drm/xe/reg_sr: Allow register_save_restore_check debugfs to verify LRC values

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.

Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patch.msgid.link/20260218-sr_verify-v4-4-35d6deeb3421@intel.com
Signed-off-by: Matt Roper <matthew.d.roper@intel.com>

diff --git a/drivers/gpu/drm/xe/xe_gt_debugfs.c b/drivers/gpu/drm/xe/xe_gt_debugfs.c
index aa43427a9f4b824b8ad41d02f634c07c76d989b2..f45306308cd66c87b261edaa8de532f6cc56499d 100644 (file)
--- 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 75aa4426b3ec6026bc13095df3c3f9cb0a794b97..83a668f2a0d5f16ea3f0b93eafb6b8e66abe3fe8 100644 (file)
--- 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 +243,32 @@ 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
+ * @hwe: Hardware engine type to check LRC for
+ * @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 cd133a09aa9b3f046dbd913aa9711250e771ee1a..1ec6e8ecf2784a3a832f30b7005f116ab7a368db 100644 (file)
--- 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);