text: /*
   * Copyright (C) 2015 Broadcom
   *
   * 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.
   */
  
  /**
   * DOC: VC4 CRTC module
   *
   * In VC4, the Pixel Valve is what most closely corresponds to the
   * DRM's concept of a CRTC.  The PV generates video timings from the
   * output's clock plus its configuration.  It pulls scaled pixels from
   * the HVS at that timing, and feeds it to the encoder.
   *
   * However, the DRM CRTC also collects the configuration of all the
   * DRM planes attached to it.  As a result, this file also manages
   * setup of the VC4 HVS's display elements on the CRTC.
   *
   * The 2835 has 3 different pixel valves.  pv0 in the audio power
   * domain feeds DSI0 or DPI, while pv1 feeds DS1 or SMI.  pv2 in the
   * image domain can feed either HDMI or the SDTV controller.  The
   * pixel valve chooses from the CPRMAN clocks (HSM for HDMI, VEC for
   * SDTV, etc.) according to which output type is chosen in the mux.
   *
   * For power management, the pixel valve's registers are all clocked
   * by the AXI clock, while the timings and FIFOs make use of the
   * output-specific clock.  Since the encoders also directly consume
   * the CPRMAN clocks, and know what timings they need, they are the
   * ones that set the clock.
   */
  
  #include "drm_atomic.h"
  #include "drm_atomic_helper.h"
  #include "drm_crtc_helper.h"
  #include "linux/clk.h"
  #include "drm_fb_cma_helper.h"
  #include "linux/component.h"
  #include "linux/of_device.h"
  #include "vc4_drv.h"
  #include "vc4_regs.h"
  
  struct vc4_crtc {
  	struct drm_crtc base;
  	const struct vc4_crtc_data *data;
  	void __iomem *regs;
  
  	/* Which HVS channel we're using for our CRTC. */
  	int channel;
  
  	u8 lut_r[256];
  	u8 lut_g[256];
  	u8 lut_b[256];
  
  	struct drm_pending_vblank_event *event;
  };
  
  struct vc4_crtc_state {
  	struct drm_crtc_state base;
  	/* Dlist area for this CRTC configuration. */
  	struct drm_mm_node mm;
  };
  
  static inline struct vc4_crtc *
  to_vc4_crtc(struct drm_crtc *crtc)
  {
  	return (struct vc4_crtc *)crtc;
  }
  
  static inline struct vc4_crtc_state *
  to_vc4_crtc_state(struct drm_crtc_state *crtc_state)
  {
  	return (struct vc4_crtc_state *)crtc_state;
  }
  
  struct vc4_crtc_data {
  	/* Which channel of the HVS this pixelvalve sources from. */
  	int hvs_channel;
  
  	enum vc4_encoder_type encoder0_type;
  	enum vc4_encoder_type encoder1_type;
  };
  
  #define CRTC_WRITE(offset, val) writel(val, vc4_crtc->regs + (offset))
  #define CRTC_READ(offset) readl(vc4_crtc->regs + (offset))
  
  #define CRTC_REG(reg) { reg, #reg }
  static const struct {
  	u32 reg;
  	const char *name;
  } crtc_regs[] = {
  	CRTC_REG(PV_CONTROL),
  	CRTC_REG(PV_V_CONTROL),
  	CRTC_REG(PV_VSYNCD_EVEN),
  	CRTC_REG(PV_HORZA),
  	CRTC_REG(PV_HORZB),
  	CRTC_REG(PV_VERTA),
  	CRTC_REG(PV_VERTB),
  	CRTC_REG(PV_VERTA_EVEN),
  	CRTC_REG(PV_VERTB_EVEN),
  	CRTC_REG(PV_INTEN),
  	CRTC_REG(PV_INTSTAT),
  	CRTC_REG(PV_STAT),
  	CRTC_REG(PV_HACT_ACT),
  };
  
  static void vc4_crtc_dump_regs(struct vc4_crtc *vc4_crtc)
  {
  	int i;
  
  	for (i = 0; i < ARRAY_SIZE(crtc_regs); i++) {
  		DRM_INFO("0x%04x (%s): 0x%08x\n",
  			 crtc_regs[i].reg, crtc_regs[i].name,
  			 CRTC_READ(crtc_regs[i].reg));
  	}
  }
  
