[Intel-gfx] [PATCH] drm/i915: Sanitycheck PCI BARs on probe

["Piorkowski, Piotr" <piotr.piorkowski@intel.com>]

From: Piotr Piórkowski <piotr.piorkowski@intel.com>

For proper operation of i915 we need usable PCI BARs:
 - GTTMMADDR BAR 0 (1 for GEN2)
 - GFXMEM BAR 2.
Lets check before we start the i915 probe that these BARs are set,
and that they have a size greater than 0.

Signed-off-by: Piotr Piórkowski <piotr.piorkowski@intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko@intel.com>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
---
 drivers/gpu/drm/i915/i915_pci.c         | 33 +++++++++++++++++++++++++
 drivers/gpu/drm/i915/intel_pci_config.h |  5 ++++
 2 files changed, 38 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_pci.c b/drivers/gpu/drm/i915/i915_pci.c
index 8261b6455747..ad60c69d9dd8 100644
--- a/drivers/gpu/drm/i915/i915_pci.c
+++ b/drivers/gpu/drm/i915/i915_pci.c
@@ -29,6 +29,8 @@
 #include "i915_drv.h"
 #include "i915_pci.h"
 
+#include "intel_pci_config.h"
+
 #define PLATFORM(x) .platform = (x)
 #define GEN(x) \
 	.graphics.ver = (x), \
@@ -1181,6 +1183,34 @@ static bool force_probe(u16 device_id, const char *devices)
 	return ret;
 }
 
+static bool __pci_resource_valid(struct pci_dev *pdev, int bar)
+{
+	if (!pci_resource_flags(pdev, bar))
+		return false;
+
+	if (pci_resource_flags(pdev, bar) & IORESOURCE_UNSET)
+		return false;
+
+	if (!pci_resource_len(pdev, bar))
+		return false;
+
+	return true;
+}
+
+static bool intel_bars_valid(struct pci_dev *pdev, struct intel_device_info *intel_info)
+{
+	const int gttmmaddr_bar = intel_info->graphics.ver == 2 ? GEN2_GTTMMADR_BAR : GTTMMADR_BAR;
+	const int gfxmem_bar = GFXMEM_BAR;
+
+	if (!__pci_resource_valid(pdev, gttmmaddr_bar))
+		return false;
+
+	if (!__pci_resource_valid(pdev, gfxmem_bar))
+		return false;
+
+	return true;
+}
+
 static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 {
 	struct intel_device_info *intel_info =
@@ -1206,6 +1236,9 @@ static int i915_pci_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
 	if (PCI_FUNC(pdev->devfn))
 		return -ENODEV;
 
+	if (!intel_bars_valid(pdev, intel_info))
+		return -ENODEV;
+
 	/* Detect if we need to wait for other drivers early on */
 	if (intel_modeset_probe_defer(pdev))
 		return -EPROBE_DEFER;
diff --git a/drivers/gpu/drm/i915/intel_pci_config.h b/drivers/gpu/drm/i915/intel_pci_config.h
index 12cd9d4f23de..c08fd5d48ada 100644
--- a/drivers/gpu/drm/i915/intel_pci_config.h
+++ b/drivers/gpu/drm/i915/intel_pci_config.h
@@ -6,6 +6,11 @@
 #ifndef __INTEL_PCI_CONFIG_H__
 #define __INTEL_PCI_CONFIG_H__
 
+/* PCI BARs */
+#define GTTMMADR_BAR				0
+#define GEN2_GTTMMADR_BAR			1
+#define GFXMEM_BAR				2
+
 /* BSM in include/drm/i915_drm.h */
 
 #define MCHBAR_I915				0x44
-- 
2.25.1