linux_kernel/drivers/gpu/drm/tegra/hub.c

/*
 * Copyright (C) 2017 NVIDIA CORPORATION.  All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/clk.h>
#include <linux/host1x.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_graph.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>

#include <drm/drmP.h>
#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc_helper.h>

#include "drm.h"
#include "dc.h"
#include "plane.h"

static const u32 tegra_shared_plane_formats[] = {
	DRM_FORMAT_ARGB1555,
	DRM_FORMAT_RGB565,
	DRM_FORMAT_RGBA5551,
	DRM_FORMAT_ARGB8888,
	DRM_FORMAT_ABGR8888,
	/* new on Tegra114 */
	DRM_FORMAT_ABGR4444,
	DRM_FORMAT_ABGR1555,
	DRM_FORMAT_BGRA5551,
	DRM_FORMAT_XRGB1555,
	DRM_FORMAT_RGBX5551,
	DRM_FORMAT_XBGR1555,
	DRM_FORMAT_BGRX5551,
	DRM_FORMAT_BGR565,
	DRM_FORMAT_XRGB8888,
	DRM_FORMAT_XBGR8888,
	/* planar formats */
	DRM_FORMAT_UYVY,
	DRM_FORMAT_YUYV,
	DRM_FORMAT_YUV420,
	DRM_FORMAT_YUV422,
};

static inline unsigned int tegra_plane_offset(struct tegra_plane *plane,
					      unsigned int offset)
{
	if (offset >= 0x500 && offset <= 0x581) {
		offset = 0x000 + (offset - 0x500);
		return plane->offset + offset;
	}

	if (offset >= 0x700 && offset <= 0x73c) {
		offset = 0x180 + (offset - 0x700);
		return plane->offset + offset;
	}

	if (offset >= 0x800 && offset <= 0x83e) {
		offset = 0x1c0 + (offset - 0x800);
		return plane->offset + offset;
	}

	dev_WARN(plane->dc->dev, "invalid offset: %x\n", offset);

	return plane->offset + offset;
}

static inline u32 tegra_plane_readl(struct tegra_plane *plane,
				    unsigned int offset)
{
	return tegra_dc_readl(plane->dc, tegra_plane_offset(plane, offset));
}

static inline void tegra_plane_writel(struct tegra_plane *plane, u32 value,
				      unsigned int offset)
{
	tegra_dc_writel(plane->dc, value, tegra_plane_offset(plane, offset));
}

static int tegra_windowgroup_enable(struct tegra_windowgroup *wgrp)
{
	mutex_lock(&wgrp->lock);

	if (wgrp->usecount == 0) {
		pm_runtime_get_sync(wgrp->parent);
		reset_control_deassert(wgrp->rst);
	}

	wgrp->usecount++;
	mutex_unlock(&wgrp->lock);

	return 0;
}

static void tegra_windowgroup_disable(struct tegra_windowgroup *wgrp)
{
	int err;

	mutex_lock(&wgrp->lock);

	if (wgrp->usecount == 1) {
		err = reset_control_assert(wgrp->rst);
		if (err < 0) {
			pr_err("failed to assert reset for window group %u\n",
			       wgrp->index);
		}

		pm_runtime_put(wgrp->parent);
	}

	wgrp->usecount--;
	mutex_unlock(&wgrp->lock);
}

int tegra_display_hub_prepare(struct tegra_display_hub *hub)
{
	unsigned int i;

	/*
	 * XXX Enabling/disabling windowgroups needs to happen when the owner
	 * display controller is disabled. There's currently no good point at
	 * which this could be executed, so unconditionally enable all window
	 * groups for now.
	 */
	for (i = 0; i < hub->soc->num_wgrps; i++) {
		struct tegra_windowgroup *wgrp = &hub->wgrps[i];

		tegra_windowgroup_enable(wgrp);
	}

	return 0;
}

void tegra_display_hub_cleanup(struct tegra_display_hub *hub)
{
	unsigned int i;