  #ifdef CONFIG_DEBUG_FS
  int vc4_crtc_debugfs_regs(struct seq_file *m, void *unused)
  {
  	struct drm_info_node *node = (struct drm_info_node *)m->private;
  	struct drm_device *dev = node->minor->dev;
  	int crtc_index = (uintptr_t)node->info_ent->data;
  	struct drm_crtc *crtc;
  	struct vc4_crtc *vc4_crtc;
  	int i;
  
  	i = 0;
  	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
  		if (i == crtc_index)
  			break;
  		i++;
  	}
  	if (!crtc)
  		return 0;
  	vc4_crtc = to_vc4_crtc(crtc);
  
  	for (i = 0; i < ARRAY_SIZE(crtc_regs); i++) {
  		seq_printf(m, "%s (0x%04x): 0x%08x\n",
  			   crtc_regs[i].name, crtc_regs[i].reg,
  			   CRTC_READ(crtc_regs[i].reg));
  	}
  
  	return 0;
  }
  #endif
  
  static void vc4_crtc_destroy(struct drm_crtc *crtc)
  {
  	drm_crtc_cleanup(crtc);
  }
  
  static void
  vc4_crtc_lut_load(struct drm_crtc *crtc)
  {
  	struct drm_device *dev = crtc->dev;
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
  	u32 i;
  
  	/* The LUT memory is laid out with each HVS channel in order,
  	 * each of which takes 256 writes for R, 256 for G, then 256
  	 * for B.
  	 */
  	HVS_WRITE(SCALER_GAMADDR,
  		  SCALER_GAMADDR_AUTOINC |
  		  (vc4_crtc->channel * 3 * crtc->gamma_size));
  
  	for (i = 0; i < crtc->gamma_size; i++)
  		HVS_WRITE(SCALER_GAMDATA, vc4_crtc->lut_r[i]);
  	for (i = 0; i < crtc->gamma_size; i++)
  		HVS_WRITE(SCALER_GAMDATA, vc4_crtc->lut_g[i]);
  	for (i = 0; i < crtc->gamma_size; i++)
  		HVS_WRITE(SCALER_GAMDATA, vc4_crtc->lut_b[i]);
  }
  
  static void
  vc4_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b,
  		   uint32_t start, uint32_t size)
  {
  	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
  	u32 i;
  
  	for (i = start; i < start + size; i++) {
  		vc4_crtc->lut_r[i] = r[i] >> 8;
  		vc4_crtc->lut_g[i] = g[i] >> 8;
  		vc4_crtc->lut_b[i] = b[i] >> 8;
  	}
  
  	vc4_crtc_lut_load(crtc);
  }
  
  static u32 vc4_get_fifo_full_level(u32 format)
  {
  	static const u32 fifo_len_bytes = 64;
  	static const u32 hvs_latency_pix = 6;
  
  	switch (format) {
  	case PV_CONTROL_FORMAT_DSIV_16:
  	case PV_CONTROL_FORMAT_DSIC_16:
  		return fifo_len_bytes - 2 * hvs_latency_pix;
  	case PV_CONTROL_FORMAT_DSIV_18:
  		return fifo_len_bytes - 14;
  	case PV_CONTROL_FORMAT_24:
  	case PV_CONTROL_FORMAT_DSIV_24:
  	default:
  		return fifo_len_bytes - 3 * hvs_latency_pix;
  	}
  }
  
  /*
   * Returns the clock select bit for the connector attached to the
   * CRTC.
   */
  static int vc4_get_clock_select(struct drm_crtc *crtc)
  {
  	struct drm_connector *connector;
  
  	drm_for_each_connector(connector, crtc->dev) {
  		if (connector->state->crtc == crtc) {
  			struct drm_encoder *encoder = connector->encoder;
  			struct vc4_encoder *vc4_encoder =
  				to_vc4_encoder(encoder);
  
  			return vc4_encoder->clock_select;
  		}
  	}
  
  	return -1;
  }
  
  static void vc4_crtc_mode_set_nofb(struct drm_crtc *crtc)
  {
  	struct drm_device *dev = crtc->dev;
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
  	struct drm_crtc_state *state = crtc->state;
  	struct drm_display_mode *mode = &state->adjusted_mode;
  	bool interlace = mode->flags & DRM_MODE_FLAG_INTERLACE;
  	u32 vactive = (mode->vdisplay >> (interlace ? 1 : 0));
  	u32 format = PV_CONTROL_FORMAT_24;
  	bool debug_dump_regs = false;
  	int clock_select = vc4_get_clock_select(crtc);
  
  	if (debug_dump_regs) {
  		DRM_INFO("CRTC %d regs before:\n", drm_crtc_index(crtc));
  		vc4_crtc_dump_regs(vc4_crtc);
  	}
  
