/*-
 * Copyright (c) 2022 Colin Percival
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/rman.h>

#include <machine/bus.h>
#include <machine/resource.h>

#include <dev/virtio/mmio/virtio_mmio.h>

/* Parse <size>@<baseaddr>:<irq>[:<id>] and add a child. */
static void
parsearg(driver_t *driver, device_t parent, char * arg)
{
        device_t child;
        char * p;
        unsigned long sz;
        unsigned long baseaddr;
        unsigned long irq;
        unsigned long id;

        /* <size> */
        sz = strtoul(arg, &p, 0);
        if ((sz == 0) || (sz == ULONG_MAX))
                goto bad;
        switch (*p) {
        case 'E': case 'e':
                sz <<= 10;
                /* FALLTHROUGH */
        case 'P': case 'p':
                sz <<= 10;
                /* FALLTHROUGH */
        case 'T': case 't':
                sz <<= 10;
                /* FALLTHROUGH */
        case 'G': case 'g':
                sz <<= 10;
                /* FALLTHROUGH */
        case 'M': case 'm':
                sz <<= 10;
                /* FALLTHROUGH */
        case 'K': case 'k':
                sz <<= 10;
                p++;
                break;
        }

        /* @<baseaddr> */
        if (*p++ != '@')
                goto bad;
        baseaddr = strtoul(p, &p, 0);
        if ((baseaddr == 0) || (baseaddr == ULONG_MAX))
                goto bad;

        /* :<irq> */
        if (*p++ != ':')
                goto bad;
        irq = strtoul(p, &p, 0);
        if ((irq == 0) || (irq == ULONG_MAX))
                goto bad;

        /* Optionally, :<id> */
        if (*p) {
                if (*p++ != ':')
                        goto bad;
                id = strtoul(p, &p, 0);
                if ((id == 0) || (id == ULONG_MAX))
                        goto bad;
        } else {
                id = 0;
        }

        /* Should have reached the end of the string. */
        if (*p)
                goto bad;

        /* Create the child and assign its resources. */
        child = BUS_ADD_CHILD(parent, 0, driver->name, id ? id : -1);
        bus_set_resource(child, SYS_RES_MEMORY, 0, baseaddr, sz);
        bus_set_resource(child, SYS_RES_IRQ, 0, irq, 1);
        device_set_driver(child, driver);

        return;

bad:
        printf("Error parsing virtio_mmio parameter: %s\n", arg);
}

static void
vtmmio_cmdline_identify(driver_t *driver, device_t parent)
{
        size_t n;
        char name[] = "virtio_mmio.device_XXXX";
        char * val;

        /* First variable just has its own name. */
        if ((val = kern_getenv("virtio_mmio.device")) == NULL)
                return;
        parsearg(driver, parent, val);
        freeenv(val);

        /* The rest have _%zu suffixes. */
        for (n = 1; n <= 9999; n++) {
                sprintf(name, "virtio_mmio.device_%zu", n);
                if ((val = kern_getenv(name)) == NULL)
                        return;
                parsearg(driver, parent, val);
                freeenv(val);
        }
}

static device_method_t vtmmio_cmdline_methods[] = {
        /* Device interface. */
        DEVMETHOD(device_identify,      vtmmio_cmdline_identify),
        DEVMETHOD(device_probe,         vtmmio_probe),

        DEVMETHOD_END
};
DEFINE_CLASS_1(virtio_mmio, vtmmio_cmdline_driver, vtmmio_cmdline_methods,
    sizeof(struct vtmmio_softc), vtmmio_driver);
DRIVER_MODULE(vtmmio_cmdline, nexus, vtmmio_cmdline_driver, 0, 0);