/* $NetBSD: ti_lcdc.c,v 1.15 2025/10/13 14:12:13 thorpej Exp $ */

/*-
 * Copyright (c) 2019 Jared D. McNeill <jmcneill@invisible.ca>
 * All rights reserved.
 *
 * 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 ``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 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ti_lcdc.c,v 1.15 2025/10/13 14:12:13 thorpej Exp $");

#include <sys/param.h>
#include <sys/bus.h>
#include <sys/device.h>
#include <sys/intr.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/conf.h>

#include <uvm/uvm_extern.h>
#include <uvm/uvm_object.h>
#include <uvm/uvm_device.h>

#include <drm/drm_crtc.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_drv.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_file.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_plane_helper.h>

#include <dev/fdt/fdtvar.h>
#include <dev/fdt/fdt_port.h>

#include <arm/ti/ti_prcm.h>
#include <arm/ti/ti_lcdc.h>
#include <arm/ti/ti_lcdcreg.h>

static const struct device_compatible_entry compat_data[] = {
        { .compat = "ti,am33xx-tilcdc" },
        DEVICE_COMPAT_EOL
};

enum {
        TILCDC_PORT_OUTPUT = 0,
};

static int      tilcdc_match(device_t, cfdata_t, void *);
static void     tilcdc_attach(device_t, device_t, void *);

static int      tilcdc_load(struct drm_device *, unsigned long);
static void     tilcdc_unload(struct drm_device *);

static void     tilcdc_drm_task_work(struct work *, void *);

static struct drm_driver tilcdc_driver = {
        .driver_features = DRIVER_MODESET | DRIVER_GEM,
        .dev_priv_size = 0,
        .load = tilcdc_load,
        .unload = tilcdc_unload,

        .gem_free_object = drm_gem_cma_free_object,
        .mmap_object = drm_gem_or_legacy_mmap_object,
        .gem_uvm_ops = &drm_gem_cma_uvm_ops,

        .dumb_create = drm_gem_cma_dumb_create,

        .name = DRIVER_NAME,
        .desc = DRIVER_DESC,
        .date = DRIVER_DATE,
        .major = DRIVER_MAJOR,
        .minor = DRIVER_MINOR,
        .patchlevel = DRIVER_PATCHLEVEL,
};

CFATTACH_DECL_NEW(ti_lcdc, sizeof(struct tilcdc_softc),
        tilcdc_match, tilcdc_attach, NULL, NULL);

static int
tilcdc_mode_do_set_base(struct drm_crtc *crtc, struct drm_framebuffer *fb,
    int x, int y, int atomic)
{
        struct tilcdc_crtc *mixer_crtc = to_tilcdc_crtc(crtc);
        struct tilcdc_softc * const sc = mixer_crtc->sc;
        struct tilcdc_framebuffer *sfb = atomic?
            to_tilcdc_framebuffer(fb) :
            to_tilcdc_framebuffer(crtc->primary->fb);

        const uint32_t paddr = (uint32_t)sfb->obj->dmamap->dm_segs[0].ds_addr;
        const u_int psize = sfb->obj->dmamap->dm_segs[0].ds_len;

        /* Framebuffer start address */
        WR4(sc, LCD_LCDDMA_FB0_BASE, paddr);
        WR4(sc, LCD_LCDDMA_FB0_CEILING, paddr + psize - 1);

        return 0;
}

static void
tilcdc_destroy(struct drm_crtc *crtc)
{
        drm_crtc_cleanup(crtc);
}

static const struct drm_crtc_funcs tilcdc_crtc_funcs = {
        .set_config = drm_crtc_helper_set_config,
        .destroy = tilcdc_destroy,
};

static void
tilcdc_dpms(struct drm_crtc *crtc, int mode)
{
}

static bool
tilcdc_mode_fixup(struct drm_crtc *crtc,
    const struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode)
{
#if 0
        adjusted_mode->hskew = mode->hsync_end - mode->hsync_start;
        adjusted_mode->flags |= DRM_MODE_FLAG_HSKEW;

