1 files changed, 1016 insertions, 0 deletions

diff --git a/drivers/gpu/drm/tegra/hub.c b/drivers/gpu/drm/tegra/hub.c
new file mode 100644
index 000000000..5ce771cba
--- /dev/null
+++ b/drivers/gpu/drm/tegra/hub.c
@@ -0,0 +1,1016 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2017 NVIDIA CORPORATION.  All rights reserved.
+ */
+
+#include <linux/clk.h>
+#include <linux/delay.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/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_probe_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 const u64 tegra_shared_plane_modifiers[] = {
+	DRM_FORMAT_MOD_LINEAR,
+	DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(0),
+	DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(1),
+	DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(2),
+	DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(3),
+	DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(4),
+	DRM_FORMAT_MOD_NVIDIA_16BX2_BLOCK(5),
+	DRM_FORMAT_MOD_INVALID
+};
+
+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)
+{
+	int err = 0;
+
+	mutex_lock(&wgrp->lock);
+
+	if (wgrp->usecount == 0) {
+		err = host1x_client_resume(wgrp->parent);
+		if (err < 0) {
+			dev_err(wgrp->parent->dev, "failed to resume: %d\n", err);
+			goto unlock;
+		}
+
+		reset_control_deassert(wgrp->rst);
+	}
+
+	wgrp->usecount++;
+
+unlock:
+	mutex_unlock(&wgrp->lock);
+	return err;
+}
+
+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);
+		}
+
+		host1x_client_suspend(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];
+
+		/* Skip orphaned window group whose parent DC is disabled */
+		if (wgrp->parent)
+			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];
+
+		/* Skip orphaned window group whose parent DC is disabled */
+		if (wgrp->parent)
+			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_plane *p = to_tegra_plane(plane);
+	struct tegra_dc *dc;
+	u32 value;
+	int err;
+
+	/* rien ne va plus */
+	if (!old_state || !old_state->crtc)
+		return;
+
+	dc = to_tegra_dc(old_state->crtc);
+
+	err = host1x_client_resume(&dc->client);
+	if (err < 0) {
+		dev_err(dc->dev, "failed to resume: %d\n", err);
+		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;
+
+	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);
+
+	host1x_client_suspend(&dc->client);
+}
+
+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);
+	dma_addr_t base;
+	u32 value;
+	int err;
+
+	/* 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;
+	}
+
+	err = host1x_client_resume(&dc->client);
+	if (err < 0) {
+		dev_err(dc->dev, "failed to resume: %d\n", err);
+		return;
+	}
+
+	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);
+
+	base = state->iova[0] + fb->offsets[0];
+
+	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);
+
+	host1x_client_suspend(&dc->client);
+}
+
+static const struct drm_plane_helper_funcs tegra_shared_plane_helper_funcs = {
+	.prepare_fb = tegra_plane_prepare_fb,
+	.cleanup_fb = tegra_plane_cleanup_fb,
+	.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;
+	const u64 *modifiers;
+	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->client;
+
+	p = &plane->base.base;
+
+	num_formats = ARRAY_SIZE(tegra_shared_plane_formats);
+	formats = tegra_shared_plane_formats;
+	modifiers = tegra_shared_plane_modifiers;
+
+	err = drm_universal_plane_init(drm, p, possible_crtcs,
+				       &tegra_plane_funcs, formats,
+				       num_formats, modifiers, 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 struct drm_private_state *
+tegra_display_hub_duplicate_state(struct drm_private_obj *obj)
+{
+	struct tegra_display_hub_state *state;
+
+	state = kmemdup(obj->state, sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return NULL;
+
+	__drm_atomic_helper_private_obj_duplicate_state(obj, &state->base);
+
+	return &state->base;
+}
+
+static void tegra_display_hub_destroy_state(struct drm_private_obj *obj,
+					    struct drm_private_state *state)
+{
+	struct tegra_display_hub_state *hub_state =
+		to_tegra_display_hub_state(state);
+
+	kfree(hub_state);
+}
+
+static const struct drm_private_state_funcs tegra_display_hub_state_funcs = {
+	.atomic_duplicate_state = tegra_display_hub_duplicate_state,
+	.atomic_destroy_state = tegra_display_hub_destroy_state,
+};
+
+static struct tegra_display_hub_state *
+tegra_display_hub_get_state(struct tegra_display_hub *hub,
+			    struct drm_atomic_state *state)
+{
+	struct drm_private_state *priv;
+
+	priv = drm_atomic_get_private_obj_state(state, &hub->base);
+	if (IS_ERR(priv))
+		return ERR_CAST(priv);
+
+	return to_tegra_display_hub_state(priv);
+}
+
+int tegra_display_hub_atomic_check(struct drm_device *drm,
+				   struct drm_atomic_state *state)
+{
+	struct tegra_drm *tegra = drm->dev_private;
+	struct tegra_display_hub_state *hub_state;
+	struct drm_crtc_state *old, *new;
+	struct drm_crtc *crtc;
+	unsigned int i;
+
+	if (!tegra->hub)
+		return 0;
+
+	hub_state = tegra_display_hub_get_state(tegra->hub, state);
+	if (IS_ERR(hub_state))
+		return PTR_ERR(hub_state);
+
+	/*
+	 * The display hub display clock needs to be fed by the display clock
+	 * with the highest frequency to ensure proper functioning of all the
+	 * displays.
