drm/i915: use FPGA_DBG for the "unclaimed register" checks

We plan to treat GEN7_ERR_INT as an interrupt, so use this register
for the checks inside I915_WRITE. This way we can have the best of
both worlds: the error message with a register address and the

V2: Split in 2 patches: one for the macro, one for changing the
register, as requested by Ben.
V3: Rebase.
Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -1133,10 +1133,10 @@ static void
 hsw_unclaimed_reg_clear(struct drm_i915_private *dev_priv, u32 reg)
 {
 	if (IS_HASWELL(dev_priv->dev) &&
-	    (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) {
+	    (I915_READ_NOTRACE(FPGA_DBG) & FPGA_DBG_RM_NOCLAIM)) {
 		DRM_ERROR("Unknown unclaimed register before writing to %x\n",
 			  reg);
-		I915_WRITE_NOTRACE(GEN7_ERR_INT, ERR_INT_MMIO_UNCLAIMED);
+		I915_WRITE_NOTRACE(FPGA_DBG, FPGA_DBG_RM_NOCLAIM);
 	}
 }
 
@@ -1144,9 +1144,9 @@ static void
 hsw_unclaimed_reg_check(struct drm_i915_private *dev_priv, u32 reg)
 {
 	if (IS_HASWELL(dev_priv->dev) &&
-	    (I915_READ_NOTRACE(GEN7_ERR_INT) & ERR_INT_MMIO_UNCLAIMED)) {
+	    (I915_READ_NOTRACE(FPGA_DBG) & FPGA_DBG_RM_NOCLAIM)) {
 		DRM_ERROR("Unclaimed write to %x\n", reg);
-		writel(ERR_INT_MMIO_UNCLAIMED, dev_priv->regs + GEN7_ERR_INT);
+		I915_WRITE_NOTRACE(FPGA_DBG, FPGA_DBG_RM_NOCLAIM);
 	}
 }
 

drivers/gpu/drm/i915/i915_reg.h

@@ -522,6 +522,9 @@
 #define GEN7_ERR_INT	0x44040
 #define   ERR_INT_MMIO_UNCLAIMED (1<<13)
 
+#define FPGA_DBG		0x42300
+#define   FPGA_DBG_RM_NOCLAIM	(1<<31)
+
 #define DERRMR		0x44050
 
 /* GM45+ chicken bits -- debug workaround bits that may be required