net: ethernet: ti: am65-cpsw: Add RX DMA Channel Teardown Quirk
authorSiddharth Vadapalli <s-vadapalli@ti.com>
Thu, 9 Feb 2023 08:44:32 +0000 (14:14 +0530)
committerJakub Kicinski <kuba@kernel.org>
Sat, 11 Feb 2023 03:22:32 +0000 (19:22 -0800)
commit0ed577e7e8e508c24e22ba07713ecc4903e147c3
tree59e1dff355f512648b9fc2d7a84f6adc79cc8bb7
parentec76d0c2da5c6dfb6a33f1545cc15997013923da
net: ethernet: ti: am65-cpsw: Add RX DMA Channel Teardown Quirk

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@ti.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Siddharth Vadapalli <s-vadapalli@ti.com>
Reviewed-by: Roger Quadros <rogerq@kernel.org>
Link: https://lore.kernel.org/r/20230209084432.189222-1-s-vadapalli@ti.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
drivers/net/ethernet/ti/am65-cpsw-nuss.c
drivers/net/ethernet/ti/am65-cpsw-nuss.h