drm/i915: Add support for GPU soft reset on Ironlake.

Ironlake's graphics reset register has to be accessed via the MCHBAR,
rather than via PCI config space, which requires some refactoring.

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 24 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 45027d5ad1e5..e88aabdfd1d9 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -334,6 +334,24 @@ static int i965_reset_complete(struct drm_device *dev)
         return gdrst & 0x1;
 }
 
+static int i965_do_reset(struct drm_device *dev, u8 flags)
+{
+        u8 gdrst;
+
+        pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);
+        pci_write_config_byte(dev->pdev, I965_GDRST, gdrst | flags | 0x1);
+
+        return wait_for(i965_reset_complete(dev), 500);
+}
+
+static int ironlake_do_reset(struct drm_device *dev, u8 flags)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        u32 gdrst = I915_READ(MCHBAR_MIRROR_BASE + ILK_GDSR);
+        I915_WRITE(MCHBAR_MIRROR_BASE + ILK_GDSR, gdrst | flags | 0x1);
+        return wait_for(I915_READ(MCHBAR_MIRROR_BASE + ILK_GDSR) & 0x1, 500);
+}
+
 /**
  * i965_reset - reset chip after a hang
  * @dev: drm device to reset
@@ -353,12 +371,12 @@ static int i965_reset_complete(struct drm_device *dev)
 int i965_reset(struct drm_device *dev, u8 flags)
 {
         drm_i915_private_t *dev_priv = dev->dev_private;
-        u8 gdrst;
         /*
          * We really should only reset the display subsystem if we actually
          * need to
          */
         bool need_display = true;
+        int ret;
 
         mutex_lock(&dev->struct_mutex);
 
@@ -375,11 +393,11 @@ int i965_reset(struct drm_device *dev, u8 flags)
          * well as the reset bit (GR/bit 0).  Setting the GR bit
          * triggers the reset; when done, the hardware will clear it.
          */
-        pci_read_config_byte(dev->pdev, I965_GDRST, &gdrst);
-        pci_write_config_byte(dev->pdev, I965_GDRST, gdrst | flags | 0x1);
-
-        /* Wait for the hardware to reset (but no more than 500 ms) */
-        if (wait_for(i965_reset_complete(dev), 500)) {
+        if (IS_IRONLAKE(dev))
+                ret = ironlake_do_reset(dev, flags);
+        else
+                ret = i965_do_reset(dev, flags);
+        if (ret) {
                 WARN(true, "i915: Failed to reset chip\n");
                 mutex_unlock(&dev->struct_mutex);
                 return -EIO;