drm/i915: move fbc-related functionality into intel_pm module

This commit moves Frame Buffer Compression-related operations and support
functions into the new intel_pm module.

Signed-off-by: Eugeni Dodonov <eugeni.dodonov@intel.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

4 files changed, 537 insertions, 484 deletions

diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index f801330..b65c06f 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -23,6 +23,7 @@ i915-y := i915_drv.o i915_dma.o i915_irq.o \
 	  intel_sdvo.o \
 	  intel_modes.o \
 	  intel_panel.o \
+	  intel_pm.o \
 	  intel_i2c.o \
 	  intel_fb.o \
 	  intel_tv.o \
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 1f844c5..6768d75 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1627,490 +1627,6 @@ static void intel_disable_pch_ports(struct drm_i915_private *dev_priv,
 	disable_pch_hdmi(dev_priv, pipe, HDMID);
 }
 
-static void i8xx_disable_fbc(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 fbc_ctl;
-
-	/* Disable compression */
-	fbc_ctl = I915_READ(FBC_CONTROL);
-	if ((fbc_ctl & FBC_CTL_EN) == 0)
-		return;
-
-	fbc_ctl &= ~FBC_CTL_EN;
-	I915_WRITE(FBC_CONTROL, fbc_ctl);
-
-	/* Wait for compressing bit to clear */
-	if (wait_for((I915_READ(FBC_STATUS) & FBC_STAT_COMPRESSING) == 0, 10)) {
-		DRM_DEBUG_KMS("FBC idle timed out\n");
-		return;
-	}
-
-	DRM_DEBUG_KMS("disabled FBC\n");
-}
-
-static void i8xx_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
-{
-	struct drm_device *dev = crtc->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct drm_framebuffer *fb = crtc->fb;
-	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
-	struct drm_i915_gem_object *obj = intel_fb->obj;
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-	int cfb_pitch;
-	int plane, i;
-	u32 fbc_ctl, fbc_ctl2;
-
-	cfb_pitch = dev_priv->cfb_size / FBC_LL_SIZE;
-	if (fb->pitches[0] < cfb_pitch)
-		cfb_pitch = fb->pitches[0];
-
-	/* FBC_CTL wants 64B units */
-	cfb_pitch = (cfb_pitch / 64) - 1;
-	plane = intel_crtc->plane == 0 ? FBC_CTL_PLANEA : FBC_CTL_PLANEB;
-
-	/* Clear old tags */
-	for (i = 0; i < (FBC_LL_SIZE / 32) + 1; i++)
-		I915_WRITE(FBC_TAG + (i * 4), 0);
-
-	/* Set it up... */
-	fbc_ctl2 = FBC_CTL_FENCE_DBL | FBC_CTL_IDLE_IMM | FBC_CTL_CPU_FENCE;
-	fbc_ctl2 |= plane;
-	I915_WRITE(FBC_CONTROL2, fbc_ctl2);
-	I915_WRITE(FBC_FENCE_OFF, crtc->y);
-
-	/* enable it... */
-	fbc_ctl = FBC_CTL_EN | FBC_CTL_PERIODIC;
-	if (IS_I945GM(dev))
-		fbc_ctl |= FBC_CTL_C3_IDLE; /* 945 needs special SR handling */
-	fbc_ctl |= (cfb_pitch & 0xff) << FBC_CTL_STRIDE_SHIFT;
-	fbc_ctl |= (interval & 0x2fff) << FBC_CTL_INTERVAL_SHIFT;
-	fbc_ctl |= obj->fence_reg;
-	I915_WRITE(FBC_CONTROL, fbc_ctl);
-
-	DRM_DEBUG_KMS("enabled FBC, pitch %d, yoff %d, plane %d, ",
-		      cfb_pitch, crtc->y, intel_crtc->plane);
-}
-
-static bool i8xx_fbc_enabled(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	return I915_READ(FBC_CONTROL) & FBC_CTL_EN;
-}
-
-static void g4x_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
-{
-	struct drm_device *dev = crtc->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct drm_framebuffer *fb = crtc->fb;
-	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
-	struct drm_i915_gem_object *obj = intel_fb->obj;
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-	int plane = intel_crtc->plane == 0 ? DPFC_CTL_PLANEA : DPFC_CTL_PLANEB;
-	unsigned long stall_watermark = 200;
-	u32 dpfc_ctl;
-
-	dpfc_ctl = plane | DPFC_SR_EN | DPFC_CTL_LIMIT_1X;
-	dpfc_ctl |= DPFC_CTL_FENCE_EN | obj->fence_reg;
-	I915_WRITE(DPFC_CHICKEN, DPFC_HT_MODIFY);
-
-	I915_WRITE(DPFC_RECOMP_CTL, DPFC_RECOMP_STALL_EN |
-		   (stall_watermark << DPFC_RECOMP_STALL_WM_SHIFT) |
-		   (interval << DPFC_RECOMP_TIMER_COUNT_SHIFT));
-	I915_WRITE(DPFC_FENCE_YOFF, crtc->y);
