drm/i915: Keep MCHBAR always enabled

As we need more and more controls within MCHBAR for memory config and
power management, this trys to keep MCHBAR enabled from driver load and
only tear down in driver unload.
Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

drivers/gpu/drm/i915/i915_dma.c

@@ -35,6 +35,8 @@
 #include "i915_drv.h"
 #include "i915_trace.h"
 #include <linux/vgaarb.h>
+#include <linux/acpi.h>
+#include <linux/pnp.h>
 
 /* Really want an OS-independent resettable timer.  Would like to have
  * this loop run for (eg) 3 sec, but have the timer reset every time
@@ -933,6 +935,120 @@ static int i915_get_bridge_dev(struct drm_device *dev)
 	return 0;
 }
 
+#define MCHBAR_I915 0x44
+#define MCHBAR_I965 0x48
+#define MCHBAR_SIZE (4*4096)
+
+#define DEVEN_REG 0x54
+#define   DEVEN_MCHBAR_EN (1 << 28)
+
+/* Allocate space for the MCH regs if needed, return nonzero on error */
+static int
+intel_alloc_mchbar_resource(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	int reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
+	u32 temp_lo, temp_hi = 0;
+	u64 mchbar_addr;
+	int ret = 0;
+
+	if (IS_I965G(dev))
+		pci_read_config_dword(dev_priv->bridge_dev, reg + 4, &temp_hi);
+	pci_read_config_dword(dev_priv->bridge_dev, reg, &temp_lo);
+	mchbar_addr = ((u64)temp_hi << 32) | temp_lo;
+
+	/* If ACPI doesn't have it, assume we need to allocate it ourselves */
+#ifdef CONFIG_PNP
+	if (mchbar_addr &&
+	    pnp_range_reserved(mchbar_addr, mchbar_addr + MCHBAR_SIZE)) {
+		ret = 0;
+		goto out;
+	}
+#endif
+
+	/* Get some space for it */
+	ret = pci_bus_alloc_resource(dev_priv->bridge_dev->bus, &dev_priv->mch_res,
+				     MCHBAR_SIZE, MCHBAR_SIZE,
+				     PCIBIOS_MIN_MEM,
+				     0,   pcibios_align_resource,
+				     dev_priv->bridge_dev);
+	if (ret) {
+		DRM_DEBUG_DRIVER("failed bus alloc: %d\n", ret);
+		dev_priv->mch_res.start = 0;
+		goto out;
+	}
+
+	if (IS_I965G(dev))
+		pci_write_config_dword(dev_priv->bridge_dev, reg + 4,
+				       upper_32_bits(dev_priv->mch_res.start));
+
+	pci_write_config_dword(dev_priv->bridge_dev, reg,
+			       lower_32_bits(dev_priv->mch_res.start));
+out:
+	return ret;
+}
+
+/* Setup MCHBAR if possible, return true if we should disable it again */
+static void
+intel_setup_mchbar(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	int mchbar_reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
+	u32 temp;
+	bool enabled;
+
+	dev_priv->mchbar_need_disable = false;
+
+	if (IS_I915G(dev) || IS_I915GM(dev)) {
+		pci_read_config_dword(dev_priv->bridge_dev, DEVEN_REG, &temp);
+		enabled = !!(temp & DEVEN_MCHBAR_EN);
+	} else {
+		pci_read_config_dword(dev_priv->bridge_dev, mchbar_reg, &temp);
+		enabled = temp & 1;
+	}
+
+	/* If it's already enabled, don't have to do anything */
+	if (enabled)
+		return;
+
+	if (intel_alloc_mchbar_resource(dev))
+		return;
+
+	dev_priv->mchbar_need_disable = true;
+
+	/* Space is allocated or reserved, so enable it. */
+	if (IS_I915G(dev) || IS_I915GM(dev)) {
+		pci_write_config_dword(dev_priv->bridge_dev, DEVEN_REG,
+				       temp | DEVEN_MCHBAR_EN);
+	} else {
+		pci_read_config_dword(dev_priv->bridge_dev, mchbar_reg, &temp);
+		pci_write_config_dword(dev_priv->bridge_dev, mchbar_reg, temp | 1);
+	}
+}
+
+static void
+intel_teardown_mchbar(struct drm_device *dev)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	int mchbar_reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
+	u32 temp;
+
+	if (dev_priv->mchbar_need_disable) {
+		if (IS_I915G(dev) || IS_I915GM(dev)) {
+			pci_read_config_dword(dev_priv->bridge_dev, DEVEN_REG, &temp);
+			temp &= ~DEVEN_MCHBAR_EN;
+			pci_write_config_dword(dev_priv->bridge_dev, DEVEN_REG, temp);
+		} else {
+			pci_read_config_dword(dev_priv->bridge_dev, mchbar_reg, &temp);
+			temp &= ~1;
+			pci_write_config_dword(dev_priv->bridge_dev, mchbar_reg, temp);
+		}
+	}
+
+	if (dev_priv->mch_res.start)
+		release_resource(&dev_priv->mch_res);
+}
+
 /**
  * i915_probe_agp - get AGP bootup configuration
  * @pdev: PCI device
@@ -1450,6 +1566,9 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
 		dev->driver->get_vblank_counter = gm45_get_vblank_counter;
 	}
 