	/*
	 * XXX Remove this once window groups can be more fine-grainedly
	 * enabled and disabled.
	 */
	for (i = 0; i < hub->soc->num_wgrps; i++) {
		struct tegra_windowgroup *wgrp = &hub->wgrps[i];

		tegra_windowgroup_disable(wgrp);
	}
}

static void tegra_shared_plane_update(struct tegra_plane *plane)
{
	struct tegra_dc *dc = plane->dc;
	unsigned long timeout;
	u32 mask, value;

	mask = COMMON_UPDATE | WIN_A_UPDATE << plane->base.index;
	tegra_dc_writel(dc, mask, DC_CMD_STATE_CONTROL);

	timeout = jiffies + msecs_to_jiffies(1000);

	while (time_before(jiffies, timeout)) {
		value = tegra_dc_readl(dc, DC_CMD_STATE_CONTROL);
		if ((value & mask) == 0)
			break;

		usleep_range(100, 400);
	}
}

static void tegra_shared_plane_activate(struct tegra_plane *plane)
{
	struct tegra_dc *dc = plane->dc;
	unsigned long timeout;
	u32 mask, value;

	mask = COMMON_ACTREQ | WIN_A_ACT_REQ << plane->base.index;
	tegra_dc_writel(dc, mask, DC_CMD_STATE_CONTROL);

	timeout = jiffies + msecs_to_jiffies(1000);

	while (time_before(jiffies, timeout)) {
		value = tegra_dc_readl(dc, DC_CMD_STATE_CONTROL);
		if ((value & mask) == 0)
			break;

		usleep_range(100, 400);
	}
}

static unsigned int
tegra_shared_plane_get_owner(struct tegra_plane *plane, struct tegra_dc *dc)
{
	unsigned int offset =
		tegra_plane_offset(plane, DC_WIN_CORE_WINDOWGROUP_SET_CONTROL);

	return tegra_dc_readl(dc, offset) & OWNER_MASK;
}

static bool tegra_dc_owns_shared_plane(struct tegra_dc *dc,
				       struct tegra_plane *plane)
{
	struct device *dev = dc->dev;

	if (tegra_shared_plane_get_owner(plane, dc) == dc->pipe) {
		if (plane->dc == dc)
			return true;

		dev_WARN(dev, "head %u owns window %u but is not attached\n",
			 dc->pipe, plane->index);
	}

	return false;
}

static int tegra_shared_plane_set_owner(struct tegra_plane *plane,
					struct tegra_dc *new)
{
	unsigned int offset =
		tegra_plane_offset(plane, DC_WIN_CORE_WINDOWGROUP_SET_CONTROL);
	struct tegra_dc *old = plane->dc, *dc = new ? new : old;
	struct device *dev = new ? new->dev : old->dev;
	unsigned int owner, index = plane->index;
	u32 value;

	value = tegra_dc_readl(dc, offset);
	owner = value & OWNER_MASK;

	if (new && (owner != OWNER_MASK && owner != new->pipe)) {
		dev_WARN(dev, "window %u owned by head %u\n", index, owner);
		return -EBUSY;
	}

	/*
	 * This seems to happen whenever the head has been disabled with one
	 * or more windows being active. This is harmless because we'll just
	 * reassign the window to the new head anyway.
	 */
	if (old && owner == OWNER_MASK)
		dev_dbg(dev, "window %u not owned by head %u but %u\n", index,
			old->pipe, owner);

	value &= ~OWNER_MASK;

	if (new)
		value |= OWNER(new->pipe);
	else
		value |= OWNER_MASK;

	tegra_dc_writel(dc, value, offset);

	plane->dc = new;

	return 0;
}

static void tegra_dc_assign_shared_plane(struct tegra_dc *dc,
					 struct tegra_plane *plane)
{
	u32 value;
	int err;

	if (!tegra_dc_owns_shared_plane(dc, plane)) {
		err = tegra_shared_plane_set_owner(plane, dc);
		if (err < 0)
			return;
	}

	value = tegra_plane_readl(plane, DC_WIN_CORE_IHUB_LINEBUF_CONFIG);
	value |= MODE_FOUR_LINES;
	tegra_plane_writel(plane, value, DC_WIN_CORE_IHUB_LINEBUF_CONFIG);

	value = tegra_plane_readl(plane, DC_WIN_CORE_IHUB_WGRP_FETCH_METER);
	value = SLOTS(1);
	tegra_plane_writel(plane, value, DC_WIN_CORE_IHUB_WGRP_FETCH_METER);