  	/* Reset the PV fifo. */
  	CRTC_WRITE(PV_CONTROL, 0);
  	CRTC_WRITE(PV_CONTROL, PV_CONTROL_FIFO_CLR | PV_CONTROL_EN);
  	CRTC_WRITE(PV_CONTROL, 0);
  
  	CRTC_WRITE(PV_HORZA,
  		   VC4_SET_FIELD(mode->htotal - mode->hsync_end,
  				 PV_HORZA_HBP) |
  		   VC4_SET_FIELD(mode->hsync_end - mode->hsync_start,
  				 PV_HORZA_HSYNC));
  	CRTC_WRITE(PV_HORZB,
  		   VC4_SET_FIELD(mode->hsync_start - mode->hdisplay,
  				 PV_HORZB_HFP) |
  		   VC4_SET_FIELD(mode->hdisplay, PV_HORZB_HACTIVE));
  
  	CRTC_WRITE(PV_VERTA,
  		   VC4_SET_FIELD(mode->vtotal - mode->vsync_end,
  				 PV_VERTA_VBP) |
  		   VC4_SET_FIELD(mode->vsync_end - mode->vsync_start,
  				 PV_VERTA_VSYNC));
  	CRTC_WRITE(PV_VERTB,
  		   VC4_SET_FIELD(mode->vsync_start - mode->vdisplay,
  				 PV_VERTB_VFP) |
  		   VC4_SET_FIELD(vactive, PV_VERTB_VACTIVE));
  
  	if (interlace) {
  		CRTC_WRITE(PV_VERTA_EVEN,
  			   VC4_SET_FIELD(mode->vtotal - mode->vsync_end - 1,
  					 PV_VERTA_VBP) |
  			   VC4_SET_FIELD(mode->vsync_end - mode->vsync_start,
  					 PV_VERTA_VSYNC));
  		CRTC_WRITE(PV_VERTB_EVEN,
  			   VC4_SET_FIELD(mode->vsync_start - mode->vdisplay,
  					 PV_VERTB_VFP) |
  			   VC4_SET_FIELD(vactive, PV_VERTB_VACTIVE));
  	}
  
  	CRTC_WRITE(PV_HACT_ACT, mode->hdisplay);
  
  	CRTC_WRITE(PV_V_CONTROL,
  		   PV_VCONTROL_CONTINUOUS |
  		   (interlace ? PV_VCONTROL_INTERLACE : 0));
  
  	CRTC_WRITE(PV_CONTROL,
  		   VC4_SET_FIELD(format, PV_CONTROL_FORMAT) |
  		   VC4_SET_FIELD(vc4_get_fifo_full_level(format),
  				 PV_CONTROL_FIFO_LEVEL) |
  		   PV_CONTROL_CLR_AT_START |
  		   PV_CONTROL_TRIGGER_UNDERFLOW |
  		   PV_CONTROL_WAIT_HSTART |
  		   VC4_SET_FIELD(clock_select, PV_CONTROL_CLK_SELECT) |
  		   PV_CONTROL_FIFO_CLR |
  		   PV_CONTROL_EN);
  
  	HVS_WRITE(SCALER_DISPBKGNDX(vc4_crtc->channel),
  		  SCALER_DISPBKGND_AUTOHS |
  		  SCALER_DISPBKGND_GAMMA |
  		  (interlace ? SCALER_DISPBKGND_INTERLACE : 0));
  
  	/* Reload the LUT, since the SRAMs would have been disabled if
  	 * all CRTCs had SCALER_DISPBKGND_GAMMA unset at once.
  	 */
  	vc4_crtc_lut_load(crtc);
  
  	if (debug_dump_regs) {
  		DRM_INFO("CRTC %d regs after:\n", drm_crtc_index(crtc));
  		vc4_crtc_dump_regs(vc4_crtc);
  	}
  }
  
  static void require_hvs_enabled(struct drm_device *dev)
  {
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  
  	WARN_ON_ONCE((HVS_READ(SCALER_DISPCTRL) & SCALER_DISPCTRL_ENABLE) !=
  		     SCALER_DISPCTRL_ENABLE);
  }
  
  static void vc4_crtc_disable(struct drm_crtc *crtc)
  {
  	struct drm_device *dev = crtc->dev;
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
  	u32 chan = vc4_crtc->channel;
  	int ret;
  	require_hvs_enabled(dev);
  
