[PATCH v2 5/6] drm/i915: Implement the is_boot_device callback function

[Sui Jingfeng <sui.jingfeng@linux.dev>]

From: Sui Jingfeng <suijingfeng@loongson.cn>

This patch add a function to identify if a device is the default boot
selected by the firmware, it require the GPU has firmware framebuffer
driver support (such as efifb). If a specific hardware doesn't have
firmware framebuffer support, then the introduced function will just
return false. But even in this case, it still do no harms.

Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
Cc: David Airlie <airlied@gmail.com>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
Cc: Lyude Paul <lyude@redhat.com>
Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
---
 drivers/gpu/drm/i915/display/intel_vga.c | 31 +++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_vga.c b/drivers/gpu/drm/i915/display/intel_vga.c
index 98d7d4dffe9f..7a0ba677c932 100644
--- a/drivers/gpu/drm/i915/display/intel_vga.c
+++ b/drivers/gpu/drm/i915/display/intel_vga.c
@@ -6,6 +6,8 @@
 #include <linux/pci.h>
 #include <linux/vgaarb.h>
 
+#include <drm/drm_aperture.h>
+
 #include <video/vga.h>
 
 #include "soc/intel_gmch.h"
@@ -113,6 +115,32 @@ intel_vga_set_decode(struct pci_dev *pdev, bool enable_decode)
 		return VGA_RSRC_NORMAL_IO | VGA_RSRC_NORMAL_MEM;
 }
 
+static bool intel_vga_is_default_boot_device(struct pci_dev *pdev)
+{
+	struct drm_i915_private *i915 = pdev_to_i915(pdev);
+	struct drm_device *drm = &i915->drm;
+	struct i915_gem_mm *mm = &i915->mm;
+	struct intel_memory_region *mr;
+	unsigned int i;
+	bool ret;
+
+	for (i = 0; i < ARRAY_SIZE(mm->regions); i++) {
+		mr = mm->regions[i];
+		if (mr) {
+			ret = drm_aperture_contain_firmware_fb(mr->io_start,
+							       mr->io_size);
+
+			if (ret) {
+				drm_dbg(drm, "%s contains firmware fb\n",
+					mr->name);
+				return true;
+			}
+		}
+	}
+
+	return false;
+}
+
 int intel_vga_register(struct drm_i915_private *i915)
 {
 	struct pci_dev *pdev = to_pci_dev(i915->drm.dev);
@@ -126,7 +154,8 @@ int intel_vga_register(struct drm_i915_private *i915)
 	 * then we do not take part in VGA arbitration and the
 	 * vga_client_register() fails with -ENODEV.
 	 */
-	ret = vga_client_register(pdev, intel_vga_set_decode, NULL);
+	ret = vga_client_register(pdev, intel_vga_set_decode,
+				  intel_vga_is_default_boot_device);
 	if (ret && ret != -ENODEV)
 		return ret;
 
-- 
2.25.1