sys/dev/uart/uart_dev_snps.c

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