imx-drm-core.c

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/*
 * Freescale i.MX drm driver
 *
 * Copyright (C) 2011 Sascha Hauer, Pengutronix
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

#include <linux/device.h>
#include <linux/platform_device.h>
#include <drm/drmP.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_crtc_helper.h>
#include <linux/fb.h>
#include <linux/module.h>
#include <drm/drm_gem_cma_helper.h>
#include <drm/drm_fb_cma_helper.h>

#include "imx-drm.h"

#define MAX_CRTC    4

struct crtc_cookie {
    void *cookie;
    int id;
    struct list_head list;
};

struct imx_drm_device {
    struct drm_device           *drm;
    struct device               *dev;
    struct list_head            crtc_list;
    struct list_head            encoder_list;
    struct list_head            connector_list;
    struct mutex                mutex;
    int                 references;
    int                 pipes;
    struct drm_fbdev_cma            *fbhelper;
};

struct imx_drm_crtc {
    struct drm_crtc             *crtc;
    struct list_head            list;
    struct imx_drm_device           *imxdrm;
    int                 pipe;
    struct imx_drm_crtc_helper_funcs    imx_drm_helper_funcs;
    struct module               *owner;
    struct crtc_cookie          cookie;
};

struct imx_drm_encoder {
    struct drm_encoder          *encoder;
    struct list_head            list;
    struct module               *owner;
    struct list_head            possible_crtcs;
};

struct imx_drm_connector {
    struct drm_connector            *connector;
    struct list_head            list;
    struct module               *owner;
};

static int imx_drm_driver_firstopen(struct drm_device *drm)
{
    if (!imx_drm_device_get())
        return -EINVAL;

    return 0;
}

static void imx_drm_driver_lastclose(struct drm_device *drm)
{
    struct imx_drm_device *imxdrm = drm->dev_private;

    if (imxdrm->fbhelper)
        drm_fbdev_cma_restore_mode(imxdrm->fbhelper);

    imx_drm_device_put();
}

static int imx_drm_driver_unload(struct drm_device *drm)
{
    struct imx_drm_device *imxdrm = drm->dev_private;

    drm_mode_config_cleanup(imxdrm->drm);
    drm_kms_helper_poll_fini(imxdrm->drm);

    return 0;
}

/*
 * We don't care at all for crtc numbers, but the core expects the
 * crtcs to be numbered
 */
static struct imx_drm_crtc *imx_drm_crtc_by_num(struct imx_drm_device *imxdrm,
        int num)
{
    struct imx_drm_crtc *imx_drm_crtc;

    list_for_each_entry(imx_drm_crtc, &imxdrm->crtc_list, list)
        if (imx_drm_crtc->pipe == num)
            return imx_drm_crtc;
    return NULL;
}

int imx_drm_crtc_panel_format(struct drm_crtc *crtc, u32 encoder_type,
        u32 interface_pix_fmt)
{
    struct imx_drm_device *imxdrm = crtc->dev->dev_private;
    struct imx_drm_crtc *imx_crtc;
    struct imx_drm_crtc_helper_funcs *helper;

    mutex_lock(&imxdrm->mutex);

    list_for_each_entry(imx_crtc, &imxdrm->crtc_list, list)
        if (imx_crtc->crtc == crtc)
            goto found;

    mutex_unlock(&imxdrm->mutex);

    return -EINVAL;
found:
    mutex_unlock(&imxdrm->mutex);

    helper = &imx_crtc->imx_drm_helper_funcs;
    if (helper->set_interface_pix_fmt)
        return helper->set_interface_pix_fmt(crtc,
                encoder_type, interface_pix_fmt);
    return 0;
}
EXPORT_SYMBOL_GPL(imx_drm_crtc_panel_format);

int imx_drm_crtc_vblank_get(struct imx_drm_crtc *imx_drm_crtc)
{
    return drm_vblank_get(imx_drm_crtc->imxdrm->drm, imx_drm_crtc->pipe);
}
EXPORT_SYMBOL_GPL(imx_drm_crtc_vblank_get);

void imx_drm_crtc_vblank_put(struct imx_drm_crtc *imx_drm_crtc)
{
    drm_vblank_put(imx_drm_crtc->imxdrm->drm, imx_drm_crtc->pipe);
}
EXPORT_SYMBOL_GPL(imx_drm_crtc_vblank_put);

