drm/i915: make reserved struct resource centric

Now that we are using struct resource to track the stolen region, it is
more convenient if we track the reserved portion of that region in a
resource as well.

v2: s/<= end + 1/< end/ (Chris)
v3: prefer DEFINE_RES_MEM

Signed-off-by: Matthew Auld <[e-mail]>
Cc: Joonas Lahtinen <[e-mail]>
Cc: Chris Wilson <[e-mail]>
Cc: Paulo Zanoni <[e-mail]>
Reviewed-by: Chris Wilson <[e-mail]>
Signed-off-by: Joonas Lahtinen <[e-mail]>
Link: https://patchwork.freedesktop.org/patch/msgid/[e-mail]

drivers/gpu/drm/i915/i915_drv.h

···
 	 * some portion of it is in fact reserved for use by hardware functions.
 	 */
 	struct resource dsm;
+	/**
+	 * Reseved portion of Data Stolen Memory
+	 */
+	struct resource dsm_reserved;
 
 	void __iomem *regs;
 

drivers/gpu/drm/i915/i915_gem_gtt.h

···
 	 * hardware functions and similarly removed from the accessible range.
 	 */
 	u32 stolen_usable_size;	/* Total size minus reserved ranges */
-	u32 stolen_reserved_base;
-	u32 stolen_reserved_size;
 
 	/** "Graphics Stolen Memory" holds the global PTEs */
 	void __iomem *gsm;

drivers/gpu/drm/i915/i915_gem_stolen.c

···
 		reserved_base = stolen_top;
 	}
 
-	if (reserved_base < dev_priv->dsm.start ||
-	    reserved_base + reserved_size > stolen_top) {
-		dma_addr_t reserved_top = reserved_base + reserved_size;
-		DRM_ERROR("Stolen reserved area [%pad - %pad] outside stolen memory %pR\n",
-			  &reserved_base, &reserved_top, &dev_priv->dsm);
+	dev_priv->dsm_reserved =
+		(struct resource) DEFINE_RES_MEM(reserved_base, reserved_size);
+
+	if (!resource_contains(&dev_priv->dsm, &dev_priv->dsm_reserved)) {
+		DRM_ERROR("Stolen reserved area %pR outside stolen memory %pR\n",
+			  &dev_priv->dsm_reserved, &dev_priv->dsm);
 		return 0;
 	}
-
-	ggtt->stolen_reserved_base = reserved_base;
-	ggtt->stolen_reserved_size = reserved_size;
 
 	/* It is possible for the reserved area to end before the end of stolen
 	 * memory, so just consider the start. */

drivers/gpu/drm/i915/intel_pm.c

···
 
 static bool bxt_check_bios_rc6_setup(struct drm_i915_private *dev_priv)
 {
-	struct i915_ggtt *ggtt = &dev_priv->ggtt;
 	bool enable_rc6 = true;
 	unsigned long rc6_ctx_base;
 	u32 rc_ctl;
···
 	 * for this check.
 	 */
 	rc6_ctx_base = I915_READ(RC6_CTX_BASE) & RC6_CTX_BASE_MASK;
-	if (!((rc6_ctx_base >= ggtt->stolen_reserved_base) &&
-	      (rc6_ctx_base + PAGE_SIZE <= ggtt->stolen_reserved_base +
-					ggtt->stolen_reserved_size))) {
+	if (!((rc6_ctx_base >= dev_priv->dsm_reserved.start) &&
+	      (rc6_ctx_base + PAGE_SIZE < dev_priv->dsm_reserved.end))) {
 		DRM_DEBUG_DRIVER("RC6 Base address not as expected.\n");
 		enable_rc6 = false;
 	}