intel_gpu_top: Support exiting the tool by pressing 'q'

Analoguous to top(1) we can enable the user to exit from the tool by
pressing 'q' on the console.

v2:
 * Fix sleep period with closed stdin. (Chris)

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

2 files changed, 73 insertions, 13 deletions

diff --git a/man/intel_gpu_top.rst b/man/intel_gpu_top.rst
index 5552e969..2e0c3a05 100644
--- a/man/intel_gpu_top.rst
+++ b/man/intel_gpu_top.rst
@@ -48,6 +48,12 @@ OPTIONS
 -d
     Select a specific GPU using supported filter.
 
+RUNTIME CONTROL
+===============
+
+Supported keys:
+
+    'q'    Exit from the tool.
 
 DEVICE SELECTION
 ================
diff --git a/tools/intel_gpu_top.c b/tools/intel_gpu_top.c
index dbd35367..46221c95 100644
--- a/tools/intel_gpu_top.c
+++ b/tools/intel_gpu_top.c
@@ -23,24 +23,26 @@
 
 #include "igt_device_scan.h"
 
-#include <stdio.h>
-#include <sys/types.h>
-#include <dirent.h>
-#include <stdint.h>
 #include <assert.h>
-#include <string.h>
 #include <ctype.h>
-#include <stdlib.h>
-#include <unistd.h>
-#include <sys/stat.h>
+#include <dirent.h>
+#include <errno.h>
 #include <fcntl.h>
 #include <inttypes.h>
-#include <sys/ioctl.h>
-#include <errno.h>
-#include <math.h>
-#include <locale.h>
 #include <limits.h>
+#include <locale.h>
+#include <math.h>
+#include <poll.h>
 #include <signal.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <termios.h>
 
 #include "igt_perf.h"
 
@@ -1246,6 +1248,54 @@ static char *tr_pmu_name(struct igt_device_card *card)
 	return device;
 }
 
+static void interactive_stdin(void)
+{
+	struct termios termios = { };
+	int ret;
+
+	ret = fcntl(0, F_GETFL, NULL);
+	ret |= O_NONBLOCK;
+	ret = fcntl(0, F_SETFL, ret);
+	assert(ret == 0);
+
+	ret = tcgetattr(0, &termios);
+	assert(ret == 0);
+
+	termios.c_lflag &= ~ICANON;
+	termios.c_cc[VMIN] = 1;
+	termios.c_cc[VTIME] = 0; /* Deciseconds only - we'll use poll. */
+
+	ret = tcsetattr(0, TCSAFLUSH, &termios);
+	assert(ret == 0);
+}
+
+static void process_stdin(unsigned int timeout_us)
+{
+	struct pollfd p = { .fd = 0, .events = POLLIN };
+	int ret;
+
+	ret = poll(&p, 1, timeout_us / 1000);
+	if (ret <= 0) {
+		if (ret < 0)
+			stop_top = true;
+		return;
+	}
+
+	for (;;) {
+		char c;
+
+		ret = read(0, &c, 1);
+		if (ret <= 0)
+			break;
+
+		switch (c) {
+		case 'q':
+			stop_top = true;
+			break;
+		};
+	}
+}
+
 int main(int argc, char **argv)
 {
 	unsigned int period_us = DEFAULT_PERIOD_MS * 1000;
@@ -1315,6 +1365,7 @@ int main(int argc, char **argv)
 	switch (output_mode) {
 	case INTERACTIVE:
 		pops = &term_pops;
+		interactive_stdin();
 		break;
 	case STDOUT:
 		pops = &stdout_pops;
@@ -1427,7 +1478,10 @@ int main(int argc, char **argv)
 		if (stop_top)
 			break;
 
-		usleep(period_us);
+		if (output_mode == INTERACTIVE)
+			process_stdin(period_us);
+		else
+			usleep(period_us);
 	}
 
 	free(codename);