[U-Boot-Users] Question about smc911x driver (16/32 Bit support)

[U-Boot-Users] Question about smc911x driver (16/32 Bit support)

[Jens Gehrlein]

Hi,

in the source code there is a preprocessor directive
#error "SMC911X: Only 32-bit bus is supported".

We use a LAN9215i, which has a 16 Bit data interface only, connected to 
an i.MX31.

The LAN9215 is in the driver's ID list.

According to the data sheet accesses have to be 2x16 Bit to build the 
device's internal 32 Bit format.

What does this non-32-Bit exclusion exactly mean?
Will the driver work on our HW configuration?

Confused,
Jens

[U-Boot-Users] Question about smc911x driver (16/32 Bit support)

[Ben Warren]

Hi Jens,

On Tue, Apr 22, 2008 at 5:18 AM, Jens Gehrlein <sew_s@tqs.de> wrote:
> Hi,
>
>  in the source code there is a preprocessor directive
>  #error "SMC911X: Only 32-bit bus is supported".
>
>  We use a LAN9215i, which has a 16 Bit data interface only, connected to
>  an i.MX31.
>
>  The LAN9215 is in the driver's ID list.
>
>  According to the data sheet accesses have to be 2x16 Bit to build the
>  device's internal 32 Bit format.
>
>  What does this non-32-Bit exclusion exactly mean?
>  Will the driver work on our HW configuration?
>
This #error message was included, because if you look at the code
you'll see that the read/write accessors are 32-bit operations *(u32 *
).  These may or may not work on your configuration.  It should be
trivial to write accessors for a 16-bit bus, but nobody had hardware
to try it out on.  Please do so and submit a patch.

>  Confused,
>  Jens

regards,
Ben

[U-Boot-Users] Question about smc911x driver (16/32 Bit support)

[Jens Gehrlein]

Hi Ben,

Ben Warren schrieb:
> Hi Jens,
> 
> On Tue, Apr 22, 2008 at 5:18 AM, Jens Gehrlein <sew_s@tqs.de> wrote:
>> Hi,
>>
>>  in the source code there is a preprocessor directive
>>  #error "SMC911X: Only 32-bit bus is supported".
>>
>>  We use a LAN9215i, which has a 16 Bit data interface only, connected to
>>  an i.MX31.
>>
>>  The LAN9215 is in the driver's ID list.
>>
>>  According to the data sheet accesses have to be 2x16 Bit to build the
>>  device's internal 32 Bit format.
>>
>>  What does this non-32-Bit exclusion exactly mean?
>>  Will the driver work on our HW configuration?
>>
> This #error message was included, because if you look at the code
> you'll see that the read/write accessors are 32-bit operations *(u32 *
> ).  These may or may not work on your configuration.  It should be
> trivial to write accessors for a 16-bit bus, but nobody had hardware
> to try it out on.  Please do so and submit a patch.

Yes, it seems, that we just need two additional functions which split a 
32 Bit access into two 16 Bit accesses. That should be easy. I'm going 
to create a patch as soon as I get the HW. But first I want to test 
whether the processor splits itself automatically.

Thank you very much.

Best Regards,
Jens

[U-Boot-Users] Question about smc911x driver (16/32 Bit support)

[Magnus Lilja]

Hi Jens,

On Wed, Apr 23, 2008 at 8:37 AM, Jens Gehrlein <sew_s@tqs.de> wrote:
>  >>  in the source code there is a preprocessor directive
>  >>  #error "SMC911X: Only 32-bit bus is supported".
>  >>
>  >>  We use a LAN9215i, which has a 16 Bit data interface only, connected to
>  >>  an i.MX31.
>  >>
>  >>  The LAN9215 is in the driver's ID list.
>  >>
>  >>  According to the data sheet accesses have to be 2x16 Bit to build the
>  >>  device's internal 32 Bit format.
>  >>
>  >>  What does this non-32-Bit exclusion exactly mean?
>  >>  Will the driver work on our HW configuration?
>  >>
>  > This #error message was included, because if you look at the code
>  > you'll see that the read/write accessors are 32-bit operations *(u32 *
>  > ).  These may or may not work on your configuration.  It should be
>  > trivial to write accessors for a 16-bit bus, but nobody had hardware
>  > to try it out on.  Please do so and submit a patch.
>
>  Yes, it seems, that we just need two additional functions which split a
>  32 Bit access into two 16 Bit accesses. That should be easy. I'm going
>  to create a patch as soon as I get the HW. But first I want to test
>  whether the processor splits itself automatically.