	/* disable watermark */
	value = tegra_plane_readl(plane, DC_WIN_CORE_IHUB_WGRP_LATENCY_CTLA);
	value &= ~LATENCY_CTL_MODE_ENABLE;
	tegra_plane_writel(plane, value, DC_WIN_CORE_IHUB_WGRP_LATENCY_CTLA);

	value = tegra_plane_readl(plane, DC_WIN_CORE_IHUB_WGRP_LATENCY_CTLB);
	value |= WATERMARK_MASK;
	tegra_plane_writel(plane, value, DC_WIN_CORE_IHUB_WGRP_LATENCY_CTLB);

	/* pipe meter */
	value = tegra_plane_readl(plane, DC_WIN_CORE_PRECOMP_WGRP_PIPE_METER);
	value = PIPE_METER_INT(0) | PIPE_METER_FRAC(0);
	tegra_plane_writel(plane, value, DC_WIN_CORE_PRECOMP_WGRP_PIPE_METER);

	/* mempool entries */
	value = tegra_plane_readl(plane, DC_WIN_CORE_IHUB_WGRP_POOL_CONFIG);
	value = MEMPOOL_ENTRIES(0x331);
	tegra_plane_writel(plane, value, DC_WIN_CORE_IHUB_WGRP_POOL_CONFIG);

	value = tegra_plane_readl(plane, DC_WIN_CORE_IHUB_THREAD_GROUP);
	value &= ~THREAD_NUM_MASK;
	value |= THREAD_NUM(plane->base.index);
	value |= THREAD_GROUP_ENABLE;
	tegra_plane_writel(plane, value, DC_WIN_CORE_IHUB_THREAD_GROUP);

	tegra_shared_plane_update(plane);
	tegra_shared_plane_activate(plane);
}

static void tegra_dc_remove_shared_plane(struct tegra_dc *dc,
					 struct tegra_plane *plane)
{
	tegra_shared_plane_set_owner(plane, NULL);
}

static int tegra_shared_plane_atomic_check(struct drm_plane *plane,
					   struct drm_plane_state *state)
{
	struct tegra_plane_state *plane_state = to_tegra_plane_state(state);
	struct tegra_shared_plane *tegra = to_tegra_shared_plane(plane);
	struct tegra_bo_tiling *tiling = &plane_state->tiling;
	struct tegra_dc *dc = to_tegra_dc(state->crtc);
	int err;

	/* no need for further checks if the plane is being disabled */
	if (!state->crtc || !state->fb)
		return 0;

	err = tegra_plane_format(state->fb->format->format,
				 &plane_state->format,
				 &plane_state->swap);
	if (err < 0)
		return err;

	err = tegra_fb_get_tiling(state->fb, tiling);
	if (err < 0)
		return err;

	if (tiling->mode == TEGRA_BO_TILING_MODE_BLOCK &&
	    !dc->soc->supports_block_linear) {
		DRM_ERROR("hardware doesn't support block linear mode\n");
		return -EINVAL;
	}

	/*
	 * Tegra doesn't support different strides for U and V planes so we
	 * error out if the user tries to display a framebuffer with such a
	 * configuration.
	 */
	if (state->fb->format->num_planes > 2) {
		if (state->fb->pitches[2] != state->fb->pitches[1]) {
			DRM_ERROR("unsupported UV-plane configuration\n");
			return -EINVAL;
		}
	}

	/* XXX scaling is not yet supported, add a check here */

	err = tegra_plane_state_add(&tegra->base, state);
	if (err < 0)
		return err;

	return 0;
}

static void tegra_shared_plane_atomic_disable(struct drm_plane *plane,
					      struct drm_plane_state *old_state)
{
	struct tegra_dc *dc = to_tegra_dc(old_state->crtc);
	struct tegra_plane *p = to_tegra_plane(plane);
	u32 value;

