drm/i915/fbdev: Use lmem physical addresses for fb_mmap() on discrete

Use local memory io BAR address for fbdev's fb_mmap() operation on
discrete, fbdev uses the physical address of our framebuffer for its
fb_mmap() fn.
Signed-off-by: Mohammed Khajapasha <mohammed.khajapasha@intel.com>
Reviewed-by: Matthew Auld <matthew.auld@intel.com>
Signed-off-by: Matthew Auld <matthew.auld@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210427085417.120246-5-matthew.auld@intel.com

drivers/gpu/drm/i915/display/intel_fbdev.c

@@ -41,6 +41,8 @@
 #include <drm/drm_fb_helper.h>
 #include <drm/drm_fourcc.h>
 
+#include "gem/i915_gem_lmem.h"
+
 #include "i915_drv.h"
 #include "intel_display_types.h"
 #include "intel_fbdev.h"
@@ -178,6 +180,7 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	unsigned long flags = 0;
 	bool prealloc = false;
 	void __iomem *vaddr;
+	struct drm_i915_gem_object *obj;
 	int ret;
 
 	if (intel_fb &&
@@ -232,13 +235,27 @@ static int intelfb_create(struct drm_fb_helper *helper,
 	info->fbops = &intelfb_ops;
 
 	/* setup aperture base/size for vesafb takeover */
-	info->apertures->ranges[0].base = ggtt->gmadr.start;
-	info->apertures->ranges[0].size = ggtt->mappable_end;
+	obj = intel_fb_obj(&intel_fb->base);
+	if (i915_gem_object_is_lmem(obj)) {
+		struct intel_memory_region *mem = obj->mm.region;
+
+		info->apertures->ranges[0].base = mem->io_start;
+		info->apertures->ranges[0].size = mem->total;
+
+		/* Use fbdev's framebuffer from lmem for discrete */
+		info->fix.smem_start =
+			(unsigned long)(mem->io_start +
+					i915_gem_object_get_dma_address(obj, 0));
+		info->fix.smem_len = obj->base.size;
+	} else {
+		info->apertures->ranges[0].base = ggtt->gmadr.start;
+		info->apertures->ranges[0].size = ggtt->mappable_end;
 
-	/* Our framebuffer is the entirety of fbdev's system memory */
-	info->fix.smem_start =
-		(unsigned long)(ggtt->gmadr.start + vma->node.start);
-	info->fix.smem_len = vma->node.size;
+		/* Our framebuffer is the entirety of fbdev's system memory */
+		info->fix.smem_start =
+			(unsigned long)(ggtt->gmadr.start + vma->node.start);
+		info->fix.smem_len = vma->node.size;
+	}
 
 	vaddr = i915_vma_pin_iomap(vma);
 	if (IS_ERR(vaddr)) {