Well, the i.MX31 Litekit board has a 16-bit LAN9117 and that seems to
work with the 32-bit flag set in the config file.

/Magnus

[U-Boot-Users] Question about smc911x driver (16/32 Bit support)

[Ben Warren]

Hi Magnus,

On Wed, Apr 23, 2008 at 6:35 AM, Magnus Lilja <lilja.magnus@gmail.com> wrote:
> Hi Jens,
>
>  On Wed, Apr 23, 2008 at 8:37 AM, Jens Gehrlein <sew_s@tqs.de> wrote:
>  >  >>  in the source code there is a preprocessor directive
>  >  >>  #error "SMC911X: Only 32-bit bus is supported".
>  >  >>
>  >  >>  We use a LAN9215i, which has a 16 Bit data interface only, connected to
>  >  >>  an i.MX31.
>  >  >>
>  >  >>  The LAN9215 is in the driver's ID list.
>  >  >>
>  >  >>  According to the data sheet accesses have to be 2x16 Bit to build the
>  >  >>  device's internal 32 Bit format.
>  >  >>
>  >  >>  What does this non-32-Bit exclusion exactly mean?
>  >  >>  Will the driver work on our HW configuration?
>  >  >>
>  >  > This #error message was included, because if you look at the code
>  >  > you'll see that the read/write accessors are 32-bit operations *(u32 *
>  >  > ).  These may or may not work on your configuration.  It should be
>  >  > trivial to write accessors for a 16-bit bus, but nobody had hardware
>  >  > to try it out on.  Please do so and submit a patch.
>  >
>  >  Yes, it seems, that we just need two additional functions which split a
>  >  32 Bit access into two 16 Bit accesses. That should be easy. I'm going
>  >  to create a patch as soon as I get the HW. But first I want to test
>  >  whether the processor splits itself automatically.
>
>  Well, the i.MX31 Litekit board has a 16-bit LAN9117 and that seems to
>  work with the 32-bit flag set in the config file.
>
That's good news.  I would prefer, though, to break this into two
16-bit accesses so we don't need to wonder what architectures it would
work on.  Would you be able to try something out, since you have
hardware?

regards,
Ben

[U-Boot-Users] Question about smc911x driver (16/32 Bit support)

[Magnus Lilja]

Hi Ben,

>  >  Well, the i.MX31 Litekit board has a 16-bit LAN9117 and that seems to
>  >  work with the 32-bit flag set in the config file.
>  >
>  That's good news.  I would prefer, though, to break this into two
>  16-bit accesses so we don't need to wonder what architectures it would
>  work on.  Would you be able to try something out, since you have
>  hardware?

If someone publishes a patch I can certainly try it on the hardware.

Regards, Magnus

[U-Boot-Users] Question about smc911x driver (16/32 Bit support)

[Jens Gehrlein]

Hi Magnus, Ben,

Magnus Lilja schrieb:
> Hi Ben,
> 
>>  >  Well, the i.MX31 Litekit board has a 16-bit LAN9117 and that seems to
>>  >  work with the 32-bit flag set in the config file.
>>  >
>>  That's good news.  I would prefer, though, to break this into two
>>  16-bit accesses so we don't need to wonder what architectures it would
>>  work on.  Would you be able to try something out, since you have
>>  hardware?
> 
> If someone publishes a patch I can certainly try it on the hardware.

I already prepared the patch, but currently I can't test it, and I'm not 
sure if I did it right. Please be patient.
Meanwhile, I report successful execution of the current driver yesterday 
on our HW developer's board with 16 bit port size. The i.MX31 splits the 
32 bit word (I knew that from PowerPC, but wasn't sure of ARM).

Regards,
Jens