[PATCH 7/9] drm/xe/guc: Add support for NPK as a GuC log target

[Stuart Summers <stuart.summers@intel.com>]

GuC provides the ability to gather logs through a hardware interface
called NPK. For certain debugging scenarios this can be advantageous
over getting logs from memory (or in addition to).

Add a hook for this alternate debugging mode via a configfs. This
translates into a parameter passed to GuC during load time.

v2: Convert to configfs from modparam (Matt)
v3: Configfs documentation formatting (Shuicheng)
    Kerneldoc/comment add + configfs entry ordering
    Only set the guc_log_target when GuC log is enabled (Daniele)

Signed-off-by: Stuart Summers <stuart.summers@intel.com>
Assisted-by: Copilot:claude-opus-4.7
---
 drivers/gpu/drm/xe/abi/guc_log_abi.h   |  8 ++++
 drivers/gpu/drm/xe/xe_configfs.c       |  2 +
 drivers/gpu/drm/xe/xe_configfs_debug.c | 64 +++++++++++++++++++++++++-
 drivers/gpu/drm/xe/xe_configfs_debug.h |  5 ++
 drivers/gpu/drm/xe/xe_configfs_types.h |  1 +
 drivers/gpu/drm/xe/xe_defaults.h       |  2 +
 drivers/gpu/drm/xe/xe_guc.c            | 11 +++--
 7 files changed, 89 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/xe/abi/guc_log_abi.h b/drivers/gpu/drm/xe/abi/guc_log_abi.h
index fbf212d59a40..e1b121bff549 100644
--- a/drivers/gpu/drm/xe/abi/guc_log_abi.h
+++ b/drivers/gpu/drm/xe/abi/guc_log_abi.h
@@ -51,6 +51,14 @@ enum guc_log_type {
 
 #define GUC_LOG_BUFFER_TYPE_MAX		3
 
+enum guc_log_target {
+	GUC_LOG_TARGET_MEM = 0,
+	GUC_LOG_TARGET_NPK,
+	GUC_LOG_TARGET_MEM_AND_NPK,
+};
+
+#define GUC_LOG_TARGET_MAX	GUC_LOG_TARGET_MEM_AND_NPK
+
 /**
  * struct guc_log_buffer_state - GuC log buffer state
  *
diff --git a/drivers/gpu/drm/xe/xe_configfs.c b/drivers/gpu/drm/xe/xe_configfs.c
index babe33e84af2..4a5bd53af443 100644
--- a/drivers/gpu/drm/xe/xe_configfs.c
+++ b/drivers/gpu/drm/xe/xe_configfs.c
@@ -107,6 +107,7 @@ const struct xe_config_device xe_configfs_device_defaults = {
 		.engines_allowed = U64_MAX,
 		.gt_types_allowed = U64_MAX,
 		.guc_log_level = XE_GUC_LOG_LEVEL_UNSET,
+		.guc_log_target = XE_DEFAULT_GUC_LOG_TARGET,
 	},
 #endif
 	.sriov = {
@@ -431,6 +432,7 @@ static void dump_custom_dev_config(struct pci_dev *pdev,
 	PRI_CUSTOM_ATTR("%llx", debug.engines_allowed);
 	PRI_CUSTOM_ATTR("%llx", debug.gt_types_allowed);
 	PRI_CUSTOM_ATTR("%d", debug.guc_log_level);
+	PRI_CUSTOM_ATTR("%d", debug.guc_log_target);
 #endif
 	PRI_CUSTOM_ATTR("%u", sriov.admin_only_pf);
 
diff --git a/drivers/gpu/drm/xe/xe_configfs_debug.c b/drivers/gpu/drm/xe/xe_configfs_debug.c
index b5c06d1ec7c9..af4ee420cf6f 100644
--- a/drivers/gpu/drm/xe/xe_configfs_debug.c
+++ b/drivers/gpu/drm/xe/xe_configfs_debug.c
@@ -45,7 +45,8 @@
  *	        ├── enable_survivability_mode
  *	        ├── engines_allowed
  *	        ├── gt_types_allowed
- *	        └── guc_log_level
+ *	        ├── guc_log_level
+ *	        └── guc_log_target
  *
  * Configure Attributes
  * ====================
@@ -209,6 +210,16 @@
  *
  * This attribute can only be set before binding to the device.
  *
+ * GuC log target:
+ * ---------------
+ *
+ * Set the destination for the GuC log. 0 - memory only (default),
+ * 1 - NPK only, 2 - memory + NPK. Example::
+ *
+ *	# echo 2 > /sys/kernel/config/xe/0000:03:00.0/debug/guc_log_target
+ *
+ * This attribute can only be set before binding to the device.
+ *
  */
 
