Changeset 206f71a in mainline for uspace/lib/usb/src/pipesinit.c

Timestamp:

2011-03-14T10:47:42Z (13 years ago)

Author:

Vojtech Horky <vojtechhorky@…>

Branches:

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

Children:

c2343cc, c69209d

Parents:

6dd35e0

Message:

Getting max_packet_size for default control pipe

File:

• uspace/lib/usb/src/pipesinit.c (modified) (2 diffs)

uspace/lib/usb/src/pipesinit.c

@@ -41 +41 @@
 #include <errno.h>
 #include <assert.h>
+
+#define CTRL_PIPE_MIN_PACKET_SIZE 8
+#define DEV_DESCR_MAX_PACKET_SIZE_OFFSET 7
 
 
@@ -371 +374 @@
 
         int rc = usb_endpoint_pipe_initialize(pipe, connection,
-            0, USB_TRANSFER_CONTROL, 8, USB_DIRECTION_BOTH);
+            0, USB_TRANSFER_CONTROL, CTRL_PIPE_MIN_PACKET_SIZE,
+            USB_DIRECTION_BOTH);
+
+        return rc;
+}
+
+/** Probe default control pipe for max packet size.
+ *
+ * The function tries to get the correct value of max packet size several
+ * time before giving up.
+ *
+ * The session on the pipe shall not be started.
+ *
+ * @param pipe Default control pipe.
+ * @return Error code.
+ */
+int usb_endpoint_pipe_probe_default_control(usb_endpoint_pipe_t *pipe)
+{
+        assert(pipe);
+        assert(DEV_DESCR_MAX_PACKET_SIZE_OFFSET < CTRL_PIPE_MIN_PACKET_SIZE);
+
+        if ((pipe->direction != USB_DIRECTION_BOTH) ||
+            (pipe->transfer_type != USB_TRANSFER_CONTROL) ||
+            (pipe->endpoint_no != 0)) {
+                return EINVAL;
+        }
+
+#define TRY_LOOP(attempt_var) \
+        for (attempt_var = 0; attempt_var < 3; attempt_var++)
+
+        size_t failed_attempts;
+        int rc;
+
+        TRY_LOOP(failed_attempts) {
+                rc = usb_endpoint_pipe_start_session(pipe);
+                if (rc == EOK) {
+                        break;
+                }
+        }
         if (rc != EOK) {
                 return rc;
         }
-        rc = usb_endpoint_pipe_start_session(pipe);
+
+
+        uint8_t dev_descr_start[CTRL_PIPE_MIN_PACKET_SIZE];
+        size_t transferred_size;
+        TRY_LOOP(failed_attempts) {
+                rc = usb_request_get_descriptor(pipe, USB_REQUEST_TYPE_STANDARD,
+                    USB_REQUEST_RECIPIENT_DEVICE, USB_DESCTYPE_DEVICE,
+                    0, 0, dev_descr_start, CTRL_PIPE_MIN_PACKET_SIZE,
+                    &transferred_size);
+                if (rc == EOK) {
+                        if (transferred_size != CTRL_PIPE_MIN_PACKET_SIZE) {
+                                rc = ELIMIT;
+                                continue;
+                        }
+                        break;
+                }
+        }
+        usb_endpoint_pipe_end_session(pipe);
         if (rc != EOK) {
                 return rc;
         }
 
-        uint8_t first[8];
-        size_t size = 0;
-        rc = usb_control_request_get(pipe, USB_REQUEST_TYPE_STANDARD,
-            USB_REQUEST_RECIPIENT_DEVICE, USB_DEVREQ_GET_DESCRIPTOR, 1 << 8,
-                        0, first, 8, &size);
-        usb_endpoint_pipe_end_session(pipe);
-        if (rc != EOK || size  != 8) {
-                return rc;
-        }
-
-        pipe->max_packet_size = first[7];
-        return rc;
+        pipe->max_packet_size
+            = dev_descr_start[DEV_DESCR_MAX_PACKET_SIZE_OFFSET];
+
+        return EOK;
 }