Instead of using a single flat array for all sensors, put all the

children of a sensor in a separate structure.

Children sensors should only be probbed if their parent is active.
This make the dependency tree explicit and will reduce the number
of I/O.

From David Higgs.

diff --git a/sys/dev/usb/upd.c b/sys/dev/usb/upd.c
index 428b2c2..93b06e9 100644 (file)
--- a/sys/dev/usb/upd.c
+++ b/sys/dev/usb/upd.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: upd.c,v 1.17 2015/04/27 09:14:45 mpi Exp $ */
+/*     $OpenBSD: upd.c,v 1.18 2015/04/30 10:00:50 mpi Exp $ */
 
 /*
  * Copyright (c) 2014 Andre de Oliveira <andre@openbsd.org>
@@ -23,6 +23,7 @@
 #include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/device.h>
+#include <sys/queue.h>
 #include <sys/sensors.h>
 
 #include <dev/usb/hid.h>
@@ -46,9 +47,11 @@ struct upd_usage_entry {
        uint8_t                 usage_id;
        enum sensor_type        senstype;
        char                    *usage_name; /* sensor string */
+       int                     nchildren;
+       struct upd_usage_entry  *children;
 };
 
-static struct upd_usage_entry upd_usage_table[] = {
+static struct upd_usage_entry upd_usage_batdep[] = {
        { HUP_BATTERY,  HUB_REL_STATEOF_CHARGE,
            SENSOR_PERCENT,      "RelativeStateOfCharge" },
        { HUP_BATTERY,  HUB_ABS_STATEOF_CHARGE,
@@ -61,25 +64,32 @@ static struct upd_usage_entry upd_usage_table[] = {
            SENSOR_INDICATOR,    "Charging" },
        { HUP_BATTERY,  HUB_DISCHARGING,
            SENSOR_INDICATOR,    "Discharging" },
+       { HUP_BATTERY,  HUB_ATRATE_TIMETOFULL,
+           SENSOR_TIMEDELTA,    "AtRateTimeToFull" }
+};
+static struct upd_usage_entry upd_usage_roots[] = {
        { HUP_BATTERY,  HUB_BATTERY_PRESENT,
-           SENSOR_INDICATOR,    "BatteryPresent" },
+           SENSOR_INDICATOR,    "BatteryPresent",
+           nitems(upd_usage_batdep),   upd_usage_batdep },
        { HUP_POWER,    HUP_SHUTDOWN_IMMINENT,
            SENSOR_INDICATOR,    "ShutdownImminent" },
        { HUP_BATTERY,  HUB_AC_PRESENT,
-           SENSOR_INDICATOR,    "ACPresent" },
-       { HUP_BATTERY,  HUB_ATRATE_TIMETOFULL,
-           SENSOR_TIMEDELTA,    "AtRateTimeToFull" }
+           SENSOR_INDICATOR,    "ACPresent" }
 };
+#define UPD_MAX_SENSORS        (nitems(upd_usage_batdep) + nitems(upd_usage_roots))
 
 struct upd_report {
        size_t          size;
        int             enabled;
 };
 
+SLIST_HEAD(upd_sensor_head, upd_sensor);
 struct upd_sensor {
-       struct ksensor          ksensor;
-       struct hid_item         hitem;
-       int                     attached;
+       struct ksensor                  ksensor;
+       struct hid_item                 hitem;
+       int                             attached;
+       struct upd_sensor_head          children;
+       SLIST_ENTRY(upd_sensor)         dep_next;
 };
 
 struct upd_softc {
@@ -92,10 +102,13 @@ struct upd_softc {
        struct sensor_task      *sc_sensortask;
        struct upd_report       *sc_reports;
        struct upd_sensor       *sc_sensors;
+       struct upd_sensor_head   sc_root_sensors;
 };
 
 int  upd_match(struct device *, void *, void *);
 void upd_attach(struct device *, struct device *, void *);
+void upd_attach_sensor_tree(struct upd_softc *, void *, int, int,
+    struct upd_usage_entry *, struct upd_sensor_head *);
 int  upd_detach(struct device *, int);
 
 void upd_refresh(void *);
@@ -134,13 +147,11 @@ upd_match(struct device *parent, void *match, void *aux)
        DPRINTF(("upd: vendor=0x%04x, product=0x%04x\n", uha->uaa->vendor,
            uha->uaa->product));
 