 struct engine_info {
@@ -284,6 +295,26 @@ bool xe_configfs_get_enable_survivability_mode(struct pci_dev *pdev)
 	return mode;
 }
 
+/**
+ * xe_configfs_get_guc_log_target - get configfs GuC log target attribute
+ * @pdev: pci device
+ *
+ * Return: guc_log_target attribute in configfs
+ */
+u8 xe_configfs_get_guc_log_target(struct pci_dev *pdev)
+{
+	struct xe_config_group_device *dev = xe_configfs_find_device(pdev);
+	u8 target;
+
+	if (!dev)
+		return xe_configfs_device_defaults.debug.guc_log_target;
+
+	target = dev->config.debug.guc_log_target;
+	config_group_put(&dev->group);
+
+	return target;
+}
+
 /**
  * xe_configfs_primary_gt_allowed - determine whether primary GTs are supported
  * @pdev: pci device
@@ -911,6 +942,35 @@ static ssize_t ctx_restore_post_bb_store(struct config_item *item,
 	return wa_bb_store(dev->config.debug.ctx_restore_post_bb, dev, data, sz);
 }
 
+static ssize_t guc_log_target_show(struct config_item *item, char *page)
+{
+	struct xe_config_device *dev = debug_to_device(item);
+
+	return sprintf(page, "%d\n", dev->debug.guc_log_target);
+}
+
+static ssize_t guc_log_target_store(struct config_item *item, const char *page, size_t len)
+{
+	struct xe_config_group_device *dev = debug_to_group_device(item);
+	u8 guc_log_target;
+	int ret;
+
+	ret = kstrtou8(page, 0, &guc_log_target);
+	if (ret)
+		return ret;
+
+	if (guc_log_target > GUC_LOG_TARGET_MAX)
+		return -EINVAL;
+
+	guard(mutex)(&dev->lock);
+	if (xe_configfs_is_bound(dev))
+		return -EBUSY;
+
+	dev->config.debug.guc_log_target = guc_log_target;
+
+	return len;
+}
+
 CONFIGFS_ATTR(, ctx_restore_mid_bb);
 CONFIGFS_ATTR(, ctx_restore_post_bb);
 CONFIGFS_ATTR(, enable_psmi);
@@ -918,6 +978,7 @@ CONFIGFS_ATTR(, enable_survivability_mode);
 CONFIGFS_ATTR(, engines_allowed);
 CONFIGFS_ATTR(, gt_types_allowed);
 CONFIGFS_ATTR(, guc_log_level);
+CONFIGFS_ATTR(, guc_log_target);
 
 static bool xe_configfs_debug_is_visible(struct config_item *item,
 					 struct configfs_attribute *attr,
@@ -945,6 +1006,7 @@ static struct configfs_attribute *xe_configfs_debug_attrs[] = {
 	&attr_engines_allowed,
 	&attr_gt_types_allowed,
 	&attr_guc_log_level,
+	&attr_guc_log_target,
 	NULL,
 };
 
diff --git a/drivers/gpu/drm/xe/xe_configfs_debug.h b/drivers/gpu/drm/xe/xe_configfs_debug.h
index b29c739435c5..68e34307b560 100644
--- a/drivers/gpu/drm/xe/xe_configfs_debug.h
+++ b/drivers/gpu/drm/xe/xe_configfs_debug.h
@@ -15,6 +15,7 @@ struct pci_dev;
 
