From: John Harrison <john.c.harri...@intel.com>

Split the GuC log dump into a two stage snapshot and print mechanism.
This allows the log to be captured at the point of an error (which may
be in a restricted context) and then dump it out later (from a regular
context such as a worker function or a sysfs file handler).

Also add a bunch of other useful pieces of information that can help
(or are fundamentally required!) to decode and parse the log.

v2: Add kerneldoc and fix a couple of comment typos - review feedback
from Michal W.
v3: Move chunking code to this patch as it makes the deltas simpler.
Fix a bunch of kerneldoc issues.
v4: Move the CS frequency out of the coredump snapshot function into
the debugfs only code (as that info is already part of the main
devcoredump). Add a header to the debugfs log to match the one in the
devcoredump to aid processing by a unified tool. Add forcewake to the
GuC timestamp read so it actually works.
v6: Add colon to GuC version string (review feedback by Julia F).

Signed-off-by: John Harrison <john.c.harri...@intel.com>
---
 drivers/gpu/drm/xe/regs/xe_guc_regs.h |   1 +
 drivers/gpu/drm/xe/xe_guc_log.c       | 178 +++++++++++++++++++++++---
 drivers/gpu/drm/xe/xe_guc_log.h       |   4 +
 drivers/gpu/drm/xe/xe_guc_log_types.h |  27 ++++
 4 files changed, 195 insertions(+), 15 deletions(-)

diff --git a/drivers/gpu/drm/xe/regs/xe_guc_regs.h 
b/drivers/gpu/drm/xe/regs/xe_guc_regs.h
index a5fd14307f94..b27b73680c12 100644
--- a/drivers/gpu/drm/xe/regs/xe_guc_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_guc_regs.h
@@ -84,6 +84,7 @@
 #define   HUC_LOADING_AGENT_GUC                        REG_BIT(1)
 #define   GUC_WOPCM_OFFSET_VALID               REG_BIT(0)
 #define GUC_MAX_IDLE_COUNT                     XE_REG(0xc3e4)
+#define GUC_PMTIMESTAMP                                XE_REG(0xc3e8)
 
 #define GUC_SEND_INTERRUPT                     XE_REG(0xc4c8)
 #define   GUC_SEND_TRIGGER                     REG_BIT(0)
diff --git a/drivers/gpu/drm/xe/xe_guc_log.c b/drivers/gpu/drm/xe/xe_guc_log.c
index be47780ec2a7..24564624e91e 100644
--- a/drivers/gpu/drm/xe/xe_guc_log.c
+++ b/drivers/gpu/drm/xe/xe_guc_log.c
@@ -6,15 +6,23 @@
 #include "xe_guc_log.h"
 
 #include <drm/drm_managed.h>
-#include <linux/vmalloc.h>
 
+#include "regs/xe_guc_regs.h"
 #include "xe_bo.h"
 #include "xe_devcoredump.h"
+#include "xe_force_wake.h"
 #include "xe_gt.h"
 #include "xe_gt_printk.h"
 #include "xe_map.h"
+#include "xe_mmio.h"
 #include "xe_module.h"
 
+static struct xe_guc *
+log_to_guc(struct xe_guc_log *log)
+{
+       return container_of(log, struct xe_guc, log);
+}
+
 static struct xe_gt *
 log_to_gt(struct xe_guc_log *log)
 {
@@ -52,35 +60,175 @@ static size_t guc_log_size(void)
                CAPTURE_BUFFER_SIZE;
 }
 
