtk_uart_bus_ioctl(struct uart_softc *, int, intptr_t);
  197 static int mtk_uart_bus_ipend(struct uart_softc *);
  198 static int mtk_uart_bus_param(struct uart_softc *, int, int, int, int);
  199 static int mtk_uart_bus_probe(struct uart_softc *);
  200 static int mtk_uart_bus_receive(struct uart_softc *);
  201 static int mtk_uart_bus_setsig(struct uart_softc *, int);
  202 static int mtk_uart_bus_transmit(struct uart_softc *);
  203 static void mtk_uart_bus_grab(struct uart_softc *);
  204 static void mtk_uart_bus_ungrab(struct uart_softc *);
  205 
  206 static kobj_method_t uart_mtk_methods[] = {
  207         KOBJMETHOD(uart_attach,         mtk_uart_bus_attach),
  208         KOBJMETHOD(uart_detach,         mtk_uart_bus_detach),
  209         KOBJMETHOD(uart_flush,          mtk_uart_bus_flush),
  210         KOBJMETHOD(uart_getsig,         mtk_uart_bus_getsig),
  211         KOBJMETHOD(uart_ioctl,          mtk_uart_bus_ioctl),
  212         KOBJMETHOD(uart_ipend,          mtk_uart_bus_ipend),
  213         KOBJMETHOD(uart_param,          mtk_uart_bus_param),
  214         KOBJMETHOD(uart_probe,          mtk_uart_bus_probe),
  215         KOBJMETHOD(uart_receive,        mtk_uart_bus_receive),
  216         KOBJMETHOD(uart_setsig,         mtk_uart_bus_setsig),
  217         KOBJMETHOD(uart_transmit,       mtk_uart_bus_transmit),
  218         KOBJMETHOD(uart_grab,           mtk_uart_bus_grab),
  219         KOBJMETHOD(uart_ungrab,         mtk_uart_bus_ungrab),
  220         { 0, 0 }
  221 };
  222 
  223 struct uart_class uart_mtk_class = {
  224         "uart_mtk",
  225         uart_mtk_methods,
  226         sizeof(struct uart_mtk_softc),
  227         .uc_ops = &uart_mtk_ops,
  228         .uc_range = 1, /* use hinted range */
  229         .uc_rclk = 0
  230 };
  231 
  232 static struct ofw_compat_data compat_data[] = {
  233         { "ralink,rt2880-uart",         (uintptr_t)&uart_mtk_class },
  234         { "ralink,rt3050-uart",         (uintptr_t)&uart_mtk_class },
  235         { "ralink,rt3352-uart",         (uintptr_t)&uart_mtk_class },
  236         { "ralink,rt3883-uart",         (uintptr_t)&uart_mtk_class },
  237         { "ralink,rt5350-uart",         (uintptr_t)&uart_mtk_class },
  238         { "ralink,mt7620a-uart",        (uintptr_t)&uart_mtk_class },
  239         { NULL,                         (uintptr_t)NULL },
  240 };
  241 UART_FDT_CLASS_AND_DEVICE(compat_data);
  242 
  243 
  244 #define SIGCHG(c, i, s, d)                              \
  245         if (c) {                                        \
  246                 i |= (i & s) ? s : s | d;               \
  247         } else {                                        \
  248                 i = (i & s) ? (i & ~s) | d : i;         \
  249         }
  250 
  251 /*
  252  * Disable TX interrupt. uart should be locked
  253  */
  254 static __inline void
  255 mtk_uart_disable_txintr(struct uart_softc *sc)
  256 {
  257         struct uart_bas *bas = &sc->sc_bas;
  258         uint8_t cr;
  259 
  260         cr = uart_getreg(bas, UART_IER_REG);
  261         cr &= ~UART_IER_ETBEI;
  262         uart_setreg(bas, UART_IER_REG, cr);
  263         uart_barrier(bas);
  264 }
  265 
  266 /*
  267  * Enable TX interrupt. uart should be locked
  268  */
  269 static __inline void
  270 mtk_uart_enable_txintr(struct uart_softc *sc)
  271 {
  272         struct uart_bas *bas = &sc->sc_bas;
  273         uint8_t cr;
  274 
  275         cr = uart_getreg(bas, UART_IER_REG);
  276         cr |= UART_IER_ETBEI;
  277         uart_setreg(bas, UART_IER_REG, cr);
  278         uart_barrier(bas);
  279 }
  280 
  281 static int
  282 mtk_uart_bus_attach(struct uart_softc *sc)
  283 {
  284         struct uart_bas *bas;
  285         struct uart_devinfo *di;
  286         struct uart_mtk_softc *usc = (struct uart_mtk_softc *)sc;
  287 
  288         bas = &sc->sc_bas;
  289 
  290         if (!bas->rclk) {
  291                 bas->rclk = mtk_soc_get_uartclk();
  292         }
  293 
  294         if (sc->sc_sysdev != NULL) {
  295                 di = sc->sc_sysdev;
  296                 mtk_uart_init(bas, di->baudrate, di->databits, di->stopbits,
  297                     di->parity);
  298         } else {
