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From: Greg Ungerer <gerg@linux-m68k.org>
To: linux-m68k@lists.linux-m68k.org
Cc: linux-kernel@vger.kernel.org, arnd@kernel.org, wei.fang@nxp.com,
	frank.li@nxp.com, shenwei.wang@nxp.com, imx@lists.linux.dev,
	netdev@vger.kernel.org, nico@fluxnic.net,
	linux-can@vger.kernel.org, linux-spi@vger.kernel.org,
	olteanv@gmail.com, andrew+netdev@lunn.ch, davem@davemloft.net,
	edumazet@google.com, kuba@kernel.org, pabeni@redhat.com
Subject: Re: [PATCHv3 2/3] net: smc91x: do not use readw()/writew() on ColdFire platforms
Date: Wed, 23 Sep 2026 23:04:56 +1000	[thread overview]
Message-ID: <6fa8c6f6-64cd-4204-a9db-6a33f5e23117@linux-m68k.org> (raw)
In-Reply-To: <20260907134037.1855408-3-gerg@linux-m68k.org>

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@linux-m68k.org>
> ---
> 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)
>  


  reply	other threads:[~2026-09-23 13:05 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-09-07 13:37 [PATCHv3 0/3] m68k: coldfire: fix non-standard readX()/writeX() functions Greg Ungerer
2026-09-07 13:37 ` [PATCHv3 1/3] net: fec: do not use readl()/writel() for ColdFire Greg Ungerer
2026-09-11  0:42   ` Jakub Kicinski
2026-09-11  7:39     ` Arnd Bergmann
2026-09-11 13:03     ` Greg Ungerer
2026-09-11 23:04       ` Jakub Kicinski
2026-09-23 13:07   ` Greg Ungerer
2026-09-23 13:23     ` Andrew Lunn
2026-09-23 14:00       ` Greg Ungerer
2026-09-23 14:15         ` Andrew Lunn
2026-09-23 14:40           ` Geert Uytterhoeven
2026-09-24  2:32           ` Michael Schmitz
2026-09-07 13:37 ` [PATCHv3 2/3] net: smc91x: do not use readw()/writew() on ColdFire platforms Greg Ungerer
2026-09-23 13:04   ` Greg Ungerer [this message]
2026-09-23 21:31   ` Arnd Bergmann
2026-09-07 13:37 ` [PATCHv3 3/3] m68k: coldfire: fix non-standard readX()/writeX() functions Greg Ungerer

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