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-rw-r--r--drivers/usb/core/hcd.c86
-rw-r--r--drivers/usb/core/hcd.h32
-rw-r--r--drivers/usb/core/message.c20
-rw-r--r--drivers/usb/core/urb.c6
4 files changed, 144 insertions, 0 deletions
diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 823744d80cb9..b2da4753b12e 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -1560,6 +1560,92 @@ rescan:
}
}
+/* Check whether a new configuration or alt setting for an interface
+ * will exceed the bandwidth for the bus (or the host controller resources).
+ * Only pass in a non-NULL config or interface, not both!
+ * Passing NULL for both new_config and new_intf means the device will be
+ * de-configured by issuing a set configuration 0 command.
+ */
+int usb_hcd_check_bandwidth(struct usb_device *udev,
+ struct usb_host_config *new_config,
+ struct usb_interface *new_intf)
+{
+ int num_intfs, i, j;
+ struct usb_interface_cache *intf_cache;
+ struct usb_host_interface *alt = 0;
+ int ret = 0;
+ struct usb_hcd *hcd;
+ struct usb_host_endpoint *ep;
+
+ hcd = bus_to_hcd(udev->bus);
+ if (!hcd->driver->check_bandwidth)
+ return 0;
+
+ /* Configuration is being removed - set configuration 0 */
+ if (!new_config && !new_intf) {
+ for (i = 1; i < 16; ++i) {
+ ep = udev->ep_out[i];
+ if (ep)
+ hcd->driver->drop_endpoint(hcd, udev, ep);
+ ep = udev->ep_in[i];
+ if (ep)
+ hcd->driver->drop_endpoint(hcd, udev, ep);
+ }
+ hcd->driver->check_bandwidth(hcd, udev);
+ return 0;
+ }
+ /* Check if the HCD says there's enough bandwidth. Enable all endpoints
+ * each interface's alt setting 0 and ask the HCD to check the bandwidth
+ * of the bus. There will always be bandwidth for endpoint 0, so it's
+ * ok to exclude it.
+ */
+ if (new_config) {
+ num_intfs = new_config->desc.bNumInterfaces;
+ /* Remove endpoints (except endpoint 0, which is always on the
+ * schedule) from the old config from the schedule
+ */
+ for (i = 1; i < 16; ++i) {
+ ep = udev->ep_out[i];
+ if (ep) {
+ ret = hcd->driver->drop_endpoint(hcd, udev, ep);
+ if (ret < 0)
+ goto reset;
+ }
+ ep = udev->ep_in[i];
+ if (ep) {
+ ret = hcd->driver->drop_endpoint(hcd, udev, ep);
+ if (ret < 0)
+ goto reset;
+ }
+ }
+ for (i = 0; i < num_intfs; ++i) {
+
+ /* Dig the endpoints for alt setting 0 out of the
+ * interface cache for this interface
+ */
+ intf_cache = new_config->intf_cache[i];
+ for (j = 0; j < intf_cache->num_altsetting; j++) {
+ if (intf_cache->altsetting[j].desc.bAlternateSetting == 0)
+ alt = &intf_cache->altsetting[j];
+ }
+ if (!alt) {
+ printk(KERN_DEBUG "Did not find alt setting 0 for intf %d\n", i);
+ continue;
+ }
+ for (j = 0; j < alt->desc.bNumEndpoints; j++) {
+ ret = hcd->driver->add_endpoint(hcd, udev, &alt->endpoint[j]);
+ if (ret < 0)
+ goto reset;
+ }
+ }
+ }
+ ret = hcd->driver->check_bandwidth(hcd, udev);
+reset:
+ if (ret < 0)
+ hcd->driver->reset_bandwidth(hcd, udev);
+ return ret;
+}
+
/* Disables the endpoint: synchronizes with the hcd to make sure all
* endpoint state is gone from hardware. usb_hcd_flush_endpoint() must
* have been called previously. Use for set_configuration, set_interface,
diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h
index ae6d9db41ca9..d397ecfd5b17 100644
--- a/drivers/usb/core/hcd.h
+++ b/drivers/usb/core/hcd.h
@@ -232,6 +232,35 @@ struct hc_driver {
int (*alloc_dev)(struct usb_hcd *, struct usb_device *);
/* Called by usb_release_dev to free HC device structures */
void (*free_dev)(struct usb_hcd *, struct usb_device *);
+
+ /* Bandwidth computation functions */
+ /* Note that add_endpoint() can only be called once per endpoint before
+ * check_bandwidth() or reset_bandwidth() must be called.
+ * drop_endpoint() can only be called once per endpoint also.
+ * A call to xhci_drop_endpoint() followed by a call to xhci_add_endpoint() will
+ * add the endpoint to the schedule with possibly new parameters denoted by a
+ * different endpoint descriptor in usb_host_endpoint.