	/* rien ne va plus */
	if (!old_state || !old_state->crtc)
		return;

	/*
	 * XXX Legacy helpers seem to sometimes call ->atomic_disable() even
	 * on planes that are already disabled. Make sure we fallback to the
	 * head for this particular state instead of crashing.
	 */
	if (WARN_ON(p->dc == NULL))
		p->dc = dc;

	pm_runtime_get_sync(dc->dev);

	value = tegra_plane_readl(p, DC_WIN_WIN_OPTIONS);
	value &= ~WIN_ENABLE;
	tegra_plane_writel(p, value, DC_WIN_WIN_OPTIONS);

	tegra_dc_remove_shared_plane(dc, p);

	pm_runtime_put(dc->dev);
}

static void tegra_shared_plane_atomic_update(struct drm_plane *plane,
					     struct drm_plane_state *old_state)
{
	struct tegra_plane_state *state = to_tegra_plane_state(plane->state);
	struct tegra_dc *dc = to_tegra_dc(plane->state->crtc);
	unsigned int zpos = plane->state->normalized_zpos;
	struct drm_framebuffer *fb = plane->state->fb;
	struct tegra_plane *p = to_tegra_plane(plane);
	struct tegra_bo *bo;
	dma_addr_t base;
	u32 value;

	/* rien ne va plus */
	if (!plane->state->crtc || !plane->state->fb)
		return;

	if (!plane->state->visible) {
		tegra_shared_plane_atomic_disable(plane, old_state);
		return;
	}

	pm_runtime_get_sync(dc->dev);

	tegra_dc_assign_shared_plane(dc, p);

	tegra_plane_writel(p, VCOUNTER, DC_WIN_CORE_ACT_CONTROL);

	/* blending */
	value = BLEND_FACTOR_DST_ALPHA_ZERO | BLEND_FACTOR_SRC_ALPHA_K2 |
		BLEND_FACTOR_DST_COLOR_NEG_K1_TIMES_SRC |
		BLEND_FACTOR_SRC_COLOR_K1_TIMES_SRC;
	tegra_plane_writel(p, value, DC_WIN_BLEND_MATCH_SELECT);

	value = BLEND_FACTOR_DST_ALPHA_ZERO | BLEND_FACTOR_SRC_ALPHA_K2 |
		BLEND_FACTOR_DST_COLOR_NEG_K1_TIMES_SRC |
		BLEND_FACTOR_SRC_COLOR_K1_TIMES_SRC;
	tegra_plane_writel(p, value, DC_WIN_BLEND_NOMATCH_SELECT);

	value = K2(255) | K1(255) | WINDOW_LAYER_DEPTH(255 - zpos);
	tegra_plane_writel(p, value, DC_WIN_BLEND_LAYER_CONTROL);

	/* bypass scaling */
	value = HORIZONTAL_TAPS_5 | VERTICAL_TAPS_5;
	tegra_plane_writel(p, value, DC_WIN_WINDOWGROUP_SET_CONTROL_INPUT_SCALER);

	value = INPUT_SCALER_VBYPASS | INPUT_SCALER_HBYPASS;
	tegra_plane_writel(p, value, DC_WIN_WINDOWGROUP_SET_INPUT_SCALER_USAGE);

	/* disable compression */
	tegra_plane_writel(p, 0, DC_WINBUF_CDE_CONTROL);

	bo = tegra_fb_get_plane(fb, 0);
	base = bo->paddr;

	tegra_plane_writel(p, state->format, DC_WIN_COLOR_DEPTH);
	tegra_plane_writel(p, 0, DC_WIN_PRECOMP_WGRP_PARAMS);

	value = V_POSITION(plane->state->crtc_y) |
		H_POSITION(plane->state->crtc_x);
	tegra_plane_writel(p, value, DC_WIN_POSITION);

