On Tue, 2018-10-02 at 10:26 +0100, Ben Dooks wrote: > The tegra driver requires alignment of the buffer, so try and > make this better by pushing the buffer start back to an word > aligned address. At the worst this makes memcpy() easier as > it is word aligned, at best it makes sure the usb can directly > map the buffer. > > Signed-off-by: Ben Dooks <ben.dooks@xxxxxxxxxxxxxxx> > [todo - make this configurable] [...] I don't think you need a separate kconfig symbol for this. Aligning RX buffers to words (or better, cache lines) is almost always a win, so long as the CPU can handle misaligned fields in the network/transport headers. You can use #ifdef CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS to check that. It seems like NET_IP_ALIGN should be defined to 0 or 2 depending on CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, but NET_IP_ALIGN predates the latter. Ben. -- Ben Hutchings, Software Developer Codethink Ltd https://www.codethink.co.uk/ Dale House, 35 Dale Street Manchester, M1 2HF, United Kingdom
