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usb: align usb_endpoint_descriptor to 16-bit boundary

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The usb_endpoint_descriptor struct is 7 bytes large and is
defined as an array (ep_desc[USB_MAXENDPOINTS])
in the usb_interface struct in include/usb.h

This fact will result in that every odd index in that
array will start at an uneven address, this in
turn makes accesses to u16 wMaxPacketSize unaligned.
Such accesses are illegal on the OpenRISC architecture
(as well as other architectures) and will render a bus error.

Setting the aligned(2) attribute on usb_endpoint_descriptor
will force wMaxPacketSize to a 16-bit boundary.

Signed-off-by: Stefan Kristiansson <stefan.kristiansson@saunalahti.fi>
This commit is contained in:
Stefan Kristiansson 2011-10-20 22:25:37 +03:00 committed by Remy Bohmer
parent 241d9a61b3
commit 9792987721
1 changed files with 1 additions and 1 deletions
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2
include/usbdescriptors.h
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@ -199,7 +199,7 @@ struct usb_endpoint_descriptor {
u8 bmAttributes;
u16 wMaxPacketSize;
u8 bInterval;
} __attribute__ ((packed));
} __attribute__ ((packed)) __attribute__ ((aligned(2)));
struct usb_interface_descriptor {
u8 bLength;