net: stmmac: Fix for mismatched host/device DMA address width

Currently DMA address width is either read from a RO device register
or force set from the platform data. This breaks DMA when the host DMA
address width is <=32it but the device is >32bit.

Right now the driver may decide to use a 2nd DMA descriptor for
another buffer (happens in case of TSO xmit) assuming that 32bit
addressing is used due to platform configuration but the device will
still use both descriptor addresses as one address.

This can be observed with the Intel EHL platform driver that sets
32bit for addr64 but the MAC reports 40bit. The TX queue gets stuck in
case of TCP with iptables NAT configuration on TSO packets.

The logic should be like this: Whatever we do on the host side (memory
allocation GFP flags) should happen with the host DMA width, whenever
we decide how to set addresses on the device registers we must use the
device DMA address width.

This patch renames the platform address width field from addr64 (term
used in device datasheet) to host_addr and uses this value exclusively
for host side operations while all chip operations consider the device
DMA width as read from the device register.

Fixes: 7cfc4486e7ea ("stmmac: intel: Configure EHL PSE0 GbE and PSE1 GbE to 32 bits DMA addressing")
Signed-off-by: Jochen Henneberg <jh@henneberg-systemdesign.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/stmmac.h b/include/linux/stmmac.h
index a152678b82b7..a2414c187483 100644
--- a/include/linux/stmmac.h
+++ b/include/linux/stmmac.h
@@ -215,7 +215,7 @@ struct plat_stmmacenet_data {
 	int unicast_filter_entries;
 	int tx_fifo_size;
 	int rx_fifo_size;
-	u32 addr64;
+	u32 host_dma_width;
 	u32 rx_queues_to_use;
 	u32 tx_queues_to_use;
 	u8 rx_sched_algorithm;