drm/i915/dram: allocate struct dram_info dynamically

Allocate struct drm_info dynamically, and convert the struct
drm_i915_private and struct xe_device dram_info member into a const
pointer. Move the struct definition to intel_dram.h, and keep it opaque
to everyone not needing it. This also removes the duplication of the
struct definition.

Reviewed-by: Vinod Govindapillai <vinod.govindapillai@intel.com>
Link: https://lore.kernel.org/r/73625095157346ea0e8614108c9b369208e5df66.1748337870.git.jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Author: jnikula

drivers/gpu/drm/i915/i915_drv.h

@@ -60,6 +60,7 @@
 #include "intel_step.h"
 #include "intel_uncore.h"
 
+struct dram_info;
 struct drm_i915_clock_gating_funcs;
 struct intel_display;
 struct intel_pxp;
@@ -282,25 +283,7 @@ struct drm_i915_private {
 	u32 suspend_count;
 	struct vlv_s0ix_state *vlv_s0ix_state;
 
-	struct dram_info {
-		bool wm_lv_0_adjust_needed;
-		u8 num_channels;
-		bool symmetric_memory;
-		enum intel_dram_type {
-			INTEL_DRAM_UNKNOWN,
-			INTEL_DRAM_DDR3,
-			INTEL_DRAM_DDR4,
-			INTEL_DRAM_LPDDR3,
-			INTEL_DRAM_LPDDR4,
-			INTEL_DRAM_DDR5,
-			INTEL_DRAM_LPDDR5,
-			INTEL_DRAM_GDDR,
-			INTEL_DRAM_GDDR_ECC,
-			__INTEL_DRAM_TYPE_MAX,
-		} type;
-		u8 num_qgv_points;
-		u8 num_psf_gv_points;
-	} dram_info;
+	const struct dram_info *dram_info;
 
 	struct intel_runtime_pm runtime_pm;
 

drivers/gpu/drm/i915/soc/intel_dram.c

@@ -5,6 +5,8 @@
 
 #include <linux/string_helpers.h>
 
+#include <drm/drm_managed.h>
+
 #include "../display/intel_display_core.h" /* FIXME */
 
 #include "i915_drv.h"
@@ -706,7 +708,7 @@ static int xelpdp_get_dram_info(struct drm_i915_private *i915, struct dram_info
 
 int intel_dram_detect(struct drm_i915_private *i915)
 {
-	struct dram_info *dram_info = &i915->dram_info;
+	struct dram_info *dram_info;
 	int ret;
 
 	detect_fsb_freq(i915);
@@ -715,6 +717,12 @@ int intel_dram_detect(struct drm_i915_private *i915)
 	if (GRAPHICS_VER(i915) < 9 || IS_DG2(i915) || !HAS_DISPLAY(i915))
 		return 0;
 
+	dram_info = drmm_kzalloc(&i915->drm, sizeof(*dram_info), GFP_KERNEL);
+	if (!dram_info)
+		return -ENOMEM;
+
+	i915->dram_info = dram_info;
+
 	/*
 	 * Assume level 0 watermark latency adjustment is needed until proven
 	 * otherwise, this w/a is not needed by bxt/glk.
@@ -749,11 +757,16 @@ int intel_dram_detect(struct drm_i915_private *i915)
 	return 0;
 }
 
+/*
+ * Returns NULL for platforms that don't have dram info. Avoid overzealous NULL
+ * checks, and prefer not dereferencing on platforms that shouldn't look at dram
+ * info, to catch accidental and incorrect dram info checks.
+ */
 const struct dram_info *intel_dram_info(struct drm_device *drm)
 {
 	struct drm_i915_private *i915 = to_i915(drm);
 
-	return &i915->dram_info;
+	return i915->dram_info;
 }
 
 static u32 gen9_edram_size_mb(struct drm_i915_private *i915, u32 cap)

drivers/gpu/drm/i915/soc/intel_dram.h

@@ -6,9 +6,30 @@
 #ifndef __INTEL_DRAM_H__
 #define __INTEL_DRAM_H__
 
+#include <linux/types.h>
+
 struct drm_i915_private;
 struct drm_device;
-struct dram_info;
+
+struct dram_info {
+	bool wm_lv_0_adjust_needed;
+	u8 num_channels;
+	bool symmetric_memory;
+	enum intel_dram_type {
+		INTEL_DRAM_UNKNOWN,
+		INTEL_DRAM_DDR3,
+		INTEL_DRAM_DDR4,
+		INTEL_DRAM_LPDDR3,
+		INTEL_DRAM_LPDDR4,
+		INTEL_DRAM_DDR5,
+		INTEL_DRAM_LPDDR5,
+		INTEL_DRAM_GDDR,
+		INTEL_DRAM_GDDR_ECC,
+		__INTEL_DRAM_TYPE_MAX,
+	} type;
+	u8 num_qgv_points;
+	u8 num_psf_gv_points;
+};
 
 void intel_dram_edram_detect(struct drm_i915_private *i915);
 int intel_dram_detect(struct drm_i915_private *i915);

drivers/gpu/drm/xe/xe_device_types.h

@@ -30,6 +30,7 @@
 #define TEST_VM_OPS_ERROR
 #endif
 
+struct dram_info;
 struct intel_display;
 struct xe_ggtt;
 struct xe_pat_ops;
@@ -585,25 +586,7 @@ struct xe_device {
 	 */
 	struct intel_display *display;
 
-	struct dram_info {
-		bool wm_lv_0_adjust_needed;
-		u8 num_channels;
-		bool symmetric_memory;
-		enum intel_dram_type {
-			INTEL_DRAM_UNKNOWN,
-			INTEL_DRAM_DDR3,
-			INTEL_DRAM_DDR4,
-			INTEL_DRAM_LPDDR3,
-			INTEL_DRAM_LPDDR4,
-			INTEL_DRAM_DDR5,
-			INTEL_DRAM_LPDDR5,
-			INTEL_DRAM_GDDR,
-			INTEL_DRAM_GDDR_ECC,
-			__INTEL_DRAM_TYPE_MAX,
-		} type;
-		u8 num_qgv_points;
-		u8 num_psf_gv_points;
-	} dram_info;
+	const struct dram_info *dram_info;
 
 	/*
 	 * edram size in MB.