add some informations about this file

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@15344 a1c6a512-1295-4272-9138-f99709370657

2 files changed, 30 insertions, 21 deletions

diff --git a/firmware/drivers/usb/arcotg_dcd.c b/firmware/drivers/usb/arcotg_dcd.c
index fe8ae803c0..c45a790c04 100644
--- a/firmware/drivers/usb/arcotg_dcd.c
+++ b/firmware/drivers/usb/arcotg_dcd.c
@@ -467,25 +467,17 @@ static void resume_int(void)
 
 static void reset_int(void)
 {
-    struct timer t;
-
     /* clear device address */
     UDC_DEVICEADDR = 0 << 25;
 
     /* update usb state */
     dcd_controller.usb_state = USB_STATE_DEFAULT;
 
-    timer_set(&t, RESET_TIMER);
-
     UDC_ENDPTSETUPSTAT = UDC_ENDPTSETUPSTAT;
     UDC_ENDPTCOMPLETE  = UDC_ENDPTCOMPLETE;
 
-    while (UDC_ENDPTPRIME) { /* prime and flush pending transfers */
-        if (timer_expired(&t)) {
-            logf("TIMEOUT->p&f");
-        }
-    }
-
+    /* prime and flush pending transfers */
+    while (UDC_ENDPTPRIME);
     UDC_ENDPTFLUSH = ~0;
 
     if ((UDC_PORTSC1 & PORTSCX_PORT_RESET) == 0) {
@@ -493,19 +485,9 @@ static void reset_int(void)
     }
 
     /* clear USB Reset status bit */
-    UDC_USBSTS = USB_STS_RESET;
-
-    /* wait for port change */
-    while ((UDC_USBSTS & USB_STS_PORT_CHANGE) == 0) {
-        if (timer_expired(&t)) {
-        logf("TIMEOUT->portchange");
-        }
-    }
-
-    UDC_USBSTS = (1 << 2);
+    UDC_USBSTS |= USB_STS_RESET;
 }
 
-
 /*-------------------------------------------------------------------------*/
 /* usb controller ops */
 
diff --git a/firmware/export/usb_ch9.h b/firmware/export/usb_ch9.h
index a40bc4e4ae..b8fe181158 100644
--- a/firmware/export/usb_ch9.h
+++ b/firmware/export/usb_ch9.h
@@ -21,6 +21,33 @@
  *
  ****************************************************************************/
 
+/*
+ * This file holds USB constants and structures that are needed for
+ * USB device APIs.  These are used by the USB device model, which is
+ * defined in chapter 9 of the USB 2.0 specification and in the
+ * Wireless USB 1.0 (spread around).
+ *
+ * USB 2.0 adds an additional "On The Go" (OTG) mode, which lets systems
+ * act either as a USB master/host or as a USB slave/device.  That means
+ * the master and slave side APIs benefit from working well together.
+ *
+ * There's also "Wireless USB", using low power short range radios for
+ * peripheral interconnection but otherwise building on the USB framework.
+ *
+ * Note all descriptors are declared '__attribute__((packed))' so that:
+ *
+ * [a] they never get padded, either internally (USB spec writers
+ *     probably handled that) or externally;
+ *
+ * [b] so that accessing bigger-than-a-bytes fields will never
+ *     generate bus errors on any platform, even when the location of
+ *     its descriptor inside a bundle isn't "naturally aligned", and
+ *
+ * [c] for consistency, removing all doubt even when it appears to
+ *     someone that the two other points are non-issues for that
+ *     particular descriptor type.
+ */
+
 #ifndef _CH9_H_
 #define _CH9_H_