void imx_drm_handle_vblank(struct imx_drm_crtc *imx_drm_crtc)
{
    drm_handle_vblank(imx_drm_crtc->imxdrm->drm, imx_drm_crtc->pipe);
}
EXPORT_SYMBOL_GPL(imx_drm_handle_vblank);

static int imx_drm_enable_vblank(struct drm_device *drm, int crtc)
{
    struct imx_drm_device *imxdrm = drm->dev_private;
    struct imx_drm_crtc *imx_drm_crtc;
    int ret;

    imx_drm_crtc = imx_drm_crtc_by_num(imxdrm, crtc);
    if (!imx_drm_crtc)
        return -EINVAL;

    if (!imx_drm_crtc->imx_drm_helper_funcs.enable_vblank)
        return -ENOSYS;

    ret = imx_drm_crtc->imx_drm_helper_funcs.enable_vblank(
            imx_drm_crtc->crtc);

    return ret;
}

static void imx_drm_disable_vblank(struct drm_device *drm, int crtc)
{
    struct imx_drm_device *imxdrm = drm->dev_private;
    struct imx_drm_crtc *imx_drm_crtc;

    imx_drm_crtc = imx_drm_crtc_by_num(imxdrm, crtc);
    if (!imx_drm_crtc)
        return;

    if (!imx_drm_crtc->imx_drm_helper_funcs.disable_vblank)
        return;

    imx_drm_crtc->imx_drm_helper_funcs.disable_vblank(imx_drm_crtc->crtc);
}

static const struct file_operations imx_drm_driver_fops = {
    .owner = THIS_MODULE,
    .open = drm_open,
    .release = drm_release,
    .unlocked_ioctl = drm_ioctl,
    .mmap = drm_gem_cma_mmap,
    .poll = drm_poll,
    .fasync = drm_fasync,
    .read = drm_read,
    .llseek = noop_llseek,
};

static struct imx_drm_device *imx_drm_device;

static struct imx_drm_device *__imx_drm_device(void)
{
    return imx_drm_device;
}

struct drm_device *imx_drm_device_get(void)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    struct imx_drm_encoder *enc;
    struct imx_drm_connector *con;
    struct imx_drm_crtc *crtc;

    mutex_lock(&imxdrm->mutex);

    list_for_each_entry(enc, &imxdrm->encoder_list, list) {
        if (!try_module_get(enc->owner)) {
            dev_err(imxdrm->dev, "could not get module %s\n",
                    module_name(enc->owner));
            goto unwind_enc;
        }
    }

    list_for_each_entry(con, &imxdrm->connector_list, list) {
        if (!try_module_get(con->owner)) {
            dev_err(imxdrm->dev, "could not get module %s\n",
                    module_name(con->owner));
            goto unwind_con;
        }
    }

    list_for_each_entry(crtc, &imxdrm->crtc_list, list) {
        if (!try_module_get(crtc->owner)) {
            dev_err(imxdrm->dev, "could not get module %s\n",
                    module_name(crtc->owner));
            goto unwind_crtc;
        }
    }

    imxdrm->references++;

    mutex_unlock(&imxdrm->mutex);

    return imxdrm->drm;

unwind_crtc:
    list_for_each_entry_continue_reverse(crtc, &imxdrm->crtc_list, list)
        module_put(crtc->owner);
unwind_con:
    list_for_each_entry_continue_reverse(con, &imxdrm->connector_list, list)
        module_put(con->owner);
unwind_enc:
    list_for_each_entry_continue_reverse(enc, &imxdrm->encoder_list, list)
        module_put(enc->owner);

    mutex_unlock(&imxdrm->mutex);

    return NULL;