	value = V_SIZE(plane->state->crtc_h) | H_SIZE(plane->state->crtc_w);
	tegra_plane_writel(p, value, DC_WIN_SIZE);

	value = WIN_ENABLE | COLOR_EXPAND;
	tegra_plane_writel(p, value, DC_WIN_WIN_OPTIONS);

	value = V_SIZE(plane->state->crtc_h) | H_SIZE(plane->state->crtc_w);
	tegra_plane_writel(p, value, DC_WIN_CROPPED_SIZE);

	tegra_plane_writel(p, upper_32_bits(base), DC_WINBUF_START_ADDR_HI);
	tegra_plane_writel(p, lower_32_bits(base), DC_WINBUF_START_ADDR);

	value = PITCH(fb->pitches[0]);
	tegra_plane_writel(p, value, DC_WIN_PLANAR_STORAGE);

	value = CLAMP_BEFORE_BLEND | DEGAMMA_SRGB | INPUT_RANGE_FULL;
	tegra_plane_writel(p, value, DC_WIN_SET_PARAMS);

	value = OFFSET_X(plane->state->src_y >> 16) |
		OFFSET_Y(plane->state->src_x >> 16);
	tegra_plane_writel(p, value, DC_WINBUF_CROPPED_POINT);

	if (dc->soc->supports_block_linear) {
		unsigned long height = state->tiling.value;

		/* XXX */
		switch (state->tiling.mode) {
		case TEGRA_BO_TILING_MODE_PITCH:
			value = DC_WINBUF_SURFACE_KIND_BLOCK_HEIGHT(0) |
				DC_WINBUF_SURFACE_KIND_PITCH;
			break;

		/* XXX not supported on Tegra186 and later */
		case TEGRA_BO_TILING_MODE_TILED:
			value = DC_WINBUF_SURFACE_KIND_TILED;
			break;

		case TEGRA_BO_TILING_MODE_BLOCK:
			value = DC_WINBUF_SURFACE_KIND_BLOCK_HEIGHT(height) |
				DC_WINBUF_SURFACE_KIND_BLOCK;
			break;
		}

		tegra_plane_writel(p, value, DC_WINBUF_SURFACE_KIND);
	}

	/* disable gamut CSC */
	value = tegra_plane_readl(p, DC_WIN_WINDOW_SET_CONTROL);
	value &= ~CONTROL_CSC_ENABLE;
	tegra_plane_writel(p, value, DC_WIN_WINDOW_SET_CONTROL);

	pm_runtime_put(dc->dev);
}

static const struct drm_plane_helper_funcs tegra_shared_plane_helper_funcs = {
	.atomic_check = tegra_shared_plane_atomic_check,
	.atomic_update = tegra_shared_plane_atomic_update,
	.atomic_disable = tegra_shared_plane_atomic_disable,
};

struct drm_plane *tegra_shared_plane_create(struct drm_device *drm,
					    struct tegra_dc *dc,
					    unsigned int wgrp,
					    unsigned int index)
{
	enum drm_plane_type type = DRM_PLANE_TYPE_OVERLAY;
	struct tegra_drm *tegra = drm->dev_private;
	struct tegra_display_hub *hub = tegra->hub;
	/* planes can be assigned to arbitrary CRTCs */
	unsigned int possible_crtcs = 0x7;
	struct tegra_shared_plane *plane;
	unsigned int num_formats;
	struct drm_plane *p;
	const u32 *formats;
	int err;

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

	plane->base.offset = 0x0a00 + 0x0300 * index;
	plane->base.index = index;

	plane->wgrp = &hub->wgrps[wgrp];
	plane->wgrp->parent = dc->dev;

	p = &plane->base.base;

	num_formats = ARRAY_SIZE(tegra_shared_plane_formats);
	formats = tegra_shared_plane_formats;

	err = drm_universal_plane_init(drm, p, possible_crtcs,
				       &tegra_plane_funcs, formats,
				       num_formats, NULL, type, NULL);
	if (err < 0) {
		kfree(plane);
		return ERR_PTR(err);
	}

