drm/i915: setup the LMEM region

Hook up the LMEM region. Addresses will start from zero, and for CPU
access we get LMEM_BAR which is just a 1:1 mapping of said region.

Based on a patch from Michel Thierry.

v2 by Jani:
- use intel_uncore_read/intel_uncore_write
- remove trailing blank line

v3: s/drm_info/drm_dbg for info which in non-pertinent for the user

Cc: Lucas De Marchi <[e-mail]>
Cc: Joonas Lahtinen <[e-mail]>
Cc: Rodrigo Vivi <[e-mail]>
Signed-off-by: Matthew Auld <[e-mail]>
Signed-off-by: Lucas De Marchi <[e-mail]>
Signed-off-by: Jani Nikula <[e-mail]>
Reviewed-by: Chris Wilson <[e-mail]>
Signed-off-by: Chris Wilson <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]
Signed-off-by: Daniel Vetter <[e-mail]>

drivers/gpu/drm/i915/gt/intel_gt.c

···
 	int id;
 	int err;
 
-	mem = intel_gt_setup_fake_lmem(gt);
+	mem = intel_gt_setup_lmem(gt);
+	if (mem == ERR_PTR(-ENODEV))
+		mem = intel_gt_setup_fake_lmem(gt);
 	if (IS_ERR(mem)) {
 		err = PTR_ERR(mem);
 		if (err == -ENODEV)

drivers/gpu/drm/i915/gt/intel_region_lmem.c

···
 
 	return mem;
 }
+
+static struct intel_memory_region *setup_lmem(struct intel_gt *gt)
+{
+	struct drm_i915_private *i915 = gt->i915;
+	struct pci_dev *pdev = i915->drm.pdev;
+	struct intel_memory_region *mem;
+	resource_size_t io_start;
+	resource_size_t size;
+
+	if (!IS_DGFX(i915))
+		return ERR_PTR(-ENODEV);
+
+	io_start = pci_resource_start(pdev, 2);
+	size = pci_resource_len(pdev, 2);
+
+	mem = intel_memory_region_create(i915,
+					 0,
+					 size,
+					 I915_GTT_PAGE_SIZE_4K,
+					 io_start,
+					 &intel_region_lmem_ops);
+	if (IS_ERR(mem))
+		return mem;
+
+	drm_dbg(&i915->drm, "Local memory: %pR\n", &mem->region);
+	drm_dbg(&i915->drm, "Local memory IO start: %pa\n",
+		&mem->io_start);
+	drm_info(&i915->drm, "Local memory available: %pa\n", &size);
+
+	return mem;
+}
+
+struct intel_memory_region *intel_gt_setup_lmem(struct intel_gt *gt)
+{
+	return setup_lmem(gt);
+}

drivers/gpu/drm/i915/gt/intel_region_lmem.h

···
 
 struct intel_gt;
 
+struct intel_memory_region *intel_gt_setup_lmem(struct intel_gt *gt);
+
 struct intel_memory_region *
 intel_gt_setup_fake_lmem(struct intel_gt *gt);