}
EXPORT_SYMBOL_GPL(imx_drm_device_get);

void imx_drm_device_put(void)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    struct imx_drm_encoder *enc;
    struct imx_drm_connector *con;
    struct imx_drm_crtc *crtc;

    mutex_lock(&imxdrm->mutex);

    list_for_each_entry(crtc, &imxdrm->crtc_list, list)
        module_put(crtc->owner);

    list_for_each_entry(con, &imxdrm->connector_list, list)
        module_put(con->owner);

    list_for_each_entry(enc, &imxdrm->encoder_list, list)
        module_put(enc->owner);

    imxdrm->references--;

    mutex_unlock(&imxdrm->mutex);
}
EXPORT_SYMBOL_GPL(imx_drm_device_put);

static int drm_mode_group_reinit(struct drm_device *dev)
{
    struct drm_mode_group *group = &dev->primary->mode_group;
    uint32_t *id_list = group->id_list;
    int ret;

    ret = drm_mode_group_init_legacy_group(dev, group);
    if (ret < 0)
        return ret;

    kfree(id_list);
    return 0;
}

/*
 * register an encoder to the drm core
 */
static int imx_drm_encoder_register(struct imx_drm_encoder *imx_drm_encoder)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();

    INIT_LIST_HEAD(&imx_drm_encoder->possible_crtcs);

    drm_encoder_init(imxdrm->drm, imx_drm_encoder->encoder,
            imx_drm_encoder->encoder->funcs,
            imx_drm_encoder->encoder->encoder_type);

    drm_mode_group_reinit(imxdrm->drm);

    return 0;
}

/*
 * unregister an encoder from the drm core
 */
static void imx_drm_encoder_unregister(struct imx_drm_encoder
        *imx_drm_encoder)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();

    drm_encoder_cleanup(imx_drm_encoder->encoder);

    drm_mode_group_reinit(imxdrm->drm);
}

/*
 * register a connector to the drm core
 */
static int imx_drm_connector_register(
        struct imx_drm_connector *imx_drm_connector)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();

    drm_connector_init(imxdrm->drm, imx_drm_connector->connector,
            imx_drm_connector->connector->funcs,
            imx_drm_connector->connector->connector_type);
    drm_mode_group_reinit(imxdrm->drm);

    return drm_sysfs_connector_add(imx_drm_connector->connector);
}

/*
 * unregister a connector from the drm core
 */
static void imx_drm_connector_unregister(
        struct imx_drm_connector *imx_drm_connector)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();

    drm_sysfs_connector_remove(imx_drm_connector->connector);
    drm_connector_cleanup(imx_drm_connector->connector);

    drm_mode_group_reinit(imxdrm->drm);
}

/*
 * register a crtc to the drm core
 */
static int imx_drm_crtc_register(struct imx_drm_crtc *imx_drm_crtc)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    int ret;

    drm_crtc_init(imxdrm->drm, imx_drm_crtc->crtc,
            imx_drm_crtc->imx_drm_helper_funcs.crtc_funcs);
    ret = drm_mode_crtc_set_gamma_size(imx_drm_crtc->crtc, 256);
    if (ret)
        return ret;

    drm_crtc_helper_add(imx_drm_crtc->crtc,
            imx_drm_crtc->imx_drm_helper_funcs.crtc_helper_funcs);

    drm_mode_group_reinit(imxdrm->drm);

    return 0;
}

/*
 * Called by the CRTC driver when all CRTCs are registered. This
 * puts all the pieces together and initializes the driver.
 * Once this is called no more CRTCs can be registered since
 * the drm core has hardcoded the number of crtcs in several
 * places.
 */
static int imx_drm_driver_load(struct drm_device *drm, unsigned long flags)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    int ret;

    imxdrm->drm = drm;

    drm->dev_private = imxdrm;

    /*
     * enable drm irq mode.
     * - with irq_enabled = 1, we can use the vblank feature.
     *
     * P.S. note that we wouldn't use drm irq handler but
     *      just specific driver own one instead because
     *      drm framework supports only one irq handler and
     *      drivers can well take care of their interrupts
     */
    drm->irq_enabled = 1;

    drm_mode_config_init(drm);
    imx_drm_mode_config_init(drm);

    mutex_lock(&imxdrm->mutex);

    drm_kms_helper_poll_init(imxdrm->drm);

    /* setup the grouping for the legacy output */
    ret = drm_mode_group_init_legacy_group(imxdrm->drm,
            &imxdrm->drm->primary->mode_group);
    if (ret)
        goto err_init;

    ret = drm_vblank_init(imxdrm->drm, MAX_CRTC);
    if (ret)
        goto err_init;

