Changeset 51a51be in mainline for uspace/drv/bus/usb/usbhub/usbhub.c

Timestamp:

2018-01-16T21:19:37Z (6 years ago)

Author:

Ondřej Hlavatý <aearsis@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

1d218bf

Parents:

4603b35

Message:

usbhub: aggregate requests for default address

File:

• uspace/drv/bus/usb/usbhub/usbhub.c (modified) (2 diffs)

uspace/drv/bus/usb/usbhub/usbhub.c

@@ -116 +116 @@
         }
         hub_dev->usb_device = usb_dev;
+
+        fibril_mutex_initialize(&hub_dev->default_address_guard);
+        fibril_condvar_initialize(&hub_dev->default_address_cv);
 
         /* Set hub's first configuration. (There should be only one) */
@@ -603 +606 @@
 
 /**
+ * Reserve a default address for a port across all other devices connected to
+ * the bus. We aggregate requests for ports to minimize delays between
+ * connecting multiple devices from one hub - which happens e.g. when the hub
+ * is connected with already attached devices.
+ */
+int usb_hub_reserve_default_address(usb_hub_dev_t *hub, async_exch_t *exch, fibril_mutex_t *guard)
+{
+        assert(hub);
+        assert(exch);
+        assert(guard);
+        assert(fibril_mutex_is_locked(guard));
+
+        fibril_mutex_lock(&hub->default_address_guard);
+        if (hub->default_address_requests++ == 0) {
+                /* We're the first to request the address, we can just do it */
+                fibril_mutex_unlock(&hub->default_address_guard);
+                int err;
+                while ((err = usbhc_reserve_default_address(exch)) == EAGAIN) {
+                        fibril_mutex_unlock(guard);
+                        async_usleep(500000);
+                        fibril_mutex_lock(guard);
+                        err = usbhc_reserve_default_address(exch);
+                }
+                return err;
+        } else {
+                /* Drop the port guard, we're going to wait */
+                fibril_mutex_unlock(guard);
+
+                /* Wait for a signal */
+                fibril_condvar_wait(&hub->default_address_cv, &hub->default_address_guard);
+
+                /* Remember ABBA, first drop the hub guard */
+                fibril_mutex_unlock(&hub->default_address_guard);
+                fibril_mutex_lock(guard);
+                return EOK;
+        }
+}
+
+/**
+ * Release the default address from a port.
+ */
+int usb_hub_release_default_address(usb_hub_dev_t *hub, async_exch_t *exch)
+{
+        fibril_mutex_lock(&hub->default_address_guard);
+        if (--hub->default_address_requests == 0) {
+                fibril_mutex_unlock(&hub->default_address_guard);
+                return usbhc_release_default_address(exch);
+        } else {
+                fibril_condvar_signal(&hub->default_address_cv);
+                fibril_mutex_unlock(&hub->default_address_guard);
+                return EOK;
+        }
+}
+
+/**
  * @}
  */