drm/xe/pxp: Add PXP debugfs support

This patch introduces 2 PXP debugfs entries:

- info: prints the current PXP status and key instance
- terminate: simulate a termination interrupt

The first one is useful for debug, while the second one can be used for
testing the termination flow.

v2: move the info prints inside the lock (John)

Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Cc: John Harrison <John.C.Harrison@Intel.com>
Reviewed-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250129174140.948829-13-daniele.ceraolospurio@intel.com

drivers/gpu/drm/xe/Makefile

@@ -88,6 +88,7 @@ xe-y += xe_bb.o \
 	xe_pt.o \
 	xe_pt_walk.o \
 	xe_pxp.o \
+	xe_pxp_debugfs.o \
 	xe_pxp_submit.o \
 	xe_query.o \
 	xe_range_fence.o \

drivers/gpu/drm/xe/xe_debugfs.c

@@ -18,6 +18,7 @@
 #include "xe_gt_printk.h"
 #include "xe_guc_ads.h"
 #include "xe_pm.h"
+#include "xe_pxp_debugfs.h"
 #include "xe_sriov.h"
 #include "xe_step.h"
 
@@ -230,5 +231,7 @@ void xe_debugfs_register(struct xe_device *xe)
 	for_each_gt(gt, xe, id)
 		xe_gt_debugfs_register(gt);
 
+	xe_pxp_debugfs_register(xe->pxp);
+
 	fault_create_debugfs_attr("fail_gt_reset", root, &gt_reset_failure);
 }

drivers/gpu/drm/xe/xe_pxp_debugfs.c

@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#include "xe_pxp_debugfs.h"
+
+#include <linux/debugfs.h>
+
+#include <drm/drm_debugfs.h>
+#include <drm/drm_managed.h>
+#include <drm/drm_print.h>
+
+#include "xe_device.h"
+#include "xe_pxp.h"
+#include "xe_pxp_types.h"
+#include "regs/xe_irq_regs.h"
+
+static struct xe_pxp *node_to_pxp(struct drm_info_node *node)
+{
+	return node->info_ent->data;
+}
+
+static const char *pxp_status_to_str(struct xe_pxp *pxp)
+{
+	lockdep_assert_held(&pxp->mutex);
+
+	switch (pxp->status) {
+	case XE_PXP_ERROR:
+		return "error";
+	case XE_PXP_NEEDS_TERMINATION:
+		return "needs termination";
+	case XE_PXP_TERMINATION_IN_PROGRESS:
+		return "termination in progress";
+	case XE_PXP_READY_TO_START:
+		return "ready to start";
+	case XE_PXP_ACTIVE:
+		return "active";
+	case XE_PXP_SUSPENDED:
+		return "suspended";
+	default:
+		return "unknown";
+	}
+};
+
+static int pxp_info(struct seq_file *m, void *data)
+{
+	struct xe_pxp *pxp = node_to_pxp(m->private);
+	struct drm_printer p = drm_seq_file_printer(m);
+	const char *status;
+
+	if (!xe_pxp_is_enabled(pxp))
+		return -ENODEV;
+
+	mutex_lock(&pxp->mutex);
+	status = pxp_status_to_str(pxp);
+
+	drm_printf(&p, "status: %s\n", status);
+	drm_printf(&p, "instance counter: %u\n", pxp->key_instance);
+	mutex_unlock(&pxp->mutex);
+
+	return 0;
+}
+
+static int pxp_terminate(struct seq_file *m, void *data)
+{
+	struct xe_pxp *pxp = node_to_pxp(m->private);
+	struct drm_printer p = drm_seq_file_printer(m);
+
+	if (!xe_pxp_is_enabled(pxp))
+		return -ENODEV;
+
+	/* simulate a termination interrupt */
+	spin_lock_irq(&pxp->xe->irq.lock);
+	xe_pxp_irq_handler(pxp->xe, KCR_PXP_STATE_TERMINATED_INTERRUPT);
+	spin_unlock_irq(&pxp->xe->irq.lock);
+
+	drm_printf(&p, "PXP termination queued\n");
+
+	return 0;
+}
+
+static const struct drm_info_list debugfs_list[] = {
+	{"info", pxp_info, 0},
+	{"terminate", pxp_terminate, 0},
+};
+
+void xe_pxp_debugfs_register(struct xe_pxp *pxp)
+{
+	struct drm_minor *minor;
+	struct drm_info_list *local;
+	struct dentry *root;
+	int i;
+
+	if (!xe_pxp_is_enabled(pxp))
+		return;
+
+	minor = pxp->xe->drm.primary;
+	if (!minor->debugfs_root)
+		return;
+
+#define DEBUGFS_SIZE	(ARRAY_SIZE(debugfs_list) * sizeof(struct drm_info_list))
+	local = drmm_kmalloc(&pxp->xe->drm, DEBUGFS_SIZE, GFP_KERNEL);
+	if (!local)
+		return;
+
+	memcpy(local, debugfs_list, DEBUGFS_SIZE);
+#undef DEBUGFS_SIZE
+
+	for (i = 0; i < ARRAY_SIZE(debugfs_list); ++i)
+		local[i].data = pxp;
+
+	root = debugfs_create_dir("pxp", minor->debugfs_root);
+	if (IS_ERR(root))
+		return;
+
+	drm_debugfs_create_files(local,
+				 ARRAY_SIZE(debugfs_list),
+				 root, minor);
+}

drivers/gpu/drm/xe/xe_pxp_debugfs.h

@@ -0,0 +1,13 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2024 Intel Corporation
+ */
+
+#ifndef __XE_PXP_DEBUGFS_H__
+#define __XE_PXP_DEBUGFS_H__
+
+struct xe_pxp;
+
+void xe_pxp_debugfs_register(struct xe_pxp *pxp);
+
+#endif /* __XE_PXP_DEBUGFS_H__ */