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net: lantiq_xrx200: add ingress SG DMA support
authorAleksander Jan Bajkowski <olek2@wp.pl>
Mon, 3 Jan 2022 19:43:16 +0000 (20:43 +0100)
committerDavid S. Miller <davem@davemloft.net>
Tue, 4 Jan 2022 12:30:34 +0000 (12:30 +0000)
commitc3e6b2c35b34214c58c1e90d65dab5f5393608e7
treef48356b97d04e8e326d3ad6a2febf6e868dae967
parent7a71c8aa0a75c8bb53de50042ff86ba047969c69
net: lantiq_xrx200: add ingress SG DMA support

This patch adds support for scatter gather DMA. DMA in PMAC splits
the packet into several buffers when the MTU on the CPU port is
less than the MTU of the switch. The first buffer starts at an
offset of NET_IP_ALIGN. In subsequent buffers, dma ignores the
offset. Thanks to this patch, the user can still connect to the
device in such a situation. For normal configurations, the patch
has no effect on performance.

Signed-off-by: Aleksander Jan Bajkowski <olek2@wp.pl>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/lantiq_xrx200.c