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From: Will Deacon <will@kernel.org>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: mark.rutland@arm.com, iommu@lists.linux-foundation.org,
	robin.murphy@arm.com, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] perf/smmuv3: Allow sharing MMIO registers with the SMMU driver
Date: Wed, 20 May 2020 13:24:53 +0100	[thread overview]
Message-ID: <20200520122453.GB25815@willie-the-truck> (raw)
In-Reply-To: <20200421155745.19815-1-jean-philippe@linaro.org>

On Tue, Apr 21, 2020 at 05:57:46PM +0200, Jean-Philippe Brucker wrote:
> Some Arm SMMUv3 implementations, for example Arm CoreLink MMU-600, embed
> the PMCG registers into the SMMU MMIO regions. It currently causes probe
> failure because the PMU and SMMU drivers request overlapping resources.
> 
> Avoid the conflict by calling devm_ioremap() directly from the PMU
> driver. We loose some sanity-checking of the memory map provided by
> firmware, which doesn't seem catastrophic.
> 
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
> 
> So this is the simplest solution, and I don't think we're missing much
> by skipping the resource reservation. I've also been exploring a more
> complex approach [1] which has the SMMU driver perform resource
> reservation on behalf of the PMU driver, but I'm not sure it's
> necessary.
> 
> Please test, I've only tried the RevC FastModel using devicetree so far.
> 
> [1] https://jpbrucker.net/git/linux/log/?h=smmu/pmu
> ---
>  drivers/perf/arm_smmuv3_pmu.c | 28 +++++++++++++++++++++-------
>  1 file changed, 21 insertions(+), 7 deletions(-)

Is this patch still needed? I can't quite follow from the discussion.

Will
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iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org>
To: Jean-Philippe Brucker <jean-philippe@linaro.org>
Cc: mark.rutland@arm.com, iommu@lists.linux-foundation.org,
	lorenzo.pieralisi@arm.com, robin.murphy@arm.com,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] perf/smmuv3: Allow sharing MMIO registers with the SMMU driver
Date: Wed, 20 May 2020 13:24:53 +0100	[thread overview]
Message-ID: <20200520122453.GB25815@willie-the-truck> (raw)
In-Reply-To: <20200421155745.19815-1-jean-philippe@linaro.org>

On Tue, Apr 21, 2020 at 05:57:46PM +0200, Jean-Philippe Brucker wrote:
> Some Arm SMMUv3 implementations, for example Arm CoreLink MMU-600, embed
> the PMCG registers into the SMMU MMIO regions. It currently causes probe
> failure because the PMU and SMMU drivers request overlapping resources.
> 
> Avoid the conflict by calling devm_ioremap() directly from the PMU
> driver. We loose some sanity-checking of the memory map provided by
> firmware, which doesn't seem catastrophic.
> 
> Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
> ---
> 
> So this is the simplest solution, and I don't think we're missing much
> by skipping the resource reservation. I've also been exploring a more
> complex approach [1] which has the SMMU driver perform resource
> reservation on behalf of the PMU driver, but I'm not sure it's
> necessary.
> 
> Please test, I've only tried the RevC FastModel using devicetree so far.
> 
> [1] https://jpbrucker.net/git/linux/log/?h=smmu/pmu
> ---
>  drivers/perf/arm_smmuv3_pmu.c | 28 +++++++++++++++++++++-------
>  1 file changed, 21 insertions(+), 7 deletions(-)

Is this patch still needed? I can't quite follow from the discussion.

Will

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel

  parent reply	other threads:[~2020-05-20 12:25 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-21 15:57 [PATCH] perf/smmuv3: Allow sharing MMIO registers with the SMMU driver Jean-Philippe Brucker
2020-04-21 15:57 ` Jean-Philippe Brucker
2020-04-21 17:25 ` Robin Murphy
2020-04-21 17:25   ` Robin Murphy
2020-04-28 18:10 ` Tuan Phan
2020-04-28 18:10   ` Tuan Phan
2020-04-29  7:21   ` Jean-Philippe Brucker
2020-04-29  7:21     ` Jean-Philippe Brucker
2020-04-29 18:01     ` Tuan Phan
2020-04-29 18:01       ` Tuan Phan
2020-05-06 16:11       ` Jean-Philippe Brucker
2020-05-06 16:11         ` Jean-Philippe Brucker
2020-05-20 12:24 ` Will Deacon [this message]
2020-05-20 12:24   ` Will Deacon
2020-05-20 12:44   ` Jean-Philippe Brucker
2020-05-20 12:44     ` Jean-Philippe Brucker

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