From: jonathan.austin@arm.com (Jonathan Austin)
To: linux-arm-kernel@lists.infradead.org
Subject: [RFC PATCH] implement read_cpuid_ext for v7-M (Was: Re: [PATCHv2 2/3] ARM: Detect support for SDIV/UDIV from ISAR0) register
Date: Tue, 07 May 2013 11:56:28 +0100 [thread overview]
Message-ID: <5188DDDC.1000201@arm.com> (raw)
In-Reply-To: <20130507092209.GD25387@mudshark.cambridge.arm.com>
Hi Will,
On 07/05/13 10:22, Will Deacon wrote:
> On Mon, May 06, 2013 at 10:30:59AM +0100, Uwe Kleine-K?nig wrote:
>> +
>> +#define read_cpuid(reg) \
>> + ({ \
>> + WARN_ON_ONCE(1); \
>> + 0; \
>> + })
>
> We do have an MIDR in PMSAv7 (not to be confused with MPIDR), so why not read
> that here?
We don't need to add/remove anything for PMSAv7 as that's already
implemented...
For V7M we have something called CPUID Base Register, not MIDR - the
layout looks the same though. That's the only one of the CPUID_X that we
have, but it is never requested directly - only via read_cpuid_id (this
is to support a hardcoded cpuid from kconfig) so what Uwe's got does
work, though I agree that it'd be much nicer to implement the underlying
function and have the accessor general for both AR and M.
Jonny
next prev parent reply other threads:[~2013-05-07 10:56 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-18 18:28 [PATCHv2 0/3] Detect UDIV/SDIV support from ISAR0 Stephen Boyd
2013-03-18 18:28 ` [PATCHv2 1/3] ARM: Clear IDIVT hwcap if CONFIG_ARM_THUMB=n Stephen Boyd
2013-03-18 18:28 ` [PATCHv2 2/3] ARM: Detect support for SDIV/UDIV from ISAR0 register Stephen Boyd
2013-04-18 9:10 ` Uwe Kleine-König
2013-05-06 9:30 ` [RFC PATCH] implement read_cpuid_ext for v7-M (Was: Re: [PATCHv2 2/3] ARM: Detect support for SDIV/UDIV from ISAR0) register Uwe Kleine-König
2013-05-06 17:31 ` Stephen Boyd
2013-05-07 9:22 ` Will Deacon
2013-05-07 9:35 ` Uwe Kleine-König
2013-05-07 9:52 ` Will Deacon
2013-05-07 10:56 ` Jonathan Austin [this message]
2013-05-07 12:40 ` Uwe Kleine-König
2013-05-07 12:54 ` Will Deacon
2013-05-07 10:30 ` Jonathan Austin
2013-03-18 18:28 ` [PATCHv2 3/3] ARM: Work around faulty ISAR0 register in some Krait CPUs Stephen Boyd
2013-03-18 18:34 ` Will Deacon
2013-03-18 18:46 ` Stephen Boyd
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