tools lib api fs: Add sysfs__read_xll function

Adding sysfs__read_xll function to be able to read sysfs files with hex
numbers in, which do not have 0x prefix.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20180206181813.10943-6-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/lib/api/fs/fs.c

@@ -432,7 +432,8 @@ int procfs__read_str(const char *entry, char **buf, size_t *sizep)
 	return filename__read_str(path, buf, sizep);
 }
 
-int sysfs__read_ull(const char *entry, unsigned long long *value)
+static int sysfs__read_ull_base(const char *entry,
+				unsigned long long *value, int base)
 {
 	char path[PATH_MAX];
 	const char *sysfs = sysfs__mountpoint();
@@ -442,7 +443,17 @@ int sysfs__read_ull(const char *entry, unsigned long long *value)
 
 	snprintf(path, sizeof(path), "%s/%s", sysfs, entry);
 
-	return filename__read_ull(path, value);
+	return filename__read_ull_base(path, value, base);
+}
+
+int sysfs__read_xll(const char *entry, unsigned long long *value)
+{
+	return sysfs__read_ull_base(entry, value, 16);
+}
+
+int sysfs__read_ull(const char *entry, unsigned long long *value)
+{
+	return sysfs__read_ull_base(entry, value, 0);
 }
 
 int sysfs__read_int(const char *entry, int *value)

tools/lib/api/fs/fs.h

@@ -40,6 +40,7 @@ int procfs__read_str(const char *entry, char **buf, size_t *sizep);
 int sysctl__read_int(const char *sysctl, int *value);
 int sysfs__read_int(const char *entry, int *value);
 int sysfs__read_ull(const char *entry, unsigned long long *value);
+int sysfs__read_xll(const char *entry, unsigned long long *value);
 int sysfs__read_str(const char *entry, char **buf, size_t *sizep);
 int sysfs__read_bool(const char *entry, bool *value);