Re: I82365 driver question

On Mon, Apr 08, 2002 at 05:10:30PM -0700, Sanjay Jain wrote:
> 
> Following code sets the card offset register.
> ...
> ...
> i365_set_pair(s, base+I365_W_STOP, i);
> 
>  i = ((mem->card_start - mem->sys_start) >> 12) & 0x3fff;
> 
>     if (mem->flags & MAP_WRPROT) i |= I365_MEM_WRPROT;
>     if (mem->flags & MAP_ATTRIB) i |= I365_MEM_REG;
>     i365_set_pair(s, base+I365_W_OFF, i);
> .....
> ......
> 
> Why mem->sys_start is being subtracted from card_start? As per
> the spec these registers should contain mem->card_start.

No, the spec says that these registers should contain the offset
between the card start and the host start addresses for each window.

I'm fairly confident in the original code because it works for a wide
range of values for card_start and sys_start, on multiple platforms.

> With this code in place, I was not able to read CIS.
> 
> I had to change it to
> 
>   i = (mem->card_start >> 12) & 0x3fff;
> 
> Now I can see card CIS.

Perhaps this means that the sys_start value you are using does not
actually correspond to the addresses that are being passed through to
the i82365 chip, on this platform.  And in fact, whatever sys_start
is, gets seen by the i82365 chip as host address 0.

But that doesn't really make sense either, now that I think about it,
because the START and STOP registers would be filled in incorrectly.

-- Dave