Extracting (boardvendor and) boardtype

[Arend van Spriel]

On 03/19/2013 12:45 PM, Arend van Spriel wrote:
> On 03/19/2013 12:37 PM, Rafał Miłecki wrote:
>> 2013/3/19 Arend van Spriel <arend at broadcom.com>:
>>> On 03/19/2013 12:18 PM, Rafał Miłecki wrote:
>>>>
>>>> 2013/3/19 Jonas Gorski <jogo at openwrt.org>:
>>>>>
>>>>> On 19 March 2013 11:36, Rafał Miłecki <zajec5 at gmail.com> wrote:
>>>>>>
>>>>>> However take a look at siutils.c you're using internally at Broadcom.
>>>>>> I've found it in:
>>>>>> GPL_RT_AC66U_3004270/asuswrt/release/src-rt-6.x/shared/siutils.c
>>>>>> This file contains si_nvram_process. This function calls that
>>>>>> si_getdevpathintvar and getintvar I'm not sure about. Does
>>>>>> si_nvram_process prefer SPROM's boardtype (offset SROM_SSID==0x2 or
>>>>>> offset SSB_SPROM1_SPID==0x4) if it's available (not 0xFFFF)?
>>>>>
>>>>>
>>>>> The getdevpathintvar and getintvar are for extracting these values
>>>>> from nvram instead of SPROM - remember that embedded bcm47xx devices
>>>>> are "sprom"-less and have these values stored in nvram. Since there is
>>>>> only one global nvram, you need to prefix these values with the
>>>>> "pci/sb" device path to differentiate if you have more than one wifi
>>>>> chip (e.g. "sb/1/boardflags" or "pci/1/boardflags"). But this isn't
>>>>> necessarily done for single wifi devices, hence the getdevpathintvar
>>>>> -> getinvar path (as the fall back).
>>>>
>>>>
>>>> So what function does Broadcom use to extract something from SPROM?
>>>
>>> srom_var_init()
>>
>> OK, so for PCI:
>> 1) srom_var_init calls initvars_srom_pci
>> 2) initvars_srom_pci calls _initvars_srom_pci
>> 3) _initvars_srom_pci calls varbuf_append for every entry
>>
>> After all we end up with varbuf_t variable filled like an NVRAM
>> (foo=bar\0baz=qux\0).
>>
>> So AFAIU getdevpathintvar and getintvar are still used to access SPROM
>> (just in a form common for NVRAM), is that right?
>>
>> If the above is right, in si_nvram_process we access SPROM (with the
>> use of getdevpathintvar/getintvar). So it seems in si_nvram_process we
>> always prefer "boardtype", no matter if it comes from SPROM of NVRAM.
>> Is that correct?
>>
>
> Yes. Non-volatile variables take precedence to PCI config info
> regardless from which device, SPROM or flash, it was loaded.

better: SPROM, OTP, or flash.

Gr. AvS