[coreboot] Cold reset in Tyan s2912

Roman Kononov kononov at dls.net
Tue Feb 5 16:51:38 CET 2008


On 2008-02-05 09:48 Roman Kononov said the following:
> On 2008-02-05 00:48 yhlu said the following:
>> On Feb 4, 2008 9:29 PM, Roman Kononov <kononov at dls.net> wrote:
>>> I have difficulty cold-resetting Tyan s2912, which has mcp55.
>>>
>>> The sequence
>>>      outb(0x2,0xcf9);
>>>      outb(0x6,0xcf9);
>>> is a warm reset. It does not reset the HyperTransport link frequency and width.
>> how do you know?
>>
>> do you have other co-processor or htx installed?
> 
> I have a co-processor.
> 
> The sequence I hope to have:
> 
> 1) Power up. Power-on reset. The co-processor takes long time to become 
> alive (~500s). By this time the CPU thinks that the HT link is dead.

~0.5s here.

> 2) CPU issues another reset.
> 3) The CPU re-initializes the HT link and the connection is happy.
> 
> With the above sequence, the step 3) is a warm reset, and the CPU does 
> not attempt to re-initialize the link.
> 
>> YH
> 
> Roman
> 




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