drm/xe: Introduce the wedged_mode debugfs

So, the wedged mode can be selected per device at runtime,
before the tests or before reproducing the issue.

v2: - s/busted/wedged
    - some locking consistency

v3: - remove mutex
    - toggle guc reset policy on any mode change

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Alan Previn <alan.previn.teres.alexis@intel.com>
Cc: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Reviewed-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240423221817.1285081-4-rodrigo.vivi@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/drivers/gpu/drm/xe/xe_debugfs.c b/drivers/gpu/drm/xe/xe_debugfs.c
index c9b30dbdc14d..0e61fa462c7b 100644
--- a/drivers/gpu/drm/xe/xe_debugfs.c
+++ b/drivers/gpu/drm/xe/xe_debugfs.c
@@ -12,6 +12,8 @@
 #include "xe_bo.h"
 #include "xe_device.h"
 #include "xe_gt_debugfs.h"
+#include "xe_gt_printk.h"
+#include "xe_guc_ads.h"
 #include "xe_pm.h"
 #include "xe_sriov.h"
 #include "xe_step.h"
@@ -117,6 +119,56 @@ static const struct file_operations forcewake_all_fops = {
 	.release = forcewake_release,
 };
 
+static ssize_t wedged_mode_show(struct file *f, char __user *ubuf,
+				size_t size, loff_t *pos)
+{
+	struct xe_device *xe = file_inode(f)->i_private;
+	char buf[32];
+	int len = 0;
+
+	len = scnprintf(buf, sizeof(buf), "%d\n", xe->wedged.mode);
+
+	return simple_read_from_buffer(ubuf, size, pos, buf, len);
+}
+
+static ssize_t wedged_mode_set(struct file *f, const char __user *ubuf,
+			       size_t size, loff_t *pos)
+{
+	struct xe_device *xe = file_inode(f)->i_private;
+	struct xe_gt *gt;
+	u32 wedged_mode;
+	ssize_t ret;
+	u8 id;
+
+	ret = kstrtouint_from_user(ubuf, size, 0, &wedged_mode);
+	if (ret)
+		return ret;
+
+	if (wedged_mode > 2)
+		return -EINVAL;
+
+	if (xe->wedged.mode == wedged_mode)
+		return 0;
+
+	xe->wedged.mode = wedged_mode;
+
+	for_each_gt(gt, xe, id) {
+		ret = xe_guc_ads_scheduler_policy_toggle_reset(&gt->uc.guc.ads);
+		if (ret) {
+			xe_gt_err(gt, "Failed to update GuC ADS scheduler policy. GuC may still cause engine reset even with wedged_mode=2\n");
+			return -EIO;
+		}
+	}
+
+	return size;
+}
+
+static const struct file_operations wedged_mode_fops = {
+	.owner = THIS_MODULE,
+	.read = wedged_mode_show,
+	.write = wedged_mode_set,
+};
+
 void xe_debugfs_register(struct xe_device *xe)
 {
 	struct ttm_device *bdev = &xe->ttm;
@@ -134,6 +186,9 @@ void xe_debugfs_register(struct xe_device *xe)
 	debugfs_create_file("forcewake_all", 0400, root, xe,
 			    &forcewake_all_fops);
 
+	debugfs_create_file("wedged_mode", 0400, root, xe,
+			    &wedged_mode_fops);
+
 	for (mem_type = XE_PL_VRAM0; mem_type <= XE_PL_VRAM1; ++mem_type) {
 		man = ttm_manager_type(bdev, mem_type);