Re: [RFC PATCH 2/3] net: sparx5: Add Sparx5 switchdev driver
From: Andrew Lunn <andrew@lunn.ch>
Date: 2020-11-29 17:17:28
Also in:
lkml
quoted hunk ↗ jump to hunk
diff --git a/drivers/net/ethernet/microchip/sparx5/sparx5_ethtool.c b/drivers/net/ethernet/microchip/sparx5/sparx5_ethtool.c new file mode 100644 index 000000000000..a91dd9532f1c --- /dev/null +++ b/drivers/net/ethernet/microchip/sparx5/sparx5_ethtool.c@@ -0,0 +1,1027 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* Microchip Sparx5 Switch driver + * + * Copyright (c) 2020 Microchip Technology Inc. and its subsidiaries. + */ + +#include <linux/ethtool.h> + +#include "sparx5_main.h" +#include "sparx5_port.h" + +/* Add a potentially wrapping 32 bit value to a 64 bit counter */ +static inline void sparx5_update_counter(u64 *cnt, u32 val) +{ + if (val < (*cnt & U32_MAX)) + *cnt += (u64)1 << 32; /* value has wrapped */ + + *cnt = (*cnt & ~(u64)U32_MAX) + val; +}
No inline functions in C files. Let the compiler decide. And i now think i get what this is doing. But i'm surprised at the hardware. Normally registers like this which are expected to wrap around, reset to 0 on read. Andrew