+	 *
+	 * Note that this isn't used before Tegra186, but it doesn't hurt and
+	 * conditionalizing it would make the code less clean.
+	 */
+	for_each_oldnew_crtc_in_state(state, crtc, old, new, i) {
+		struct tegra_dc_state *dc = to_dc_state(new);
+
+		if (new->active) {
+			if (!hub_state->clk || dc->pclk > hub_state->rate) {
+				hub_state->dc = to_tegra_dc(dc->base.crtc);
+				hub_state->clk = hub_state->dc->clk;
+				hub_state->rate = dc->pclk;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static void tegra_display_hub_update(struct tegra_dc *dc)
+{
+	u32 value;
+	int err;
+
+	err = host1x_client_resume(&dc->client);
+	if (err < 0) {
+		dev_err(dc->dev, "failed to resume: %d\n", err);
+		return;
+	}
+
+	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);
+
+	host1x_client_suspend(&dc->client);
+}
+
+void tegra_display_hub_atomic_commit(struct drm_device *drm,
+				     struct drm_atomic_state *state)
+{
+	struct tegra_drm *tegra = drm->dev_private;
+	struct tegra_display_hub *hub = tegra->hub;
+	struct tegra_display_hub_state *hub_state;
+	struct device *dev = hub->client.dev;
+	int err;
+
+	hub_state = to_tegra_display_hub_state(hub->base.state);
+
+	if (hub_state->clk) {
+		err = clk_set_rate(hub_state->clk, hub_state->rate);
+		if (err < 0)
+			dev_err(dev, "failed to set rate of %pC to %lu Hz\n",
+				hub_state->clk, hub_state->rate);
+
+		err = clk_set_parent(hub->clk_disp, hub_state->clk);
+		if (err < 0)
+			dev_err(dev, "failed to set parent of %pC to %pC: %d\n",
+				hub->clk_disp, hub_state->clk, err);
+	}
+
+	if (hub_state->dc)
+		tegra_display_hub_update(hub_state->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->host);
+	struct tegra_drm *tegra = drm->dev_private;
+	struct tegra_display_hub_state *state;
+
+	state = kzalloc(sizeof(*state), GFP_KERNEL);
+	if (!state)
+		return -ENOMEM;
+
+	drm_atomic_private_obj_init(drm, &hub->base, &state->base,
+				    &tegra_display_hub_state_funcs);
+
+	tegra->hub = hub;
+
+	return 0;
+}
+
+static int tegra_display_hub_exit(struct host1x_client *client)
+{
+	struct drm_device *drm = dev_get_drvdata(client->host);
+	struct tegra_drm *tegra = drm->dev_private;
+
+	drm_atomic_private_obj_fini(&tegra->hub->base);
+	tegra->hub = NULL;
+
+	return 0;
+}
+
+static int tegra_display_hub_runtime_suspend(struct host1x_client *client)
+{
+	struct tegra_display_hub *hub = to_tegra_display_hub(client);
+	struct device *dev = client->dev;
+	unsigned int i = hub->num_heads;
+	int err;
+
+	err = reset_control_assert(hub->rst);
+	if (err < 0)
+		return err;
+
+	while (i--)
+		clk_disable_unprepare(hub->clk_heads[i]);
+
+	clk_disable_unprepare(hub->clk_hub);
+	clk_disable_unprepare(hub->clk_dsc);
+	clk_disable_unprepare(hub->clk_disp);
+
+	pm_runtime_put_sync(dev);
+
+	return 0;
+}
+
+static int tegra_display_hub_runtime_resume(struct host1x_client *client)
+{
+	struct tegra_display_hub *hub = to_tegra_display_hub(client);
+	struct device *dev = client->dev;
+	unsigned int i;
+	int err;
+
+	err = pm_runtime_resume_and_get(dev);
+	if (err < 0) {
+		dev_err(dev, "failed to get runtime PM: %d\n", err);
+		return err;
+	}
+
+	err = clk_prepare_enable(hub->clk_disp);
