linux-mips
[Top] [All Lists]

Re: [PATCH] malta4kec hang in calibrate_delay fix

To: "Nigel Stephens" <nigel@mips.com>, "Thiemo Seufer" <ths@networkno.de>
Subject: Re: [PATCH] malta4kec hang in calibrate_delay fix
From: "Kevin D. Kissell" <kevink@mips.com>
Date: Tue, 4 Sep 2007 14:19:28 +0200
Cc: "yshi" <yang.shi@windriver.com>, <linux-mips@linux-mips.org>
Original-recipient: rfc822;linux-mips@linux-mips.org
References: <46DD1CD1.5040306@windriver.com> <006901c7eeda$d8049a50$10eca8c0@grendel> <1188901951.4106.16.camel@yshi.CORP> <006f01c7eee5$bbe77c60$10eca8c0@grendel> <20070904115527.GA848@networkno.de> <46DD49B9.2090306@mips.com>
Sender: linux-mips-bounce@linux-mips.org
> >> In that case, your core is a 4Kc and not a 4KEc.    
> >
> > Not quite true, early revisions of the 4KEc were only release 1. This
> > seems to be a bug in arch/mips/cpu-probe.c:
> >
> > static inline void cpu_probe_mips(struct cpuinfo_mips *c)
> > {
> >         decode_configs(c);
> >         switch (c->processor_id & 0xff00) {
> >         case PRID_IMP_4KC:
> >                 c->cputype = CPU_4KC;
> >                 break;
> >         case PRID_IMP_4KEC:
> >                 c->cputype = CPU_4KEC;
> >                 break;
> >         case PRID_IMP_4KECR2:
> >                 c->cputype = CPU_4KEC;
> >                 break;
> > ...
> >
> > The type for PRID_IMP_4KEC should be CPU_4KC.
> >
> >   
> 
> Maybe the probing code should read the ISA revision level from the AR 
> bits (12:10) of the Config0 register to figure out which revision of the 
> ISA is implemented.

It does.  c->cputype isn't what needs to be modulated here, it's c->isa_level,
which gets decoded as part of decode_configs(), as near as I can tell correctly
in the most recent source tree I've got. And it's isa_level that's being tested
by the cpu_has_mips32r2 et. al. macros.

            Regards,

            Kevin K.

<Prev in Thread] Current Thread [Next in Thread>