 #if IS_ENABLED(CONFIG_DRM_XE_DEBUG) && IS_ENABLED(CONFIG_CONFIGFS_FS)
 bool xe_configfs_get_enable_survivability_mode(struct pci_dev *pdev);
+u8 xe_configfs_get_guc_log_target(struct pci_dev *pdev);
 bool xe_configfs_primary_gt_allowed(struct pci_dev *pdev);
 bool xe_configfs_media_gt_allowed(struct pci_dev *pdev);
 u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev);
@@ -32,6 +33,10 @@ u32 xe_configfs_get_ctx_restore_post_bb(struct pci_dev *pdev,
  * wrapped in CONFIG_DRM_XE_DEBUG.
  */
 static inline bool xe_configfs_get_enable_survivability_mode(struct pci_dev *pdev) { return false; }
+static inline u8 xe_configfs_get_guc_log_target(struct pci_dev *pdev)
+{
+	return XE_DEFAULT_GUC_LOG_TARGET;
+}
 static inline bool xe_configfs_primary_gt_allowed(struct pci_dev *pdev) { return true; }
 static inline bool xe_configfs_media_gt_allowed(struct pci_dev *pdev) { return true; }
 static inline u64 xe_configfs_get_engines_allowed(struct pci_dev *pdev) { return U64_MAX; }
diff --git a/drivers/gpu/drm/xe/xe_configfs_types.h b/drivers/gpu/drm/xe/xe_configfs_types.h
index ba920c37c44d..8773adeffd4e 100644
--- a/drivers/gpu/drm/xe/xe_configfs_types.h
+++ b/drivers/gpu/drm/xe/xe_configfs_types.h
@@ -38,6 +38,7 @@ struct xe_config_group_device {
 			u64 engines_allowed;
 			u64 gt_types_allowed;
 			int guc_log_level;
+			u8 guc_log_target;
 		} debug;
 		struct {
 			bool admin_only_pf;
diff --git a/drivers/gpu/drm/xe/xe_defaults.h b/drivers/gpu/drm/xe/xe_defaults.h
index df88078e84b8..9330e08727a8 100644
--- a/drivers/gpu/drm/xe/xe_defaults.h
+++ b/drivers/gpu/drm/xe/xe_defaults.h
@@ -5,6 +5,7 @@
 #ifndef _XE_DEFAULTS_H_
 #define _XE_DEFAULTS_H_
 
+#include "abi/guc_log_abi.h"
 #include "xe_device_types.h"
 
 #if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
@@ -12,6 +13,7 @@
 #else
 #define XE_DEFAULT_GUC_LOG_LEVEL		1
 #endif
+#define XE_DEFAULT_GUC_LOG_TARGET		GUC_LOG_TARGET_MEM
 
 /* Sentinel value for guc_log_level configfs: not set, fall back to module param */
 #define XE_GUC_LOG_LEVEL_UNSET			-1
diff --git a/drivers/gpu/drm/xe/xe_guc.c b/drivers/gpu/drm/xe/xe_guc.c
index e520afbf1f22..c486b9641178 100644
--- a/drivers/gpu/drm/xe/xe_guc.c
+++ b/drivers/gpu/drm/xe/xe_guc.c
@@ -74,13 +74,18 @@ static u32 guc_bo_ggtt_addr(struct xe_guc *guc,
 
 static u32 guc_ctl_debug_flags(struct xe_guc *guc)
 {
+	struct pci_dev *pdev = to_pci_dev(guc_to_xe(guc)->drm.dev);
 	u32 level = xe_guc_log_get_level(&guc->log);
 	u32 flags = 0;
 
-	if (!GUC_LOG_LEVEL_IS_VERBOSE(level))
+	if (!GUC_LOG_LEVEL_IS_VERBOSE(level)) {
 		flags |= GUC_LOG_DISABLED;
-	else
-		flags |= FIELD_PREP(GUC_LOG_VERBOSITY, GUC_LOG_LEVEL_TO_VERBOSITY(level));
+	} else {
+		flags |= FIELD_PREP(GUC_LOG_VERBOSITY,
+				    GUC_LOG_LEVEL_TO_VERBOSITY(level));
+		flags |= FIELD_PREP(GUC_LOG_DESTINATION,
+				    xe_configfs_get_guc_log_target(pdev));
+	}
 
 	return flags;
 }
-- 
2.43.0