Re: [patch] net/fec: "u32" is more explicit than "unsigned long"

Ben Hutchings
2013-08-23T12:44:29Z

On Fri, 2013-08-23 at 12:49 +0300, Dan Carpenter wrote:
> tmpaddr[] is a six byte array. We want to set the first four bytes on
> the first line and the remaining two on the next line. The code assumes
> that "unsigned long" is 32 bits and obviously that's not true on 64 bit
> arches. It's better to just use u32 instead.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> This is a static checker thing and I can't compile this file.
>
> diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
> index fdf9307..422b125 100644
> --- a/drivers/net/ethernet/freescale/fec_main.c
> +++ b/drivers/net/ethernet/freescale/fec_main.c
> @@ -1100,9 +1100,9 @@ static void fec_get_mac(struct net_device *ndev)
> * 4) FEC mac registers set by bootloader
> */
> if (!is_valid_ether_addr(iap)) {
> - *((unsigned long *) &tmpaddr[0]) > + *((u32 *) &tmpaddr[0]) > be32_to_cpu(readl(fep->hwp + FEC_ADDR_LOW));
> - *((unsigned short *) &tmpaddr[4]) > + *((u16 *) &tmpaddr[4]) > be16_to_cpu(readl(fep->hwp + FEC_ADDR_HIGH) >> 16);
> iap = &tmpaddr[0];
> }

This code also seems to have CPU vs big-endian byte order the wrong way
round. readl() returns bytes in native order whereas we always store
MAC addresses in network (big-endian) order. So I think it should be
doing:

*((__be32 *) &tmpaddr[0]) cpu_to_be32(readl(fep->hwp + FEC_ADDR_LOW));
*((__be16 *) &tmpaddr[4]) cpu_to_be16(readl(fep->hwp + FEC_ADDR_HIGH) >> 16);

Ben.

--
Ben Hutchings, Staff Engineer, Solarflare
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