        adjusted_mode->flags &= ~(DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PHSYNC);
        if (mode->flags & DRM_MODE_FLAG_NHSYNC)
                adjusted_mode->flags |= DRM_MODE_FLAG_PHSYNC;
        else
                adjusted_mode->flags |= DRM_MODE_FLAG_NHSYNC;
#endif

        return true;
}

static int
tilcdc_mode_set(struct drm_crtc *crtc, struct drm_display_mode *mode,
    struct drm_display_mode *adjusted_mode, int x, int y,
    struct drm_framebuffer *old_fb)
{
        struct tilcdc_crtc *mixer_crtc = to_tilcdc_crtc(crtc);
        struct tilcdc_softc * const sc = mixer_crtc->sc;
        int clk_div, div, diff, best_diff;
        uint32_t val;

        const u_int hspw = adjusted_mode->crtc_hsync_end - adjusted_mode->crtc_hsync_start;
        const u_int hbp = adjusted_mode->crtc_htotal - adjusted_mode->crtc_hsync_end;
        const u_int hfp = adjusted_mode->crtc_hsync_start - adjusted_mode->crtc_hdisplay;
        const u_int vspw = adjusted_mode->crtc_vsync_end - adjusted_mode->crtc_vsync_start;
        const u_int vbp = adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vsync_end;
        const u_int vfp = adjusted_mode->crtc_vsync_start - adjusted_mode->crtc_vdisplay;

        const u_int rate = clk_get_rate(sc->sc_clk);

        clk_div = 255;
        best_diff = -1;
        for (div = 2; div < 255; div++) {
                const int pixel_clock = (rate / div) / 1000;
                diff = abs(adjusted_mode->crtc_clock - pixel_clock);
                if (best_diff == -1 || diff < best_diff) {
                        best_diff = diff;
                        clk_div = div;
                }
        }
        if (clk_div == 255) {
                device_printf(sc->sc_dev, "couldn't configure pixel clock (%u)\n",
                    adjusted_mode->crtc_clock);
                return ERANGE;
        }

        val = CTRL_RASTER_MODE |
              (clk_div << CTRL_DIV_SHIFT);
        WR4(sc, LCD_CTRL, val);

        val = RASTER_TIMING_0_HFP(hfp) |
              RASTER_TIMING_0_HBP(hbp) |
              RASTER_TIMING_0_HSW(hspw) |
              RASTER_TIMING_0_PPL(adjusted_mode->hdisplay);
        WR4(sc, LCD_RASTER_TIMING_0, val);

        val = RASTER_TIMING_1_VFP(vfp) |
              RASTER_TIMING_1_VBP(vbp) |
              RASTER_TIMING_1_VSW(vspw) |
              RASTER_TIMING_1_LPP(adjusted_mode->vdisplay);
        WR4(sc, LCD_RASTER_TIMING_1, val);

        val = RASTER_TIMING_2_HFP(hfp) |
              RASTER_TIMING_2_HBP(hbp) |
              RASTER_TIMING_2_HSW(hspw) |
              RASTER_TIMING_2_LPP(adjusted_mode->vdisplay);
        /* XXX TDA HDMI TX */
        val |= RASTER_TIMING_2_IPC;
        val |= RASTER_TIMING_2_PHSVS;
        val |= RASTER_TIMING_2_PHSVS_RISE;
        val |= RASTER_TIMING_2_ACB(255);
        val |= RASTER_TIMING_2_ACBI(0);
        WR4(sc, LCD_RASTER_TIMING_2, val);

        val = (4 << LCDDMA_CTRL_BURST_SIZE_SHIFT) |
              (0 << LCDDMA_CTRL_TH_FIFO_RDY_SHIFT) |
              LCDDMA_CTRL_FB0_ONLY;
        WR4(sc, LCD_LCDDMA_CTRL, val);

