[PATCH net] net: ethernet: ti: am65-cpsw: Add RX DMA Channel Teardown Quirk

[Roger Quadros]

On 09/02/2023 10:44, Siddharth Vadapalli wrote:
> In TI's AM62x/AM64x SoCs, successful teardown of RX DMA Channel raises an
> interrupt. The process of servicing this interrupt involves flushing all
> pending RX DMA descriptors and clearing the teardown completion marker
> (TDCM). The am65_cpsw_nuss_rx_packets() function invoked from the RX
> NAPI callback services the interrupt. Thus, it is necessary to wait for
> this handler to run, drain all packets and clear TDCM, before calling
> napi_disable() in am65_cpsw_nuss_common_stop() function post channel
> teardown. If napi_disable() executes before ensuring that TDCM is
> cleared, the TDCM remains set when the interfaces are down, resulting in
> an interrupt storm when the interfaces are brought up again.
> 
> Since the interrupt raised to indicate the RX DMA Channel teardown is
> specific to the AM62x and AM64x SoCs, add a quirk for it.
> 
> Fixes: 4f7cce272403 ("net: ethernet: ti: am65-cpsw: add support for am64x cpsw3g")
> Co-developed-by: Vignesh Raghavendra <vigneshr at ti.com>
> Signed-off-by: Vignesh Raghavendra <vigneshr at ti.com>
> Signed-off-by: Siddharth Vadapalli <s-vadapalli at ti.com>

Reviewed-by: Roger Quadros <rogerq at kernel.org>