  299                 mtk_uart_init(bas, 57600, 8, 1, 0);
  300         }
  301 
  302         sc->sc_rxfifosz = 16;
  303         sc->sc_txfifosz = 16;
  304 
  305         (void)mtk_uart_bus_getsig(sc);
  306 
  307         /* Enable FIFO */
  308         uart_setreg(bas, UART_FCR_REG,
  309             uart_getreg(bas, UART_FCR_REG) |
  310             UART_FCR_FIFOEN | UART_FCR_TXTGR_1 | UART_FCR_RXTGR_1);
  311         uart_barrier(bas);
  312         /* Enable interrupts */
  313         usc->ier_mask = 0xf0;
  314         uart_setreg(bas, UART_IER_REG,
  315             UART_IER_EDSSI | UART_IER_ELSI | UART_IER_ERBFI);
  316         uart_barrier(bas);
  317 
  318         return (0);
  319 }
  320 
  321 static int
  322 mtk_uart_bus_detach(struct uart_softc *sc)
  323 {
  324         return (0);
  325 }
  326 
  327 static int
  328 mtk_uart_bus_flush(struct uart_softc *sc, int what)
  329 {
  330         struct uart_bas *bas = &sc->sc_bas;
  331         uint32_t fcr = uart_getreg(bas, UART_FCR_REG);
  332 
  333         if (what & UART_FLUSH_TRANSMITTER) {
  334                 uart_setreg(bas, UART_FCR_REG, fcr|UART_FCR_TXRST);
  335                 uart_barrier(bas);
  336         }
  337         if (what & UART_FLUSH_RECEIVER) {
  338                 uart_setreg(bas, UART_FCR_REG, fcr|UART_FCR_RXRST);
  339                 uart_barrier(bas);
  340         }
  341         uart_setreg(bas, UART_FCR_REG, fcr);
  342         uart_barrier(bas);
  343         return (0);
  344 }
  345 
  346 static int
  347 mtk_uart_bus_getsig(struct uart_softc *sc)
  348 {
  349         uint32_t new, old, sig;
  350         uint8_t bes;
  351 
  352         return(0);
  353         do {
  354                 old = sc->sc_hwsig;
  355                 sig = old;
  356                 uart_lock(sc->sc_hwmtx);
  357                 bes = uart_getreg(&sc->sc_bas, UART_MSR_REG);
  358                 uart_unlock(sc->sc_hwmtx);
  359                 /* XXX: chip can show delta */
  360                 SIGCHG(bes & UART_MSR_CTS, sig, SER_CTS, SER_DCTS);
  361                 SIGCHG(bes & UART_MSR_DCD, sig, SER_DCD, SER_DDCD);
  362                 SIGCHG(bes & UART_MSR_DSR, sig, SER_DSR, SER_DDSR);
  363                 new = sig & ~SER_MASK_DELTA;
  364         } while (!atomic_cmpset_32(&sc->sc_hwsig, old, new));
  365 
  366         return (sig);
  367 }
  368 
  369 static int
  370 mtk_uart_bus_ioctl(struct uart_softc *sc, int request, intptr_t data)
  371 {
  372         struct uart_bas *bas;
  373         int baudrate, divisor, error;
  374 
  375         bas = &sc->sc_bas;
  376         error = 0;
  377         uart_lock(sc->sc_hwmtx);
  378         switch (request) {
  379         case UART_IOCTL_BREAK:
  380                 /* TODO: Send BREAK */
  381                 break;
  382         case UART_IOCTL_BAUD:
  383                 divisor = uart_getreg(bas, UART_CDDL_REG);
  384                 baudrate = bas->rclk / (divisor * 16);
  385                 *(int*)data = baudrate;
  386                 break;
  387         default:
  388                 error = EINVAL;
  389                 break;
  390         }
  391         uart_unlock(sc->sc_hwmtx);
  392         return (error);
  393 }
  394 
  395 static int
  396 mtk_uart_bus_ipend(struct uart_softc *sc)
  397 {
  398         struct uart_bas *bas;
  399         int ipend;
  400         uint8_t iir, lsr, msr;
  401 
  402 //      breakpoint();
  403 
  404         bas = &sc->sc_bas;
  405         ipend = 0;
  406 
  407         uart_lock(sc->sc_hwmtx);
  408         iir = uart_getreg(&sc->sc_bas, UART_IIR_REG);
  409         lsr = uart_getreg(&sc->sc_bas, UART_LSR_REG);
  410         uart_setreg(&sc->sc_bas, UART_LSR_REG, lsr);
  411         msr = uart_getreg(&sc->sc_bas, UART_MSR_REG);
  412         uart_setreg(&sc->sc_bas, UART_MSR_REG, msr);
  413         if (iir & UART_IIR_INTP) {
  414                 uart_unlock(sc->sc_hwmtx);
  415                 return (0);
  416         }
  417         switch ((iir >> 1) & 0x07) {
  418         case UART_IIR_ID_THRE:
  419                 ipend |= SER_INT_TXIDLE;
  420                 break;
  421         case UART_IIR_ID_DR2:
  422                 mtk_uart_bus_flush(sc, UART_FLUSH_RECEIVER);
  423                 /* passthrough */
