[PATCH] only refresh when the clock tree is changed in debugfs

[yong.shen at linaro.org]

From: Yong Shen <yong.shen at linaro.org>

add a inotify watch on clock tree, only when clock tree is changed,
the clock info structure is rebuild and screen will be refreshed.

Signed-off-by: Yong Shen <yong.shen at linaro.org>
---
 clocks.c     |   51 +++++++++++++++++++++++++++++++++++++++++++++++++++
 powerdebug.c |    6 +++++-
 powerdebug.h |    4 ++++
 3 files changed, 60 insertions(+), 1 deletions(-)

diff --git a/clocks.c b/clocks.c
index 9a76c19..4c21f4f 100644
--- a/clocks.c
+++ b/clocks.c
@@ -13,12 +13,17 @@
  *       - initial API and implementation
  *******************************************************************************/
 
+#include <sys/inotify.h>
+#include <poll.h>
 #include "powerdebug.h"
 #include "clocks.h"
 
 static char clk_dir_path[PATH_MAX];
 static char clk_name[NAME_MAX];
 static int  bold[MAX_LINES];
+int inotify_fd;
+int inotify_wd;
+static struct pollfd fds;
 
 int init_clock_details(void)
 {
@@ -58,6 +63,19 @@ int init_clock_details(void)
 				" information at %s.\n", clk_dir_path);
 			exit(1);
 		}
+	} else {
+		inotify_fd = inotify_init();
+		if ( inotify_fd < 0 ) {
+			fprintf(stderr, "inotify_init error.\n" );
+			exit(1);
+		}
+
+		inotify_wd = inotify_add_watch(inotify_fd, clk_dir_path, 
+			IN_ALL_EVENTS );
+
+		fds.fd = inotify_fd;
+		fds.events = POLLIN;
+
 	}
 	strcpy(clk_name, "");
 	return(0);
@@ -98,6 +116,39 @@ void find_parents_for_clock(char *clkname, int complete)
 	dump_all_parents(clkname);
 }
 
+#define EVENT_SIZE  ( sizeof (struct inotify_event) )
+#define BUF_LEN     ( 1024 * ( EVENT_SIZE + 16 ) )
+
+int need_refresh(void)
+{
+	int length, i = 0;
+	char buffer[BUF_LEN];
+
+	if (inotify_fd <= 0) {
+		return 1;
+	}
+
+	poll(&fds, 1, 1);
+	if (fds.revents != POLLIN) {
+		return 0;
+	}
+
+	length = read(inotify_fd, buffer, BUF_LEN);
+
+	if (length < 0)
+		return 0;
+
+	while (i < length) {
+		struct inotify_event *event = (struct inotify_event *) &buffer[i];
+		if (event->mask & IN_ALL_EVENTS)
+			return 1;
+
+		i += EVENT_SIZE + event->len;
+	}
+
+	return 0;
+}
+
 int read_and_print_clock_info(int verbose, int hrow, int selected)
 {
 	print_one_clock(0, "Reading Clock Tree ...", 1, 1);
diff --git a/powerdebug.c b/powerdebug.c
index 3f4d60c..d142a04 100644
--- a/powerdebug.c
+++ b/powerdebug.c
@@ -14,6 +14,7 @@
  *******************************************************************************/
 
 #include <getopt.h>
+#include <sys/inotify.h>
 #include "powerdebug.h"
 
 int dump;
@@ -199,7 +200,7 @@ int main(int argc, char **argv)
 
 					if (enter_hit)
 						command = CLOCK_SELECTED;
-					if (refreshwin)
+					if (refreshwin && need_refresh())
 						command = REFRESH_WINDOW;
 					hrow = read_and_print_clock_info(
 						verbose,
@@ -313,5 +314,8 @@ int main(int argc, char **argv)
 				refreshwin = 0;
 		}
 	}
+	inotify_rm_watch(inotify_fd, inotify_wd);
+	close(inotify_fd);
+
 	exit(0);
 }
diff --git a/powerdebug.h b/powerdebug.h
index 8a3b5bd..c0eb316 100644
--- a/powerdebug.h
+++ b/powerdebug.h
@@ -71,3 +71,7 @@ extern void show_header(void);
 extern void create_windows(void);
 extern void create_selectedwindow(void);
 extern void show_regulator_info(int verbose);
+
+extern int inotify_fd;
+extern int inotify_wd;
+extern int need_refresh(void);
-- 
1.7.1