    /*
     * with vblank_disable_allowed = 1, vblank interrupt will be disabled
     * by drm timer once a current process gives up ownership of
     * vblank event.(after drm_vblank_put function is called)
     */
    imxdrm->drm->vblank_disable_allowed = 1;

    ret = 0;

err_init:
    mutex_unlock(&imxdrm->mutex);

    return ret;
}

static void imx_drm_update_possible_crtcs(void)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    struct imx_drm_crtc *imx_drm_crtc;
    struct imx_drm_encoder *enc;
    struct crtc_cookie *cookie;

    list_for_each_entry(enc, &imxdrm->encoder_list, list) {
        u32 possible_crtcs = 0;

        list_for_each_entry(cookie, &enc->possible_crtcs, list) {
            list_for_each_entry(imx_drm_crtc, &imxdrm->crtc_list, list) {
                if (imx_drm_crtc->cookie.cookie == cookie->cookie &&
                        imx_drm_crtc->cookie.id == cookie->id) {
                    possible_crtcs |= 1 << imx_drm_crtc->pipe;
                }
            }
        }
        enc->encoder->possible_crtcs = possible_crtcs;
        enc->encoder->possible_clones = possible_crtcs;
    }
}

/*
 * imx_drm_add_crtc - add a new crtc
 *
 * The return value if !NULL is a cookie for the caller to pass to
 * imx_drm_remove_crtc later.
 */
int imx_drm_add_crtc(struct drm_crtc *crtc,
        struct imx_drm_crtc **new_crtc,
        const struct imx_drm_crtc_helper_funcs *imx_drm_helper_funcs,
        struct module *owner, void *cookie, int id)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    struct imx_drm_crtc *imx_drm_crtc;
    const struct drm_crtc_funcs *crtc_funcs;
    int ret;

    mutex_lock(&imxdrm->mutex);

    if (imxdrm->references) {
        ret = -EBUSY;
        goto err_busy;
    }

    imx_drm_crtc = kzalloc(sizeof(*imx_drm_crtc), GFP_KERNEL);
    if (!imx_drm_crtc) {
        ret = -ENOMEM;
        goto err_alloc;
    }

    imx_drm_crtc->imx_drm_helper_funcs = *imx_drm_helper_funcs;
    imx_drm_crtc->pipe = imxdrm->pipes++;
    imx_drm_crtc->cookie.cookie = cookie;
    imx_drm_crtc->cookie.id = id;

    crtc_funcs = imx_drm_helper_funcs->crtc_funcs;

    imx_drm_crtc->crtc = crtc;
    imx_drm_crtc->imxdrm = imxdrm;

    imx_drm_crtc->owner = owner;

    list_add_tail(&imx_drm_crtc->list, &imxdrm->crtc_list);

    *new_crtc = imx_drm_crtc;

    ret = imx_drm_crtc_register(imx_drm_crtc);
    if (ret)
        goto err_register;

    imx_drm_update_possible_crtcs();

    mutex_unlock(&imxdrm->mutex);

    return 0;

err_register:
    kfree(imx_drm_crtc);
err_alloc:
err_busy:
    mutex_unlock(&imxdrm->mutex);
    return ret;
}
EXPORT_SYMBOL_GPL(imx_drm_add_crtc);

/*
 * imx_drm_remove_crtc - remove a crtc
 */
int imx_drm_remove_crtc(struct imx_drm_crtc *imx_drm_crtc)
{
    struct imx_drm_device *imxdrm = imx_drm_crtc->imxdrm;

    mutex_lock(&imxdrm->mutex);

    drm_crtc_cleanup(imx_drm_crtc->crtc);

    list_del(&imx_drm_crtc->list);

    drm_mode_group_reinit(imxdrm->drm);

    mutex_unlock(&imxdrm->mutex);

    kfree(imx_drm_crtc);

    return 0;
}
EXPORT_SYMBOL_GPL(imx_drm_remove_crtc);

/*
 * imx_drm_add_encoder - add a new encoder
 */
int imx_drm_add_encoder(struct drm_encoder *encoder,
        struct imx_drm_encoder **newenc, struct module *owner)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    struct imx_drm_encoder *imx_drm_encoder;
    int ret;

    mutex_lock(&imxdrm->mutex);

    if (imxdrm->references) {
        ret = -EBUSY;
        goto err_busy;
    }

    imx_drm_encoder = kzalloc(sizeof(*imx_drm_encoder), GFP_KERNEL);
    if (!imx_drm_encoder) {
        ret = -ENOMEM;
        goto err_alloc;
    }

    imx_drm_encoder->encoder = encoder;
    imx_drm_encoder->owner = owner;

    ret = imx_drm_encoder_register(imx_drm_encoder);
    if (ret) {
        kfree(imx_drm_encoder);
        ret = -ENOMEM;
        goto err_register;
    }

    list_add_tail(&imx_drm_encoder->list, &imxdrm->encoder_list);