  424         case UART_IIR_ID_DR:
  425                 ipend |= SER_INT_RXREADY;
  426                 break;
  427         case UART_IIR_ID_MST:
  428         case UART_IIR_ID_LINESTATUS:
  429                 ipend |= SER_INT_SIGCHG;
  430                 if (lsr & UART_LSR_BI)
  431                         ipend |= SER_INT_BREAK;
  432                 if (lsr & UART_LSR_OE)
  433                         ipend |= SER_INT_OVERRUN;
  434                 break;
  435         default:
  436                 /* XXX: maybe return error here */
  437                 break;
  438         }
  439 
  440         uart_unlock(sc->sc_hwmtx);
  441 
  442         return (ipend);
  443 }
  444 
  445 static int
  446 mtk_uart_bus_param(struct uart_softc *sc, int baudrate, int databits,
  447     int stopbits, int parity)
  448 {
  449         uart_lock(sc->sc_hwmtx);
  450         mtk_uart_init(&sc->sc_bas, baudrate, databits, stopbits, parity);
  451         uart_unlock(sc->sc_hwmtx);
  452         return (0);
  453 }
  454 
  455 static int
  456 mtk_uart_bus_probe(struct uart_softc *sc)
  457 {
  458         int error;
  459 
  460         error = mtk_uart_probe(&sc->sc_bas);
  461         if (error)
  462                 return (error);
  463                 
  464         device_set_desc(sc->sc_dev, "MTK UART Controller");
  465 
  466         return (0);
  467 }
  468 
  469 static int
  470 mtk_uart_bus_receive(struct uart_softc *sc)
  471 {
  472         struct uart_bas *bas;
  473         int xc;
  474         uint8_t lsr;
  475 
  476         bas = &sc->sc_bas;
  477         uart_lock(sc->sc_hwmtx);
  478         lsr = uart_getreg(bas, UART_LSR_REG);
  479         while ((lsr & UART_LSR_DR)) {
  480                 if (uart_rx_full(sc)) {
  481                         sc->sc_rxbuf[sc->sc_rxput] = UART_STAT_OVERRUN;
  482                         break;
  483                 }
  484                 xc = 0;
  485                 xc = uart_getreg(bas, UART_RX_REG);
  486                 if (lsr & UART_LSR_FE)
  487                         xc |= UART_STAT_FRAMERR;
  488                 if (lsr & UART_LSR_PE)
  489                         xc |= UART_STAT_PARERR;
  490                 if (lsr & UART_LSR_OE)
  491                         xc |= UART_STAT_OVERRUN;
  492                 uart_barrier(bas);
  493                 uart_rx_put(sc, xc);
  494                 lsr = uart_getreg(bas, UART_LSR_REG);
  495         }
  496 
  497         uart_unlock(sc->sc_hwmtx);
  498         return (0);
  499 }
  500 
  501 static int
  502 mtk_uart_bus_setsig(struct uart_softc *sc, int sig)
  503 {
  504         /* TODO: implement (?) */
  505         return (sig);
  506 }
  507 
  508 static int
  509 mtk_uart_bus_transmit(struct uart_softc *sc)
  510 {
  511         struct uart_bas *bas = &sc->sc_bas;
  512         int i;
  513 
  514         if (!uart_output) return (0);
  515 
  516         bas = &sc->sc_bas;
  517         uart_lock(sc->sc_hwmtx);
  518         while ((uart_getreg(bas, UART_LSR_REG) & UART_LSR_THRE) == 0);
  519         mtk_uart_enable_txintr(sc);
  520         for (i = 0; i < sc->sc_txdatasz; i++) {
  521                 uart_setreg(bas, UART_TX_REG, sc->sc_txbuf[i]);
  522                 uart_barrier(bas);
  523         }
  524         sc->sc_txbusy = 1;
  525         uart_unlock(sc->sc_hwmtx);
  526         return (0);
  527 }
  528 
  529 void
  530 mtk_uart_bus_grab(struct uart_softc *sc)
  531 {
  532         struct uart_bas *bas = &sc->sc_bas;
  533         struct uart_mtk_softc *usc = (struct uart_mtk_softc *)sc;
  534 
  535         uart_lock(sc->sc_hwmtx);
  536         usc->ier = uart_getreg(bas, UART_IER_REG);
  537         uart_setreg(bas, UART_IER_REG, usc->ier & usc->ier_mask);
  538         uart_barrier(bas);
  539         uart_unlock(sc->sc_hwmtx);
  540 }
  541 
  542 void
  543 mtk_uart_bus_ungrab(struct uart_softc *sc)
  544 {
  545         struct uart_mtk_softc *usc = (struct uart_mtk_softc *)sc;
  546         struct uart_bas *bas = &sc->sc_bas;
  547 
  548         uart_lock(sc->sc_hwmtx);
  549         uart_setreg(bas, UART_IER_REG, usc->ier);
  550         uart_barrier(bas);
  551         uart_unlock(sc->sc_hwmtx);
  552 }

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