Dear Markus,
Dear Christian,
"Christian Eggers" ceggers@gmx.de writes:
I've recognized that a lot of USB code in U-Boot uses the macros swap_16() and swap_32() which are defined in usb.h. The behaviour of the macros is controlled by the define LITTLEENDIAN.
Is there a good reason NOT to use the macros provided in asm/byteorder.h (as in the appropriate code in Linux-2.4 )?
Largely not. But be carefull. Besides big and little endian CPUs we also have controllers that operate in big or little endian (see CFG_OHCI_BE_CONTROLLER), and then there are PCI controllers whose registers need to be accessed as little endian (CFG_OHCI_SWAP_REG_ACCESS).
I didn't change much in usb_ohci.c. But I think there has been a small error with byteorder conversion (see patch).
But your right, there is no real for LITTLEENDIAN.
I think that switching to these functions might be useful in order to eliminate the need to use the LITTLEENDIAN define for specifying the byteorder. It seems that LITTLEENDIAN is not used outside the USB code.
Right. Patches cleaning this up are more than welcome! Please note that cleaning up USB drivers under the cpu/ directory is a waste of time though. Boards using these drivers should be converted to use the generic infrastructure in drivers/usb/ instead.
The main focus of my patch is on common/usb.c, common/usb_kbd.c and common/usb_storage.c. Unfortunately I couldn't test my changes in usb_kbd.c because I don't have such a device.
Removing the LITTLEENDIAN define seems not to be as easy as I thought first. A bunch of other modules use the swap_16() and swap_32() defines from usb.h so I wasn't able to remove these for now.
regards Christian Eggers
Signed-off-by: Christian Eggers christian.eggers@kathrein.de