        /* XXX TDA HDMI TX */
        val = RASTER_CTRL_LCDTFT |
              RASTER_CTRL_TFT24 |
              RASTER_CTRL_TFT24_UNPACKED |
              RASTER_CTRL_REQDLY(0x80) |
              RASTER_CTRL_PALMODE_DATA_ONLY;
        WR4(sc, LCD_RASTER_CTRL, val);

        tilcdc_mode_do_set_base(crtc, old_fb, x, y, 0);

        return 0;
}

static int
tilcdc_mode_set_base(struct drm_crtc *crtc, int x, int y,
    struct drm_framebuffer *old_fb)
{
        tilcdc_mode_do_set_base(crtc, old_fb, x, y, 0);

        return 0;
}

static int
tilcdc_mode_set_base_atomic(struct drm_crtc *crtc, struct drm_framebuffer *fb,
    int x, int y, enum mode_set_atomic state)
{
        tilcdc_mode_do_set_base(crtc, fb, x, y, 1);

        return 0;
}

static void
tilcdc_disable(struct drm_crtc *crtc)
{
}

static void
tilcdc_prepare(struct drm_crtc *crtc)
{
}

static void
tilcdc_commit(struct drm_crtc *crtc)
{
        struct tilcdc_crtc *mixer_crtc = to_tilcdc_crtc(crtc);
        struct tilcdc_softc * const sc = mixer_crtc->sc;
        uint32_t val;

        WR4(sc, LCD_CLKC_ENABLE, CLKC_ENABLE_DMA | CLKC_ENABLE_CORE);
        WR4(sc, LCD_CLKC_RESET, CLKC_RESET_MAIN);
        delay(100);
        WR4(sc, LCD_CLKC_RESET, 0);

        val = RD4(sc, LCD_RASTER_CTRL);
        WR4(sc, LCD_RASTER_CTRL, val | RASTER_CTRL_LCDEN);
}

static const struct drm_crtc_helper_funcs tilcdc_crtc_helper_funcs = {
        .dpms = tilcdc_dpms,
        .mode_fixup = tilcdc_mode_fixup,
        .mode_set = tilcdc_mode_set,
        .mode_set_base = tilcdc_mode_set_base,
        .mode_set_base_atomic = tilcdc_mode_set_base_atomic,
        .disable = tilcdc_disable,
        .prepare = tilcdc_prepare,
        .commit = tilcdc_commit,
};

static void
tilcdc_encoder_destroy(struct drm_encoder *encoder)
{
}

static const struct drm_encoder_funcs tilcdc_encoder_funcs = {
        .destroy = tilcdc_encoder_destroy,
};

static void
tilcdc_encoder_dpms(struct drm_encoder *encoder, int mode)
{
}

static bool
tilcdc_encoder_mode_fixup(struct drm_encoder *encoder,
    const struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode)
{
        return true;
}

static void
tilcdc_encoder_mode_set(struct drm_encoder *encoder,
    struct drm_display_mode *mode, struct drm_display_mode *adjusted_mode)
{
}

static void
tilcdc_encoder_prepare(struct drm_encoder *encoder)
{
}

static void
tilcdc_encoder_commit(struct drm_encoder *encoder)
{
}

static const struct drm_encoder_helper_funcs tilcdc_encoder_helper_funcs = {
        .dpms = tilcdc_encoder_dpms,
        .mode_fixup = tilcdc_encoder_mode_fixup,
        .prepare = tilcdc_encoder_prepare,
        .commit = tilcdc_encoder_commit,
        .mode_set = tilcdc_encoder_mode_set,
};

static int
tilcdc_ep_activate(device_t dev, struct fdt_endpoint *ep, bool activate)
{
        struct tilcdc_softc * const sc = device_private(dev);
        struct drm_device *ddev = sc->sc_ddev;

        if (!activate)
                return EINVAL;

        sc->sc_crtc.sc = sc;

        WR4(sc, LCD_SYSCONFIG, SYSCONFIG_STANDBY_SMART | SYSCONFIG_IDLE_SMART);

        drm_crtc_init(ddev, &sc->sc_crtc.base, &tilcdc_crtc_funcs);
        drm_crtc_helper_add(&sc->sc_crtc.base, &tilcdc_crtc_helper_funcs);

        sc->sc_encoder.sc = sc;
        sc->sc_encoder.base.possible_crtcs = 1 << drm_crtc_index(&sc->sc_crtc.base);