-
-	/* enable it... */
-	I915_WRITE(DPFC_CONTROL, I915_READ(DPFC_CONTROL) | DPFC_CTL_EN);
-
-	DRM_DEBUG_KMS("enabled fbc on plane %d\n", intel_crtc->plane);
-}
-
-static void g4x_disable_fbc(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 dpfc_ctl;
-
-	/* Disable compression */
-	dpfc_ctl = I915_READ(DPFC_CONTROL);
-	if (dpfc_ctl & DPFC_CTL_EN) {
-		dpfc_ctl &= ~DPFC_CTL_EN;
-		I915_WRITE(DPFC_CONTROL, dpfc_ctl);
-
-		DRM_DEBUG_KMS("disabled FBC\n");
-	}
-}
-
-static bool g4x_fbc_enabled(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	return I915_READ(DPFC_CONTROL) & DPFC_CTL_EN;
-}
-
-static void sandybridge_blit_fbc_update(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 blt_ecoskpd;
-
-	/* Make sure blitter notifies FBC of writes */
-	gen6_gt_force_wake_get(dev_priv);
-	blt_ecoskpd = I915_READ(GEN6_BLITTER_ECOSKPD);
-	blt_ecoskpd |= GEN6_BLITTER_FBC_NOTIFY <<
-		GEN6_BLITTER_LOCK_SHIFT;
-	I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
-	blt_ecoskpd |= GEN6_BLITTER_FBC_NOTIFY;
-	I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
-	blt_ecoskpd &= ~(GEN6_BLITTER_FBC_NOTIFY <<
-			 GEN6_BLITTER_LOCK_SHIFT);
-	I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
-	POSTING_READ(GEN6_BLITTER_ECOSKPD);
-	gen6_gt_force_wake_put(dev_priv);
-}
-
-static void ironlake_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
-{
-	struct drm_device *dev = crtc->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct drm_framebuffer *fb = crtc->fb;
-	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
-	struct drm_i915_gem_object *obj = intel_fb->obj;
-	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
-	int plane = intel_crtc->plane == 0 ? DPFC_CTL_PLANEA : DPFC_CTL_PLANEB;
-	unsigned long stall_watermark = 200;
-	u32 dpfc_ctl;
-
-	dpfc_ctl = I915_READ(ILK_DPFC_CONTROL);
-	dpfc_ctl &= DPFC_RESERVED;
-	dpfc_ctl |= (plane | DPFC_CTL_LIMIT_1X);
-	/* Set persistent mode for front-buffer rendering, ala X. */
-	dpfc_ctl |= DPFC_CTL_PERSISTENT_MODE;
-	dpfc_ctl |= (DPFC_CTL_FENCE_EN | obj->fence_reg);
-	I915_WRITE(ILK_DPFC_CHICKEN, DPFC_HT_MODIFY);
-
-	I915_WRITE(ILK_DPFC_RECOMP_CTL, DPFC_RECOMP_STALL_EN |
-		   (stall_watermark << DPFC_RECOMP_STALL_WM_SHIFT) |
-		   (interval << DPFC_RECOMP_TIMER_COUNT_SHIFT));
-	I915_WRITE(ILK_DPFC_FENCE_YOFF, crtc->y);
-	I915_WRITE(ILK_FBC_RT_BASE, obj->gtt_offset | ILK_FBC_RT_VALID);
-	/* enable it... */
-	I915_WRITE(ILK_DPFC_CONTROL, dpfc_ctl | DPFC_CTL_EN);
-
-	if (IS_GEN6(dev)) {
-		I915_WRITE(SNB_DPFC_CTL_SA,
-			   SNB_CPU_FENCE_ENABLE | obj->fence_reg);
-		I915_WRITE(DPFC_CPU_FENCE_OFFSET, crtc->y);
-		sandybridge_blit_fbc_update(dev);
-	}
-
-	DRM_DEBUG_KMS("enabled fbc on plane %d\n", intel_crtc->plane);
-}
-
-static void ironlake_disable_fbc(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	u32 dpfc_ctl;
-
-	/* Disable compression */
-	dpfc_ctl = I915_READ(ILK_DPFC_CONTROL);
-	if (dpfc_ctl & DPFC_CTL_EN) {
-		dpfc_ctl &= ~DPFC_CTL_EN;
-		I915_WRITE(ILK_DPFC_CONTROL, dpfc_ctl);
-
-		DRM_DEBUG_KMS("disabled FBC\n");
-	}
-}
-
-static bool ironlake_fbc_enabled(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	return I915_READ(ILK_DPFC_CONTROL) & DPFC_CTL_EN;
-}
-
-bool intel_fbc_enabled(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	if (!dev_priv->display.fbc_enabled)
-		return false;
-
-	return dev_priv->display.fbc_enabled(dev);
-}
-
-static void intel_fbc_work_fn(struct work_struct *__work)
-{
-	struct intel_fbc_work *work =
-		container_of(to_delayed_work(__work),
-			     struct intel_fbc_work, work);
-	struct drm_device *dev = work->crtc->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	mutex_lock(&dev->struct_mutex);
-	if (work == dev_priv->fbc_work) {
-		/* Double check that we haven't switched fb without cancelling
-		 * the prior work.
