scmi.c

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    1 /*-
    2  * SPDX-License-Identifier: BSD-2-Clause
    3  *
    4  * Copyright (c) 2022 Ruslan Bukin <br@bsdpad.com>
    5  *
    6  * This work was supported by Innovate UK project 105694, "Digital Security
    7  * by Design (DSbD) Technology Platform Prototype".
    8  *
    9  * Redistribution and use in source and binary forms, with or without
   10  * modification, are permitted provided that the following conditions
   11  * are met:
   12  * 1. Redistributions of source code must retain the above copyright
   13  *    notice, this list of conditions and the following disclaimer.
   14  * 2. Redistributions in binary form must reproduce the above copyright
   15  *    notice, this list of conditions and the following disclaimer in the
   16  *    documentation and/or other materials provided with the distribution.
   17  *
   18  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   28  * SUCH DAMAGE.
   29  */
   30 
   31 #include <sys/cdefs.h>
   32 __FBSDID("$FreeBSD$");
   33 
   34 #include <sys/param.h>
   35 #include <sys/systm.h>
   36 #include <sys/bus.h>
   37 #include <sys/cpu.h>
   38 #include <sys/kernel.h>
   39 #include <sys/lock.h>
   40 #include <sys/module.h>
   41 #include <sys/mutex.h>
   42 
   43 #include <dev/extres/clk/clk.h>
   44 #include <dev/fdt/simplebus.h>
   45 #include <dev/fdt/fdt_common.h>
   46 #include <dev/ofw/ofw_bus_subr.h>
   47 
   48 #include "dev/mailbox/arm/arm_doorbell.h"
   49 
   50 #include "scmi.h"
   51 #include "scmi_protocols.h"
   52 
   53 struct scmi_softc {
   54         struct simplebus_softc  simplebus_sc;
   55         device_t                dev;
   56         device_t                tx_shmem;
   57         struct arm_doorbell     *db;
   58         struct mtx              mtx;
   59         int                     req_done;
   60 };
   61 
   62 static device_t
   63 scmi_get_shmem(struct scmi_softc *sc, int index)
   64 {
   65         phandle_t *shmems;
   66         phandle_t node;
   67         device_t dev;
   68         size_t len;
   69 
   70         node = ofw_bus_get_node(sc->dev);
   71         if (node <= 0)
   72                 return (NULL);
   73 
   74         len = OF_getencprop_alloc_multi(node, "shmem", sizeof(*shmems),
   75             (void **)&shmems);
   76         if (len <= 0) {
   77                 device_printf(sc->dev, "%s: Can't get shmem node.\n", __func__);
   78                 return (NULL);
   79         }
   80 
   81         if (index >= len) {
   82                 OF_prop_free(shmems);
   83                 return (NULL);
   84         }
   85 
   86         dev = OF_device_from_xref(shmems[index]);
   87         if (dev == NULL)
   88                 device_printf(sc->dev, "%s: Can't get shmem device.\n",
   89                     __func__);
   90 
   91         OF_prop_free(shmems);
   92 
   93         return (dev);
   94 }
   95 
   96 static void
   97 scmi_callback(void *arg)
   98 {
   99         struct scmi_softc *sc;
  100 
  101         sc = arg;
  102 
  103         dprintf("%s sc %p\n", __func__, sc);
  104 
  105         SCMI_LOCK(sc);
  106         sc->req_done = 1;
  107         wakeup(sc);
  108         SCMI_UNLOCK(sc);
  109 }
  110 
  111 static int
  112 scmi_request_locked(struct scmi_softc *sc, struct scmi_req *req)
  113 {
  114         struct scmi_smt_header hdr;
  115         int timeout;
  116 
  117         bzero(&hdr, sizeof(struct scmi_smt_header));
  118 
  119         SCMI_ASSERT_LOCKED(sc);
  120 
  121         /* Read header */
  122         scmi_shmem_read(sc->tx_shmem, 0, &hdr, SMT_HEADER_SIZE);
  123 
  124         if ((hdr.channel_status & SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE) == 0)
  125                 return (1);
  126 
  127         /* Update header */
  128         hdr.channel_status &= ~SCMI_SHMEM_CHAN_STAT_CHANNEL_FREE;
  129         hdr.msg_header = req->protocol_id << SMT_HEADER_PROTOCOL_ID_S;
  130         hdr.msg_header |= req->message_id << SMT_HEADER_MESSAGE_ID_S;
  131         hdr.length = sizeof(hdr.msg_header) + req->in_size;
  132         hdr.flags |= SCMI_SHMEM_FLAG_INTR_ENABLED;
  133 
  134         /* Write header */
  135         scmi_shmem_write(sc->tx_shmem, 0, &hdr, SMT_HEADER_SIZE);