        drm_encoder_init(ddev, &sc->sc_encoder.base, &tilcdc_encoder_funcs,
            DRM_MODE_ENCODER_TMDS, NULL);
        drm_encoder_helper_add(&sc->sc_encoder.base,
            &tilcdc_encoder_helper_funcs);

        return fdt_endpoint_activate(ep, activate);
}

static void *
tilcdc_ep_get_data(device_t dev, struct fdt_endpoint *ep)
{
        struct tilcdc_softc * const sc = device_private(dev);

        return &sc->sc_encoder.base;
}

static int
tilcdc_match(device_t parent, cfdata_t cf, void *aux)
{
        struct fdt_attach_args * const faa = aux;

        return of_compatible_match(faa->faa_phandle, compat_data);
}

static void
tilcdc_attach(device_t parent, device_t self, void *aux)
{
        struct tilcdc_softc * const sc = device_private(self);
        struct fdt_attach_args * const faa = aux;
        const int phandle = faa->faa_phandle;
        struct drm_driver * const driver = &tilcdc_driver;
        bus_addr_t addr;
        bus_size_t size;
        int error;

        if (device_getprop_bool(self, "disabled")) {
                aprint_normal(": TI LCDC (disabled)\n");
                return;
        }

#ifdef WSDISPLAY_MULTICONS
        device_setprop_bool(self, "is_console", true);
#endif

        if (fdtbus_get_reg(phandle, 0, &addr, &size) != 0) {
                aprint_error(": couldn't get registers\n");
                return;
        }

        sc->sc_dev = self;
        sc->sc_phandle = faa->faa_phandle;
        sc->sc_dmat = faa->faa_dmat;
        sc->sc_bst = faa->faa_bst;
        if (bus_space_map(sc->sc_bst, addr, size, 0, &sc->sc_bsh) != 0) {
                aprint_error(": couldn't map registers\n");
                return;
        }
        sc->sc_clk = ti_prcm_get_hwmod(phandle, 0);
        if (sc->sc_clk == NULL || clk_enable(sc->sc_clk) != 0) {
                aprint_error(": couldn't enable module\n");
                return;
        }

        aprint_naive("\n");
        aprint_normal(": TI LCDC\n");

        sc->sc_ports.dp_ep_activate = tilcdc_ep_activate;
        sc->sc_ports.dp_ep_get_data = tilcdc_ep_get_data;
        fdt_ports_register(&sc->sc_ports, self, phandle, EP_DRM_ENCODER);

        sc->sc_task_thread = NULL;
        SIMPLEQ_INIT(&sc->sc_tasks);
        if (workqueue_create(&sc->sc_task_wq, "tilcdcdrm",
            &tilcdc_drm_task_work, NULL, PRI_NONE, IPL_NONE, WQ_MPSAFE)) {
                aprint_error_dev(self, "unable to create workqueue\n");
                sc->sc_task_wq = NULL;
                return;
        }

        sc->sc_ddev = drm_dev_alloc(driver, sc->sc_dev);
        if (IS_ERR(sc->sc_ddev)) {
                aprint_error_dev(self, "couldn't allocate DRM device\n");
                return;
        }
        sc->sc_ddev->dev_private = sc;
        sc->sc_ddev->bst = sc->sc_bst;
        sc->sc_ddev->bus_dmat = sc->sc_dmat;
        sc->sc_ddev->dmat = sc->sc_ddev->bus_dmat;
        sc->sc_ddev->dmat_subregion_p = false;

        /*
         * Cause any tasks issued synchronously during attach to be
         * processed at the end of this function.
         */
        sc->sc_task_thread = curlwp;

        error = -drm_dev_register(sc->sc_ddev, 0);
        if (error) {
                drm_dev_put(sc->sc_ddev);
                sc->sc_ddev = NULL;
                aprint_error_dev(self, "couldn't register DRM device: %d\n",
                    error);
                goto out;
        }
        sc->sc_dev_registered = true;

        aprint_normal_dev(self, "initialized %s %d.%d.%d %s on minor %d\n",
            driver->name, driver->major, driver->minor, driver->patchlevel,
            driver->date, sc->sc_ddev->primary->index);