+	/* Try to make sure MCHBAR is enabled before poking at it */
+	intel_setup_mchbar(dev);
+
 	i915_gem_load(dev);
 
 	/* Init HWS */
@@ -1569,6 +1688,8 @@ int i915_driver_unload(struct drm_device *dev)
 		intel_cleanup_overlay(dev);
 	}
 
+	intel_teardown_mchbar(dev);
+
 	pci_dev_put(dev_priv->bridge_dev);
 	kfree(dev->dev_private);
 

drivers/gpu/drm/i915/i915_drv.h

@@ -590,6 +590,7 @@ typedef struct drm_i915_private {
 	int child_dev_num;
 	struct child_device_config *child_dev;
 	struct drm_connector *int_lvds_connector;
+	bool mchbar_need_disable;
 } drm_i915_private_t;
 
 /** driver private structure attached to each drm_gem_object */

drivers/gpu/drm/i915/i915_gem_tiling.c

@@ -25,8 +25,6 @@
  *
  */
 
-#include <linux/acpi.h>
-#include <linux/pnp.h>
 #include "linux/string.h"
 #include "linux/bitops.h"
 #include "drmP.h"
@@ -83,120 +81,6 @@
  * to match what the GPU expects.
  */
 
-#define MCHBAR_I915 0x44
-#define MCHBAR_I965 0x48
-#define MCHBAR_SIZE (4*4096)
-
-#define DEVEN_REG 0x54
-#define   DEVEN_MCHBAR_EN (1 << 28)
-
-/* Allocate space for the MCH regs if needed, return nonzero on error */
-static int
-intel_alloc_mchbar_resource(struct drm_device *dev)
-{
-	drm_i915_private_t *dev_priv = dev->dev_private;
-	int reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
-	u32 temp_lo, temp_hi = 0;
-	u64 mchbar_addr;
-	int ret = 0;
-
-	if (IS_I965G(dev))
-		pci_read_config_dword(dev_priv->bridge_dev, reg + 4, &temp_hi);
-	pci_read_config_dword(dev_priv->bridge_dev, reg, &temp_lo);
-	mchbar_addr = ((u64)temp_hi << 32) | temp_lo;
-
-	/* If ACPI doesn't have it, assume we need to allocate it ourselves */
-#ifdef CONFIG_PNP
-	if (mchbar_addr &&
-	    pnp_range_reserved(mchbar_addr, mchbar_addr + MCHBAR_SIZE)) {
-		ret = 0;
-		goto out;
-	}
-#endif
-
-	/* Get some space for it */
-	ret = pci_bus_alloc_resource(dev_priv->bridge_dev->bus, &dev_priv->mch_res,
-				     MCHBAR_SIZE, MCHBAR_SIZE,
-				     PCIBIOS_MIN_MEM,
-				     0,   pcibios_align_resource,
-				     dev_priv->bridge_dev);
-	if (ret) {
-		DRM_DEBUG_DRIVER("failed bus alloc: %d\n", ret);
-		dev_priv->mch_res.start = 0;
-		goto out;
-	}
-
-	if (IS_I965G(dev))
-		pci_write_config_dword(dev_priv->bridge_dev, reg + 4,
-				       upper_32_bits(dev_priv->mch_res.start));
-
-	pci_write_config_dword(dev_priv->bridge_dev, reg,
-			       lower_32_bits(dev_priv->mch_res.start));
-out:
-	return ret;
-}
-
-/* Setup MCHBAR if possible, return true if we should disable it again */
-static bool
-intel_setup_mchbar(struct drm_device *dev)
-{
-	drm_i915_private_t *dev_priv = dev->dev_private;
-	int mchbar_reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
-	u32 temp;
-	bool need_disable = false, enabled;