  	CRTC_WRITE(PV_V_CONTROL,
  		   CRTC_READ(PV_V_CONTROL) & ~PV_VCONTROL_VIDEN);
  	ret = wait_for(!(CRTC_READ(PV_V_CONTROL) & PV_VCONTROL_VIDEN), 1);
  	WARN_ONCE(ret, "Timeout waiting for !PV_VCONTROL_VIDEN\n");
  
  	if (HVS_READ(SCALER_DISPCTRLX(chan)) &
  	    SCALER_DISPCTRLX_ENABLE) {
  		HVS_WRITE(SCALER_DISPCTRLX(chan),
  			  SCALER_DISPCTRLX_RESET);
  
  		/* While the docs say that reset is self-clearing, it
  		 * seems it doesn't actually.
  		 */
  		HVS_WRITE(SCALER_DISPCTRLX(chan), 0);
  	}
  
  	/* Once we leave, the scaler should be disabled and its fifo empty. */
  
  	WARN_ON_ONCE(HVS_READ(SCALER_DISPCTRLX(chan)) & SCALER_DISPCTRLX_RESET);
  
  	WARN_ON_ONCE(VC4_GET_FIELD(HVS_READ(SCALER_DISPSTATX(chan)),
  				   SCALER_DISPSTATX_MODE) !=
  		     SCALER_DISPSTATX_MODE_DISABLED);
  
  	WARN_ON_ONCE((HVS_READ(SCALER_DISPSTATX(chan)) &
  		      (SCALER_DISPSTATX_FULL | SCALER_DISPSTATX_EMPTY)) !=
  		     SCALER_DISPSTATX_EMPTY);
  }
  
  static void vc4_crtc_enable(struct drm_crtc *crtc)
  {
  	struct drm_device *dev = crtc->dev;
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
  	struct drm_crtc_state *state = crtc->state;
  	struct drm_display_mode *mode = &state->adjusted_mode;
  
  	require_hvs_enabled(dev);
  
  	/* Turn on the scaler, which will wait for vstart to start
  	 * compositing.
  	 */
  	HVS_WRITE(SCALER_DISPCTRLX(vc4_crtc->channel),
  		  VC4_SET_FIELD(mode->hdisplay, SCALER_DISPCTRLX_WIDTH) |
  		  VC4_SET_FIELD(mode->vdisplay, SCALER_DISPCTRLX_HEIGHT) |
  		  SCALER_DISPCTRLX_ENABLE);
  
  	/* Turn on the pixel valve, which will emit the vstart signal. */
  	CRTC_WRITE(PV_V_CONTROL,
  		   CRTC_READ(PV_V_CONTROL) | PV_VCONTROL_VIDEN);
  }
  
  static int vc4_crtc_atomic_check(struct drm_crtc *crtc,
  				 struct drm_crtc_state *state)
  {
  	struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(state);
  	struct drm_device *dev = crtc->dev;
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct drm_plane *plane;
  	unsigned long flags;
  	u32 dlist_count = 0;
  	int ret;
  
  	/* The pixelvalve can only feed one encoder (and encoders are
  	 * 1:1 with connectors.)
  	 */
  	if (hweight32(state->connector_mask) > 1)
  		return -EINVAL;
  
  	drm_atomic_crtc_state_for_each_plane(plane, state) {
  		struct drm_plane_state *plane_state =
  			state->state->plane_states[drm_plane_index(plane)];
  
  		/* plane might not have changed, in which case take
  		 * current state:
  		 */
  		if (!plane_state)
  			plane_state = plane->state;
  
  		dlist_count += vc4_plane_dlist_size(plane_state);
  	}
  
  	dlist_count++; /* Account for SCALER_CTL0_END. */
  
  	spin_lock_irqsave(&vc4->hvs->mm_lock, flags);
  	ret = drm_mm_insert_node(&vc4->hvs->dlist_mm, &vc4_state->mm,
  				 dlist_count, 1, 0);
  	spin_unlock_irqrestore(&vc4->hvs->mm_lock, flags);
  	if (ret)
  		return ret;
  
  	return 0;
  }
  
  static void vc4_crtc_atomic_flush(struct drm_crtc *crtc,
  				  struct drm_crtc_state *old_state)
  {
  	struct drm_device *dev = crtc->dev;
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
  	struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state);
  	struct drm_plane *plane;
  	bool debug_dump_regs = false;
  	u32 __iomem *dlist_start = vc4->hvs->dlist + vc4_state->mm.start;
  	u32 __iomem *dlist_next = dlist_start;
  
  	if (debug_dump_regs) {
  		DRM_INFO("CRTC %d HVS before:\n", drm_crtc_index(crtc));
  		vc4_hvs_dump_state(dev);
  	}
  
