[PATCH] net: smc91x: Fix m68k kernel compilation for ColdFire CPU

[PATCH] net: smc91x: Fix m68k kernel compilation for ColdFire CPU

[Thorsten Blum]

Compiling the m68k kernel with support for the ColdFire CPU family fails
with the following error:

In file included from drivers/net/ethernet/smsc/smc91x.c:80:
drivers/net/ethernet/smsc/smc91x.c: In function ‘smc_reset’:
drivers/net/ethernet/smsc/smc91x.h:160:40: error: implicit declaration of function ‘_swapw’; did you mean ‘swap’? [-Werror=implicit-function-declaration]
  160 | #define SMC_outw(lp, v, a, r)   writew(_swapw(v), (a) + (r))
      |                                        ^~~~~~
drivers/net/ethernet/smsc/smc91x.h:904:25: note: in expansion of macro ‘SMC_outw’
  904 |                         SMC_outw(lp, x, ioaddr, BANK_SELECT);           \
      |                         ^~~~~~~~
drivers/net/ethernet/smsc/smc91x.c:250:9: note: in expansion of macro ‘SMC_SELECT_BANK’
  250 |         SMC_SELECT_BANK(lp, 2);
      |         ^~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

The function _swapw() was removed in commit d97cf70af097 ("m68k: use
asm-generic/io.h for non-MMU io access functions"), but is still used in
drivers/net/ethernet/smsc/smc91x.h.

Re-adding the previously deleted _swapw() function resolves the error.

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
---
 drivers/net/ethernet/smsc/smc91x.h | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/ethernet/smsc/smc91x.h b/drivers/net/ethernet/smsc/smc91x.h
index 46eee747c699..e5d7f49915c6 100644
--- a/drivers/net/ethernet/smsc/smc91x.h
+++ b/drivers/net/ethernet/smsc/smc91x.h
@@ -156,6 +156,11 @@ static inline void mcf_outsw(void *a, unsigned char *p, int l)
 		writew(*wp++, a);
 }
 
+static inline unsigned short _swapw(volatile unsigned short v)
+{
+	return ((v << 8) | (v >> 8));
+}
+
 #define SMC_inw(a, r)		_swapw(readw((a) + (r)))
 #define SMC_outw(lp, v, a, r)	writew(_swapw(v), (a) + (r))
 #define SMC_insw(a, r, p, l)	mcf_insw(a + r, p, l)
-- 
2.45.0

Re: [PATCH] net: smc91x: Fix m68k kernel compilation for ColdFire CPU

[Andrew Lunn]

On Thu, May 09, 2024 at 02:17:14PM +0200, Thorsten Blum wrote:
> Compiling the m68k kernel with support for the ColdFire CPU family fails
> with the following error:
> 
> In file included from drivers/net/ethernet/smsc/smc91x.c:80:
> drivers/net/ethernet/smsc/smc91x.c: In function ‘smc_reset’:
> drivers/net/ethernet/smsc/smc91x.h:160:40: error: implicit declaration of function ‘_swapw’; did you mean ‘swap’? [-Werror=implicit-function-declaration]
>   160 | #define SMC_outw(lp, v, a, r)   writew(_swapw(v), (a) + (r))
>       |                                        ^~~~~~
> drivers/net/ethernet/smsc/smc91x.h:904:25: note: in expansion of macro ‘SMC_outw’
>   904 |                         SMC_outw(lp, x, ioaddr, BANK_SELECT);           \
>       |                         ^~~~~~~~
> drivers/net/ethernet/smsc/smc91x.c:250:9: note: in expansion of macro ‘SMC_SELECT_BANK’
>   250 |         SMC_SELECT_BANK(lp, 2);
>       |         ^~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
> 
> The function _swapw() was removed in commit d97cf70af097 ("m68k: use
> asm-generic/io.h for non-MMU io access functions"), but is still used in
> drivers/net/ethernet/smsc/smc91x.h.
> 
> Re-adding the previously deleted _swapw() function resolves the error.

This seems like the wrong fix.

commit d97cf70af09721ef416c61faa44543e3b84c9a55
Author: Greg Ungerer <gerg@linux-m68k.org>
Date:   Fri Mar 23 23:39:10 2018 +1000

    m68k: use asm-generic/io.h for non-MMU io access functions
    
    There is nothing really special about the non-MMU m68k IO access functions.
    So we can easily switch to using the asm-generic/io.h functions.

So it rather than put something back which there is an aim to remove,
please find the generic replacement. This _swapw() swaps a 16 bit
word. The generic for that is swab16().

I'm also surprised it took 6 years to find this. Has something else
changed recently?

    Andrew

---
pw-bot: cr

Re: [PATCH] net: smc91x: Fix m68k kernel compilation for ColdFire CPU

[Arnd Bergmann]

On Thu, May 9, 2024, at 14:17, Thorsten Blum wrote:
> 
> +static inline unsigned short _swapw(volatile unsigned short v)
> +{
> +	return ((v << 8) | (v >> 8));
> +}
> +
>  #define SMC_inw(a, r)		_swapw(readw((a) + (r)))
>  #define SMC_outw(lp, v, a, r)	writew(_swapw(v), (a) + (r))
>  #define SMC_insw(a, r, p, l)	mcf_insw(a + r, p, l)

I think you can just use iowrite16_be() and ioread16_be()
here in place of the little-endian access plus swap.