-       /*
-        * look for at least one sensor of our table
-        */
+       /* need at least one sensor from root of tree */
        uhidev_get_report_desc(uha->parent, &desc, &size);
-       for (i = 0; i < nitems(upd_usage_table); i++)
+       for (i = 0; i < nitems(upd_usage_roots); i++)
                if (upd_lookup_usage_entry(desc, size,
-                   upd_usage_table + i, &item)) {
+                   upd_usage_roots + i, &item)) {
                        ret = UMATCH_VENDOR_PRODUCT;
                        break;
                }
@@ -153,9 +164,6 @@ upd_attach(struct device *parent, struct device *self, void *aux)
 {
        struct upd_softc         *sc = (struct upd_softc *)self;
        struct uhidev_attach_arg *uha = (struct uhidev_attach_arg *)aux;
-       struct hid_item           item;
-       struct upd_usage_entry   *entry;
-       struct upd_sensor        *sensor;
        int                       size;
        int                       i;
        void                     *desc;
@@ -164,6 +172,7 @@ upd_attach(struct device *parent, struct device *self, void *aux)
        sc->sc_hdev.sc_parent = uha->parent;
        sc->sc_reports = NULL;
        sc->sc_sensors = NULL;
+       SLIST_INIT(&sc->sc_root_sensors);
 
        strlcpy(sc->sc_sensordev.xname, DEVNAME(sc),
            sizeof(sc->sc_sensordev.xname));
@@ -174,13 +183,41 @@ upd_attach(struct device *parent, struct device *self, void *aux)
 
        sc->sc_reports = mallocarray(sc->sc_max_repid,
            sizeof(struct upd_report), M_USBDEV, M_WAITOK | M_ZERO);
-       sc->sc_sensors = mallocarray(nitems(upd_usage_table),
+       sc->sc_sensors = mallocarray(UPD_MAX_SENSORS,
            sizeof(struct upd_sensor), M_USBDEV, M_WAITOK | M_ZERO);
-       sc->sc_num_sensors = 0;
+       for (i = 0; i < UPD_MAX_SENSORS; i++)
+               SLIST_INIT(&sc->sc_sensors[i].children);
 
+       sc->sc_num_sensors = 0;
        uhidev_get_report_desc(uha->parent, &desc, &size);
-       for (i = 0; i < nitems(upd_usage_table); i++) {
-               entry = &upd_usage_table[i];
+       upd_attach_sensor_tree(sc, desc, size, nitems(upd_usage_roots),
+           upd_usage_roots, &sc->sc_root_sensors);
+       DPRINTF(("upd: sc_num_sensors=%d\n", sc->sc_num_sensors));
+
+       sc->sc_sensortask = sensor_task_register(sc, upd_refresh, 6);
+       if (sc->sc_sensortask == NULL) {
+               printf(", unable to register update task\n");
+               return;
+       }
+       sensordev_install(&sc->sc_sensordev);
+
+       printf("\n");
+
+       DPRINTF(("upd_attach: complete\n"));
+}
+
+void
+upd_attach_sensor_tree(struct upd_softc *sc, void *desc, int size,
+    int nentries, struct upd_usage_entry *entries,
+    struct upd_sensor_head *queue)
+{
+       struct hid_item           item;
+       struct upd_usage_entry   *entry;
+       struct upd_sensor        *sensor;
+       int                       i;
+
+       for (i = 0; i < nentries; i++) {
+               entry = entries + i;
                if (!upd_lookup_usage_entry(desc, size, entry, &item))
                        continue;
 
@@ -200,27 +237,18 @@ upd_attach(struct device *parent, struct device *self, void *aux)
                sensor->ksensor.value = 0;
                sensor_attach(&sc->sc_sensordev, &sensor->ksensor);
                sensor->attached = 1;
+               SLIST_INSERT_HEAD(queue, sensor, dep_next);
                sc->sc_num_sensors++;
 
+               upd_attach_sensor_tree(sc, desc, size, entry->nchildren,
+                   entry->children, &sensor->children);
+
                if (sc->sc_reports[item.report_ID].enabled)
                        continue;
-
                sc->sc_reports[item.report_ID].size = hid_report_size(desc,
                    size, item.kind, item.report_ID);
                sc->sc_reports[item.report_ID].enabled = 1;
        }
-       DPRINTF(("upd: sc_num_sensors=%d\n", sc->sc_num_sensors));
-
-       sc->sc_sensortask = sensor_task_register(sc, upd_refresh, 6);
-       if (sc->sc_sensortask == NULL) {
-               printf(", unable to register update task\n");
-               return;
-       }
-       sensordev_install(&sc->sc_sensordev);
-
-       printf("\n");
-
-       DPRINTF(("upd_attach: complete\n"));
 }
 
 int