  	/* Copy all the active planes' dlist contents to the hardware dlist. */
  	drm_atomic_crtc_for_each_plane(plane, crtc) {
  		dlist_next += vc4_plane_write_dlist(plane, dlist_next);
  	}
  
  	writel(SCALER_CTL0_END, dlist_next);
  	dlist_next++;
  
  	WARN_ON_ONCE(dlist_next - dlist_start != vc4_state->mm.size);
  
  	if (crtc->state->event) {
  		unsigned long flags;
  
  		crtc->state->event->pipe = drm_crtc_index(crtc);
  
  		WARN_ON(drm_crtc_vblank_get(crtc) != 0);
  
  		spin_lock_irqsave(&dev->event_lock, flags);
  		vc4_crtc->event = crtc->state->event;
  		crtc->state->event = NULL;
  
  		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
  			  vc4_state->mm.start);
  
  		spin_unlock_irqrestore(&dev->event_lock, flags);
  	} else {
  		HVS_WRITE(SCALER_DISPLISTX(vc4_crtc->channel),
  			  vc4_state->mm.start);
  	}
  
  	if (debug_dump_regs) {
  		DRM_INFO("CRTC %d HVS after:\n", drm_crtc_index(crtc));
  		vc4_hvs_dump_state(dev);
  	}
  }
  
  int vc4_enable_vblank(struct drm_device *dev, unsigned int crtc_id)
  {
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct vc4_crtc *vc4_crtc = vc4->crtc[crtc_id];
  
  	CRTC_WRITE(PV_INTEN, PV_INT_VFP_START);
  
  	return 0;
  }
  
  void vc4_disable_vblank(struct drm_device *dev, unsigned int crtc_id)
  {
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct vc4_crtc *vc4_crtc = vc4->crtc[crtc_id];
  
  	CRTC_WRITE(PV_INTEN, 0);
  }
  
  static void vc4_crtc_handle_page_flip(struct vc4_crtc *vc4_crtc)
  {
  	struct drm_crtc *crtc = &vc4_crtc->base;
  	struct drm_device *dev = crtc->dev;
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(crtc->state);
  	u32 chan = vc4_crtc->channel;
  	unsigned long flags;
  
  	spin_lock_irqsave(&dev->event_lock, flags);
  	if (vc4_crtc->event &&
  	    (vc4_state->mm.start == HVS_READ(SCALER_DISPLACTX(chan)))) {
  		drm_crtc_send_vblank_event(crtc, vc4_crtc->event);
  		vc4_crtc->event = NULL;
  		drm_crtc_vblank_put(crtc);
  	}
  	spin_unlock_irqrestore(&dev->event_lock, flags);
  }
  
  static irqreturn_t vc4_crtc_irq_handler(int irq, void *data)
  {
  	struct vc4_crtc *vc4_crtc = data;
  	u32 stat = CRTC_READ(PV_INTSTAT);
  	irqreturn_t ret = IRQ_NONE;
  
  	if (stat & PV_INT_VFP_START) {
  		CRTC_WRITE(PV_INTSTAT, PV_INT_VFP_START);
  		drm_crtc_handle_vblank(&vc4_crtc->base);
  		vc4_crtc_handle_page_flip(vc4_crtc);
  		ret = IRQ_HANDLED;
  	}
  
  	return ret;
  }
  
  struct vc4_async_flip_state {
  	struct drm_crtc *crtc;
  	struct drm_framebuffer *fb;
  	struct drm_pending_vblank_event *event;
  
  	struct vc4_seqno_cb cb;
  };
  
