drm/xe/pm: Init pcode and restore vram on power lost

Don't init pcode and restore VRAM objects in vain.
We can rely on primary GT GUC_STATUS to detect whether
card has really lost power even when d3cold is allowed by xe.
Adding d3cold.lost_power flag to avoid pcode init and vram
restoration.
Also cleaning up the TODO code comment.

v2:
- %s/xe_guc_has_lost_power()/xe_guc_in_reset().
- Used existing gt instead of new variable. [Rodrigo]
- Added kernel-doc function comment. [Rodrigo]
- xe_guc_in_reset() return true if failed to get fw.

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Signed-off-by: Anshuman Gupta <anshuman.gupta@intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230718080703.239343-6-anshuman.gupta@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
index 14b15ec..0897719 100644 (file)
--- a/drivers/gpu/drm/xe/xe_device_types.h
+++ b/drivers/gpu/drm/xe/xe_device_types.h
@@ -335,6 +335,9 @@ struct xe_device {
                /** @allowed: Indicates if d3cold is a valid device state */
                bool allowed;
 
+               /** @power_lost: Indicates if card has really lost power. */
+               bool power_lost;
+
                /**
                 * @vram_threshold:
                 *

diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
index d44537a..ed90d73 100644 (file)
--- a/drivers/gpu/drm/xe/xe_guc.c
+++ b/drivers/gpu/drm/xe/xe_guc.c
@@ -844,3 +844,30 @@ void xe_guc_print_info(struct xe_guc *guc, struct drm_printer *p)
        xe_guc_ct_print(&guc->ct, p, false);
        xe_guc_submit_print(guc, p);
 }
+
+/**
+ * xe_guc_in_reset() - Detect if GuC MIA is in reset.
+ * @guc: The GuC object
+ *
+ * This function detects runtime resume from d3cold by leveraging
+ * GUC_STATUS, GUC doesn't get reset during d3hot,
+ * it strictly to be called from RPM resume handler.
+ *
+ * Return: true if failed to get forcewake or GuC MIA is in Reset,
+ * otherwise false.
+ */
+bool xe_guc_in_reset(struct xe_guc *guc)
+{
+       struct xe_gt *gt = guc_to_gt(guc);
+       u32 status;
+       int err;
+
+       err = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
+       if (err)
+               return true;
+
+       status = xe_mmio_read32(gt, GUC_STATUS);
+       xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
+
+       return  status & GS_MIA_IN_RESET;
+}

diff --git a/drivers/gpu/drm/xe/xe_guc.h b/drivers/gpu/drm/xe/xe_guc.h
index 74a7405..f64f22e 100644 (file)
--- a/drivers/gpu/drm/xe/xe_guc.h
+++ b/drivers/gpu/drm/xe/xe_guc.h
@@ -35,6 +35,7 @@ void xe_guc_reset_wait(struct xe_guc *guc);
 void xe_guc_stop_prepare(struct xe_guc *guc);
 int xe_guc_stop(struct xe_guc *guc);
 int xe_guc_start(struct xe_guc *guc);
+bool xe_guc_in_reset(struct xe_guc *guc);
 
 static inline u16 xe_engine_class_to_guc_class(enum xe_engine_class class)
 {

diff --git a/drivers/gpu/drm/xe/xe_pci.c b/drivers/gpu/drm/xe/xe_pci.c
index 6d04e57..ae6e139 100644 (file)
--- a/drivers/gpu/drm/xe/xe_pci.c
+++ b/drivers/gpu/drm/xe/xe_pci.c
@@ -818,8 +818,6 @@ static int xe_pci_runtime_idle(struct device *dev)
                 * but maybe include some other conditions. So, before
                 * we can re-enable the D3cold, we need to:
                 * 1. rewrite the VRAM save / restore to avoid buffer object locks
-                * 2. at resume, detect if we really lost power and avoid memory
-                *    restoration if we were only up to d3cold
                 */
                xe->d3cold.allowed = false;
        }

diff --git a/drivers/gpu/drm/xe/xe_pm.c b/drivers/gpu/drm/xe/xe_pm.c
index 21964e4..f336aec 100644 (file)
--- a/drivers/gpu/drm/xe/xe_pm.c
+++ b/drivers/gpu/drm/xe/xe_pm.c
@@ -16,6 +16,7 @@
 #include "xe_device_sysfs.h"
 #include "xe_ggtt.h"
 #include "xe_gt.h"
+#include "xe_guc.h"
 #include "xe_irq.h"
 #include "xe_pcode.h"
 
@@ -186,7 +187,15 @@ int xe_pm_runtime_resume(struct xe_device *xe)
        u8 id;
        int err;
 
-       if (xe->d3cold.allowed) {
+       /*
+        * It can be possible that xe has allowed d3cold but other pcie devices
+        * in gfx card soc would have blocked d3cold, therefore card has not
+        * really lost power. Detecting primary Gt power is sufficient.
+        */
+       gt = xe_device_get_gt(xe, 0);
+       xe->d3cold.power_lost = xe_guc_in_reset(&gt->uc.guc);
+
+       if (xe->d3cold.allowed && xe->d3cold.power_lost) {
                for_each_gt(gt, xe, id) {
                        err = xe_pcode_init(gt);
                        if (err)
@@ -207,7 +216,7 @@ int xe_pm_runtime_resume(struct xe_device *xe)
        for_each_gt(gt, xe, id)
                xe_gt_resume(gt);
 
-       if (xe->d3cold.allowed) {
+       if (xe->d3cold.allowed && xe->d3cold.power_lost) {
                err = xe_bo_restore_user(xe);
                if (err)
                        return err;