[PATCH] arm: xscale: correct auxiliary register in suspend/resume
dbaryshkov at gmail.com
Sun Nov 9 08:14:53 PST 2014
2014-11-09 18:23 GMT+03:00 Robert Jarzmik <robert.jarzmik at free.fr>:
> Dmitry Eremin-Solenikov <dbaryshkov at gmail.com> writes:
>> According to the manuals I have, XScale auxiliary register should be
>> reached with opc_2 = 1 instead of crn = 1. cpu_xscale_proc_init
>> correctly uses c1, c0, 1 arguments, but cpu_xscale_do_suspend and
>> cpu_xscale_do_resume use c1, c1, 0. Correct suspend/resume functions to
>> also use c1, c0, 1.
>> - mrc p15, 0, r8, c1, c1, 0 @ auxiliary control reg
>> + mrc p15, 0, r8, c1, c0, 1 @ auxiliary control reg
> My PXA320 manual says (PXA320 Developer's Guide, chapter 2.16.1, table 5) :
> - Auxiliary Register: Crn=1, Crm=0, Opcode1=0, Opcode2=1
> => that is what your patch changes
> My PXA270 manual says (PXA270 Developer's Guide, chapter 22.214.171.124) :
> - Auxiliary Register: Crn=1, Crm=<don't care>, Opcode1=0, Opcode2=1
> => same story as for the PX320
> My PXA255 manual doesn't say anything, but the Intel XScale Core Architecture
> manual seems to be applicable to it, and gives you reason.
> Moreover the CP15, Opcode=1, Crn=1, Crm=0, Opcode2=* doesn't point to any valid
> register in XScale architecture AFAIK.
> So your patch looks correct to me. I have a couple of questions :
> - did you see an incorrect behaviour without your patch or is this coming from
> code inspection ?
Noticed thanks to qemu that reported 'unsupported instruction' on suspend.
> - did you test this patch during a suspend/resume cycle, and if so on which
> variants (pxa25x and tosa maybe) ?
Tested on tosa (that is pxa255).
> As you might haved guessed, I'd like all these questions to have an answer in
> the commit message.
Do you need an updated message?
With best wishes
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