    *newenc = imx_drm_encoder;

    mutex_unlock(&imxdrm->mutex);

    return 0;

err_register:
    kfree(imx_drm_encoder);
err_alloc:
err_busy:
    mutex_unlock(&imxdrm->mutex);

    return ret;
}
EXPORT_SYMBOL_GPL(imx_drm_add_encoder);

int imx_drm_encoder_add_possible_crtcs(
        struct imx_drm_encoder *imx_drm_encoder,
        struct device_node *np)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    struct of_phandle_args args;
    struct crtc_cookie *c;
    int ret = 0;
    int i;

    if (!list_empty(&imx_drm_encoder->possible_crtcs))
        return -EBUSY;

    for (i = 0; !ret; i++) {
        ret = of_parse_phandle_with_args(np, "crtcs",
                "#crtc-cells", i, &args);
        if (ret < 0)
            break;

        c = kzalloc(sizeof(*c), GFP_KERNEL);
        if (!c) {
            of_node_put(args.np);
            return -ENOMEM;
        }

        c->cookie = args.np;
        c->id = args.args_count > 0 ? args.args[0] : 0;

        of_node_put(args.np);

        mutex_lock(&imxdrm->mutex);

        list_add_tail(&c->list, &imx_drm_encoder->possible_crtcs);

        mutex_unlock(&imxdrm->mutex);
    }

    imx_drm_update_possible_crtcs();

    return 0;
}
EXPORT_SYMBOL_GPL(imx_drm_encoder_add_possible_crtcs);

int imx_drm_encoder_get_mux_id(struct imx_drm_encoder *imx_drm_encoder,
        struct drm_crtc *crtc)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    struct imx_drm_crtc *imx_crtc;
    int i = 0;

    mutex_lock(&imxdrm->mutex);

    list_for_each_entry(imx_crtc, &imxdrm->crtc_list, list) {
        if (imx_crtc->crtc == crtc)
            goto found;
        i++;
    }

    mutex_unlock(&imxdrm->mutex);

    return -EINVAL;
found:
    mutex_unlock(&imxdrm->mutex);

    return i;
}

/*
 * imx_drm_remove_encoder - remove an encoder
 */
int imx_drm_remove_encoder(struct imx_drm_encoder *imx_drm_encoder)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    struct crtc_cookie *c, *tmp;

    mutex_lock(&imxdrm->mutex);

    imx_drm_encoder_unregister(imx_drm_encoder);

    list_del(&imx_drm_encoder->list);

    list_for_each_entry_safe(c, tmp, &imx_drm_encoder->possible_crtcs,
            list)
        kfree(c);

    mutex_unlock(&imxdrm->mutex);

    kfree(imx_drm_encoder);

    return 0;
}
EXPORT_SYMBOL_GPL(imx_drm_remove_encoder);

/*
 * imx_drm_add_connector - add a connector
 */
int imx_drm_add_connector(struct drm_connector *connector,
        struct imx_drm_connector **new_con,
        struct module *owner)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();
    struct imx_drm_connector *imx_drm_connector;
    int ret;

    mutex_lock(&imxdrm->mutex);

    if (imxdrm->references) {
        ret = -EBUSY;
        goto err_busy;
    }

    imx_drm_connector = kzalloc(sizeof(*imx_drm_connector), GFP_KERNEL);
    if (!imx_drm_connector) {
        ret = -ENOMEM;
        goto err_alloc;
    }

    imx_drm_connector->connector = connector;
    imx_drm_connector->owner = owner;

    ret = imx_drm_connector_register(imx_drm_connector);
    if (ret)
        goto err_register;

    list_add_tail(&imx_drm_connector->list, &imxdrm->connector_list);