+#define GUC_LOG_CHUNK_SIZE     SZ_2M
+
+static struct xe_guc_log_snapshot *xe_guc_log_snapshot_alloc(struct xe_guc_log 
*log, bool atomic)
+{
+       struct xe_guc_log_snapshot *snapshot;
+       size_t remain;
+       int i;
+
+       snapshot = kzalloc(sizeof(*snapshot), atomic ? GFP_ATOMIC : GFP_KERNEL);
+       if (!snapshot)
+               return NULL;
+
+       /*
+        * NB: kmalloc has a hard limit well below the maximum GuC log buffer 
size.
+        * Also, can't use vmalloc as might be called from atomic context. So 
need
+        * to break the buffer up into smaller chunks that can be allocated.
+        */
+       snapshot->size = log->bo->size;
+       snapshot->num_chunks = DIV_ROUND_UP(snapshot->size, GUC_LOG_CHUNK_SIZE);
+
+       snapshot->copy = kcalloc(snapshot->num_chunks, sizeof(*snapshot->copy),
+                                atomic ? GFP_ATOMIC : GFP_KERNEL);
+       if (!snapshot->copy)
+               goto fail_snap;
+
+       remain = snapshot->size;
+       for (i = 0; i < snapshot->num_chunks; i++) {
+               size_t size = min(GUC_LOG_CHUNK_SIZE, remain);
+
+               snapshot->copy[i] = kmalloc(size, atomic ? GFP_ATOMIC : 
GFP_KERNEL);
+               if (!snapshot->copy[i])
+                       goto fail_copy;
+               remain -= size;
+       }
+
+       return snapshot;
+
+fail_copy:
+       for (i = 0; i < snapshot->num_chunks; i++)
+               kfree(snapshot->copy[i]);
+       kfree(snapshot->copy);
+fail_snap:
+       kfree(snapshot);
+       return NULL;
+}
+
 /**
- * xe_guc_log_print - dump a copy of the GuC log to some useful location
+ * xe_guc_log_snapshot_free - free a previously captured GuC log snapshot
+ * @snapshot: GuC log snapshot structure
+ *
+ * Return: pointer to a newly allocated snapshot object or null if out of 
memory. Caller is
+ * responsible for calling xe_guc_log_snapshot_free when done with the 
snapshot.
+ */
+void xe_guc_log_snapshot_free(struct xe_guc_log_snapshot *snapshot)
+{
+       int i;
+
+       if (!snapshot)
+               return;
+
+       if (!snapshot->copy) {
+               for (i = 0; i < snapshot->num_chunks; i++)
+                       kfree(snapshot->copy[i]);
+               kfree(snapshot->copy);
+       }
+
+       kfree(snapshot);
+}
+
+/**
+ * xe_guc_log_snapshot_capture - create a new snapshot copy the GuC log for 
later dumping
  * @log: GuC log structure
- * @p: the printer object to output to
+ * @atomic: is the call inside an atomic section of some kind?
+ *
+ * Return: pointer to a newly allocated snapshot object or null if out of 
memory. Caller is
+ * responsible for calling xe_guc_log_snapshot_free when done with the 
snapshot.
  */
-void xe_guc_log_print(struct xe_guc_log *log, struct drm_printer *p)
+struct xe_guc_log_snapshot *xe_guc_log_snapshot_capture(struct xe_guc_log 
*log, bool atomic)
 {
+       struct xe_guc_log_snapshot *snapshot;
        struct xe_device *xe = log_to_xe(log);
-       size_t size;
-       void *copy;
+       struct xe_guc *guc = log_to_guc(log);
+       struct xe_gt *gt = log_to_gt(log);
+       size_t remain;
+       int i, err;
 
        if (!log->bo) {
-               drm_puts(p, "GuC log buffer not allocated");
-               return;
+               xe_gt_err(gt, "GuC log buffer not allocated\n");
+               return NULL;
+       }
+
+       snapshot = xe_guc_log_snapshot_alloc(log, atomic);
+       if (!snapshot) {
+               xe_gt_err(gt, "GuC log snapshot not allocated\n");
+               return NULL;
        }
 
-       size = log->bo->size;
+       remain = snapshot->size;
+       for (i = 0; i < snapshot->num_chunks; i++) {
+               size_t size = min(GUC_LOG_CHUNK_SIZE, remain);
+
+               xe_map_memcpy_from(xe, snapshot->copy[i], &log->bo->vmap,
+                                  i * GUC_LOG_CHUNK_SIZE, size);
+               remain -= size;
+       }
+
+       err = xe_force_wake_get(gt_to_fw(gt), XE_FW_GT);
+       if (err) {
+               snapshot->stamp = ~0;
+       } else {
+               snapshot->stamp = xe_mmio_read32(&gt->mmio, GUC_PMTIMESTAMP);
+               xe_force_wake_put(gt_to_fw(gt), XE_FW_GT);
+       }
+       snapshot->ktime = ktime_get_boottime_ns();
+       snapshot->level = log->level;
+       snapshot->ver_found = guc->fw.versions.found[XE_UC_FW_VER_RELEASE];
+       snapshot->ver_want = guc->fw.versions.wanted;
+       snapshot->path = guc->fw.path;
+
+       return snapshot;
+}
+
+/**
+ * xe_guc_log_snapshot_print - dump a previously saved copy of the GuC log to 
some useful location
+ * @snapshot: a snapshot of the GuC log
+ * @p: the printer object to output to
+ */
+void xe_guc_log_snapshot_print(struct xe_guc_log_snapshot *snapshot, struct 
drm_printer *p)
+{
+       size_t remain;
+       int i;
 
-       copy = vmalloc(size);
-       if (!copy) {
-               drm_printf(p, "Failed to allocate %zu", size);
+       if (!snapshot) {
+               drm_printf(p, "GuC log snapshot not allocated!\n");
                return;
        }
 
