drm/i915: BIOS and power context stolen mem handling for VLV v7

But we need to get the right stolen base and make pre-allocated objects
for BIOS stuff so we don't clobber it.  If the BIOS hasn't allocated a
power context, we allocate one here too, from stolen space as required
by the docs.

v2: fix stolen to phys if ladder (Ben)
    keep BIOS reserved space out of allocator altogether (Ben)
v3: fix mask of stolen base (Ben)
v4: clean up preallocated object on unload (Ben)
    don't zero reg on unload (Jesse)
    fix mask harder (Jesse)
v5: use unref for freeing stolen bits (Chris)
    move alloc/free to intel_pm.c (Chris)
v6: NULL pctx at disable time so error paths work (Ben)
v7: use correct PCI device for config read (Jesse)

Reviewed-by: Ben Widawsky <benjamin.widawsky@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.h

@@ -1073,6 +1073,8 @@ typedef struct drm_i915_private {
 
 	struct i915_gpu_error gpu_error;
 
+	struct drm_i915_gem_object *vlv_pctx;
+
 	/* list of fbdev register on this device */
 	struct intel_fbdev *fbdev;
 

drivers/gpu/drm/i915/i915_gem_stolen.c

@@ -62,7 +62,10 @@ static unsigned long i915_stolen_to_physical(struct drm_device *dev)
 	 * its value of TOLUD.
 	 */
 	base = 0;
-	if (INTEL_INFO(dev)->gen >= 6) {
+	if (IS_VALLEYVIEW(dev)) {
+		pci_read_config_dword(dev->pdev, 0x5c, &base);
+		base &= ~((1<<20) - 1);
+	} else if (INTEL_INFO(dev)->gen >= 6) {
 		/* Read Base Data of Stolen Memory Register (BDSM) directly.
 		 * Note that there is also a MCHBAR miror at 0x1080c0 or
 		 * we could use device 2:0x5c instead.
@@ -183,6 +186,7 @@ void i915_gem_cleanup_stolen(struct drm_device *dev)
 int i915_gem_init_stolen(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
+	int bios_reserved = 0;
 
 	dev_priv->mm.stolen_base = i915_stolen_to_physical(dev);
 	if (dev_priv->mm.stolen_base == 0)
@@ -191,8 +195,12 @@ int i915_gem_init_stolen(struct drm_device *dev)
 	DRM_DEBUG_KMS("found %zd bytes of stolen memory at %08lx\n",
 		      dev_priv->gtt.stolen_size, dev_priv->mm.stolen_base);
 
+	if (IS_VALLEYVIEW(dev))
+		bios_reserved = 1024*1024; /* top 1M on VLV/BYT */
+
 	/* Basic memrange allocator for stolen space */
-	drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_size);
+	drm_mm_init(&dev_priv->mm.stolen, 0, dev_priv->gtt.stolen_size -
+		    bios_reserved);
 
 	return 0;
 }

drivers/gpu/drm/i915/i915_reg.h

@@ -700,6 +700,7 @@
 #define VLV_IIR		(VLV_DISPLAY_BASE + 0x20a4)
 #define VLV_IMR		(VLV_DISPLAY_BASE + 0x20a8)
 #define VLV_ISR		(VLV_DISPLAY_BASE + 0x20ac)
+#define VLV_PCBR	(VLV_DISPLAY_BASE + 0x2120)
 #define   I915_PIPE_CONTROL_NOTIFY_INTERRUPT		(1<<18)
 #define   I915_DISPLAY_PORT_INTERRUPT			(1<<17)
 #define   I915_RENDER_COMMAND_PARSER_ERROR_INTERRUPT	(1<<15)

drivers/gpu/drm/i915/intel_pm.c

@@ -2566,6 +2566,11 @@ static void valleyview_disable_rps(struct drm_device *dev)
 	spin_unlock_irq(&dev_priv->rps.lock);
 
 	I915_WRITE(GEN6_PMIIR, I915_READ(GEN6_PMIIR));
+
+	if (dev_priv->vlv_pctx) {
+		drm_gem_object_unreference(&dev_priv->vlv_pctx->base);
+		dev_priv->vlv_pctx = NULL;
+	}
 }
 
 int intel_enable_rc6(const struct drm_device *dev)
@@ -2860,6 +2865,48 @@ static void vlv_rps_timer_work(struct work_struct *work)
 	mutex_unlock(&dev_priv->rps.hw_lock);
 }
 
+static void valleyview_setup_pctx(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct drm_i915_gem_object *pctx;
+	unsigned long pctx_paddr;
+	u32 pcbr;
+	int pctx_size = 24*1024;
+
+	pcbr = I915_READ(VLV_PCBR);
+	if (pcbr) {
+		/* BIOS set it up already, grab the pre-alloc'd space */
+		int pcbr_offset;
+
+		pcbr_offset = (pcbr & (~4095)) - dev_priv->mm.stolen_base;
+		pctx = i915_gem_object_create_stolen_for_preallocated(dev_priv->dev,
+								      pcbr_offset,
+								      pcbr_offset,
+								      pctx_size);
+		goto out;
+	}
+
+	/*
+	 * From the Gunit register HAS:
+	 * The Gfx driver is expected to program this register and ensure
+	 * proper allocation within Gfx stolen memory.  For example, this
+	 * register should be programmed such than the PCBR range does not
+	 * overlap with other ranges, such as the frame buffer, protected
+	 * memory, or any other relevant ranges.
+	 */
+	pctx = i915_gem_object_create_stolen(dev, pctx_size);
+	if (!pctx) {
+		DRM_DEBUG("not enough stolen space for PCTX, disabling\n");
+		return;
+	}
+
+	pctx_paddr = dev_priv->mm.stolen_base + pctx->stolen->start;
+	I915_WRITE(VLV_PCBR, pctx_paddr);
+
+out:
+	dev_priv->vlv_pctx = pctx;
+}
+
 static void valleyview_enable_rps(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -2874,6 +2921,8 @@ static void valleyview_enable_rps(struct drm_device *dev)
 		I915_WRITE(GTFIFODBG, gtfifodbg);
 	}
 
+	valleyview_setup_pctx(dev);
+
 	gen6_gt_force_wake_get(dev_priv);
 
 	I915_WRITE(GEN6_RP_UP_THRESHOLD, 59400);