The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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FreeBSD/Linux Kernel Cross Reference
sys/dev/uart/uart_dev_snps.c

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    1 /*-
    2  * Copyright (c) 2016 Jared McNeill <jmcneill@invisible.ca>
    3  *
    4  * Redistribution and use in source and binary forms, with or without
    5  * modification, are permitted provided that the following conditions
    6  * are met:
    7  * 1. Redistributions of source code must retain the above copyright
    8  *    notice, this list of conditions and the following disclaimer.
    9  * 2. Redistributions in binary form must reproduce the above copyright
   10  *    notice, this list of conditions and the following disclaimer in the
   11  *    documentation and/or other materials provided with the distribution.
   12  *
   13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
   14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
   15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
   16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
   17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
   18  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   19  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
   20  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   21  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   23  * SUCH DAMAGE.
   24  *
   25  * $FreeBSD$
   26  */
   27 
   28 #include <sys/cdefs.h>
   29 __FBSDID("$FreeBSD$");
   30 
   31 #include <sys/param.h>
   32 #include <sys/systm.h>
   33 #include <sys/bus.h>
   34 #include <sys/kernel.h>
   35 #include <sys/module.h>
   36 #include <machine/bus.h>
   37 
   38 #include <dev/uart/uart.h>
   39 #include <dev/uart/uart_bus.h>
   40 #include <dev/uart/uart_cpu_fdt.h>
   41 #include <dev/uart/uart_dev_ns8250.h>
   42 
   43 #include <dev/ofw/ofw_bus.h>
   44 #include <dev/ofw/ofw_bus_subr.h>
   45 
   46 #include <dev/extres/clk/clk.h>
   47 #include <dev/extres/hwreset/hwreset.h>
   48 
   49 #include "uart_if.h"
   50 
   51 struct snps_softc {
   52         struct ns8250_softc     ns8250;
   53 
   54         clk_t                   baudclk;
   55         clk_t                   apb_pclk;
   56         hwreset_t               reset;
   57 };
   58 
   59 /*
   60  * To use early printf on 64 bits Allwinner SoC, add to kernel config
   61  * options SOCDEV_PA=0x0
   62  * options SOCDEV_VA=0x40000000
   63  * options EARLY_PRINTF
   64  *
   65  * To use early printf on 32 bits Allwinner SoC, add to kernel config
   66  * options SOCDEV_PA=0x01C00000
   67  * options SOCDEV_VA=0x10000000
   68  * options EARLY_PRINTF
   69  *
   70  * remove the if 0
   71 */
   72 #if 0
   73 #ifdef EARLY_PRINTF
   74 static void
   75 uart_snps_early_putc(int c)
   76 {
   77         volatile uint32_t *stat;
   78         volatile uint32_t *tx;
   79 
   80 #ifdef ALLWINNER_64
   81         stat = (uint32_t *) (SOCDEV_VA + 0x1C2807C);
   82         tx = (uint32_t *) (SOCDEV_VA + 0x1C28000);
   83 #endif
   84 #ifdef ALLWINNER_32
   85         stat = (uint32_t *) (SOCDEV_VA + 0x2807C);
   86         tx = (uint32_t *) (SOCDEV_VA + 0x28000);
   87 #endif
   88 
   89         while ((*stat & (1 << 2)) == 0)
   90                 continue;
   91         *tx = c;
   92 }
   93 early_putc_t *early_putc = uart_snps_early_putc;
   94 #endif /* EARLY_PRINTF */
   95 #endif
   96 
   97 static kobj_method_t snps_methods[] = {
   98         KOBJMETHOD(uart_probe,          ns8250_bus_probe),
   99         KOBJMETHOD(uart_attach,         ns8250_bus_attach),
  100         KOBJMETHOD(uart_detach,         ns8250_bus_detach),
  101         KOBJMETHOD(uart_flush,          ns8250_bus_flush),
  102         KOBJMETHOD(uart_getsig,         ns8250_bus_getsig),
  103         KOBJMETHOD(uart_ioctl,          ns8250_bus_ioctl),
  104         KOBJMETHOD(uart_ipend,          ns8250_bus_ipend),
  105         KOBJMETHOD(uart_param,          ns8250_bus_param),
  106         KOBJMETHOD(uart_receive,        ns8250_bus_receive),
  107         KOBJMETHOD(uart_setsig,         ns8250_bus_setsig),
  108         KOBJMETHOD(uart_transmit,       ns8250_bus_transmit),
  109         KOBJMETHOD(uart_grab,           ns8250_bus_grab),
  110         KOBJMETHOD(uart_ungrab,         ns8250_bus_ungrab),
  111         KOBJMETHOD_END
  112 };
  113 
  114 struct uart_class uart_snps_class = {
  115         "snps",
  116         snps_methods,
  117         sizeof(struct snps_softc),
  118         .uc_ops = &uart_ns8250_ops,
  119         .uc_range = 8,
  120         .uc_rclk = 0,
  121 };
  122 
  123 static struct ofw_compat_data compat_data[] = {
  124         { "snps,dw-apb-uart",           (uintptr_t)&uart_snps_class },
  125         { "marvell,armada-38x-uart",    (uintptr_t)&uart_snps_class },
  126         { NULL,                         (uintptr_t)NULL }
  127 };
  128 UART_FDT_CLASS(compat_data);
  129 
  130 static int
  131 snps_get_clocks(device_t dev, clk_t *baudclk, clk_t *apb_pclk)
  132 {
  133 
  134         *baudclk = NULL;
  135         *apb_pclk = NULL;
  136 
  137         /* Baud clock is either named "baudclk", or there is a single
  138          * unnamed clock.