-		 */
-		if (work->crtc->fb == work->fb) {
-			dev_priv->display.enable_fbc(work->crtc,
-						     work->interval);
-
-			dev_priv->cfb_plane = to_intel_crtc(work->crtc)->plane;
-			dev_priv->cfb_fb = work->crtc->fb->base.id;
-			dev_priv->cfb_y = work->crtc->y;
-		}
-
-		dev_priv->fbc_work = NULL;
-	}
-	mutex_unlock(&dev->struct_mutex);
-
-	kfree(work);
-}
-
-static void intel_cancel_fbc_work(struct drm_i915_private *dev_priv)
-{
-	if (dev_priv->fbc_work == NULL)
-		return;
-
-	DRM_DEBUG_KMS("cancelling pending FBC enable\n");
-
-	/* Synchronisation is provided by struct_mutex and checking of
-	 * dev_priv->fbc_work, so we can perform the cancellation
-	 * entirely asynchronously.
-	 */
-	if (cancel_delayed_work(&dev_priv->fbc_work->work))
-		/* tasklet was killed before being run, clean up */
-		kfree(dev_priv->fbc_work);
-
-	/* Mark the work as no longer wanted so that if it does
-	 * wake-up (because the work was already running and waiting
-	 * for our mutex), it will discover that is no longer
-	 * necessary to run.
-	 */
-	dev_priv->fbc_work = NULL;
-}
-
-static void intel_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
-{
-	struct intel_fbc_work *work;
-	struct drm_device *dev = crtc->dev;
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	if (!dev_priv->display.enable_fbc)
-		return;
-
-	intel_cancel_fbc_work(dev_priv);
-
-	work = kzalloc(sizeof *work, GFP_KERNEL);
-	if (work == NULL) {
-		dev_priv->display.enable_fbc(crtc, interval);
-		return;
-	}
-
-	work->crtc = crtc;
-	work->fb = crtc->fb;
-	work->interval = interval;
-	INIT_DELAYED_WORK(&work->work, intel_fbc_work_fn);
-
-	dev_priv->fbc_work = work;
-
-	DRM_DEBUG_KMS("scheduling delayed FBC enable\n");
-
-	/* Delay the actual enabling to let pageflipping cease and the
-	 * display to settle before starting the compression. Note that
-	 * this delay also serves a second purpose: it allows for a
-	 * vblank to pass after disabling the FBC before we attempt
-	 * to modify the control registers.
-	 *
-	 * A more complicated solution would involve tracking vblanks
-	 * following the termination of the page-flipping sequence
-	 * and indeed performing the enable as a co-routine and not
-	 * waiting synchronously upon the vblank.
-	 */
-	schedule_delayed_work(&work->work, msecs_to_jiffies(50));
-}
-
-void intel_disable_fbc(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-
-	intel_cancel_fbc_work(dev_priv);
-
-	if (!dev_priv->display.disable_fbc)
-		return;
-
-	dev_priv->display.disable_fbc(dev);
-	dev_priv->cfb_plane = -1;
-}
-
-/**
- * intel_update_fbc - enable/disable FBC as needed
- * @dev: the drm_device
- *
- * Set up the framebuffer compression hardware at mode set time.  We
- * enable it if possible:
- *   - plane A only (on pre-965)
- *   - no pixel mulitply/line duplication
- *   - no alpha buffer discard
- *   - no dual wide
- *   - framebuffer <= 2048 in width, 1536 in height
- *
- * We can't assume that any compression will take place (worst case),
- * so the compressed buffer has to be the same size as the uncompressed
- * one.  It also must reside (along with the line length buffer) in
- * stolen memory.
- *
- * We need to enable/disable FBC on a global basis.
- */
-static void intel_update_fbc(struct drm_device *dev)
-{
-	struct drm_i915_private *dev_priv = dev->dev_private;
-	struct drm_crtc *crtc = NULL, *tmp_crtc;
-	struct intel_crtc *intel_crtc;
-	struct drm_framebuffer *fb;
-	struct intel_framebuffer *intel_fb;
-	struct drm_i915_gem_object *obj;
-	int enable_fbc;
-
-	DRM_DEBUG_KMS("\n");
-
-	if (!i915_powersave)
-		return;
-
-	if (!I915_HAS_FBC(dev))
-		return;
-
-	/*
-	 * If FBC is already on, we just have to verify that we can
-	 * keep it that way...
-	 * Need to disable if:
-	 *   - more than one pipe is active
-	 *   - changing FBC params (stride, fence, mode)
-	 *   - new fb is too large to fit in compressed buffer
-	 *   - going to an unsupported config (interlace, pixel multiply, etc.)