-       xe_map_memcpy_from(xe, copy, &log->bo->vmap, 0, size);
+       drm_printf(p, "GuC firmware: %s\n", snapshot->path);
+       drm_printf(p, "GuC version: %u.%u.%u (wanted %u.%u.%u)\n",
+                  snapshot->ver_found.major, snapshot->ver_found.minor, 
snapshot->ver_found.patch,
+                  snapshot->ver_want.major, snapshot->ver_want.minor, 
snapshot->ver_want.patch);
+       drm_printf(p, "Kernel timestamp: 0x%08llX [%llu]\n", snapshot->ktime, 
snapshot->ktime);
+       drm_printf(p, "GuC timestamp: 0x%08X [%u]\n", snapshot->stamp, 
snapshot->stamp);
+       drm_printf(p, "Log level: %u\n", snapshot->level);
+
+       remain = snapshot->size;
+       for (i = 0; i < snapshot->num_chunks; i++) {
+               size_t size = min(GUC_LOG_CHUNK_SIZE, remain);
+
+               xe_print_blob_ascii85(p, i ? NULL : "Log data", 
snapshot->copy[i], 0, size);
+               remain -= size;
+       }
+}
+
+/**
+ * xe_guc_log_print - dump a copy of the GuC log to some useful location
+ * @log: GuC log structure
+ * @p: the printer object to output to
+ */
+void xe_guc_log_print(struct xe_guc_log *log, struct drm_printer *p)
+{
+       struct xe_guc_log_snapshot *snapshot;
 
-       xe_print_blob_ascii85(p, "Log data", copy, 0, size);
+       drm_printf(p, "**** GuC Log ****\n");
 
-       vfree(copy);
+       snapshot = xe_guc_log_snapshot_capture(log, false);
+       drm_printf(p, "CS reference clock: %u\n", 
log_to_gt(log)->info.reference_clock);
+       xe_guc_log_snapshot_print(snapshot, p);
+       xe_guc_log_snapshot_free(snapshot);
 }
 
 int xe_guc_log_init(struct xe_guc_log *log)
diff --git a/drivers/gpu/drm/xe/xe_guc_log.h b/drivers/gpu/drm/xe/xe_guc_log.h
index 2d25ab28b4b3..949d2c98343d 100644
--- a/drivers/gpu/drm/xe/xe_guc_log.h
+++ b/drivers/gpu/drm/xe/xe_guc_log.h
@@ -9,6 +9,7 @@
 #include "xe_guc_log_types.h"
 
 struct drm_printer;
+struct xe_device;
 
 #if IS_ENABLED(CONFIG_DRM_XE_LARGE_GUC_BUFFER)
 #define CRASH_BUFFER_SIZE       SZ_1M
@@ -38,6 +39,9 @@ struct drm_printer;
 
 int xe_guc_log_init(struct xe_guc_log *log);
 void xe_guc_log_print(struct xe_guc_log *log, struct drm_printer *p);
+struct xe_guc_log_snapshot *xe_guc_log_snapshot_capture(struct xe_guc_log 
*log, bool atomic);
+void xe_guc_log_snapshot_print(struct xe_guc_log_snapshot *snapshot, struct 
drm_printer *p);
+void xe_guc_log_snapshot_free(struct xe_guc_log_snapshot *snapshot);
 
 static inline u32
 xe_guc_log_get_level(struct xe_guc_log *log)
diff --git a/drivers/gpu/drm/xe/xe_guc_log_types.h 
b/drivers/gpu/drm/xe/xe_guc_log_types.h
index 125080d138a7..962b9edbd9eb 100644
--- a/drivers/gpu/drm/xe/xe_guc_log_types.h
+++ b/drivers/gpu/drm/xe/xe_guc_log_types.h
@@ -8,8 +8,35 @@
 
 #include <linux/types.h>
 
+#include "xe_uc_fw_types.h"
+
 struct xe_bo;
 
+/**
+ * struct xe_guc_log_snapshot:
+ * Capture of the GuC log plus various state useful for decoding the log
+ */
+struct xe_guc_log_snapshot {
+       /** @size: Size in bytes of the @copy allocation */
+       size_t size;
+       /** @copy: Host memory copy of the log buffer for later dumping, split 
into chunks */
+       void **copy;
+       /** @num_chunks: Number of chunks within @copy */
+       int num_chunks;
+       /** @ktime: Kernel time the snapshot was taken */
+       u64 ktime;
+       /** @stamp: GuC timestamp at which the snapshot was taken */
+       u32 stamp;
+       /** @level: GuC log verbosity level */
+       u32 level;
+       /** @ver_found: GuC firmware version */
+       struct xe_uc_fw_version ver_found;
+       /** @ver_want: GuC firmware version that driver expected */
+       struct xe_uc_fw_version ver_want;
+       /** @path: Path of GuC firmware blob */
+       const char *path;
+};
+
 /**
  * struct xe_guc_log - GuC log
  */
-- 
2.46.0

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