drm/i915: FPGA_DBG is display-specific

Although the bspec's description doesn't make it very clear, the
hardware architects have confirmed that the FPGA_DBG register that we
use to check for unclaimed MMIO accesses is display-specific and will
only properly flag unclaimed MMIO transactions for registers in the
display range.  If a platform doesn't have display, FPGA_DBG itself will
not be available and should not be checked.  Let's move the feature flag
into intel_device_info.display to more accurately reflect this.

Given that we now know FPGA_DBG is display-specific, it could be argued
that we should only check it on out intel_de_*() functions.  However
let's not make that change right now; keeping the checks in all of the
existing locations still helps us catch cases where regular
intel_uncore_*() functions use bad MMIO offset math / base addresses and
accidentally wind up landing within an unused area within the display
MMIO range.  It will also help catch cases where userspace-initiated
MMIO (e.g., IGT's intel_reg tool) attempt to read bad offsets within the
display range.

v2:  Add missing hunk with the update to the HAS_FPGA_DBG_UNCLAIMED
     macro.  (CI)

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210212222049.3516344-1-matthew.d.roper@intel.com

drivers/gpu/drm/i915/i915_drv.h

@@ -1690,7 +1690,7 @@ tgl_stepping_get(struct drm_i915_private *dev_priv)
 #define HAS_DP_MST(dev_priv)	(INTEL_INFO(dev_priv)->display.has_dp_mst)
 
 #define HAS_DDI(dev_priv)		 (INTEL_INFO(dev_priv)->display.has_ddi)
-#define HAS_FPGA_DBG_UNCLAIMED(dev_priv) (INTEL_INFO(dev_priv)->has_fpga_dbg)
+#define HAS_FPGA_DBG_UNCLAIMED(dev_priv) (INTEL_INFO(dev_priv)->display.has_fpga_dbg)
 #define HAS_PSR(dev_priv)		 (INTEL_INFO(dev_priv)->display.has_psr)
 #define HAS_PSR_HW_TRACKING(dev_priv) \
 	(INTEL_INFO(dev_priv)->display.has_psr_hw_tracking)

drivers/gpu/drm/i915/i915_pci.c

@@ -536,7 +536,7 @@ static const struct intel_device_info vlv_info = {
 	.cpu_transcoder_mask = BIT(TRANSCODER_A) | BIT(TRANSCODER_B) | \
 		BIT(TRANSCODER_C) | BIT(TRANSCODER_EDP), \
 	.display.has_ddi = 1, \
-	.has_fpga_dbg = 1, \
+	.display.has_fpga_dbg = 1, \
 	.display.has_psr = 1, \
 	.display.has_psr_hw_tracking = 1, \
 	.display.has_dp_mst = 1, \
@@ -688,7 +688,7 @@ static const struct intel_device_info skl_gt4_info = {
 		BIT(TRANSCODER_DSI_A) | BIT(TRANSCODER_DSI_C), \
 	.has_64bit_reloc = 1, \
 	.display.has_ddi = 1, \
-	.has_fpga_dbg = 1, \
+	.display.has_fpga_dbg = 1, \
 	.display.has_fbc = 1, \
 	.display.has_hdcp = 1, \
 	.display.has_psr = 1, \

drivers/gpu/drm/i915/intel_device_info.h

@@ -117,7 +117,6 @@ enum intel_ppgtt_type {
 	func(has_64bit_reloc); \
 	func(gpu_reset_clobbers_display); \
 	func(has_reset_engine); \
-	func(has_fpga_dbg); \
 	func(has_global_mocs); \
 	func(has_gt_uc); \
 	func(has_l3_dpf); \
@@ -144,6 +143,7 @@ enum intel_ppgtt_type {
 	func(has_dsb); \
 	func(has_dsc); \
 	func(has_fbc); \
+	func(has_fpga_dbg); \
 	func(has_gmch); \
 	func(has_hdcp); \
 	func(has_hotplug); \