drm/i915: Pin tiled objects for L-shaped configs

Let's just throw in the towel on this one and take the cheap way out.

Based on a patch from Chris Wilson, but checking for a different bit.
Chris' patch checked for even bank layout, this one here for a magic
bit. Given the evidence we've gathered (not much) both work I think,
but checking for the magic bit might be more accurate.

Anyway, works on my gm45 here.

For paranoi restrict to gen4 (and mobile), since we've only ever seen
this on gm45 and i965gm.

Also add some debugfs output so that we can skip the tiled swapping
tests properly in these cases.

v2: Clean up the quirk'ed pin count in free_object to avoid upsetting
the WARN_ON. Spotted by Chris.

Cc: Chris Wilson <chris@chris-wilson.co.uk>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=28813
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=45092
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_debugfs.c

@@ -1983,6 +1983,8 @@ static int i915_swizzle_info(struct seq_file *m, void *data)
 	if (IS_GEN3(dev) || IS_GEN4(dev)) {
 		seq_printf(m, "DDC = 0x%08x\n",
 			   I915_READ(DCC));
+		seq_printf(m, "DDC2 = 0x%08x\n",
+			   I915_READ(DCC2));
 		seq_printf(m, "C0DRB3 = 0x%04x\n",
 			   I915_READ16(C0DRB3));
 		seq_printf(m, "C1DRB3 = 0x%04x\n",
@@ -2005,6 +2007,10 @@ static int i915_swizzle_info(struct seq_file *m, void *data)
 		seq_printf(m, "DISP_ARB_CTL = 0x%08x\n",
 			   I915_READ(DISP_ARB_CTL));
 	}
+
+	if (dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES)
+		seq_puts(m, "L-shaped memory detected\n");
+
 	intel_runtime_pm_put(dev_priv);
 	mutex_unlock(&dev->struct_mutex);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -764,6 +764,7 @@ enum intel_sbi_destination {
 #define QUIRK_INVERT_BRIGHTNESS (1<<2)
 #define QUIRK_BACKLIGHT_PRESENT (1<<3)
 #define QUIRK_PIPEB_FORCE (1<<4)
+#define QUIRK_PIN_SWIZZLED_PAGES (1<<5)
 
 struct intel_fbdev;
 struct intel_fbc_work;

drivers/gpu/drm/i915/i915_gem.c

@@ -2176,6 +2176,10 @@ i915_gem_object_get_pages_gtt(struct drm_i915_gem_object *obj)
 	if (i915_gem_object_needs_bit17_swizzle(obj))
 		i915_gem_object_do_bit_17_swizzle(obj);
 
+	if (obj->tiling_mode != I915_TILING_NONE &&
+	    dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES)
+		i915_gem_object_pin_pages(obj);
+
 	return 0;
 
 err_pages:
@@ -4374,6 +4378,7 @@ int
 i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
 		       struct drm_file *file_priv)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct drm_i915_gem_madvise *args = data;
 	struct drm_i915_gem_object *obj;
 	int ret;
@@ -4401,6 +4406,15 @@ i915_gem_madvise_ioctl(struct drm_device *dev, void *data,
 		goto out;
 	}
 
+	if (obj->pages &&
+	    obj->tiling_mode != I915_TILING_NONE &&
+	    dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
+		if (obj->madv == I915_MADV_WILLNEED)
+			i915_gem_object_unpin_pages(obj);
+		if (args->madv == I915_MADV_WILLNEED)
+			i915_gem_object_pin_pages(obj);
+	}
+
 	if (obj->madv != __I915_MADV_PURGED)
 		obj->madv = args->madv;
 
@@ -4550,6 +4564,11 @@ void i915_gem_free_object(struct drm_gem_object *gem_obj)
 
 	WARN_ON(obj->frontbuffer_bits);
 
+	if (obj->pages && obj->madv == I915_MADV_WILLNEED &&
+	    dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES &&
+	    obj->tiling_mode != I915_TILING_NONE)
+		i915_gem_object_unpin_pages(obj);
+
 	if (WARN_ON(obj->pages_pin_count))
 		obj->pages_pin_count = 0;
 	if (discard_backing_storage(obj))

drivers/gpu/drm/i915/i915_gem_tiling.c

@@ -178,6 +178,15 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
 			}
 			break;
 		}
+
+		/* check for L-shaped memory aka modified enhanced addressing */
+		if (IS_GEN4(dev)) {
+			uint32_t ddc2 = I915_READ(DCC2);
+
+			if (!(ddc2 & DCC2_MODIFIED_ENHANCED_DISABLE))
+				dev_priv->quirks |= QUIRK_PIN_SWIZZLED_PAGES;
+		}
+
 		if (dcc == 0xffffffff) {
 			DRM_ERROR("Couldn't read from MCHBAR.  "
 				  "Disabling tiling.\n");
@@ -380,6 +389,15 @@ i915_gem_set_tiling(struct drm_device *dev, void *data,
 			ret = i915_gem_object_ggtt_unbind(obj);
 
 		if (ret == 0) {
+			if (obj->pages &&
+			    obj->madv == I915_MADV_WILLNEED &&
+			    dev_priv->quirks & QUIRK_PIN_SWIZZLED_PAGES) {
+				if (args->tiling_mode == I915_TILING_NONE)
+					i915_gem_object_unpin_pages(obj);
+				if (obj->tiling_mode == I915_TILING_NONE)
+					i915_gem_object_pin_pages(obj);
+			}
+
 			obj->fence_dirty =
 				obj->last_fenced_seqno ||
 				obj->fence_reg != I915_FENCE_REG_NONE;

drivers/gpu/drm/i915/i915_reg.h

@@ -2043,6 +2043,8 @@ enum punit_power_well {
 #define DCC_ADDRESSING_MODE_MASK			(3 << 0)
 #define DCC_CHANNEL_XOR_DISABLE				(1 << 10)
 #define DCC_CHANNEL_XOR_BIT_17				(1 << 9)
+#define DCC2			0x10204
+#define DCC2_MODIFIED_ENHANCED_DISABLE			(1 << 20)
 
 /* Pineview MCH register contains DDR3 setting */
 #define CSHRDDR3CTL            0x101a8