[RFC 2/6] drm/xe/vrsr: Detect vrsr capability

[Anshuman Gupta <anshuman.gupta@intel.com>]

Detect VRAM Self Refresh(vrsr) Capability.

Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
---
 drivers/gpu/drm/xe/regs/xe_regs.h    |  3 +++
 drivers/gpu/drm/xe/xe_device_types.h |  4 ++++
 drivers/gpu/drm/xe/xe_pm.c           | 27 +++++++++++++++++++++++++++
 3 files changed, 34 insertions(+)

diff --git a/drivers/gpu/drm/xe/regs/xe_regs.h b/drivers/gpu/drm/xe/regs/xe_regs.h
index 6cf282618836..21563e9d958b 100644
--- a/drivers/gpu/drm/xe/regs/xe_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_regs.h
@@ -57,6 +57,9 @@
 #define MTL_MPE_FREQUENCY			XE_REG(0x13802c)
 #define   MTL_RPE_MASK				REG_GENMASK(8, 0)
 
+#define VRAM_CAPABILITY                         XE_REG(0x138144)
+#define   VRAM_SUPPORTED                        REG_BIT(0)
+
 #define VF_CAP_REG				XE_REG(0x1901f8, XE_REG_OPTION_VF)
 #define   VF_CAP				REG_BIT(0)
 
diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 4656305dd45a..c2ab2c91c968 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -490,6 +490,9 @@ struct xe_device {
 		/** @d3cold.allowed: Indicates if d3cold is a valid device state */
 		bool allowed;
 
+		/** @d3cold.vrsr_capable: Indicates if d3cold VRAM Self Refresh is supported */
+		bool vrsr_capable;
+
 		/**
 		 * @d3cold.vram_threshold:
 		 *
@@ -500,6 +503,7 @@ struct xe_device {
 		 * Default threshold value is 300mb.
 		 */
 		u32 vram_threshold;
+
 		/** @d3cold.lock: protect vram_threshold */
 		struct mutex lock;
 	} d3cold;
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index 12200be7b43d..dead236355d8 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -17,12 +17,15 @@
 #include "xe_bo_evict.h"
 #include "xe_device.h"
 #include "xe_device_sysfs.h"
+#include "xe_force_wake.h"
 #include "xe_ggtt.h"
 #include "xe_gt.h"
 #include "xe_guc.h"
 #include "xe_irq.h"
+#include "xe_mmio.h"
 #include "xe_pcode.h"
 #include "xe_pxp.h"
+#include "regs/xe_regs.h"
 #include "xe_trace.h"
 #include "xe_wa.h"
 
@@ -236,6 +239,28 @@ static bool xe_pm_pci_d3cold_capable(struct xe_device *xe)
 	return true;
 }
 
+static bool xe_pm_vrsr_capable(struct xe_device *xe)
+{
+	struct xe_mmio *mmio = xe_root_tile_mmio(xe);
+	unsigned int fw_ref;
+	struct xe_gt *gt;
+	u32 val;
+
+	gt = xe_root_mmio_gt(xe);
+
+	if (!xe->info.probe_display)
+		return false;
+
+	fw_ref = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
+	if (!fw_ref)
+		return false;
+
+	val = xe_mmio_read32(mmio, VRAM_CAPABILITY);
+	xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL);
+
+	return val & VRAM_SUPPORTED;
+}
+
 static void xe_pm_runtime_init(struct xe_device *xe)
 {
 	struct device *dev = xe->drm.dev;
@@ -303,6 +328,8 @@ int xe_pm_init(struct xe_device *xe)
 		err = xe_pm_set_vram_threshold(xe, DEFAULT_VRAM_THRESHOLD);
 		if (err)
 			return err;
+
+		xe->d3cold.vrsr_capable = xe_pm_vrsr_capable(xe);
 	}
 
 	xe_pm_runtime_init(xe);
-- 
2.34.1