  /* Called when the V3D execution for the BO being flipped to is done, so that
   * we can actually update the plane's address to point to it.
   */
  static void
  vc4_async_page_flip_complete(struct vc4_seqno_cb *cb)
  {
  	struct vc4_async_flip_state *flip_state =
  		container_of(cb, struct vc4_async_flip_state, cb);
  	struct drm_crtc *crtc = flip_state->crtc;
  	struct drm_device *dev = crtc->dev;
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct drm_plane *plane = crtc->primary;
  
  	vc4_plane_async_set_fb(plane, flip_state->fb);
  	if (flip_state->event) {
  		unsigned long flags;
  
  		spin_lock_irqsave(&dev->event_lock, flags);
  		drm_crtc_send_vblank_event(crtc, flip_state->event);
  		spin_unlock_irqrestore(&dev->event_lock, flags);
  	}
  
  	drm_crtc_vblank_put(crtc);
  	drm_framebuffer_unreference(flip_state->fb);
  	kfree(flip_state);
  
  	up(&vc4->async_modeset);
  }
  
  /* Implements async (non-vblank-synced) page flips.
   *
   * The page flip ioctl needs to return immediately, so we grab the
   * modeset semaphore on the pipe, and queue the address update for
   * when V3D is done with the BO being flipped to.
   */
  static int vc4_async_page_flip(struct drm_crtc *crtc,
  			       struct drm_framebuffer *fb,
  			       struct drm_pending_vblank_event *event,
  			       uint32_t flags)
  {
  	struct drm_device *dev = crtc->dev;
  	struct vc4_dev *vc4 = to_vc4_dev(dev);
  	struct drm_plane *plane = crtc->primary;
  	int ret = 0;
  	struct vc4_async_flip_state *flip_state;
  	struct drm_gem_cma_object *cma_bo = drm_fb_cma_get_gem_obj(fb, 0);
  	struct vc4_bo *bo = to_vc4_bo(&cma_bo->base);
  
  	flip_state = kzalloc(sizeof(*flip_state), GFP_KERNEL);
  	if (!flip_state)
  		return -ENOMEM;
  
  	drm_framebuffer_reference(fb);
  	flip_state->fb = fb;
  	flip_state->crtc = crtc;
  	flip_state->event = event;
  
  	/* Make sure all other async modesetes have landed. */
  	ret = down_interruptible(&vc4->async_modeset);
  	if (ret) {
  		drm_framebuffer_unreference(fb);
  		kfree(flip_state);
  		return ret;
  	}
  
  	WARN_ON(drm_crtc_vblank_get(crtc) != 0);
  
  	/* Immediately update the plane's legacy fb pointer, so that later
  	 * modeset prep sees the state that will be present when the semaphore
  	 * is released.
  	 */
  	drm_atomic_set_fb_for_plane(plane->state, fb);
  	plane->fb = fb;
  
  	vc4_queue_seqno_cb(dev, &flip_state->cb, bo->seqno,
  			   vc4_async_page_flip_complete);
  
  	/* Driver takes ownership of state on successful async commit. */
  	return 0;
  }
  
  static int vc4_page_flip(struct drm_crtc *crtc,
  			 struct drm_framebuffer *fb,
  			 struct drm_pending_vblank_event *event,
  			 uint32_t flags)
  {
  	if (flags & DRM_MODE_PAGE_FLIP_ASYNC)
  		return vc4_async_page_flip(crtc, fb, event, flags);
  	else
  		return drm_atomic_helper_page_flip(crtc, fb, event, flags);
  }
  
  static struct drm_crtc_state *vc4_crtc_duplicate_state(struct drm_crtc *crtc)
  {
  	struct vc4_crtc_state *vc4_state;
  
  	vc4_state = kzalloc(sizeof(*vc4_state), GFP_KERNEL);
  	if (!vc4_state)
  		return NULL;
  
  	__drm_atomic_helper_crtc_duplicate_state(crtc, &vc4_state->base);
  	return &vc4_state->base;
  }
  
  static void vc4_crtc_destroy_state(struct drm_crtc *crtc,
  				   struct drm_crtc_state *state)
  {
  	struct vc4_dev *vc4 = to_vc4_dev(crtc->dev);
  	struct vc4_crtc_state *vc4_state = to_vc4_crtc_state(state);
  
  	if (vc4_state->mm.allocated) {
  		unsigned long flags;
  
  		spin_lock_irqsave(&vc4->hvs->mm_lock, flags);
  		drm_mm_remove_node(&vc4_state->mm);
  		spin_unlock_irqrestore(&vc4->hvs->mm_lock, flags);
  
