msm: perf: add debug patch logging framework
Provide a mechanism to track which msm perf patches
are present in a kernel. Some kernel branches do
not include all patches which causes problems trying
to debug perf issues. This framework provides a way
to keep track of which patches have been included
in a build.
Change-Id: Ib8ef311454564c4609d94decd93e039c80104275
Signed-off-by: Neil Leeder <nleeder@codeaurora.org>
diff --git a/arch/arm/mach-msm/perf_debug.c b/arch/arm/mach-msm/perf_debug.c
new file mode 100644
index 0000000..52e58a2
--- /dev/null
+++ b/arch/arm/mach-msm/perf_debug.c
@@ -0,0 +1,64 @@
+/* Copyright (c) 2013, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/types.h>
+#include <linux/uaccess.h>
+#include <linux/debugfs.h>
+
+/*
+ * Subsequent patches should add an entry to end of this string.
+ * Format is incrementing sequence number followed by text of
+ * patch commit title with newline.
+ * Note trailing ';' is on its own line to simplify addition of
+ * future strings.
+ */
+static char *descriptions =
+ "0 msm: perf: add debug patch logging framework\n"
+;
+
+static ssize_t desc_read(struct file *fp, char __user *buf,
+ size_t count, loff_t *pos)
+{
+ return simple_read_from_buffer(buf, count, pos, descriptions,
+ strlen(descriptions));
+}
+
+static const struct file_operations perf_debug_desc_fops = {
+ .read = desc_read,
+};
+
+static int msm_perf_debugfs_init(void)
+{
+ int ret = 0;
+ struct dentry *dir;
+ struct dentry *file;
+
+ dir = debugfs_create_dir("msm-perf-patches", NULL);
+ if (IS_ERR_OR_NULL(dir)) {
+ pr_err("failed to create msm-perf-patches dir in debugfs\n");
+ ret = PTR_ERR(dir);
+ goto init_exit;
+ }
+
+ file = debugfs_create_file("descriptions", 0444, dir, NULL,
+ &perf_debug_desc_fops);
+ if (IS_ERR_OR_NULL(file)) {
+ debugfs_remove(dir);
+ pr_err("failed to create descriptions file for msm-perf-patches\n");
+ ret = PTR_ERR(file);
+ goto init_exit;
+ }
+
+init_exit:
+ return ret;
+}
+late_initcall(msm_perf_debugfs_init);