Re: esp_scsi QTAG in FAS216

[Michael Schmitz <schmitzmic@gmail.com>]

Hi Finn,

Am 30.10.2016 um 15:33 schrieb Finn Thain:
> 
> On Sat, 29 Oct 2016, I wrote:
> 
>>
>> On Sun, 13 Apr 2014, David Miller wrote:
>>
>>>
>>> But oddly in the NCR53CX docs:
>>>
>>> 	http://www.ibiblio.org/pub/historic-linux/early-ports/Sparc/NCR/NCR53C9X.txt
>>>
>>> it speaks as if ESP_CONFIG3_TMS and ESP_CONFIG3_TENB are merely finer 
>>> grained versions of config2 register setting ESP_CONFIG2_SCSI2ENAB, 
>>> which enables both features.
>>
>> Yes, so setting the ESP_CONFIG2_SCSI2ENAB bit is correct. The only 
>> problem is, doesn't the ESP_CONFIG3_TMS bit get cleared again later, 
>> when the CONFIG3 register is written to?
>>
> 
> Nevermind my question. To falsify my own theory, I see that 
> ESP_CONFIG3_TMS == ESP_CONFIG3_FCLK, and thus esp_scsi does actually set 
> the relevant bit, and therefore "the FSC can receive 3-byte messages 
> during businitiated select with ATN."

>From my reading of the quoted docs,ESP_CONFIG3_TMS is valid for FAS100A
(and later?). What esp_scsi sets (for FAS236 chips) is fast SCSI clock
mode. The relevant bit for three byte message support for Mac and Amiga
ESP hardware should be ESP_CONFIG3_TENB.

I had tried to set that bit in zorro_esp_slave_configure but had not
done a proper job of it - I'd only set esp->config3 and forgot to set
tp->esp_config3. Time to retest this ...

Cheers,

	Michael