[PATCH v4 2/2] drm/xe/guc: Improve robustness of GuC log dumping to dmesg

[John.C.Harrison@Intel.com]

From: John Harrison <John.C.Harrison@Intel.com>

There is a debug mechanism for dumping the GuC log as an ASCII hex
stream via dmesg. This is extremely useful for situations where it is
not possibe to query the log from debugfs (self tests, bugs that cause
the driver to fail to load, system hangs, etc.). However, dumping via
dmesg is not the most reliable. The dmesg buffer is limited in size,
can be rate limited and a simple hex stream is hard to parse by tools.

So add extra information to the dump to make it more robust and
parsable. This includes adding start and end tags to delimit the dump,
using longer lines to reduce the per line overhead, adding a rolling
count to check for missing lines and interleaved concurrent dumps and
adding other important information such as the GuC version number and
timestamp offset.

v2: Remove pm get/put as unnecessary (review feedback from Matthew B).
v3: Add firmware filename and 'wanted' version number.
v4: Add kernel doc and undef macros when done (review feedback from
Michal W).

Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
---
 drivers/gpu/drm/xe/regs/xe_guc_regs.h |   1 +
 drivers/gpu/drm/xe/xe_guc_log.c       | 101 ++++++++++++++++++++++----
 2 files changed, 87 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 11682e675e0f..45fb3707fabe 100644
--- a/drivers/gpu/drm/xe/regs/xe_guc_regs.h
+++ b/drivers/gpu/drm/xe/regs/xe_guc_regs.h
@@ -82,6 +82,7 @@
 #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 a37ee3419428..596946c4a541 100644
--- a/drivers/gpu/drm/xe/xe_guc_log.c
+++ b/drivers/gpu/drm/xe/xe_guc_log.c
@@ -7,11 +7,19 @@
 
 #include <drm/drm_managed.h>
 
+#include "regs/xe_guc_regs.h"
 #include "xe_bo.h"
 #include "xe_gt.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)
 {
@@ -49,32 +57,95 @@ static size_t guc_log_size(void)
 		CAPTURE_BUFFER_SIZE;
 }
 
+/**
+ * xe_guc_log_print - Dump the GuC log to the given printer
+ * @log: the &xe_guc_log to print out
+ * @p: the printer to use
+ *
+ * This can be used to convert the binary log to ASCII form and print it to an
+ * arbitrary printer object. Expected usage is a debugfs file interface and for
+ * dumping to the kernel log (i.e. dmesg, by passing in a DRM printk type printer
+ * such as 'drm_info_printer(drm->dev)').
+ */
 void xe_guc_log_print(struct xe_guc_log *log, struct drm_printer *p)
 {
+#define BYTES_PER_WORD		sizeof(u32)
+#define WORDS_PER_DUMP		8
+#define DUMPS_PER_LINE		4
+#define LINES_PER_READ		4
+#define WORDS_PER_READ		(WORDS_PER_DUMP * DUMPS_PER_LINE * LINES_PER_READ)
+
+	static int g_count;
+	struct xe_gt *gt = log_to_gt(log);
+	struct xe_guc *guc = log_to_guc(log);
+	struct xe_uc_fw_version *ver_f = &guc->fw.versions.found[XE_UC_FW_VER_RELEASE];
+	struct xe_uc_fw_version *ver_w = &guc->fw.versions.wanted;
 	struct xe_device *xe = log_to_xe(log);
 	size_t size;
-	int i, j;
+	char line_buff[DUMPS_PER_LINE * WORDS_PER_DUMP * 9 + 1];
+	int l_count = g_count++;
+	int line = 0;
+	int i, j, k;
+	u64 ktime;
+	u32 stamp;
 
 	xe_assert(xe, log->bo);
 
 	size = log->bo->size;
 
-#define DW_PER_READ		128
-	xe_assert(xe, !(size % (DW_PER_READ * sizeof(u32))));
-	for (i = 0; i < size / sizeof(u32); i += DW_PER_READ) {
-		u32 read[DW_PER_READ];
-
-		xe_map_memcpy_from(xe, read, &log->bo->vmap, i * sizeof(u32),
-				   DW_PER_READ * sizeof(u32));
-#define DW_PER_PRINT		4
-		for (j = 0; j < DW_PER_READ / DW_PER_PRINT; ++j) {
-			u32 *print = read + j * DW_PER_PRINT;
-
-			drm_printf(p, "0x%08x 0x%08x 0x%08x 0x%08x\n",
-				   *(print + 0), *(print + 1),
-				   *(print + 2), *(print + 3));
+	drm_printf(p, "[Capture/%d.%d] Dumping GuC log for %ps...\n",
+		   l_count, line++, __builtin_return_address(0));
+
+	drm_printf(p, "[Capture/%d.%d] GuC version %u.%u.%u (wanted %u.%u.%u)\n",
+		   l_count, line++,
+		   ver_f->major, ver_f->minor, ver_f->patch,
+		   ver_w->major, ver_w->minor, ver_w->patch);
+	drm_printf(p, "[Capture/%d.%d] GuC firmware: %s\n", l_count, line++, guc->fw.path);
+
+	ktime = ktime_get_boottime_ns();
+	drm_printf(p, "[Capture/%d.%d] Kernel timestamp: 0x%08llX [%llu]\n",
+		   l_count, line++, ktime, ktime);
+
+	stamp = xe_mmio_read32(gt, GUC_PMTIMESTAMP);
+	drm_printf(p, "[Capture/%d.%d] GuC timestamp: 0x%08X [%u]\n",
+		   l_count, line++, stamp, stamp);
+
+	drm_printf(p, "[Capture/%d.%d] CS timestamp frequency: %u Hz\n",
+		   l_count, line++, gt->info.reference_clock);
+
+	xe_assert(xe, !(size % (WORDS_PER_READ * BYTES_PER_WORD)));
+	for (i = 0; i < size / BYTES_PER_WORD; i += WORDS_PER_READ) {
+		u32 read[WORDS_PER_READ];
+
+		xe_map_memcpy_from(xe, read, &log->bo->vmap, i * BYTES_PER_WORD,
+				   WORDS_PER_READ * BYTES_PER_WORD);
+
+		for (j = 0; j < WORDS_PER_READ; ) {
+			u32 done = 0;
+
+			for (k = 0; k < DUMPS_PER_LINE; k++) {
+				line_buff[done++] = ' ';
+				done += hex_dump_to_buffer(read + j,
+							   sizeof(*read) * (WORDS_PER_READ - j),
+							   WORDS_PER_DUMP * BYTES_PER_WORD,
+							   BYTES_PER_WORD,
+							   line_buff + done,
+							   sizeof(line_buff) - done,
+							   false);
+				j += WORDS_PER_DUMP;
+			}
+
+			drm_printf(p, "[Capture/%d.%d]%s\n", l_count, line++, line_buff);
 		}
 	}
+
+	drm_printf(p, "[Capture/%d.%d] Done.\n", l_count, line++);
+
+#undef BYTES_PER_WORD
+#undef WORDS_PER_DUMP
+#undef DUMPS_PER_LINE
+#undef LINES_PER_READ
+#undef WORDS_PER_READ
 }
 
 int xe_guc_log_init(struct xe_guc_log *log)
-- 
2.43.2