  139          */
  140         if (clk_get_by_ofw_name(dev, 0, "baudclk", baudclk) != 0 &&
  141             clk_get_by_ofw_index(dev, 0, 0, baudclk) != 0)
  142                 return (ENOENT);
  143 
  144         /* APB peripheral clock is optional */
  145         (void)clk_get_by_ofw_name(dev, 0, "apb_pclk", apb_pclk);
  146 
  147         return (0);
  148 }
  149 
  150 static int
  151 snps_probe(device_t dev)
  152 {
  153         struct snps_softc *sc;
  154         struct uart_class *uart_class;
  155         phandle_t node;
  156         uint32_t shift, iowidth, clock;
  157         uint64_t freq;
  158         int error;
  159         clk_t baudclk, apb_pclk;
  160         hwreset_t reset;
  161 
  162         if (!ofw_bus_status_okay(dev))
  163                 return (ENXIO);
  164 
  165         uart_class = (struct uart_class *)ofw_bus_search_compatible(dev,
  166             compat_data)->ocd_data;
  167         if (uart_class == NULL)
  168                 return (ENXIO);
  169 
  170         freq = 0;
  171         sc = device_get_softc(dev);
  172         sc->ns8250.base.sc_class = uart_class;
  173 
  174         node = ofw_bus_get_node(dev);
  175         if (OF_getencprop(node, "reg-shift", &shift, sizeof(shift)) <= 0)
  176                 shift = 0;
  177         if (OF_getencprop(node, "reg-io-width", &iowidth, sizeof(iowidth)) <= 0)
  178                 iowidth = 1;
  179         if (OF_getencprop(node, "clock-frequency", &clock, sizeof(clock)) <= 0)
  180                 clock = 0;
  181 
  182         if (hwreset_get_by_ofw_idx(dev, 0, 0, &reset) == 0) {
  183                 error = hwreset_deassert(reset);
  184                 if (error != 0) {
  185                         device_printf(dev, "cannot de-assert reset\n");
  186                         return (error);
  187                 }
  188         }
  189 
  190         if (snps_get_clocks(dev, &baudclk, &apb_pclk) == 0) {
  191                 error = clk_enable(baudclk);
  192                 if (error != 0) {
  193                         device_printf(dev, "cannot enable baud clock\n");
  194                         return (error);
  195                 }
  196                 if (apb_pclk != NULL) {
  197                         error = clk_enable(apb_pclk);
  198                         if (error != 0) {
  199                                 device_printf(dev,
  200                                     "cannot enable peripheral clock\n");
  201                                 return (error);
  202                         }
  203                 }
  204 
  205                 if (clock == 0) {
  206                         error = clk_get_freq(baudclk, &freq);
  207                         if (error != 0) {
  208                                 device_printf(dev, "cannot get frequency\n");
  209                                 return (error);
  210                         }
  211                         clock = (uint32_t)freq;
  212                 }
  213         }
  214 
  215         if (bootverbose && clock == 0)
  216                 device_printf(dev, "could not determine frequency\n");
  217 
  218         error = uart_bus_probe(dev, (int)shift, (int)iowidth, (int)clock, 0, 0, UART_F_BUSY_DETECT);
  219         if (error != 0)
  220                 return (error);
  221 
  222         /* XXX uart_bus_probe has changed the softc, so refresh it */
  223         sc = device_get_softc(dev);
  224 
  225         /* Store clock and reset handles for detach */
  226         sc->baudclk = baudclk;
  227         sc->apb_pclk = apb_pclk;
  228         sc->reset = reset;
  229 
  230         return (0);
  231 }
  232 
  233 static int
  234 snps_detach(device_t dev)
  235 {
  236         struct snps_softc *sc;
  237         clk_t baudclk, apb_pclk;
  238         hwreset_t reset;
  239         int error;
  240 
  241         sc = device_get_softc(dev);
  242         baudclk = sc->baudclk;
  243         apb_pclk = sc->apb_pclk;
  244         reset = sc->reset;
  245 
  246         error = uart_bus_detach(dev);
  247         if (error != 0)
  248                 return (error);
  249 
  250         if (reset != NULL) {
  251                 error = hwreset_assert(reset);
  252                 if (error != 0) {
  253                         device_printf(dev, "cannot assert reset\n");
  254                         return (error);
  255                 }
  256                 hwreset_release(reset);
  257         }
  258         if (apb_pclk != NULL) {
  259                 error = clk_release(apb_pclk);
  260                 if (error != 0) {
  261                         device_printf(dev, "cannot release peripheral clock\n");
  262                         return (error);
  263                 }
  264         }
  265         if (baudclk != NULL) {
  266                 error = clk_release(baudclk);
  267                 if (error != 0) {
  268                         device_printf(dev, "cannot release baud clock\n");
  269                         return (error);
  270                 }
  271         }
  272 
  273         return (0);
  274 }
  275 
  276 static device_method_t snps_bus_methods[] = {
  277         /* Device interface */
  278         DEVMETHOD(device_probe,         snps_probe),
  279         DEVMETHOD(device_attach,        uart_bus_attach),
  280         DEVMETHOD(device_detach,        snps_detach),
  281         DEVMETHOD_END
  282 };
  283 
  284 static driver_t snps_uart_driver = {
  285         uart_driver_name,
  286         snps_bus_methods,
  287         sizeof(struct snps_softc)
  288 };
  289 
  290 DRIVER_MODULE(uart_snps, simplebus, snps_uart_driver, uart_devclass, 0, 0);

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