[U-Boot] [PATCH 1/1] at91: Update MEESC board support
Daniel Gorsulowski
Daniel.Gorsulowski at esd.eu
Fri Sep 11 09:03:31 CEST 2009
Dear Wolfgang Denk,
Wolfgang Denk wrote:
> Dear Daniel Gorsulowski,
>
> In message <4AA90821.1060106 at esd.eu> you wrote:
>>>> - /* arch number of MEESC-Board */
>>>> - gd->bd->bi_arch_number = MACH_TYPE_MEESC;
>>>> + /* initialize ET1100 Controller */
>>>> + meesc_ethercat_hw_init();
>>> I thought we had agreed not to initialize the Ethernet hardware if it
>>> not used by U-Boot?
>>>
>> We had, but this does not initialize unused hardware. This is needed for
>> detecting hw_type and setting correct arch_number.
>
> meesc_ethercat_hw_init() "is needed for ... setting correct
> arch_number" ??
>
> Best regards,
>
> Wolfgang Denk
>
Please take a look at function checkboard().
There is a call "hw_type = readb(CONFIG_ET1100_BASE);" to read the ET1100
type register. The read value is used to determine the correct arch_number.
valid value (ET1100 present) --> arch_number = MACH_TYPE_MEESC
invalid value (no ET1100 present) --> arch_number = MACH_TYPE_ETHERCAN2
For accessing the ET1100 type register, it is mandatory to initialize the
memory controller. Thus, meesc_ethercat_hw_init() is needed and does not
initialize unused hardware!
Btw. the function meesc_ethercat_hw_init() is not new in this patch. I
entirely moved the function call.
Best regards,
Daniel Gorsulowski
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