[PATCH v2 4/4] drm/xe/reg_sr: Allow register_save_restore_check debugfs to verify LRC values

[Matt Roper <matthew.d.roper@intel.com>]

reg_sr programming that applies to an engines LRC cannot be verified by
a simple CPU-based register readout because the reg_sr's values may not
be in effect if no context is executing on the hardware at the time we
check.  Instead, we should verify correct reg_sr application by
searching for the register in the default_lrc.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
 drivers/gpu/drm/xe/xe_gt_debugfs.c |  4 ++--
 drivers/gpu/drm/xe/xe_reg_sr.c     | 29 +++++++++++++++++++++++++++++
 drivers/gpu/drm/xe/xe_reg_sr.h     |  4 ++++
 3 files changed, 35 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_gt_debugfs.c b/drivers/gpu/drm/xe/xe_gt_debugfs.c
index aa43427a9f4b..f45306308cd6 100644
--- a/drivers/gpu/drm/xe/xe_gt_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_gt_debugfs.c
@@ -173,8 +173,8 @@ static int register_save_restore_check(struct xe_gt *gt, struct drm_printer *p)
 	xe_reg_sr_readback_check(&gt->reg_sr, gt, p);
 	for_each_hw_engine(hwe, gt, id)
 		xe_reg_sr_readback_check(&hwe->reg_sr, gt, p);
-
-	/* TODO: Check hwe->reg_lrc against contents of default_lrc. */
+	for_each_hw_engine(hwe, gt, id)
+		xe_reg_sr_lrc_check(&hwe->reg_lrc, gt, hwe, p);
 
 	return 0;
 }
diff --git a/drivers/gpu/drm/xe/xe_reg_sr.c b/drivers/gpu/drm/xe/xe_reg_sr.c
index 75aa4426b3ec..27a9447a672b 100644
--- a/drivers/gpu/drm/xe/xe_reg_sr.c
+++ b/drivers/gpu/drm/xe/xe_reg_sr.c
@@ -21,6 +21,7 @@
 #include "xe_gt_printk.h"
 #include "xe_gt_types.h"
 #include "xe_hw_engine_types.h"
+#include "xe_lrc.h"
 #include "xe_mmio.h"
 #include "xe_rtp_types.h"
 
@@ -242,3 +243,31 @@ void xe_reg_sr_readback_check(struct xe_reg_sr *sr,
 				   offset, mask, entry->set_bits, val & mask);
 	}
 }
+
+/**
+ * xe_reg_sr_lrc_check() - Check LRC for registers referenced in save/restore
+ *     entries and check whether the programming is in place.
+ * @sr: Save/restore entries
+ * @gt: GT to read register from
+ * @p: DRM printer to report discrepancies on
+ */
+void xe_reg_sr_lrc_check(struct xe_reg_sr *sr,
+			 struct xe_gt *gt,
+			 struct xe_hw_engine *hwe,
+			 struct drm_printer *p)
+{
+	struct xe_reg_sr_entry *entry;
+	unsigned long offset;
+
+	xa_for_each(&sr->xa, offset, entry) {
+		u32 val;
+		int ret = xe_lrc_lookup_default_reg_value(gt, hwe->class, offset, &val);
+		u32 mask = entry->clr_bits | entry->set_bits;
+
+		if (ret == -ENOENT)
+			drm_printf(p, "%#8lx :: not found in LRC for %s\n", offset, hwe->name);
+		else if ((val & mask) != entry->set_bits)
+			drm_printf(p, "%#8lx & %#10x :: expected %#10x got %#10x\n",
+				   offset, mask, entry->set_bits, val & mask);
+	}
+}
diff --git a/drivers/gpu/drm/xe/xe_reg_sr.h b/drivers/gpu/drm/xe/xe_reg_sr.h
index cd133a09aa9b..1ec6e8ecf278 100644
--- a/drivers/gpu/drm/xe/xe_reg_sr.h
+++ b/drivers/gpu/drm/xe/xe_reg_sr.h
@@ -22,6 +22,10 @@ void xe_reg_sr_dump(struct xe_reg_sr *sr, struct drm_printer *p);
 void xe_reg_sr_readback_check(struct xe_reg_sr *sr,
 			      struct xe_gt *gt,
 			      struct drm_printer *p);
+void xe_reg_sr_lrc_check(struct xe_reg_sr *sr,
+			 struct xe_gt *gt,
+			 struct xe_hw_engine *hwe,
+			 struct drm_printer *p);
 
 int xe_reg_sr_add(struct xe_reg_sr *sr, const struct xe_reg_sr_entry *e,
 		  struct xe_gt *gt);
-- 
2.53.0