Early revisions of certain SoCs cannot do multiple DMA RX streams in
parallel. To avoid data corruption, only allow one DMA RX channel and
fall back to PIO, if needed.
Signed-off-by: NWolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: NYoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Tested-by: NNguyen Viet Dung <dung.nguyen.aj@renesas.com>
Reviewed-by: NSimon Horman <horms+renesas@verge.net.au>
Cc: stable@vger.kernel.org
Signed-off-by: NUlf Hansson <ulf.hansson@linaro.org>