+	if (err < 0)
+		goto put_rpm;
+
+	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;
+
+	for (i = 0; i < hub->num_heads; i++) {
+		err = clk_prepare_enable(hub->clk_heads[i]);
+		if (err < 0)
+			goto disable_heads;
+	}
+
+	err = reset_control_deassert(hub->rst);
+	if (err < 0)
+		goto disable_heads;
+
+	return 0;
+
+disable_heads:
+	while (i--)
+		clk_disable_unprepare(hub->clk_heads[i]);
+
+	clk_disable_unprepare(hub->clk_hub);
+disable_dsc:
+	clk_disable_unprepare(hub->clk_dsc);
+disable_disp:
+	clk_disable_unprepare(hub->clk_disp);
+put_rpm:
+	pm_runtime_put_sync(dev);
+	return err;
+}
+
+static const struct host1x_client_ops tegra_display_hub_ops = {
+	.init = tegra_display_hub_init,
+	.exit = tegra_display_hub_exit,
+	.suspend = tegra_display_hub_runtime_suspend,
+	.resume = tegra_display_hub_runtime_resume,
+};
+
+static int tegra_display_hub_probe(struct platform_device *pdev)
+{
+	struct device_node *child = NULL;
+	struct tegra_display_hub *hub;
+	struct clk *clk;
+	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;
+	}
+
+	if (hub->soc->supports_dsc) {
+		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;
+	}
+
+	hub->num_heads = of_get_child_count(pdev->dev.of_node);
+
+	hub->clk_heads = devm_kcalloc(&pdev->dev, hub->num_heads, sizeof(clk),
+				      GFP_KERNEL);
+	if (!hub->clk_heads)
+		return -ENOMEM;
+
+	for (i = 0; i < hub->num_heads; i++) {
+		child = of_get_next_child(pdev->dev.of_node, child);
+		if (!child) {
+			dev_err(&pdev->dev, "failed to find node for head %u\n",
+				i);
+			return -ENODEV;
+		}
+
+		clk = devm_get_clk_from_child(&pdev->dev, child, "dc");
+		if (IS_ERR(clk)) {
+			dev_err(&pdev->dev, "failed to get clock for head %u\n",
+				i);
+			of_node_put(child);
+			return PTR_ERR(clk);
+		}
+
+		hub->clk_heads[i] = clk;
+	}
+
+	of_node_put(child);
+
+	/* 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);
+
+	err = devm_of_platform_populate(&pdev->dev);
+	if (err < 0)
+		goto unregister;
+
+	return err;
+
+unregister:
+	host1x_client_unregister(&hub->client);
+	pm_runtime_disable(&pdev->dev);
+	return err;
+}
+
+static int tegra_display_hub_remove(struct platform_device *pdev)
+{
+	struct tegra_display_hub *hub = platform_get_drvdata(pdev);
+	unsigned int i;
+	int err;
+
+	err = host1x_client_unregister(&hub->client);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to unregister host1x client: %d\n",
+			err);
+	}
+
+	for (i = 0; i < hub->soc->num_wgrps; i++) {
+		struct tegra_windowgroup *wgrp = &hub->wgrps[i];
+
+		mutex_destroy(&wgrp->lock);
+	}
+
+	pm_runtime_disable(&pdev->dev);
+
+	return err;
+}
+
+static const struct tegra_display_hub_soc tegra186_display_hub = {
+	.num_wgrps = 6,
+	.supports_dsc = true,
+};
+
+static const struct tegra_display_hub_soc tegra194_display_hub = {
+	.num_wgrps = 6,
+	.supports_dsc = false,
+};
+
+static const struct of_device_id tegra_display_hub_of_match[] = {
+	{
+		.compatible = "nvidia,tegra194-display",
+		.data = &tegra194_display_hub
+	}, {
+		.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,
+	},
+	.probe = tegra_display_hub_probe,
+	.remove = tegra_display_hub_remove,
+};