From: Ido Schimmel idosch@nvidia.com
[ Upstream commit 1f64757ee2bb22a93ec89b4c71707297e8cca0ba ]
During initialization the driver issues a reset command via its command interface in order to remove previous configuration from the device.
After issuing the reset, the driver waits for 200ms before polling on the "system_status" register using memory-mapped IO until the device reaches a ready state (0x5E). The wait is necessary because the reset command only triggers the reset, but the reset itself happens asynchronously. If the driver starts polling too soon, the read of the "system_status" register will never return and the system will crash [1].
The issue was discovered when the device was flashed with a development firmware version where the reset routine took longer to complete. The issue was fixed in the firmware, but it exposed the fact that the current wait time is borderline.
Fix by increasing the wait time from 200ms to 400ms. With this patch and the buggy firmware version, the issue did not reproduce in 10 reboots whereas without the patch the issue is reproduced quite consistently.
[1] mce: CPUs not responding to MCE broadcast (may include false positives): 0,4 mce: CPUs not responding to MCE broadcast (may include false positives): 0,4 Kernel panic - not syncing: Timeout: Not all CPUs entered broadcast exception handler Shutting down cpus with NMI Kernel Offset: 0x12000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
Fixes: ac004e84164e ("mlxsw: pci: Wait longer before accessing the device after reset") Signed-off-by: Ido Schimmel idosch@nvidia.com Reviewed-by: Petr Machata petrm@nvidia.com Signed-off-by: Petr Machata petrm@nvidia.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/mellanox/mlxsw/pci_hw.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/mellanox/mlxsw/pci_hw.h b/drivers/net/ethernet/mellanox/mlxsw/pci_hw.h index 7b531228d6c0f..25e9f47db2a62 100644 --- a/drivers/net/ethernet/mellanox/mlxsw/pci_hw.h +++ b/drivers/net/ethernet/mellanox/mlxsw/pci_hw.h @@ -26,7 +26,7 @@ #define MLXSW_PCI_CIR_TIMEOUT_MSECS 1000
#define MLXSW_PCI_SW_RESET_TIMEOUT_MSECS 900000 -#define MLXSW_PCI_SW_RESET_WAIT_MSECS 200 +#define MLXSW_PCI_SW_RESET_WAIT_MSECS 400 #define MLXSW_PCI_FW_READY 0xA1844 #define MLXSW_PCI_FW_READY_MASK 0xFFFF #define MLXSW_PCI_FW_READY_MAGIC 0x5E