1 files changed, 102 insertions, 0 deletions
diff --git a/Documentation/mic/mpssd/sysfs.c b/Documentation/mic/mpssd/sysfs.c
new file mode 100644
index 000000000000..8dd326936083
--- /dev/null
+++ b/Documentation/mic/mpssd/sysfs.c
@@ -0,0 +1,102 @@
+/*
+ * Intel MIC Platform Software Stack (MPSS)
+ *
+ * Copyright(c) 2013 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, 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.
+ *
+ * The full GNU General Public License is included in this distribution in
+ * the file called "COPYING".
+ *
+ * Intel MIC User Space Tools.
+ */
+
+#include "mpssd.h"
+
+#define PAGE_SIZE 4096
+
+char *
+readsysfs(char *dir, char *entry)
+{
+	char filename[PATH_MAX];
+	char value[PAGE_SIZE];
+	char *string = NULL;
+	int fd;
+	int len;
+
+	if (dir == NULL)
+		snprintf(filename, PATH_MAX, "%s/%s", MICSYSFSDIR, entry);
+	else
+		snprintf(filename, PATH_MAX,
+			 "%s/%s/%s", MICSYSFSDIR, dir, entry);
+
+	fd = open(filename, O_RDONLY);
+	if (fd < 0) {
+		mpsslog("Failed to open sysfs entry '%s': %s\n",
+			filename, strerror(errno));
+		return NULL;
+	}
+
+	len = read(fd, value, sizeof(value));
+	if (len < 0) {
+		mpsslog("Failed to read sysfs entry '%s': %s\n",
+			filename, strerror(errno));
+		goto readsys_ret;
+	}
+	if (len == 0)
+		goto readsys_ret;
+
+	value[len - 1] = '\0';
+
+	string = malloc(strlen(value) + 1);
+	if (string)
+		strcpy(string, value);
+
+readsys_ret:
+	close(fd);
+	return string;
+}
+
+int
+setsysfs(char *dir, char *entry, char *value)
+{
+	char filename[PATH_MAX];
+	char *oldvalue;
+	int fd, ret = 0;
+
+	if (dir == NULL)
+		snprintf(filename, PATH_MAX, "%s/%s", MICSYSFSDIR, entry);
+	else
+		snprintf(filename, PATH_MAX, "%s/%s/%s",
+			 MICSYSFSDIR, dir, entry);
+
+	oldvalue = readsysfs(dir, entry);
+
+	fd = open(filename, O_RDWR);
+	if (fd < 0) {
+		ret = errno;
+		mpsslog("Failed to open sysfs entry '%s': %s\n",
+			filename, strerror(errno));
+		goto done;
+	}
+
+	if (!oldvalue || strcmp(value, oldvalue)) {
+		if (write(fd, value, strlen(value)) < 0) {
+			ret = errno;
+			mpsslog("Failed to write new sysfs entry '%s': %s\n",
+				filename, strerror(errno));
+		}
+	}
+	close(fd);
+done:
+	if (oldvalue)
+		free(oldvalue);
+	return ret;
+}