  	}
  
  	__drm_atomic_helper_crtc_destroy_state(state);
  }
  
  static const struct drm_crtc_funcs vc4_crtc_funcs = {
  	.set_config = drm_atomic_helper_set_config,
  	.destroy = vc4_crtc_destroy,
  	.page_flip = vc4_page_flip,
  	.set_property = NULL,
  	.cursor_set = NULL, /* handled by drm_mode_cursor_universal */
  	.cursor_move = NULL, /* handled by drm_mode_cursor_universal */
  	.reset = drm_atomic_helper_crtc_reset,
  	.atomic_duplicate_state = vc4_crtc_duplicate_state,
  	.atomic_destroy_state = vc4_crtc_destroy_state,
  	.gamma_set = vc4_crtc_gamma_set,
  };
  
  static const struct drm_crtc_helper_funcs vc4_crtc_helper_funcs = {
  	.mode_set_nofb = vc4_crtc_mode_set_nofb,
  	.disable = vc4_crtc_disable,
  	.enable = vc4_crtc_enable,
  	.atomic_check = vc4_crtc_atomic_check,
  	.atomic_flush = vc4_crtc_atomic_flush,
  };
  
  static const struct vc4_crtc_data pv0_data = {
  	.hvs_channel = 0,
  	.encoder0_type = VC4_ENCODER_TYPE_DSI0,
  	.encoder1_type = VC4_ENCODER_TYPE_DPI,
  };
  
  static const struct vc4_crtc_data pv1_data = {
  	.hvs_channel = 2,
  	.encoder0_type = VC4_ENCODER_TYPE_DSI1,
  	.encoder1_type = VC4_ENCODER_TYPE_SMI,
  };
  
  static const struct vc4_crtc_data pv2_data = {
  	.hvs_channel = 1,
  	.encoder0_type = VC4_ENCODER_TYPE_VEC,
  	.encoder1_type = VC4_ENCODER_TYPE_HDMI,
  };
  
  static const struct of_device_id vc4_crtc_dt_match[] = {
  	{ .compatible = "brcm,bcm2835-pixelvalve0", .data = &pv0_data },
  	{ .compatible = "brcm,bcm2835-pixelvalve1", .data = &pv1_data },
  	{ .compatible = "brcm,bcm2835-pixelvalve2", .data = &pv2_data },
  	{}
  };
  
  static void vc4_set_crtc_possible_masks(struct drm_device *drm,
  					struct drm_crtc *crtc)
  {
  	struct vc4_crtc *vc4_crtc = to_vc4_crtc(crtc);
  	struct drm_encoder *encoder;
  
  	drm_for_each_encoder(encoder, drm) {
  		struct vc4_encoder *vc4_encoder = to_vc4_encoder(encoder);
  
  		if (vc4_encoder->type == vc4_crtc->data->encoder0_type) {
  			vc4_encoder->clock_select = 0;
  			encoder->possible_crtcs |= drm_crtc_mask(crtc);
  		} else if (vc4_encoder->type == vc4_crtc->data->encoder1_type) {
  			vc4_encoder->clock_select = 1;
  			encoder->possible_crtcs |= drm_crtc_mask(crtc);
  		}
  	}
  }
  
  static int vc4_crtc_bind(struct device *dev, struct device *master, void *data)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct drm_device *drm = dev_get_drvdata(master);
  	struct vc4_dev *vc4 = to_vc4_dev(drm);
  	struct vc4_crtc *vc4_crtc;
  	struct drm_crtc *crtc;
  	struct drm_plane *primary_plane, *cursor_plane, *destroy_plane, *temp;
  	const struct of_device_id *match;
  	int ret, i;
  
  	vc4_crtc = devm_kzalloc(dev, sizeof(*vc4_crtc), GFP_KERNEL);
  	if (!vc4_crtc)
  		return -ENOMEM;
  	crtc = &vc4_crtc->base;
  
  	match = of_match_device(vc4_crtc_dt_match, dev);
  	if (!match)
  		return -ENODEV;
  	vc4_crtc->data = match->data;
  
  	vc4_crtc->regs = vc4_ioremap_regs(pdev, 0);
  	if (IS_ERR(vc4_crtc->regs))
  		return PTR_ERR(vc4_crtc->regs);
  
