intel_display_crc: A new tool to play with display CRCs

The CRC debug interface is a bit more than a simple textual file in
debugfs as there are a small command language to control what we want
from them.

This tool starts, slowly, by allowing us to dump the pipe CRCs whenever
we want. It can be handy to check what is the current CRC when we reach
a certain state on the screen (when using --interactive-debug for
instance) against a known CRC.

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

tools/.gitignore

@@ -4,6 +4,7 @@ intel_audio_dump
 intel_backlight
 intel_bios_dumper
 intel_bios_reader
+intel_display_crc
 intel_display_poller
 intel_dump_decode
 intel_error_decode

tools/Makefile.sources

@@ -10,6 +10,7 @@ bin_PROGRAMS = 				\
 	intel_backlight 		\
 	intel_bios_dumper 		\
 	intel_bios_reader 		\
+	intel_display_crc		\
 	intel_display_poller		\
 	intel_dump_decode 		\
 	intel_error_decode 		\

tools/intel_display_crc.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright © 2015 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ * Authors:
+ *    Damien Lespiau <damien.lespiau@intel.com>
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "igt_core.h"
+#include "igt_debugfs.h"
+#include "igt_kms.h"
+
+typedef struct {
+	int fd;
+	int pipe;
+	int n_crcs;
+} display_crc_t;
+
+static int pipe_from_str(const char *str)
+{
+	unsigned char c;
+
+	if (!str || strlen(str) != 1)
+		return -1;
+
+	c = str[0];
+
+	if (c >= 'A' && c <= 'C')
+		return c - 'A';
+
+	if (c >= 'a' && c <= 'c')
+		return c - 'a';
+
+	if (c >= '0' && c <= '3')
+		return c - '0';
+
+	return -1;
+}
+
+static void print_crcs(display_crc_t *ctx)
+{
+	igt_pipe_crc_t *pipe_crc;
+	igt_crc_t crc;
+	char *crc_str;
+	int i;
+
+	pipe_crc = igt_pipe_crc_new(ctx->pipe, INTEL_PIPE_CRC_SOURCE_AUTO);
+
+	for (i = 0; i < ctx->n_crcs; i++) {
+		igt_pipe_crc_collect_crc(pipe_crc, &crc);
+
+		crc_str = igt_crc_to_string(&crc);
+		printf("CRC on pipe %s: %s\n", kmstest_pipe_name(ctx->pipe),
+		       crc_str);
+		free(crc_str);
+	}
+
+	igt_pipe_crc_free(pipe_crc);
+}
+
+static display_crc_t ctx;
+
+int main(int argc, char **argv)
+{
+	int opt;
+
+	ctx.n_crcs = 1;
+
+	while ((opt = getopt(argc, argv, "p:n:")) != -1) {
+		switch (opt) {
+		case 'p':
+			ctx.pipe = pipe_from_str(optarg);
+			if (ctx.pipe == -1) {
+				fprintf(stderr, "Unknown pipe %s\n", optarg);
+				exit(1);
+			}
+			break;
+		case 'n':
+			ctx.n_crcs = atoi(optarg);
+			break;
+		default:
+			igt_assert(0);
+		}
+	}
+
+	print_crcs(&ctx);
+}