Also, it looks like it's been broken for six years without
anyone noticing the problem, so I wonder if there are even
still any machines that use this driver and get kernel
updates.

     Arnd

Re: [PATCH] net: smc91x: Fix m68k kernel compilation for ColdFire CPU

[Thorsten Blum]

On 9. May 2024, at 22:36, Andrew Lunn <andrew@lunn.ch> wrote:
> This seems like the wrong fix.
> 
> commit d97cf70af09721ef416c61faa44543e3b84c9a55
> Author: Greg Ungerer <gerg@linux-m68k.org>
> Date:   Fri Mar 23 23:39:10 2018 +1000
> 
>    m68k: use asm-generic/io.h for non-MMU io access functions
> 
>    There is nothing really special about the non-MMU m68k IO access functions.
>    So we can easily switch to using the asm-generic/io.h functions.
> 
> So it rather than put something back which there is an aim to remove,
> please find the generic replacement. This _swapw() swaps a 16 bit
> word. The generic for that is swab16().

Thanks. I will use ioread16be() and iowrite16be() as suggested by Arnd
instead and submit a v2 shortly.

Thorsten

[PATCH v2] net: smc91x: Fix m68k kernel compilation for ColdFire CPU

[Thorsten Blum]

Compiling the m68k kernel with support for the ColdFire CPU family fails
with the following error:

In file included from drivers/net/ethernet/smsc/smc91x.c:80:
drivers/net/ethernet/smsc/smc91x.c: In function ‘smc_reset’:
drivers/net/ethernet/smsc/smc91x.h:160:40: error: implicit declaration of function ‘_swapw’; did you mean ‘swap’? [-Werror=implicit-function-declaration]
  160 | #define SMC_outw(lp, v, a, r)   writew(_swapw(v), (a) + (r))
      |                                        ^~~~~~
drivers/net/ethernet/smsc/smc91x.h:904:25: note: in expansion of macro ‘SMC_outw’
  904 |                         SMC_outw(lp, x, ioaddr, BANK_SELECT);           \
      |                         ^~~~~~~~
drivers/net/ethernet/smsc/smc91x.c:250:9: note: in expansion of macro ‘SMC_SELECT_BANK’
  250 |         SMC_SELECT_BANK(lp, 2);
      |         ^~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

The function _swapw() was removed in commit d97cf70af097 ("m68k: use
asm-generic/io.h for non-MMU io access functions"), but is still used in
drivers/net/ethernet/smsc/smc91x.h.

Use ioread16be() and iowrite16be() to resolve the error.

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
---
Changes in v2:
- Use ioread16be() and iowrite16be() directly instead of re-adding
  _swapw() as suggested by Arnd Bergmann and Andrew Lunn
---
 drivers/net/ethernet/smsc/smc91x.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/smsc/smc91x.h b/drivers/net/ethernet/smsc/smc91x.h
index 46eee747c699..45ef5ac0788a 100644
--- a/drivers/net/ethernet/smsc/smc91x.h
+++ b/drivers/net/ethernet/smsc/smc91x.h
@@ -156,8 +156,8 @@ static inline void mcf_outsw(void *a, unsigned char *p, int l)
 		writew(*wp++, a);
 }
 
-#define SMC_inw(a, r)		_swapw(readw((a) + (r)))
-#define SMC_outw(lp, v, a, r)	writew(_swapw(v), (a) + (r))
+#define SMC_inw(a, r)		ioread16be((a) + (r))
+#define SMC_outw(lp, v, a, r)	iowrite16be(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)
 
-- 
2.45.0

[PATCH v3] net: smc91x: Fix m68k kernel compilation for ColdFire CPU

[Thorsten Blum]

Compiling the m68k kernel with support for the ColdFire CPU family fails
with the following error:

In file included from drivers/net/ethernet/smsc/smc91x.c:80:
drivers/net/ethernet/smsc/smc91x.c: In function ‘smc_reset’:
drivers/net/ethernet/smsc/smc91x.h:160:40: error: implicit declaration of function ‘_swapw’; did you mean ‘swap’? [-Werror=implicit-function-declaration]
  160 | #define SMC_outw(lp, v, a, r)   writew(_swapw(v), (a) + (r))
      |                                        ^~~~~~
drivers/net/ethernet/smsc/smc91x.h:904:25: note: in expansion of macro ‘SMC_outw’
  904 |                         SMC_outw(lp, x, ioaddr, BANK_SELECT);           \
      |                         ^~~~~~~~
drivers/net/ethernet/smsc/smc91x.c:250:9: note: in expansion of macro ‘SMC_SELECT_BANK’
  250 |         SMC_SELECT_BANK(lp, 2);
      |         ^~~~~~~~~~~~~~~
cc1: some warnings being treated as errors

The function _swapw() was removed in commit d97cf70af097 ("m68k: use
asm-generic/io.h for non-MMU io access functions"), but is still used in
drivers/net/ethernet/smsc/smc91x.h.

