[PATCH] drm/xe/pm: Enable RPM via PCIe PM capability

[Satyanarayana K V P]

Enable Runtime Power Management (RPM) for PCI Express devices by utilizing
their native Power Management (PM) capabilities.

Signed-off-by: Satyanarayana K V P <satyanarayana.k.v.p at intel.com>
Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
Cc: Matthew Brost <matthew.brost at intel.com>
Cc: Michał Winiarski <michal.winiarski at intel.com>
Cc: Anshuman Gupta <anshuman.gupta at intel.com>
---
 drivers/gpu/drm/xe/xe_device_types.h | 2 ++
 drivers/gpu/drm/xe/xe_pm.c           | 9 +++++++++
 drivers/gpu/drm/xe/xe_pm.h           | 4 ++++
 3 files changed, 15 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 38c8329b4d2c..3bbfc46044a0 100644
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -285,6 +285,8 @@ struct xe_device {
 		 * pcode mailbox commands.
 		 */
 		u8 has_mbx_power_limits:1;
+		/** @info.has_pm_capability: Device has PCI pm capability */
+		u8 has_pm_capability:1;
 		/** @info.has_pxp: Device has PXP support */
 		u8 has_pxp:1;
 		/** @info.has_range_tlb_invalidation: Has range based TLB invalidations */
diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index 44aaf154ddf7..5e6311964685 100644
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -244,6 +244,9 @@ static void xe_pm_runtime_init(struct xe_device *xe)
 {
 	struct device *dev = xe->drm.dev;
 
+	if (!IS_RPM_SUPPORTED(xe))
+		return;
+
 	/*
 	 * Disable the system suspend direct complete optimization.
 	 * We need to ensure that the regular device suspend/resume functions
@@ -265,6 +268,7 @@ static void xe_pm_runtime_init(struct xe_device *xe)
 
 int xe_pm_init_early(struct xe_device *xe)
 {
+	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
 	int err;
 
 	INIT_LIST_HEAD(&xe->mem_access.vram_userfault.list);
@@ -278,6 +282,8 @@ int xe_pm_init_early(struct xe_device *xe)
 		return err;
 
 	xe->d3cold.capable = xe_pm_pci_d3cold_capable(xe);
+	xe->info.has_pm_capability = !!pdev->pm_cap;
+
 	return 0;
 }
 ALLOW_ERROR_INJECTION(xe_pm_init_early, ERRNO); /* See xe_pci_probe() */
@@ -364,6 +370,9 @@ static void xe_pm_runtime_fini(struct xe_device *xe)
 {
 	struct device *dev = xe->drm.dev;
 
+	if (!IS_RPM_SUPPORTED(xe))
+		return;
+
 	pm_runtime_get_sync(dev);
 	pm_runtime_forbid(dev);
 }
diff --git a/drivers/gpu/drm/xe/xe_pm.h b/drivers/gpu/drm/xe/xe_pm.h
index 59678b310e55..55b65728f522 100644
--- a/drivers/gpu/drm/xe/xe_pm.h
+++ b/drivers/gpu/drm/xe/xe_pm.h
@@ -9,6 +9,10 @@
 #include <linux/pm_runtime.h>
 
 #define DEFAULT_VRAM_THRESHOLD 300 /* in MB */
+#define IS_RPM_SUPPORTED(xe) ({ \
+		struct xe_device *___xe = (xe); \
+		___xe->info.has_pm_capability; \
+		})
 
 struct xe_device;
 
-- 
2.43.0