/* wld: drm.c
 *
 * Copyright (c) 2013, 2014 Michael Forney
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "drm.h"
#include "drm-private.h"

#include <sys/sysmacros.h>

const static struct drm_driver * drivers[] = {
#if WITH_DRM_INTEL
    &intel_drm_driver,
#endif
#if WITH_DRM_NOUVEAU
    &nouveau_drm_driver,
#endif
    &dumb_drm_driver
};

static const struct drm_driver * find_driver(int fd)
{
    char path[64], id[32];
    uint32_t vendor_id, device_id;
    char * path_part;
    struct stat st;
    FILE * file;
    uint32_t index;
    int n;

    if (fstat(fd, &st) == -1)
        return NULL;

    if (getenv("WLD_DRM_DUMB"))
        goto dumb;

    n = snprintf(path, sizeof(path), "/sys/dev/char/%u:%u/device/", major(st.st_rdev), minor(st.st_rdev));
    if (n + 6 >= sizeof(path))
        return NULL;
    path_part = path + n;

    strcpy(path_part, "vendor");
    file = fopen(path, "r");
    if (!file)
        goto dumb;
    fgets(id, sizeof id, file);
    fclose(file);
    vendor_id = strtoul(id, NULL, 0);

    strcpy(path_part, "device");
    file = fopen(path, "r");
    if (!file)
        goto dumb;
    fgets(id, sizeof id, file);
    fclose(file);
    device_id = strtoul(id, NULL, 0);

    for (index = 0; index < ARRAY_LENGTH(drivers); ++index)
    {
        DEBUG("Trying DRM driver `%s'\n", drivers[index]->name);
        if (drivers[index]->device_supported(vendor_id, device_id))
            return drivers[index];
    }

    DEBUG("No DRM driver supports device 0x%x:0x%x\n", vendor_id, device_id);

    return NULL;

dumb:
    return &dumb_drm_driver;
}

EXPORT
struct wld_context * wld_drm_create_context(int fd)
{
    const struct drm_driver * driver;

    if (!(driver = find_driver(fd)))
        return NULL;

    return driver->create_context(fd);
}

EXPORT
bool wld_drm_is_dumb(struct wld_context * context)
{
    return context->impl == dumb_context_impl;
}