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[RFC PATCH v2 2/5] hw/misc/led: Add LED_STATUS_CHANGED QAPI event
From: |
Philippe Mathieu-Daudé |
Subject: |
[RFC PATCH v2 2/5] hw/misc/led: Add LED_STATUS_CHANGED QAPI event |
Date: |
Fri, 12 Jun 2020 19:54:37 +0200 |
Allow LED devices to emit STATUS_CHANGED events on a QMP chardev.
QMP event examples:
{
"timestamp": {
"seconds": 1591704274,
"microseconds": 520850
},
"event": "LED_STATUS_CHANGED",
"data": {
"name": "Green LED #0",
"status": "on"
}
}
{
"timestamp": {
"seconds": 1591704275,
"microseconds": 530912
},
"event": "LED_STATUS_CHANGED",
"data": {
"name": "Green LED #0",
"status": "off"
}
}
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
---
Since v1: rate limit 4/sec (eblake)
---
qapi/led.json | 47 +++++++++++++++++++++++++++++++++++++++++++
qapi/qapi-schema.json | 1 +
include/hw/misc/led.h | 1 +
hw/misc/led.c | 24 +++++++++++++++++++++-
MAINTAINERS | 1 +
qapi/Makefile.objs | 2 +-
6 files changed, 74 insertions(+), 2 deletions(-)
create mode 100644 qapi/led.json
diff --git a/qapi/led.json b/qapi/led.json
new file mode 100644
index 0000000000..b6cef8a5dd
--- /dev/null
+++ b/qapi/led.json
@@ -0,0 +1,47 @@
+# -*- Mode: Python -*-
+#
+
+##
+# = LED device
+##
+
+##
+# @LedState:
+#
+# Status of a LED
+#
+# @on: device is emitting
+#
+# @off: device is off
+#
+# Since: 5.1
+##
+{ 'enum': 'LedState', 'data': [ 'on', 'off' ] }
+
+##
+# @LED_STATUS_CHANGED:
+#
+# Emitted when LED status changed
+#
+# @name: LED description
+#
+# @status: New status
+#
+# Since: 5.1
+#
+# Example:
+#
+# <- {"timestamp": {"seconds": 1541579657, "microseconds": 986760},
+# "event": "LED_STATUS_CHANGED",
+# "data":
+# {"name": "Blue LED #3",
+# "status": "on"
+# }
+# }
+#
+##
+{ 'event': 'LED_STATUS_CHANGED',
+ 'data': { 'name' : 'str',
+ 'status' : 'LedState'
+ }
+}
diff --git a/qapi/qapi-schema.json b/qapi/qapi-schema.json
index 43b0ba0dea..6f3ffc0ae1 100644
--- a/qapi/qapi-schema.json
+++ b/qapi/qapi-schema.json
@@ -84,3 +84,4 @@
{ 'include': 'misc.json' }
{ 'include': 'misc-target.json' }
{ 'include': 'audio.json' }
+{ 'include': 'led.json' }
diff --git a/include/hw/misc/led.h b/include/hw/misc/led.h
index 427ca1418e..9300d4db6c 100644
--- a/include/hw/misc/led.h
+++ b/include/hw/misc/led.h
@@ -21,6 +21,7 @@ typedef struct LEDState {
qemu_irq irq;
uint8_t current_state;
+ int64_t last_event_ms;
/* Properties */
char *name;
diff --git a/hw/misc/led.c b/hw/misc/led.c
index 1bae1a34c0..11c7e8bb89 100644
--- a/hw/misc/led.c
+++ b/hw/misc/led.c
@@ -7,18 +7,40 @@
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
+#include "qapi/qapi-events-led.h"
+#include "qemu/timer.h"
#include "migration/vmstate.h"
#include "hw/qdev-properties.h"
#include "hw/misc/led.h"
#include "hw/irq.h"
#include "trace.h"
+#define MAX_QMP_LED_EVENTS_PER_SEC 4 /* TODO shared between LED children? */
+
+static void emit_led_status_changed_event(LEDState *s, int state)
+{
+ static const int64_t delay_min_ms = NANOSECONDS_PER_SECOND / SCALE_MS
+ / MAX_QMP_LED_EVENTS_PER_SEC;
+ int64_t now = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+
+ if (now - s->last_event_ms > delay_min_ms) {
+ qapi_event_send_led_status_changed(s->name, state
+ ? LED_STATE_ON
+ : LED_STATE_OFF);
+ } else {
+ /* TODO count skipped events? */
+ }
+ s->last_event_ms = now;
+}
+
static void led_set(void *opaque, int line, int new_state)
{
LEDState *s = LED(opaque);
trace_led_set(s->name, s->current_state, new_state);
-
+ if (new_state != s->current_state) {
+ emit_led_status_changed_event(s, new_state);
+ }
s->current_state = new_state;
}
diff --git a/MAINTAINERS b/MAINTAINERS
index 10593863dc..266b07c4b4 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1860,6 +1860,7 @@ F: stubs/vmgenid.c
LED
M: Philippe Mathieu-Daudé <f4bug@amsat.org>
S: Maintained
+F: qapi/led.json
F: include/hw/misc/led.h
F: hw/misc/led.c
diff --git a/qapi/Makefile.objs b/qapi/Makefile.objs
index 4673ab7490..e9f6570c32 100644
--- a/qapi/Makefile.objs
+++ b/qapi/Makefile.objs
@@ -6,7 +6,7 @@ util-obj-y += qmp-event.o
util-obj-y += qapi-util.o
QAPI_COMMON_MODULES = audio authz block-core block char common control crypto
-QAPI_COMMON_MODULES += dump error introspect job machine migration misc
+QAPI_COMMON_MODULES += dump error introspect job led machine migration misc
QAPI_COMMON_MODULES += net pragma qdev qom rdma rocker run-state sockets tpm
QAPI_COMMON_MODULES += trace transaction ui
QAPI_TARGET_MODULES = machine-target misc-target
--
2.21.3