    *new_con = imx_drm_connector;

    mutex_unlock(&imxdrm->mutex);

    return 0;

err_register:
    kfree(imx_drm_connector);
err_alloc:
err_busy:
    mutex_unlock(&imxdrm->mutex);

    return ret;
}
EXPORT_SYMBOL_GPL(imx_drm_add_connector);

void imx_drm_fb_helper_set(struct drm_fbdev_cma *fbdev_helper)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();

    imxdrm->fbhelper = fbdev_helper;
}
EXPORT_SYMBOL_GPL(imx_drm_fb_helper_set);

/*
 * imx_drm_remove_connector - remove a connector
 */
int imx_drm_remove_connector(struct imx_drm_connector *imx_drm_connector)
{
    struct imx_drm_device *imxdrm = __imx_drm_device();

    mutex_lock(&imxdrm->mutex);

    imx_drm_connector_unregister(imx_drm_connector);

    list_del(&imx_drm_connector->list);

    mutex_unlock(&imxdrm->mutex);

    kfree(imx_drm_connector);

    return 0;
}
EXPORT_SYMBOL_GPL(imx_drm_remove_connector);

static struct drm_ioctl_desc imx_drm_ioctls[] = {
    /* none so far */
};

static struct drm_driver imx_drm_driver = {
    .driver_features    = DRIVER_MODESET | DRIVER_GEM,
    .load           = imx_drm_driver_load,
    .unload         = imx_drm_driver_unload,
    .firstopen      = imx_drm_driver_firstopen,
    .lastclose      = imx_drm_driver_lastclose,
    .gem_free_object    = drm_gem_cma_free_object,
    .gem_vm_ops     = &drm_gem_cma_vm_ops,
    .dumb_create        = drm_gem_cma_dumb_create,
    .dumb_map_offset    = drm_gem_cma_dumb_map_offset,
    .dumb_destroy       = drm_gem_cma_dumb_destroy,

    .get_vblank_counter = drm_vblank_count,
    .enable_vblank      = imx_drm_enable_vblank,
    .disable_vblank     = imx_drm_disable_vblank,
    .ioctls         = imx_drm_ioctls,
    .num_ioctls     = ARRAY_SIZE(imx_drm_ioctls),
    .fops           = &imx_drm_driver_fops,
    .name           = "imx-drm",
    .desc           = "i.MX DRM graphics",
    .date           = "20120507",
    .major          = 1,
    .minor          = 0,
    .patchlevel     = 0,
};

static int imx_drm_platform_probe(struct platform_device *pdev)
{
    imx_drm_device->dev = &pdev->dev;

    return drm_platform_init(&imx_drm_driver, pdev);
}

static int imx_drm_platform_remove(struct platform_device *pdev)
{
    drm_platform_exit(&imx_drm_driver, pdev);

    return 0;
}

static struct platform_driver imx_drm_pdrv = {
    .probe      = imx_drm_platform_probe,
    .remove     = __devexit_p(imx_drm_platform_remove),
    .driver     = {
        .owner  = THIS_MODULE,
        .name   = "imx-drm",
    },
};

static struct platform_device *imx_drm_pdev;

static int __init imx_drm_init(void)
{
    int ret;

    imx_drm_device = kzalloc(sizeof(*imx_drm_device), GFP_KERNEL);
    if (!imx_drm_device)
        return -ENOMEM;

    mutex_init(&imx_drm_device->mutex);
    INIT_LIST_HEAD(&imx_drm_device->crtc_list);
    INIT_LIST_HEAD(&imx_drm_device->connector_list);
    INIT_LIST_HEAD(&imx_drm_device->encoder_list);

    imx_drm_pdev = platform_device_register_simple("imx-drm", -1, NULL, 0);
    if (!imx_drm_pdev) {
        ret = -EINVAL;
        goto err_pdev;
    }

    imx_drm_pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32),

    ret = platform_driver_register(&imx_drm_pdrv);
    if (ret)
        goto err_pdrv;

    return 0;

err_pdrv:
    platform_device_unregister(imx_drm_pdev);
err_pdev:
    kfree(imx_drm_device);

    return ret;
}

static void __exit imx_drm_exit(void)
{
    platform_device_unregister(imx_drm_pdev);
    platform_driver_unregister(&imx_drm_pdrv);

    kfree(imx_drm_device);
}

module_init(imx_drm_init);
module_exit(imx_drm_exit);

MODULE_AUTHOR("Sascha Hauer <[email protected]>");
MODULE_DESCRIPTION("i.MX drm driver core");
MODULE_LICENSE("GPL");