	drm_plane_helper_add(p, &tegra_shared_plane_helper_funcs);
	drm_plane_create_zpos_property(p, 0, 0, 255);

	return p;
}

static void tegra_display_hub_update(struct tegra_dc *dc)
{
	u32 value;

	pm_runtime_get_sync(dc->dev);

	value = tegra_dc_readl(dc, DC_CMD_IHUB_COMMON_MISC_CTL);
	value &= ~LATENCY_EVENT;
	tegra_dc_writel(dc, value, DC_CMD_IHUB_COMMON_MISC_CTL);

	value = tegra_dc_readl(dc, DC_DISP_IHUB_COMMON_DISPLAY_FETCH_METER);
	value = CURS_SLOTS(1) | WGRP_SLOTS(1);
	tegra_dc_writel(dc, value, DC_DISP_IHUB_COMMON_DISPLAY_FETCH_METER);

	tegra_dc_writel(dc, COMMON_UPDATE, DC_CMD_STATE_CONTROL);
	tegra_dc_readl(dc, DC_CMD_STATE_CONTROL);
	tegra_dc_writel(dc, COMMON_ACTREQ, DC_CMD_STATE_CONTROL);
	tegra_dc_readl(dc, DC_CMD_STATE_CONTROL);

	pm_runtime_put(dc->dev);
}

void tegra_display_hub_atomic_commit(struct drm_device *drm,
				     struct drm_atomic_state *state)
{
	struct tegra_atomic_state *s = to_tegra_atomic_state(state);
	struct tegra_drm *tegra = drm->dev_private;
	struct tegra_display_hub *hub = tegra->hub;
	struct device *dev = hub->client.dev;
	int err;

	if (s->clk_disp) {
		err = clk_set_rate(s->clk_disp, s->rate);
		if (err < 0)
			dev_err(dev, "failed to set rate of %pC to %lu Hz\n",
				s->clk_disp, s->rate);

		err = clk_set_parent(hub->clk_disp, s->clk_disp);
		if (err < 0)
			dev_err(dev, "failed to set parent of %pC to %pC: %d\n",
				hub->clk_disp, s->clk_disp, err);
	}

	if (s->dc)
		tegra_display_hub_update(s->dc);
}

static int tegra_display_hub_init(struct host1x_client *client)
{
	struct tegra_display_hub *hub = to_tegra_display_hub(client);
	struct drm_device *drm = dev_get_drvdata(client->parent);
	struct tegra_drm *tegra = drm->dev_private;

	tegra->hub = hub;

	return 0;
}

static int tegra_display_hub_exit(struct host1x_client *client)
{
	struct drm_device *drm = dev_get_drvdata(client->parent);
	struct tegra_drm *tegra = drm->dev_private;

	tegra->hub = NULL;

	return 0;
}

static const struct host1x_client_ops tegra_display_hub_ops = {
	.init = tegra_display_hub_init,
	.exit = tegra_display_hub_exit,
};

static int tegra_display_hub_probe(struct platform_device *pdev)
{
	struct tegra_display_hub *hub;
	unsigned int i;
	int err;

	hub = devm_kzalloc(&pdev->dev, sizeof(*hub), GFP_KERNEL);
	if (!hub)
		return -ENOMEM;

	hub->soc = of_device_get_match_data(&pdev->dev);

	hub->clk_disp = devm_clk_get(&pdev->dev, "disp");
	if (IS_ERR(hub->clk_disp)) {
		err = PTR_ERR(hub->clk_disp);
		return err;
	}

	hub->clk_dsc = devm_clk_get(&pdev->dev, "dsc");
	if (IS_ERR(hub->clk_dsc)) {
		err = PTR_ERR(hub->clk_dsc);
		return err;
	}

	hub->clk_hub = devm_clk_get(&pdev->dev, "hub");
	if (IS_ERR(hub->clk_hub)) {
		err = PTR_ERR(hub->clk_hub);
		return err;
	}

	hub->rst = devm_reset_control_get(&pdev->dev, "misc");
	if (IS_ERR(hub->rst)) {
		err = PTR_ERR(hub->rst);
		return err;
	}