+ * A call to xhci_add_endpoint() followed by a call to xhci_drop_endpoint() is
+ * not allowed.
+ */
+ /* Allocate endpoint resources and add them to a new schedule */
+ int (*add_endpoint)(struct usb_hcd *, struct usb_device *, struct usb_host_endpoint *);
+ /* Drop an endpoint from a new schedule */
+ int (*drop_endpoint)(struct usb_hcd *, struct usb_device *, struct usb_host_endpoint *);
+ /* Check that a new hardware configuration, set using
+ * endpoint_enable and endpoint_disable, does not exceed bus
+ * bandwidth. This must be called before any set configuration
+ * or set interface requests are sent to the device.
+ */
+ int (*check_bandwidth)(struct usb_hcd *, struct usb_device *);
+ /* Reset the device schedule to the last known good schedule,
+ * which was set from a previous successful call to
+ * check_bandwidth(). This reverts any add_endpoint() and
+ * drop_endpoint() calls since that last successful call.
+ * Used for when a check_bandwidth() call fails due to resource
+ * or bandwidth constraints.
+ */
+ void (*reset_bandwidth)(struct usb_hcd *, struct usb_device *);
/* Returns the hardware-chosen device address */
int (*address_device)(struct usb_hcd *, struct usb_device *udev);
};
@@ -252,6 +281,9 @@ extern void usb_hcd_disable_endpoint(struct usb_device *udev,
extern void usb_hcd_reset_endpoint(struct usb_device *udev,
struct usb_host_endpoint *ep);
extern void usb_hcd_synchronize_unlinks(struct usb_device *udev);
+extern int usb_hcd_check_bandwidth(struct usb_device *udev,
+ struct usb_host_config *new_config,
+ struct usb_interface *new_intf);
extern int usb_hcd_get_frame_number(struct usb_device *udev);
extern struct usb_hcd *usb_create_hcd(const struct hc_driver *driver,
diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
index 9bd26dec7599..3a2e69ec2f29 100644
--- a/drivers/usb/core/message.c
+++ b/drivers/usb/core/message.c
@@ -510,6 +510,10 @@ EXPORT_SYMBOL_GPL(usb_sg_init);
* could be transferred. That capability is less useful for low or full
* speed interrupt endpoints, which allow at most one packet per millisecond,
* of at most 8 or 64 bytes (respectively).
+ *
+ * It is not necessary to call this function to reserve bandwidth for devices
+ * under an xHCI host controller, as the bandwidth is reserved when the
+ * configuration or interface alt setting is selected.
*/
void usb_sg_wait(struct usb_sg_request *io)
{
@@ -1653,6 +1657,21 @@ free_interfaces:
if (ret)
goto free_interfaces;
+ /* Make sure we have bandwidth (and available HCD resources) for this
+ * configuration. Remove endpoints from the schedule if we're dropping
+ * this configuration to set configuration 0. After this point, the
+ * host controller will not allow submissions to dropped endpoints. If
+ * this call fails, the device state is unchanged.
+ */
+ if (cp)
+ ret = usb_hcd_check_bandwidth(dev, cp, NULL);
+ else
+ ret = usb_hcd_check_bandwidth(dev, NULL, NULL);
+ if (ret < 0) {
+ usb_autosuspend_device(dev);
+ goto free_interfaces;
+ }
+
/* if it's already configured, clear out old state first.
* getting rid of old interfaces means unbinding their drivers.
*/
@@ -1675,6 +1694,7 @@ free_interfaces:
dev->actconfig = cp;
if (!cp) {
usb_set_device_state(dev, USB_STATE_ADDRESS);
+ usb_hcd_check_bandwidth(dev, NULL, NULL);
usb_autosuspend_device(dev);
goto free_interfaces;
}
diff --git a/drivers/usb/core/urb.c b/drivers/usb/core/urb.c
index 02eb0ef7a4c3..0885d4abdc62 100644
--- a/drivers/usb/core/urb.c
+++ b/drivers/usb/core/urb.c
@@ -241,6 +241,12 @@ EXPORT_SYMBOL_GPL(usb_unanchor_urb);
* If the USB subsystem can't allocate sufficient bandwidth to perform
* the periodic request, submitting such a periodic request should fail.
*
+ * For devices under xHCI, the bandwidth is reserved at configuration time, or
+ * when the alt setting is selected. If there is not enough bus bandwidth, the
+ * configuration/alt setting request will fail. Therefore, submissions to
+ * periodic endpoints on devices under xHCI should never fail due to bandwidth
+ * constraints.
+ *
* Device drivers must explicitly request that repetition, by ensuring that
* some URB is always on the endpoint's queue (except possibly for short
* periods during completion callacks). When there is no longer an urb