        /*
         * Process asynchronous tasks queued synchronously during
         * attach.  This will be for display detection to attach a
         * framebuffer, so we have the opportunity for a console device
         * to attach before autoconf has completed, in time for init(8)
         * to find that console without panicking.
         */
        while (!SIMPLEQ_EMPTY(&sc->sc_tasks)) {
                struct tilcdc_drm_task *const task =
                    SIMPLEQ_FIRST(&sc->sc_tasks);

                SIMPLEQ_REMOVE_HEAD(&sc->sc_tasks, tdt_u.queue);
                (*task->tdt_fn)(task);
        }

out:    /* Cause any subsequent tasks to be processed by the workqueue.  */
        atomic_store_relaxed(&sc->sc_task_thread, NULL);
}

static int
tilcdc_fb_create_handle(struct drm_framebuffer *fb,
    struct drm_file *file, unsigned int *handle)
{
        struct tilcdc_framebuffer *sfb = to_tilcdc_framebuffer(fb);

        return drm_gem_handle_create(file, &sfb->obj->base, handle);
}

static void
tilcdc_fb_destroy(struct drm_framebuffer *fb)
{
        struct tilcdc_framebuffer *sfb = to_tilcdc_framebuffer(fb);

        drm_framebuffer_cleanup(fb);
        drm_gem_object_put_unlocked(&sfb->obj->base);
        kmem_free(sfb, sizeof(*sfb));
}

static const struct drm_framebuffer_funcs tilcdc_framebuffer_funcs = {
        .create_handle = tilcdc_fb_create_handle,
        .destroy = tilcdc_fb_destroy,
};

static struct drm_framebuffer *
tilcdc_fb_create(struct drm_device *ddev, struct drm_file *file,
    const struct drm_mode_fb_cmd2 *cmd)
{
        struct tilcdc_framebuffer *fb;
        struct drm_gem_object *gem_obj;
        int error;

        if (cmd->flags)
                return NULL;

        gem_obj = drm_gem_object_lookup(file, cmd->handles[0]);
        if (gem_obj == NULL)
                return NULL;

        fb = kmem_zalloc(sizeof(*fb), KM_SLEEP);
        drm_helper_mode_fill_fb_struct(ddev, &fb->base, cmd);
        fb->obj = to_drm_gem_cma_obj(gem_obj);

        error = drm_framebuffer_init(ddev, &fb->base,
            &tilcdc_framebuffer_funcs);
        if (error != 0)
                goto dealloc;

        return &fb->base;

dealloc:
        drm_framebuffer_cleanup(&fb->base);
        kmem_free(fb, sizeof(*fb));
        drm_gem_object_put_unlocked(gem_obj);

        return NULL;
}

static struct drm_mode_config_funcs tilcdc_mode_config_funcs = {
        .fb_create = tilcdc_fb_create,
};

static int
tilcdc_fb_probe(struct drm_fb_helper *helper, struct drm_fb_helper_surface_size *sizes)
{
        struct tilcdc_softc * const sc = tilcdc_private(helper->dev);
        struct drm_device *ddev = helper->dev;
        struct tilcdc_framebuffer *sfb = to_tilcdc_framebuffer(helper->fb);
        struct drm_framebuffer *fb = helper->fb;
        struct tilcdcfb_attach_args tfa;
        const char *br_wiring;
        uint32_t pixel_format;
        int error;

        const u_int width = sizes->surface_width;
        const u_int height = sizes->surface_height;
        const u_int pitch = width * (32 / 8);

        br_wiring = fdtbus_get_string(sc->sc_phandle, "blue-and-red-wiring");
        if (br_wiring && strcmp(br_wiring, "straight") == 0) {
                pixel_format = DRM_FORMAT_XBGR8888;
        } else {
                pixel_format = DRM_FORMAT_XRGB8888;
        }

        const size_t size = roundup(height * pitch, PAGE_SIZE);

        sfb->obj = drm_gem_cma_create(ddev, size);
        if (sfb->obj == NULL) {
                DRM_ERROR("failed to allocate memory for framebuffer\n");
                return -ENOMEM;
        }

