lib: Add a small helper to open debugfs files

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

lib/Makefile.am

@@ -11,6 +11,8 @@ libintel_tools_la_SOURCES = 	\
 	i830_reg.h		\
 	i915_3d.h		\
 	i915_reg.h		\
+	igt_debugfs.c		\
+	igt_debugfs.h		\
 	instdone.c		\
 	instdone.h		\
 	intel_batchbuffer.c	\

lib/igt_debugfs.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright © 2013 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.
+ *
+ */
+
+#include <sys/stat.h>
+#include <sys/mount.h>
+#include <errno.h>
+#include <stdio.h>
+#include <string.h>
+#include <fcntl.h>
+
+#include "igt_debugfs.h"
+
+int igt_debugfs_init(igt_debugfs_t *debugfs)
+{
+	const char *path = "/sys/kernel/debug";
+	struct stat st;
+	int n;
+
+	if (stat("/debug/dri", &st) == 0) {
+		path = "/debug/dri";
+		goto find_minor;
+	}
+
+	if (stat("/sys/kernel/debug/dri", &st) == 0)
+		goto find_minor;
+
+	if (stat("/sys/kernel/debug", &st))
+		return errno;
+
+	if (mount("debug", "/sys/kernel/debug", "debugfs", 0, 0))
+		return errno;
+
+find_minor:
+	strcpy(debugfs->root, path);
+	for (n = 0; n < 16; n++) {
+		int len = sprintf(debugfs->dri_path, "%s/dri/%d", path, n);
+		sprintf(debugfs->dri_path + len, "/i915_error_state");
+		if (stat(debugfs->dri_path, &st) == 0) {
+			debugfs->dri_path[len] = '\0';
+			return 0;
+		}
+	}
+
+	debugfs->dri_path[0] = '\0';
+	return ENOENT;
+}
+
+int igt_debugfs_open(igt_debugfs_t *debugfs, const char *filename)
+{
+	char buf[1024];
+
+	sprintf(buf, "%s/%s", debugfs->dri_path, filename);
+	return open(buf, O_RDONLY);
+}

lib/igt_debugfs.h

@@ -0,0 +1,36 @@
+/*
+ * Copyright © 2013 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.
+ *
+ */
+
+#ifndef __IGT_DEBUGFS_H__
+#define __IGT_DEBUGFS_H__
+
+typedef struct {
+	char root[128];
+	char dri_path[128];
+} igt_debugfs_t;
+
+int igt_debugfs_init(igt_debugfs_t *debugfs);
+int igt_debugfs_open(igt_debugfs_t *debugfs, const char *filename);
+
+#endif /* __IGT_DEBUGFS_H__ */