From: Horatiu Vultur horatiu.vultur@microchip.com
commit 600761245952d7f70280add6ce02894f1528992b upstream.
It was noticing that after a while when unloading/loading the driver and sending traffic through the switch, it would stop working. It would stop forwarding any traffic and the only way to get out of this was to do a power cycle of the board. The root cause seems to be that the switch core is initialized twice. Apparently initializing twice the switch core disturbs the pointers in the queue systems in the HW, so after a while it would stop sending the traffic. Unfortunetly, it is not possible to use a reset of the switch here, because the reset line is connected to multiple devices like MDIO, SGPIO, FAN, etc. So then all the devices will get reseted when the network driver will be loaded. So the fix is to check if the core is initialized already and if that is the case don't initialize it again.
Fixes: db8bcaad5393 ("net: lan966x: add the basic lan966x driver") Signed-off-by: Horatiu Vultur horatiu.vultur@microchip.com Reviewed-by: Simon Horman simon.horman@corigine.com Link: https://lore.kernel.org/r/20230522120038.3749026-1-horatiu.vultur@microchip.... Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/microchip/lan966x/lan966x_main.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
--- a/drivers/net/ethernet/microchip/lan966x/lan966x_main.c +++ b/drivers/net/ethernet/microchip/lan966x/lan966x_main.c @@ -987,6 +987,16 @@ static int lan966x_reset_switch(struct l
reset_control_reset(switch_reset);
+ /* Don't reinitialize the switch core, if it is already initialized. In + * case it is initialized twice, some pointers inside the queue system + * in HW will get corrupted and then after a while the queue system gets + * full and no traffic is passing through the switch. The issue is seen + * when loading and unloading the driver and sending traffic through the + * switch. + */ + if (lan_rd(lan966x, SYS_RESET_CFG) & SYS_RESET_CFG_CORE_ENA) + return 0; + lan_wr(SYS_RESET_CFG_CORE_ENA_SET(0), lan966x, SYS_RESET_CFG); lan_wr(SYS_RAM_INIT_RAM_INIT_SET(1), lan966x, SYS_RAM_INIT); ret = readx_poll_timeout(lan966x_ram_init, lan966x,