-
-	if (IS_I915G(dev) || IS_I915GM(dev)) {
-		pci_read_config_dword(dev_priv->bridge_dev, DEVEN_REG, &temp);
-		enabled = !!(temp & DEVEN_MCHBAR_EN);
-	} else {
-		pci_read_config_dword(dev_priv->bridge_dev, mchbar_reg, &temp);
-		enabled = temp & 1;
-	}
-
-	/* If it's already enabled, don't have to do anything */
-	if (enabled)
-		goto out;
-
-	if (intel_alloc_mchbar_resource(dev))
-		goto out;
-
-	need_disable = true;
-
-	/* Space is allocated or reserved, so enable it. */
-	if (IS_I915G(dev) || IS_I915GM(dev)) {
-		pci_write_config_dword(dev_priv->bridge_dev, DEVEN_REG,
-				       temp | DEVEN_MCHBAR_EN);
-	} else {
-		pci_read_config_dword(dev_priv->bridge_dev, mchbar_reg, &temp);
-		pci_write_config_dword(dev_priv->bridge_dev, mchbar_reg, temp | 1);
-	}
-out:
-	return need_disable;
-}
-
-static void
-intel_teardown_mchbar(struct drm_device *dev, bool disable)
-{
-	drm_i915_private_t *dev_priv = dev->dev_private;
-	int mchbar_reg = IS_I965G(dev) ? MCHBAR_I965 : MCHBAR_I915;
-	u32 temp;
-
-	if (disable) {
-		if (IS_I915G(dev) || IS_I915GM(dev)) {
-			pci_read_config_dword(dev_priv->bridge_dev, DEVEN_REG, &temp);
-			temp &= ~DEVEN_MCHBAR_EN;
-			pci_write_config_dword(dev_priv->bridge_dev, DEVEN_REG, temp);
-		} else {
-			pci_read_config_dword(dev_priv->bridge_dev, mchbar_reg, &temp);
-			temp &= ~1;
-			pci_write_config_dword(dev_priv->bridge_dev, mchbar_reg, temp);
-		}
-	}
-
-	if (dev_priv->mch_res.start)
-		release_resource(&dev_priv->mch_res);
-}
-
 /**
  * Detects bit 6 swizzling of address lookup between IGD access and CPU
  * access through main memory.
@@ -207,7 +91,6 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
 	drm_i915_private_t *dev_priv = dev->dev_private;
 	uint32_t swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
 	uint32_t swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
-	bool need_disable;
 
 	if (IS_IRONLAKE(dev)) {
 		/* On Ironlake whatever DRAM config, GPU always do
@@ -224,9 +107,6 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
 	} else if (IS_MOBILE(dev)) {
 		uint32_t dcc;
 
-		/* Try to make sure MCHBAR is enabled before poking at it */
-		need_disable = intel_setup_mchbar(dev);
-
 		/* On mobile 9xx chipsets, channel interleave by the CPU is
 		 * determined by DCC.  For single-channel, neither the CPU
 		 * nor the GPU do swizzling.  For dual channel interleaved,
@@ -266,8 +146,6 @@ i915_gem_detect_bit_6_swizzle(struct drm_device *dev)
 			swizzle_x = I915_BIT_6_SWIZZLE_UNKNOWN;
 			swizzle_y = I915_BIT_6_SWIZZLE_UNKNOWN;
 		}
-
-		intel_teardown_mchbar(dev, need_disable);
 	} else {
 		/* The 965, G33, and newer, have a very flexible memory
 		 * configuration.  It will enable dual-channel mode