Re: [PATCHv3 2/3] net: smc91x: do not use readw()/writew() on ColdFire platforms
From: Greg Ungerer
Date: Wed Sep 23 2026 - 09:13:08 EST
Ping...
On 7/9/26 23:37, Greg Ungerer wrote:
> Modify the access macros and functions used to access the smsc hardware
> registers when used on ColdFire SoC platforms so they do not use readw()
> or writew(), or derived functions like ioread16be() and iowrite16be().
>
> The current set of readX()/writeX() access methods for ColdFire have
> historically been non-standard, in that they mostly access memory
> big-endian instead of the expected little-endian. Before fixing the
> ColdFire readX() and writeX() supporting code to properly work with
> little-endian data existing driver uses need to be fixed. Convert the
> smsc driver ColdFire uses of these to use the raw access macros - which
> are well defined to be (native) big-endian on ColdFire. This change
> requires some byte swapping at time of access to retain existing correct
> behavior.
>
> Signed-off-by: Greg Ungerer <gerg@xxxxxxxxxxxxxx>
> ---
> v2: changed from RFC to PATCH
> v3: no change
>
> Resending with expanded CC list as per get_maintainers.pl, hoping to get
> this picked up.
>
> drivers/net/ethernet/smsc/smc91x.h | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/smsc/smc91x.h b/drivers/net/ethernet/smsc/smc91x.h
> index 38aa4374e813..1290335629c1 100644
> --- a/drivers/net/ethernet/smsc/smc91x.h
> +++ b/drivers/net/ethernet/smsc/smc91x.h
> @@ -142,22 +142,26 @@ static inline void _SMC_outw_align4(u16 val, void __iomem *ioaddr, int reg,
> #define SMC_CAN_USE_32BIT 0
> #define SMC_NOWAIT 1
>
> +/*
> + * Access SMSC device registers using raw IO access primitives. Byte
> + * swap as required for device registers, but not data.
> + */
> static inline void mcf_insw(void __iomem *a, unsigned char *p, int l)
> {
> u16 *wp = (u16 *) p;
> while (l-- > 0)
> - *wp++ = readw(a);
> + *wp++ = __raw_readw(a);
> }
>
> static inline void mcf_outsw(void __iomem *a, unsigned char *p, int l)
> {
> u16 *wp = (u16 *) p;
> while (l-- > 0)
> - writew(*wp++, a);
> + __raw_writew(*wp++, a);
> }
>
> -#define SMC_inw(a, r) ioread16be((a) + (r))
> -#define SMC_outw(lp, v, a, r) iowrite16be(v, (a) + (r))
> +#define SMC_inw(a, r) swab16(__raw_readw((a) + (r)))
> +#define SMC_outw(lp, v, a, r) __raw_writew(swab16(v), (a) + (r))
> #define SMC_insw(a, r, p, l) mcf_insw(a + r, p, l)
> #define SMC_outsw(a, r, p, l) mcf_outsw(a + r, p, l)
>