-	 */
-	list_for_each_entry(tmp_crtc, &dev->mode_config.crtc_list, head) {
-		if (tmp_crtc->enabled && tmp_crtc->fb) {
-			if (crtc) {
-				DRM_DEBUG_KMS("more than one pipe active, disabling compression\n");
-				dev_priv->no_fbc_reason = FBC_MULTIPLE_PIPES;
-				goto out_disable;
-			}
-			crtc = tmp_crtc;
-		}
-	}
-
-	if (!crtc || crtc->fb == NULL) {
-		DRM_DEBUG_KMS("no output, disabling\n");
-		dev_priv->no_fbc_reason = FBC_NO_OUTPUT;
-		goto out_disable;
-	}
-
-	intel_crtc = to_intel_crtc(crtc);
-	fb = crtc->fb;
-	intel_fb = to_intel_framebuffer(fb);
-	obj = intel_fb->obj;
-
-	enable_fbc = i915_enable_fbc;
-	if (enable_fbc < 0) {
-		DRM_DEBUG_KMS("fbc set to per-chip default\n");
-		enable_fbc = 1;
-		if (INTEL_INFO(dev)->gen <= 6)
-			enable_fbc = 0;
-	}
-	if (!enable_fbc) {
-		DRM_DEBUG_KMS("fbc disabled per module param\n");
-		dev_priv->no_fbc_reason = FBC_MODULE_PARAM;
-		goto out_disable;
-	}
-	if (intel_fb->obj->base.size > dev_priv->cfb_size) {
-		DRM_DEBUG_KMS("framebuffer too large, disabling "
-			      "compression\n");
-		dev_priv->no_fbc_reason = FBC_STOLEN_TOO_SMALL;
-		goto out_disable;
-	}
-	if ((crtc->mode.flags & DRM_MODE_FLAG_INTERLACE) ||
-	    (crtc->mode.flags & DRM_MODE_FLAG_DBLSCAN)) {
-		DRM_DEBUG_KMS("mode incompatible with compression, "
-			      "disabling\n");
-		dev_priv->no_fbc_reason = FBC_UNSUPPORTED_MODE;
-		goto out_disable;
-	}
-	if ((crtc->mode.hdisplay > 2048) ||
-	    (crtc->mode.vdisplay > 1536)) {
-		DRM_DEBUG_KMS("mode too large for compression, disabling\n");
-		dev_priv->no_fbc_reason = FBC_MODE_TOO_LARGE;
-		goto out_disable;
-	}
-	if ((IS_I915GM(dev) || IS_I945GM(dev)) && intel_crtc->plane != 0) {
-		DRM_DEBUG_KMS("plane not 0, disabling compression\n");
-		dev_priv->no_fbc_reason = FBC_BAD_PLANE;
-		goto out_disable;
-	}
-
-	/* The use of a CPU fence is mandatory in order to detect writes
-	 * by the CPU to the scanout and trigger updates to the FBC.
-	 */
-	if (obj->tiling_mode != I915_TILING_X ||
-	    obj->fence_reg == I915_FENCE_REG_NONE) {
-		DRM_DEBUG_KMS("framebuffer not tiled or fenced, disabling compression\n");
-		dev_priv->no_fbc_reason = FBC_NOT_TILED;
-		goto out_disable;
-	}
-
-	/* If the kernel debugger is active, always disable compression */
-	if (in_dbg_master())
-		goto out_disable;
-
-	/* If the scanout has not changed, don't modify the FBC settings.
-	 * Note that we make the fundamental assumption that the fb->obj
-	 * cannot be unpinned (and have its GTT offset and fence revoked)
-	 * without first being decoupled from the scanout and FBC disabled.
-	 */
-	if (dev_priv->cfb_plane == intel_crtc->plane &&
-	    dev_priv->cfb_fb == fb->base.id &&
-	    dev_priv->cfb_y == crtc->y)
-		return;
-
-	if (intel_fbc_enabled(dev)) {
-		/* We update FBC along two paths, after changing fb/crtc
-		 * configuration (modeswitching) and after page-flipping
-		 * finishes. For the latter, we know that not only did
-		 * we disable the FBC at the start of the page-flip
-		 * sequence, but also more than one vblank has passed.
-		 *
-		 * For the former case of modeswitching, it is possible
-		 * to switch between two FBC valid configurations
-		 * instantaneously so we do need to disable the FBC
-		 * before we can modify its control registers. We also
-		 * have to wait for the next vblank for that to take
-		 * effect. However, since we delay enabling FBC we can
-		 * assume that a vblank has passed since disabling and
-		 * that we can safely alter the registers in the deferred
-		 * callback.
-		 *
-		 * In the scenario that we go from a valid to invalid
-		 * and then back to valid FBC configuration we have
-		 * no strict enforcement that a vblank occurred since
-		 * disabling the FBC. However, along all current pipe
-		 * disabling paths we do need to wait for a vblank at
-		 * some point. And we wait before enabling FBC anyway.