Use ioread16be() and iowrite16be() to resolve the error.

Fixes: d97cf70af097 ("m68k: use asm-generic/io.h for non-MMU io access functions")
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
---
Changes in v2:
- Use ioread16be() and iowrite16be() directly instead of re-adding
  _swapw() as suggested by Arnd Bergmann and Andrew Lunn

Changes in v3:
- Add Fixes: tag
---
 drivers/net/ethernet/smsc/smc91x.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/smsc/smc91x.h b/drivers/net/ethernet/smsc/smc91x.h
index 46eee747c699..45ef5ac0788a 100644
--- a/drivers/net/ethernet/smsc/smc91x.h
+++ b/drivers/net/ethernet/smsc/smc91x.h
@@ -156,8 +156,8 @@ static inline void mcf_outsw(void *a, unsigned char *p, int l)
 		writew(*wp++, a);
 }
 
-#define SMC_inw(a, r)		_swapw(readw((a) + (r)))
-#define SMC_outw(lp, v, a, r)	writew(_swapw(v), (a) + (r))
+#define SMC_inw(a, r)		ioread16be((a) + (r))
+#define SMC_outw(lp, v, a, r)	iowrite16be(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)
 
-- 
2.45.0

Re: [PATCH v3] net: smc91x: Fix m68k kernel compilation for ColdFire CPU

[Andrew Lunn]

On Fri, May 10, 2024 at 01:30:55PM +0200, Thorsten Blum wrote:
> Compiling the m68k kernel with support for the ColdFire CPU family fails
> with the following error:
> 
> In file included from drivers/net/ethernet/smsc/smc91x.c:80:
> drivers/net/ethernet/smsc/smc91x.c: In function ‘smc_reset’:
> drivers/net/ethernet/smsc/smc91x.h:160:40: error: implicit declaration of function ‘_swapw’; did you mean ‘swap’? [-Werror=implicit-function-declaration]
>   160 | #define SMC_outw(lp, v, a, r)   writew(_swapw(v), (a) + (r))
>       |                                        ^~~~~~
> drivers/net/ethernet/smsc/smc91x.h:904:25: note: in expansion of macro ‘SMC_outw’
>   904 |                         SMC_outw(lp, x, ioaddr, BANK_SELECT);           \
>       |                         ^~~~~~~~
> drivers/net/ethernet/smsc/smc91x.c:250:9: note: in expansion of macro ‘SMC_SELECT_BANK’
>   250 |         SMC_SELECT_BANK(lp, 2);
>       |         ^~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
> 
> The function _swapw() was removed in commit d97cf70af097 ("m68k: use
> asm-generic/io.h for non-MMU io access functions"), but is still used in
> drivers/net/ethernet/smsc/smc91x.h.
> 
> Use ioread16be() and iowrite16be() to resolve the error.
> 
> Fixes: d97cf70af097 ("m68k: use asm-generic/io.h for non-MMU io access functions")
> Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
> ---
> Changes in v2:
> - Use ioread16be() and iowrite16be() directly instead of re-adding
>   _swapw() as suggested by Arnd Bergmann and Andrew Lunn
> 
> Changes in v3:
> - Add Fixes: tag

This is for net.

Cc: <stable@vger.kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>

    Andrew

Re: [PATCH v3] net: smc91x: Fix m68k kernel compilation for ColdFire CPU

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 10 May 2024 13:30:55 +0200 you wrote:
> Compiling the m68k kernel with support for the ColdFire CPU family fails
> with the following error:
> 
> In file included from drivers/net/ethernet/smsc/smc91x.c:80:
> drivers/net/ethernet/smsc/smc91x.c: In function ‘smc_reset’:
> drivers/net/ethernet/smsc/smc91x.h:160:40: error: implicit declaration of function ‘_swapw’; did you mean ‘swap’? [-Werror=implicit-function-declaration]
>   160 | #define SMC_outw(lp, v, a, r)   writew(_swapw(v), (a) + (r))
>       |                                        ^~~~~~
> drivers/net/ethernet/smsc/smc91x.h:904:25: note: in expansion of macro ‘SMC_outw’
>   904 |                         SMC_outw(lp, x, ioaddr, BANK_SELECT);           \
>       |                         ^~~~~~~~
> drivers/net/ethernet/smsc/smc91x.c:250:9: note: in expansion of macro ‘SMC_SELECT_BANK’
>   250 |         SMC_SELECT_BANK(lp, 2);
>       |         ^~~~~~~~~~~~~~~
> cc1: some warnings being treated as errors
> 
> [...]

Here is the summary with links:
  - [v3] net: smc91x: Fix m68k kernel compilation for ColdFire CPU
    https://git.kernel.org/netdev/net/c/5eefb477d21a

You are awesome, thank you!
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