From: sboyd@codeaurora.org (Stephen Boyd)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCHv2 3/3] ARM: Work around faulty ISAR0 register in some Krait CPUs
Date: Mon, 18 Mar 2013 11:46:27 -0700 [thread overview]
Message-ID: <51476103.40901@codeaurora.org> (raw)
In-Reply-To: <20130318183435.GD31193@mudshark.cambridge.arm.com>
On 03/18/13 11:34, Will Deacon wrote:
> On Mon, Mar 18, 2013 at 06:28:57PM +0000, Stephen Boyd wrote:
>> From: Stepan Moskovchenko <stepanm@codeaurora.org>
>>
>> Some early versions of the Krait CPU design incorrectly indicate
>> that they only support the UDIV and SDIV instructions in Thumb
>> mode when they actually support them in ARM and Thumb mode. It
>> seems that these CPUs follow the DDI0406B ARM ARM which has two
>> possible values for the divide instructions field, instead of the
>> DDI0406C document which has three possible values.
>>
>> Work around this problem by checking the MIDR against Krait CPUs
>> with this faulty ISAR0 register and force the hwcaps to indicate
>> support in both modes.
>>
>> Cc: Will Deacon <will.deacon@arm.com>
>> Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
>> [sboyd: Rewrote commit text to reflect real reasoning now that
>> we autodetect udiv/sdiv]
>> Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
>> ---
>> arch/arm/mm/proc-v7.S | 15 +++++++++++++++
>> 1 file changed, 15 insertions(+)
> Acked-by: Will Deacon <will.deacon@arm.com>
>
Thanks. Put all three in the patch tracker.
--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation
prev parent reply other threads:[~2013-03-18 18:46 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
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 [this message]
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