-		 */
-		DRM_DEBUG_KMS("disabling active FBC for update\n");
-		intel_disable_fbc(dev);
-	}
-
-	intel_enable_fbc(crtc, 500);
-	return;
-
-out_disable:
-	/* Multiple disables should be harmless */
-	if (intel_fbc_enabled(dev)) {
-		DRM_DEBUG_KMS("unsupported config, disabling FBC\n");
-		intel_disable_fbc(dev);
-	}
-}
-
 int
 intel_pin_and_fence_fb_obj(struct drm_device *dev,
 			   struct drm_i915_gem_object *obj,
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 8748e5e..def112e 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -434,4 +434,19 @@ extern int intel_sprite_get_colorkey(struct drm_device *dev, void *data,
 
 extern u32 intel_dpio_read(struct drm_i915_private *dev_priv, int reg);
 
+/* Power-related functions, located in intel_pm.c */
+/* FBC */
+extern void i8xx_disable_fbc(struct drm_device *dev);
+extern void i8xx_enable_fbc(struct drm_crtc *crtc, unsigned long interval);
+extern bool i8xx_fbc_enabled(struct drm_device *dev);
+extern void g4x_enable_fbc(struct drm_crtc *crtc, unsigned long interval);
+extern void g4x_disable_fbc(struct drm_device *dev);
+extern bool g4x_fbc_enabled(struct drm_device *dev);
+extern void ironlake_enable_fbc(struct drm_crtc *crtc, unsigned long interval);
+extern void ironlake_disable_fbc(struct drm_device *dev);
+extern bool ironlake_fbc_enabled(struct drm_device *dev);
+extern bool intel_fbc_enabled(struct drm_device *dev);
+extern void intel_enable_fbc(struct drm_crtc *crtc, unsigned long interval);
+extern void intel_update_fbc(struct drm_device *dev);
+
 #endif /* __INTEL_DRV_H__ */
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
new file mode 100644
index 0000000..7fbd305
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -0,0 +1,521 @@
+/*
+ * Copyright © 2012 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Eugeni Dodonov <eugeni.dodonov@intel.com>
+ *
+ */
+
+#include "i915_drv.h"
+#include "intel_drv.h"
+
+/* FBC, or Frame Buffer Compression, is a technique employed to compress the framebuffer contents in-memory, aiming at reducing the required bandwidth during in-memory transfers and, therefore, reduce the power packet.
+ *
+ * The benefits of FBC are mostly visible with solid backgrounds and variation-less patterns.
+ *
+ * FBC-related functionality can be enabled by the means of the i915.i915_enable_fbc parameter
+ */
+
+void i8xx_disable_fbc(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 fbc_ctl;
+
+	/* Disable compression */
+	fbc_ctl = I915_READ(FBC_CONTROL);
+	if ((fbc_ctl & FBC_CTL_EN) == 0)
+		return;
+
+	fbc_ctl &= ~FBC_CTL_EN;
+	I915_WRITE(FBC_CONTROL, fbc_ctl);
+
+	/* Wait for compressing bit to clear */
+	if (wait_for((I915_READ(FBC_STATUS) & FBC_STAT_COMPRESSING) == 0, 10)) {
+		DRM_DEBUG_KMS("FBC idle timed out\n");
+		return;
+	}
+
+	DRM_DEBUG_KMS("disabled FBC\n");
+}
+
+void i8xx_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_framebuffer *fb = crtc->fb;
+	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
+	struct drm_i915_gem_object *obj = intel_fb->obj;
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	int cfb_pitch;
+	int plane, i;
+	u32 fbc_ctl, fbc_ctl2;
+
+	cfb_pitch = dev_priv->cfb_size / FBC_LL_SIZE;
+	if (fb->pitches[0] < cfb_pitch)
+		cfb_pitch = fb->pitches[0];
+
+	/* FBC_CTL wants 64B units */
+	cfb_pitch = (cfb_pitch / 64) - 1;
+	plane = intel_crtc->plane == 0 ? FBC_CTL_PLANEA : FBC_CTL_PLANEB;
+
+	/* Clear old tags */
+	for (i = 0; i < (FBC_LL_SIZE / 32) + 1; i++)
+		I915_WRITE(FBC_TAG + (i * 4), 0);
+
+	/* Set it up... */
+	fbc_ctl2 = FBC_CTL_FENCE_DBL | FBC_CTL_IDLE_IMM | FBC_CTL_CPU_FENCE;
+	fbc_ctl2 |= plane;
+	I915_WRITE(FBC_CONTROL2, fbc_ctl2);
+	I915_WRITE(FBC_FENCE_OFF, crtc->y);
+
+	/* enable it... */
+	fbc_ctl = FBC_CTL_EN | FBC_CTL_PERIODIC;
+	if (IS_I945GM(dev))
+		fbc_ctl |= FBC_CTL_C3_IDLE; /* 945 needs special SR handling */
+	fbc_ctl |= (cfb_pitch & 0xff) << FBC_CTL_STRIDE_SHIFT;
+	fbc_ctl |= (interval & 0x2fff) << FBC_CTL_INTERVAL_SHIFT;
+	fbc_ctl |= obj->fence_reg;
+	I915_WRITE(FBC_CONTROL, fbc_ctl);
+
+	DRM_DEBUG_KMS("enabled FBC, pitch %d, yoff %d, plane %d, ",
+		      cfb_pitch, crtc->y, intel_crtc->plane);
+}
+
+bool i8xx_fbc_enabled(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	return I915_READ(FBC_CONTROL) & FBC_CTL_EN;
+}
+
+void g4x_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_framebuffer *fb = crtc->fb;