	hub->wgrps = devm_kcalloc(&pdev->dev, hub->soc->num_wgrps,
				  sizeof(*hub->wgrps), GFP_KERNEL);
	if (!hub->wgrps)
		return -ENOMEM;

	for (i = 0; i < hub->soc->num_wgrps; i++) {
		struct tegra_windowgroup *wgrp = &hub->wgrps[i];
		char id[8];

		snprintf(id, sizeof(id), "wgrp%u", i);
		mutex_init(&wgrp->lock);
		wgrp->usecount = 0;
		wgrp->index = i;

		wgrp->rst = devm_reset_control_get(&pdev->dev, id);
		if (IS_ERR(wgrp->rst))
			return PTR_ERR(wgrp->rst);

		err = reset_control_assert(wgrp->rst);
		if (err < 0)
			return err;
	}

	/* XXX: enable clock across reset? */
	err = reset_control_assert(hub->rst);
	if (err < 0)
		return err;

	platform_set_drvdata(pdev, hub);
	pm_runtime_enable(&pdev->dev);

	INIT_LIST_HEAD(&hub->client.list);
	hub->client.ops = &tegra_display_hub_ops;
	hub->client.dev = &pdev->dev;

	err = host1x_client_register(&hub->client);
	if (err < 0)
		dev_err(&pdev->dev, "failed to register host1x client: %d\n",
			err);

	return err;
}

static int tegra_display_hub_remove(struct platform_device *pdev)
{
	struct tegra_display_hub *hub = platform_get_drvdata(pdev);
	int err;

	err = host1x_client_unregister(&hub->client);
	if (err < 0) {
		dev_err(&pdev->dev, "failed to unregister host1x client: %d\n",
			err);
	}

	pm_runtime_disable(&pdev->dev);

	return err;
}

static int __maybe_unused tegra_display_hub_suspend(struct device *dev)
{
	struct tegra_display_hub *hub = dev_get_drvdata(dev);
	int err;

	err = reset_control_assert(hub->rst);
	if (err < 0)
		return err;

	clk_disable_unprepare(hub->clk_hub);
	clk_disable_unprepare(hub->clk_dsc);
	clk_disable_unprepare(hub->clk_disp);

	return 0;
}

static int __maybe_unused tegra_display_hub_resume(struct device *dev)
{
	struct tegra_display_hub *hub = dev_get_drvdata(dev);
	int err;

	err = clk_prepare_enable(hub->clk_disp);
	if (err < 0)
		return err;

	err = clk_prepare_enable(hub->clk_dsc);
	if (err < 0)
		goto disable_disp;

	err = clk_prepare_enable(hub->clk_hub);
	if (err < 0)
		goto disable_dsc;

	err = reset_control_deassert(hub->rst);
	if (err < 0)
		goto disable_hub;

	return 0;

disable_hub:
	clk_disable_unprepare(hub->clk_hub);
disable_dsc:
	clk_disable_unprepare(hub->clk_dsc);
disable_disp:
	clk_disable_unprepare(hub->clk_disp);
	return err;
}

static const struct dev_pm_ops tegra_display_hub_pm_ops = {
	SET_RUNTIME_PM_OPS(tegra_display_hub_suspend,
			   tegra_display_hub_resume, NULL)
};

static const struct tegra_display_hub_soc tegra186_display_hub = {
	.num_wgrps = 6,
};

static const struct of_device_id tegra_display_hub_of_match[] = {
	{
		.compatible = "nvidia,tegra186-display",
		.data = &tegra186_display_hub
	}, {
		/* sentinel */
	}
};
MODULE_DEVICE_TABLE(of, tegra_display_hub_of_match);

struct platform_driver tegra_display_hub_driver = {
	.driver = {
		.name = "tegra-display-hub",
		.of_match_table = tegra_display_hub_of_match,
		.pm = &tegra_display_hub_pm_ops,
	},
	.probe = tegra_display_hub_probe,
	.remove = tegra_display_hub_remove,
};