Changeset ecbad17 in mainline for uspace/lib/usbhost/src/bandwidth.c

Timestamp:

2018-01-07T17:13:57Z (7 years ago)

Author:

Ondřej Hlavatý <aearsis@…>

Branches:

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

Children:

eb928c4

Parents:

3dc3f99

git-author:

Ondřej Hlavatý <aearsis@…> (2018-01-07 17:12:35)

git-committer:

Ondřej Hlavatý <aearsis@…> (2018-01-07 17:13:57)

Message:

usbhost: Implemented bandwidth accounting for USB 2.0

File:

• uspace/lib/usbhost/src/bandwidth.c (modified) (2 diffs)

uspace/lib/usbhost/src/bandwidth.c

@@ -96 +96 @@
 
 /** Calculate bandwidth that needs to be reserved for communication with EP.
- * Calculation follows USB 2.0 specification.
+ * Calculation follows USB 2.0 specification, chapter 5.11.3.
+ *
  * @param speed Device's speed.
  * @param type Type of the transfer.
  * @param size Number of byte to transfer.
  * @param max_packet_size Maximum bytes in one packet.
+ * @return Number of nanoseconds transaction with @c size bytes payload will
+ *         take.
  */
 ssize_t bandwidth_count_usb20(endpoint_t *ep, size_t size)
@@ -113 +116 @@
                 return 0;
         }
-        //TODO Implement
-        return 0;
+
+        // FIXME: Come up with some upper bound for these (in ns).
+        const size_t host_delay = 0;
+        const size_t hub_ls_setup = 0;
+
+        // Approx. Floor(3.167 + BitStuffTime(Data_bc))
+        const size_t base_time = (size * 8 + 19) / 6;
+
+        switch (ep->device->speed) {
+        case USB_SPEED_LOW:
+                if (ep->direction == USB_DIRECTION_IN)
+                        return 64060 + (2 * hub_ls_setup) + (677 * base_time) + host_delay;
+                else
+                        return 64107 + (2 * hub_ls_setup) + (667 * base_time) + host_delay;
+
+        case USB_SPEED_FULL:
+                if (ep->transfer_type == USB_TRANSFER_INTERRUPT)
+                        return 9107 + 84 * base_time + host_delay;
+
+                if (ep->direction == USB_DIRECTION_IN)
+                        return 7268 + 84 * base_time + host_delay;
+                else
+                        return 6265 + 84 * base_time + host_delay;
+
+        case USB_SPEED_HIGH:
+                if (ep->transfer_type == USB_TRANSFER_INTERRUPT)
+                        return (3648 + 25 * base_time + 11) / 12 + host_delay;
+                else
+                        return (5280 + 25 * base_time + 11) / 12 + host_delay;
+
+        default:
+                return 0;
+        }
 }