+	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
+	struct drm_i915_gem_object *obj = intel_fb->obj;
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	int plane = intel_crtc->plane == 0 ? DPFC_CTL_PLANEA : DPFC_CTL_PLANEB;
+	unsigned long stall_watermark = 200;
+	u32 dpfc_ctl;
+
+	dpfc_ctl = plane | DPFC_SR_EN | DPFC_CTL_LIMIT_1X;
+	dpfc_ctl |= DPFC_CTL_FENCE_EN | obj->fence_reg;
+	I915_WRITE(DPFC_CHICKEN, DPFC_HT_MODIFY);
+
+	I915_WRITE(DPFC_RECOMP_CTL, DPFC_RECOMP_STALL_EN |
+		   (stall_watermark << DPFC_RECOMP_STALL_WM_SHIFT) |
+		   (interval << DPFC_RECOMP_TIMER_COUNT_SHIFT));
+	I915_WRITE(DPFC_FENCE_YOFF, crtc->y);
+
+	/* enable it... */
+	I915_WRITE(DPFC_CONTROL, I915_READ(DPFC_CONTROL) | DPFC_CTL_EN);
+
+	DRM_DEBUG_KMS("enabled fbc on plane %d\n", intel_crtc->plane);
+}
+
+void g4x_disable_fbc(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 dpfc_ctl;
+
+	/* Disable compression */
+	dpfc_ctl = I915_READ(DPFC_CONTROL);
+	if (dpfc_ctl & DPFC_CTL_EN) {
+		dpfc_ctl &= ~DPFC_CTL_EN;
+		I915_WRITE(DPFC_CONTROL, dpfc_ctl);
+
+		DRM_DEBUG_KMS("disabled FBC\n");
+	}
+}
+
+bool g4x_fbc_enabled(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	return I915_READ(DPFC_CONTROL) & DPFC_CTL_EN;
+}
+
+static void sandybridge_blit_fbc_update(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 blt_ecoskpd;
+
+	/* Make sure blitter notifies FBC of writes */
+	gen6_gt_force_wake_get(dev_priv);
+	blt_ecoskpd = I915_READ(GEN6_BLITTER_ECOSKPD);
+	blt_ecoskpd |= GEN6_BLITTER_FBC_NOTIFY <<
+		GEN6_BLITTER_LOCK_SHIFT;
+	I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
+	blt_ecoskpd |= GEN6_BLITTER_FBC_NOTIFY;
+	I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
+	blt_ecoskpd &= ~(GEN6_BLITTER_FBC_NOTIFY <<
+			 GEN6_BLITTER_LOCK_SHIFT);
+	I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
+	POSTING_READ(GEN6_BLITTER_ECOSKPD);
+	gen6_gt_force_wake_put(dev_priv);
+}
+
+void ironlake_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_framebuffer *fb = crtc->fb;
+	struct intel_framebuffer *intel_fb = to_intel_framebuffer(fb);
+	struct drm_i915_gem_object *obj = intel_fb->obj;
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	int plane = intel_crtc->plane == 0 ? DPFC_CTL_PLANEA : DPFC_CTL_PLANEB;
+	unsigned long stall_watermark = 200;
+	u32 dpfc_ctl;
+
+	dpfc_ctl = I915_READ(ILK_DPFC_CONTROL);
+	dpfc_ctl &= DPFC_RESERVED;
+	dpfc_ctl |= (plane | DPFC_CTL_LIMIT_1X);
+	/* Set persistent mode for front-buffer rendering, ala X. */
+	dpfc_ctl |= DPFC_CTL_PERSISTENT_MODE;
+	dpfc_ctl |= (DPFC_CTL_FENCE_EN | obj->fence_reg);
+	I915_WRITE(ILK_DPFC_CHICKEN, DPFC_HT_MODIFY);
+
+	I915_WRITE(ILK_DPFC_RECOMP_CTL, DPFC_RECOMP_STALL_EN |
+		   (stall_watermark << DPFC_RECOMP_STALL_WM_SHIFT) |
+		   (interval << DPFC_RECOMP_TIMER_COUNT_SHIFT));
+	I915_WRITE(ILK_DPFC_FENCE_YOFF, crtc->y);
+	I915_WRITE(ILK_FBC_RT_BASE, obj->gtt_offset | ILK_FBC_RT_VALID);
+	/* enable it... */
+	I915_WRITE(ILK_DPFC_CONTROL, dpfc_ctl | DPFC_CTL_EN);
+
+	if (IS_GEN6(dev)) {
+		I915_WRITE(SNB_DPFC_CTL_SA,
+			   SNB_CPU_FENCE_ENABLE | obj->fence_reg);
+		I915_WRITE(DPFC_CPU_FENCE_OFFSET, crtc->y);
+		sandybridge_blit_fbc_update(dev);
+	}
+
+	DRM_DEBUG_KMS("enabled fbc on plane %d\n", intel_crtc->plane);
+}
+
+void ironlake_disable_fbc(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 dpfc_ctl;
+
+	/* Disable compression */
+	dpfc_ctl = I915_READ(ILK_DPFC_CONTROL);
+	if (dpfc_ctl & DPFC_CTL_EN) {
+		dpfc_ctl &= ~DPFC_CTL_EN;
+		I915_WRITE(ILK_DPFC_CONTROL, dpfc_ctl);
+
+		DRM_DEBUG_KMS("disabled FBC\n");
+	}
+}
+
+bool ironlake_fbc_enabled(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	return I915_READ(ILK_DPFC_CONTROL) & DPFC_CTL_EN;
+}
+
+bool intel_fbc_enabled(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (!dev_priv->display.fbc_enabled)
+		return false;
+
+	return dev_priv->display.fbc_enabled(dev);
+}
+
+static void intel_fbc_work_fn(struct work_struct *__work)
+{
+	struct intel_fbc_work *work =
+		container_of(to_delayed_work(__work),
+			     struct intel_fbc_work, work);
+	struct drm_device *dev = work->crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	mutex_lock(&dev->struct_mutex);
+	if (work == dev_priv->fbc_work) {
+		/* Double check that we haven't switched fb without cancelling
+		 * the prior work.