  	/* For now, we create just the primary and the legacy cursor
  	 * planes.  We should be able to stack more planes on easily,
  	 * but to do that we would need to compute the bandwidth
  	 * requirement of the plane configuration, and reject ones
  	 * that will take too much.
  	 */
  	primary_plane = vc4_plane_init(drm, DRM_PLANE_TYPE_PRIMARY);
  	if (IS_ERR(primary_plane)) {
  		dev_err(dev, "failed to construct primary plane\n");
  		ret = PTR_ERR(primary_plane);
  		goto err;
  	}
  
  	drm_crtc_init_with_planes(drm, crtc, primary_plane, NULL,
  				  &vc4_crtc_funcs, NULL);
  	drm_crtc_helper_add(crtc, &vc4_crtc_helper_funcs);
  	primary_plane->crtc = crtc;
  	vc4->crtc[drm_crtc_index(crtc)] = vc4_crtc;
  	vc4_crtc->channel = vc4_crtc->data->hvs_channel;
  	drm_mode_crtc_set_gamma_size(crtc, ARRAY_SIZE(vc4_crtc->lut_r));
  
  	/* Set up some arbitrary number of planes.  We're not limited
  	 * by a set number of physical registers, just the space in
  	 * the HVS (16k) and how small an plane can be (28 bytes).
  	 * However, each plane we set up takes up some memory, and
  	 * increases the cost of looping over planes, which atomic
  	 * modesetting does quite a bit.  As a result, we pick a
  	 * modest number of planes to expose, that should hopefully
  	 * still cover any sane usecase.
  	 */
  	for (i = 0; i < 8; i++) {
  		struct drm_plane *plane =
  			vc4_plane_init(drm, DRM_PLANE_TYPE_OVERLAY);
  
  		if (IS_ERR(plane))
  			continue;
  
  		plane->possible_crtcs = 1 << drm_crtc_index(crtc);
  	}
  
  	/* Set up the legacy cursor after overlay initialization,
  	 * since we overlay planes on the CRTC in the order they were
  	 * initialized.
  	 */
  	cursor_plane = vc4_plane_init(drm, DRM_PLANE_TYPE_CURSOR);
  	if (!IS_ERR(cursor_plane)) {
  		cursor_plane->possible_crtcs = 1 << drm_crtc_index(crtc);
  		cursor_plane->crtc = crtc;
  		crtc->cursor = cursor_plane;
  	}
  
  	CRTC_WRITE(PV_INTEN, 0);
  	CRTC_WRITE(PV_INTSTAT, PV_INT_VFP_START);
  	ret = devm_request_irq(dev, platform_get_irq(pdev, 0),
  			       vc4_crtc_irq_handler, 0, "vc4 crtc", vc4_crtc);
  	if (ret)
  		goto err_destroy_planes;
  
  	vc4_set_crtc_possible_masks(drm, crtc);
  
  	for (i = 0; i < crtc->gamma_size; i++) {
  		vc4_crtc->lut_r[i] = i;
  		vc4_crtc->lut_g[i] = i;
  		vc4_crtc->lut_b[i] = i;
  	}
  
  	platform_set_drvdata(pdev, vc4_crtc);
  
  	return 0;
  
  err_destroy_planes:
  	list_for_each_entry_safe(destroy_plane, temp,
  				 &drm->mode_config.plane_list, head) {
  		if (destroy_plane->possible_crtcs == 1 << drm_crtc_index(crtc))
  		    destroy_plane->funcs->destroy(destroy_plane);
  	}
  err:
  	return ret;
  }
  
  static void vc4_crtc_unbind(struct device *dev, struct device *master,
  			    void *data)
  {
  	struct platform_device *pdev = to_platform_device(dev);
  	struct vc4_crtc *vc4_crtc = dev_get_drvdata(dev);
  
  	vc4_crtc_destroy(&vc4_crtc->base);
  
  	CRTC_WRITE(PV_INTEN, 0);
  
  	platform_set_drvdata(pdev, NULL);
  }
  
  static const struct component_ops vc4_crtc_ops = {
  	.bind   = vc4_crtc_bind,
  	.unbind = vc4_crtc_unbind,
  };
  
  static int vc4_crtc_dev_probe(struct platform_device *pdev)
  {
  	return component_add(&pdev->dev, &vc4_crtc_ops);
  }
  
  static int vc4_crtc_dev_remove(struct platform_device *pdev)
  {
  	component_del(&pdev->dev, &vc4_crtc_ops);
  	return 0;
  }
  
  struct platform_driver vc4_crtc_driver = {
  	.probe = vc4_crtc_dev_probe,
  	.remove = vc4_crtc_dev_remove,
  	.driver = {
  		.name = "vc4_crtc",
  		.of_match_table = vc4_crtc_dt_match,
  	},
  };
  