        fb->pitches[0] = pitch;
        fb->offsets[0] = 0;
        fb->width = width;
        fb->height = height;
        fb->modifier = 0;
        fb->flags = 0;
        fb->format = drm_format_info(pixel_format);
        fb->dev = ddev;

        error = drm_framebuffer_init(ddev, fb, &tilcdc_framebuffer_funcs);
        if (error != 0) {
                DRM_ERROR("failed to initialize framebuffer\n");
                return error;
        }

        memset(&tfa, 0, sizeof(tfa));
        tfa.tfa_drm_dev = ddev;
        tfa.tfa_fb_helper = helper;
        tfa.tfa_fb_sizes = *sizes;
        tfa.tfa_fb_bst = sc->sc_bst;
        tfa.tfa_fb_dmat = sc->sc_dmat;
        tfa.tfa_fb_linebytes = helper->fb->pitches[0];

        helper->fbdev = config_found(ddev->dev, &tfa, NULL,
            CFARGS(.iattr = "tilcdcfbbus"));
        if (helper->fbdev == NULL) {
                DRM_ERROR("unable to attach framebuffer\n");
                return -ENXIO;
        }

        return 0;
}

static struct drm_fb_helper_funcs tilcdc_fb_helper_funcs = {
        .fb_probe = tilcdc_fb_probe,
};

static int
tilcdc_load(struct drm_device *ddev, unsigned long flags)
{
        struct tilcdc_softc * const sc = tilcdc_private(ddev);
        struct tilcdc_fbdev *fbdev;
        struct fdt_endpoint *ep;
        int error;

        drm_mode_config_init(ddev);
        ddev->mode_config.min_width = 0;
        ddev->mode_config.min_height = 0;
        ddev->mode_config.max_width = 2048;
        ddev->mode_config.max_height = 2048;
        ddev->mode_config.funcs = &tilcdc_mode_config_funcs;

        ep = fdt_endpoint_get_from_index(&sc->sc_ports, TILCDC_PORT_OUTPUT, 0);
        if (ep == NULL) {
                aprint_error_dev(sc->sc_dev, "couldn't find endpoint\n");
                error = ENXIO;
                goto drmerr;
        }
        error = fdt_endpoint_activate_direct(ep, true);
        if (error != 0) {
                aprint_error_dev(sc->sc_dev, "couldn't activate endpoint: %d\n", error);
                error = ENXIO;
                goto drmerr;
        }

        fbdev = kmem_zalloc(sizeof(*fbdev), KM_SLEEP);

        drm_fb_helper_prepare(ddev, &fbdev->helper, &tilcdc_fb_helper_funcs);

        error = drm_fb_helper_init(ddev, &fbdev->helper, 1);
        if (error)
                goto allocerr;

        fbdev->helper.fb = kmem_zalloc(sizeof(struct tilcdc_framebuffer),
            KM_SLEEP);

        drm_fb_helper_single_add_all_connectors(&fbdev->helper);

        drm_helper_disable_unused_functions(ddev);

        drm_fb_helper_initial_config(&fbdev->helper, 32);

        return 0;

allocerr:
        kmem_free(fbdev, sizeof(*fbdev));
drmerr:
        drm_mode_config_cleanup(ddev);

        return error;
}

static void
tilcdc_unload(struct drm_device *ddev)
{

        drm_mode_config_cleanup(ddev);
}

static void
tilcdc_drm_task_work(struct work *work, void *cookie)
{
        struct tilcdc_drm_task *task = container_of(work,
            struct tilcdc_drm_task, tdt_u.work);

        (*task->tdt_fn)(task);
}

void
tilcdc_task_init(struct tilcdc_drm_task *task,
    void (*fn)(struct tilcdc_drm_task *))
{

        task->tdt_fn = fn;
}

void
tilcdc_task_schedule(device_t self, struct tilcdc_drm_task *task)
{
        struct tilcdc_softc *sc = device_private(self);

        if (atomic_load_relaxed(&sc->sc_task_thread) == curlwp)
                SIMPLEQ_INSERT_TAIL(&sc->sc_tasks, task, tdt_u.queue);
        else
                workqueue_enqueue(sc->sc_task_wq, &task->tdt_u.work, NULL);
}