+		 */
+		if (work->crtc->fb == work->fb) {
+			dev_priv->display.enable_fbc(work->crtc,
+						     work->interval);
+
+			dev_priv->cfb_plane = to_intel_crtc(work->crtc)->plane;
+			dev_priv->cfb_fb = work->crtc->fb->base.id;
+			dev_priv->cfb_y = work->crtc->y;
+		}
+
+		dev_priv->fbc_work = NULL;
+	}
+	mutex_unlock(&dev->struct_mutex);
+
+	kfree(work);
+}
+
+static void intel_cancel_fbc_work(struct drm_i915_private *dev_priv)
+{
+	if (dev_priv->fbc_work == NULL)
+		return;
+
+	DRM_DEBUG_KMS("cancelling pending FBC enable\n");
+
+	/* Synchronisation is provided by struct_mutex and checking of
+	 * dev_priv->fbc_work, so we can perform the cancellation
+	 * entirely asynchronously.
+	 */
+	if (cancel_delayed_work(&dev_priv->fbc_work->work))
+		/* tasklet was killed before being run, clean up */
+		kfree(dev_priv->fbc_work);
+
+	/* Mark the work as no longer wanted so that if it does
+	 * wake-up (because the work was already running and waiting
+	 * for our mutex), it will discover that is no longer
+	 * necessary to run.
+	 */
+	dev_priv->fbc_work = NULL;
+}
+
+void intel_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
+{
+	struct intel_fbc_work *work;
+	struct drm_device *dev = crtc->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	if (!dev_priv->display.enable_fbc)
+		return;
+
+	intel_cancel_fbc_work(dev_priv);
+
+	work = kzalloc(sizeof *work, GFP_KERNEL);
+	if (work == NULL) {
+		dev_priv->display.enable_fbc(crtc, interval);
+		return;
+	}
+
+	work->crtc = crtc;
+	work->fb = crtc->fb;
+	work->interval = interval;
+	INIT_DELAYED_WORK(&work->work, intel_fbc_work_fn);
+
+	dev_priv->fbc_work = work;
+
+	DRM_DEBUG_KMS("scheduling delayed FBC enable\n");
+
+	/* Delay the actual enabling to let pageflipping cease and the
+	 * display to settle before starting the compression. Note that
+	 * this delay also serves a second purpose: it allows for a
+	 * vblank to pass after disabling the FBC before we attempt
+	 * to modify the control registers.
+	 *
+	 * A more complicated solution would involve tracking vblanks
+	 * following the termination of the page-flipping sequence
+	 * and indeed performing the enable as a co-routine and not
+	 * waiting synchronously upon the vblank.
+	 */
+	schedule_delayed_work(&work->work, msecs_to_jiffies(50));
+}
+
+void intel_disable_fbc(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	intel_cancel_fbc_work(dev_priv);
+
+	if (!dev_priv->display.disable_fbc)
+		return;
+
+	dev_priv->display.disable_fbc(dev);
+	dev_priv->cfb_plane = -1;
+}
+
+/**
+ * intel_update_fbc - enable/disable FBC as needed
+ * @dev: the drm_device
+ *
+ * Set up the framebuffer compression hardware at mode set time.  We
+ * enable it if possible:
+ *   - plane A only (on pre-965)
+ *   - no pixel mulitply/line duplication
+ *   - no alpha buffer discard
+ *   - no dual wide
+ *   - framebuffer <= 2048 in width, 1536 in height
+ *
+ * We can't assume that any compression will take place (worst case),
+ * so the compressed buffer has to be the same size as the uncompressed
+ * one.  It also must reside (along with the line length buffer) in
+ * stolen memory.
+ *
+ * We need to enable/disable FBC on a global basis.
+ */
+void intel_update_fbc(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_crtc *crtc = NULL, *tmp_crtc;
+	struct intel_crtc *intel_crtc;
+	struct drm_framebuffer *fb;
+	struct intel_framebuffer *intel_fb;
+	struct drm_i915_gem_object *obj;
+	int enable_fbc;
+
+	DRM_DEBUG_KMS("\n");
+
+	if (!i915_powersave)
+		return;
+
+	if (!I915_HAS_FBC(dev))
+		return;
+
+	/*
+	 * If FBC is already on, we just have to verify that we can
+	 * keep it that way...
+	 * Need to disable if:
+	 *   - more than one pipe is active
+	 *   - changing FBC params (stride, fence, mode)
+	 *   - new fb is too large to fit in compressed buffer
+	 *   - going to an unsupported config (interlace, pixel multiply, etc.)