  136 
  137         /* Write request */
  138         scmi_shmem_write(sc->tx_shmem, SMT_HEADER_SIZE, req->in_buf,
  139             req->in_size);
  140 
  141         sc->req_done = 0;
  142 
  143         /* Interrupt SCP firmware. */
  144         arm_doorbell_set(sc->db);
  145 
  146         timeout = 200;
  147 
  148         dprintf("%s: request\n", __func__);
  149 
  150         do {
  151                 if (cold) {
  152                         if (arm_doorbell_get(sc->db))
  153                                 break;
  154                         DELAY(10000);
  155                 } else {
  156                         msleep(sc, &sc->mtx, 0, "scmi", hz / 10);
  157                         if (sc->req_done)
  158                                 break;
  159                 }
  160         } while (timeout--);
  161 
  162         if (timeout <= 0)
  163                 return (-1);
  164 
  165         dprintf("%s: got reply, timeout %d\n", __func__, timeout);
  166 
  167         /* Read header. */
  168         scmi_shmem_read(sc->tx_shmem, 0, &hdr, SMT_HEADER_SIZE);
  169 
  170         /* Read response */
  171         scmi_shmem_read(sc->tx_shmem, SMT_HEADER_SIZE, req->out_buf,
  172             req->out_size);
  173 
  174         return (0);
  175 }
  176 
  177 int
  178 scmi_request(device_t dev, struct scmi_req *req)
  179 {
  180         struct scmi_softc *sc;
  181         int error;
  182 
  183         sc = device_get_softc(dev);
  184 
  185         SCMI_LOCK(sc);
  186         error = scmi_request_locked(sc, req);
  187         SCMI_UNLOCK(sc);
  188 
  189         return (error);
  190 }
  191 
  192 static int
  193 scmi_probe(device_t dev)
  194 {
  195 
  196         if (!ofw_bus_is_compatible(dev, "arm,scmi"))
  197                 return (ENXIO);
  198 
  199         if (!ofw_bus_status_okay(dev))
  200                 return (ENXIO);
  201 
  202         device_set_desc(dev, "ARM SCMI interface driver");
  203 
  204         return (BUS_PROBE_DEFAULT);
  205 }
  206 
  207 static int
  208 scmi_attach(device_t dev)
  209 {
  210         struct scmi_softc *sc;
  211         phandle_t node;
  212         int error;
  213 
  214         sc = device_get_softc(dev);
  215         sc->dev = dev;
  216 
  217         node = ofw_bus_get_node(dev);
  218         if (node == -1)
  219                 return (ENXIO);
  220 
  221         sc->tx_shmem = scmi_get_shmem(sc, 0);
  222         if (sc->tx_shmem == NULL) {
  223                 device_printf(dev, "TX shmem dev not found.\n");
  224                 return (ENXIO);
  225         }
  226 
  227         sc->db = arm_doorbell_ofw_get(sc->dev, "tx");
  228         if (sc->db == NULL) {
  229                 device_printf(dev, "Doorbell device not found.\n");
  230                 return (ENXIO);
  231         }
  232 
  233         mtx_init(&sc->mtx, device_get_nameunit(dev), "SCMI", MTX_DEF);
  234 
  235         arm_doorbell_set_handler(sc->db, scmi_callback, sc);
  236 
  237         simplebus_init(dev, node);
  238 
  239         /*
  240          * Allow devices to identify.
  241          */
  242         bus_generic_probe(dev);
  243 
  244         /*
  245          * Now walk the OFW tree and attach top-level devices.
  246          */
  247         for (node = OF_child(node); node > 0; node = OF_peer(node))
  248                 simplebus_add_device(dev, node, 0, NULL, -1, NULL);
  249 
  250         error = bus_generic_attach(dev);
  251 
  252         return (error);
  253 }
  254 
  255 static int
  256 scmi_detach(device_t dev)
  257 {
  258 
  259         return (0);
  260 }
  261 
  262 static device_method_t scmi_methods[] = {
  263         DEVMETHOD(device_probe,         scmi_probe),
  264         DEVMETHOD(device_attach,        scmi_attach),
  265         DEVMETHOD(device_detach,        scmi_detach),
  266         DEVMETHOD_END
  267 };
  268 
  269 DEFINE_CLASS_1(scmi, scmi_driver, scmi_methods, sizeof(struct scmi_softc),
  270     simplebus_driver);
  271 
  272 DRIVER_MODULE(scmi, simplebus, scmi_driver, 0, 0);
  273 MODULE_VERSION(scmi, 1);

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FreeBSD/Linux Kernel Cross Reference sys/dev/firmware/arm/scmi.c

FreeBSD/Linux Kernel Cross Reference
sys/dev/firmware/arm/scmi.c