+	 */
+	list_for_each_entry(tmp_crtc, &dev->mode_config.crtc_list, head) {
+		if (tmp_crtc->enabled && tmp_crtc->fb) {
+			if (crtc) {
+				DRM_DEBUG_KMS("more than one pipe active, disabling compression\n");
+				dev_priv->no_fbc_reason = FBC_MULTIPLE_PIPES;
+				goto out_disable;
+			}
+			crtc = tmp_crtc;
+		}
+	}
+
+	if (!crtc || crtc->fb == NULL) {
+		DRM_DEBUG_KMS("no output, disabling\n");
+		dev_priv->no_fbc_reason = FBC_NO_OUTPUT;
+		goto out_disable;
+	}
+
+	intel_crtc = to_intel_crtc(crtc);
+	fb = crtc->fb;
+	intel_fb = to_intel_framebuffer(fb);
+	obj = intel_fb->obj;
+
+	enable_fbc = i915_enable_fbc;
+	if (enable_fbc < 0) {
+		DRM_DEBUG_KMS("fbc set to per-chip default\n");
+		enable_fbc = 1;
+		if (INTEL_INFO(dev)->gen <= 6)
+			enable_fbc = 0;
+	}
+	if (!enable_fbc) {
+		DRM_DEBUG_KMS("fbc disabled per module param\n");
+		dev_priv->no_fbc_reason = FBC_MODULE_PARAM;
+		goto out_disable;
+	}
+	if (intel_fb->obj->base.size > dev_priv->cfb_size) {
+		DRM_DEBUG_KMS("framebuffer too large, disabling "
+			      "compression\n");
+		dev_priv->no_fbc_reason = FBC_STOLEN_TOO_SMALL;
+		goto out_disable;
+	}
+	if ((crtc->mode.flags & DRM_MODE_FLAG_INTERLACE) ||
+	    (crtc->mode.flags & DRM_MODE_FLAG_DBLSCAN)) {
+		DRM_DEBUG_KMS("mode incompatible with compression, "
+			      "disabling\n");
+		dev_priv->no_fbc_reason = FBC_UNSUPPORTED_MODE;
+		goto out_disable;
+	}
+	if ((crtc->mode.hdisplay > 2048) ||
+	    (crtc->mode.vdisplay > 1536)) {
+		DRM_DEBUG_KMS("mode too large for compression, disabling\n");
+		dev_priv->no_fbc_reason = FBC_MODE_TOO_LARGE;
+		goto out_disable;
+	}
+	if ((IS_I915GM(dev) || IS_I945GM(dev)) && intel_crtc->plane != 0) {
+		DRM_DEBUG_KMS("plane not 0, disabling compression\n");
+		dev_priv->no_fbc_reason = FBC_BAD_PLANE;
+		goto out_disable;
+	}
+
+	/* The use of a CPU fence is mandatory in order to detect writes
+	 * by the CPU to the scanout and trigger updates to the FBC.
+	 */
+	if (obj->tiling_mode != I915_TILING_X ||
+	    obj->fence_reg == I915_FENCE_REG_NONE) {
+		DRM_DEBUG_KMS("framebuffer not tiled or fenced, disabling compression\n");
+		dev_priv->no_fbc_reason = FBC_NOT_TILED;
+		goto out_disable;
+	}
+
+	/* If the kernel debugger is active, always disable compression */
+	if (in_dbg_master())
+		goto out_disable;
+
+	/* If the scanout has not changed, don't modify the FBC settings.
+	 * Note that we make the fundamental assumption that the fb->obj
+	 * cannot be unpinned (and have its GTT offset and fence revoked)
+	 * without first being decoupled from the scanout and FBC disabled.
+	 */
+	if (dev_priv->cfb_plane == intel_crtc->plane &&
+	    dev_priv->cfb_fb == fb->base.id &&
+	    dev_priv->cfb_y == crtc->y)
+		return;
+
+	if (intel_fbc_enabled(dev)) {
+		/* We update FBC along two paths, after changing fb/crtc
+		 * configuration (modeswitching) and after page-flipping
+		 * finishes. For the latter, we know that not only did
+		 * we disable the FBC at the start of the page-flip
+		 * sequence, but also more than one vblank has passed.
+		 *
+		 * For the former case of modeswitching, it is possible
+		 * to switch between two FBC valid configurations
+		 * instantaneously so we do need to disable the FBC
+		 * before we can modify its control registers. We also
+		 * have to wait for the next vblank for that to take
+		 * effect. However, since we delay enabling FBC we can
+		 * assume that a vblank has passed since disabling and
+		 * that we can safely alter the registers in the deferred
+		 * callback.
+		 *
+		 * In the scenario that we go from a valid to invalid
+		 * and then back to valid FBC configuration we have
+		 * no strict enforcement that a vblank occurred since
+		 * disabling the FBC. However, along all current pipe
+		 * disabling paths we do need to wait for a vblank at
+		 * some point. And we wait before enabling FBC anyway.
+		 */
+		DRM_DEBUG_KMS("disabling active FBC for update\n");
+		intel_disable_fbc(dev);
+	}
+
+	intel_enable_fbc(crtc, 500);
+	return;
+
+out_disable:
+	/* Multiple disables should be harmless */
+	if (intel_fbc_enabled(dev)) {
+		DRM_DEBUG_KMS("unsupported config, disabling FBC\n");
+		intel_disable_fbc(dev);
+	}
+}
+