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From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Will Deacon <will@kernel.org>, Joerg Roedel <joro@8bytes.org>,
	Sibi Sankar <sibis@codeaurora.org>,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Jordan Crouse <jcrouse@codeaurora.org>,
	Rob Clark <robdclark@gmail.com>,
	Stephen Boyd <swboyd@chromium.org>,
	iommu@lists.linux-foundation.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
	Matthias Kaehlcke <mka@chromium.org>,
	Evan Green <evgreen@chromium.org>
Subject: Re: [PATCHv3 4/6] iommu/arm-smmu-qcom: Request direct mapping for modem device
Date: Mon, 20 Apr 2020 23:40:42 +0530	[thread overview]
Message-ID: <98fa2940456ade2bd0998dfaa6386653@codeaurora.org> (raw)
In-Reply-To: <49c8c377-961b-3f95-a99c-08528def4cb7@arm.com>

Hi Robin,

On 2020-04-20 22:39, Robin Murphy wrote:
> On 2020-04-20 5:42 pm, Sai Prakash Ranjan wrote:
>> From: Sibi Sankar <sibis@codeaurora.org>
>> 
>> Request direct mapping for modem on platforms which don't have 
>> TrustZone
>> (which programs the modem SIDs) to prevent the following global faults 
>> seen
>> on Cheza/Trogdor:
> 
> Not strictly true - it's patch #6/6 that prevents *those* faults (and
> these days the driver should be reporting unmatched streams a little
> more helpfully). This change would resolve the context faults and/or
> weird memory corruption that might result from applying patch #6 alone
> - this is the crazy thing where transactions sometimes go directly to
> DRAM round the side of the SMMU so we can never safely remap anything,
> right?
> 

True this doesnt prevent global faults, the fault details should go to 
patch6.
I'll update the commit msg something like below:

The Q6 modem sub-system has direct access to DDR through memnoc.
Also SMMU is not expected to provide access control/translation for 
these SIDs
(sandboxing of the modem is achieved through XPUs engaged using SMC 
calls).

Thanks,
Sai

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a 
member
of Code Aurora Forum, hosted by The Linux Foundation

WARNING: multiple messages have this Message-ID (diff)
From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Evan Green <evgreen@chromium.org>,
	linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Matthias Kaehlcke <mka@chromium.org>,
	Sibi Sankar <sibis@codeaurora.org>,
	linux-arm-msm@vger.kernel.org, Stephen Boyd <swboyd@chromium.org>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCHv3 4/6] iommu/arm-smmu-qcom: Request direct mapping for modem device
Date: Mon, 20 Apr 2020 23:40:42 +0530	[thread overview]
Message-ID: <98fa2940456ade2bd0998dfaa6386653@codeaurora.org> (raw)
In-Reply-To: <49c8c377-961b-3f95-a99c-08528def4cb7@arm.com>

Hi Robin,

On 2020-04-20 22:39, Robin Murphy wrote:
> On 2020-04-20 5:42 pm, Sai Prakash Ranjan wrote:
>> From: Sibi Sankar <sibis@codeaurora.org>
>> 
>> Request direct mapping for modem on platforms which don't have 
>> TrustZone
>> (which programs the modem SIDs) to prevent the following global faults 
>> seen
>> on Cheza/Trogdor:
> 
> Not strictly true - it's patch #6/6 that prevents *those* faults (and
> these days the driver should be reporting unmatched streams a little
> more helpfully). This change would resolve the context faults and/or
> weird memory corruption that might result from applying patch #6 alone
> - this is the crazy thing where transactions sometimes go directly to
> DRAM round the side of the SMMU so we can never safely remap anything,
> right?
> 

True this doesnt prevent global faults, the fault details should go to 
patch6.
I'll update the commit msg something like below:

The Q6 modem sub-system has direct access to DDR through memnoc.
Also SMMU is not expected to provide access control/translation for 
these SIDs
(sandboxing of the modem is achieved through XPUs engaged using SMC 
calls).

Thanks,
Sai

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a 
member
of Code Aurora Forum, hosted by The Linux Foundation
_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Evan Green <evgreen@chromium.org>,
	linux-kernel@vger.kernel.org, Joerg Roedel <joro@8bytes.org>,
	Jordan Crouse <jcrouse@codeaurora.org>,
	iommu@lists.linux-foundation.org,
	Bjorn Andersson <bjorn.andersson@linaro.org>,
	Rob Clark <robdclark@gmail.com>,
	Matthias Kaehlcke <mka@chromium.org>,
	Sibi Sankar <sibis@codeaurora.org>,
	linux-arm-msm@vger.kernel.org, Stephen Boyd <swboyd@chromium.org>,
	Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCHv3 4/6] iommu/arm-smmu-qcom: Request direct mapping for modem device
Date: Mon, 20 Apr 2020 23:40:42 +0530	[thread overview]
Message-ID: <98fa2940456ade2bd0998dfaa6386653@codeaurora.org> (raw)
In-Reply-To: <49c8c377-961b-3f95-a99c-08528def4cb7@arm.com>

Hi Robin,

On 2020-04-20 22:39, Robin Murphy wrote:
> On 2020-04-20 5:42 pm, Sai Prakash Ranjan wrote:
>> From: Sibi Sankar <sibis@codeaurora.org>
>> 
>> Request direct mapping for modem on platforms which don't have 
>> TrustZone
>> (which programs the modem SIDs) to prevent the following global faults 
>> seen
>> on Cheza/Trogdor:
> 
> Not strictly true - it's patch #6/6 that prevents *those* faults (and
> these days the driver should be reporting unmatched streams a little
> more helpfully). This change would resolve the context faults and/or
> weird memory corruption that might result from applying patch #6 alone
> - this is the crazy thing where transactions sometimes go directly to
> DRAM round the side of the SMMU so we can never safely remap anything,
> right?
> 

True this doesnt prevent global faults, the fault details should go to 
patch6.
I'll update the commit msg something like below:

The Q6 modem sub-system has direct access to DDR through memnoc.
Also SMMU is not expected to provide access control/translation for 
these SIDs
(sandboxing of the modem is achieved through XPUs engaged using SMC 
calls).

Thanks,
Sai

-- 
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a 
member
of Code Aurora Forum, hosted by The Linux Foundation

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

  reply	other threads:[~2020-04-20 18:11 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-20 16:41 [PATCHv3 0/6] iommu/arm-smmu: Allow client devices to select identity mapping Sai Prakash Ranjan
2020-04-20 16:41 ` Sai Prakash Ranjan
2020-04-20 16:41 ` Sai Prakash Ranjan
2020-04-20 16:41 ` [PATCHv3 1/6] iommu: arm-smmu-impl: Convert to a generic reset implementation Sai Prakash Ranjan
2020-04-20 16:41   ` Sai Prakash Ranjan
2020-04-20 16:41   ` Sai Prakash Ranjan
2020-04-20 16:42 ` [PATCHv3 2/6] iommu/arm-smmu: Allow client devices to select direct mapping Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan
2020-04-20 16:57   ` Robin Murphy
2020-04-20 16:57     ` Robin Murphy
2020-04-20 16:57     ` Robin Murphy
2020-04-20 18:36     ` Sai Prakash Ranjan
2020-04-20 18:36       ` Sai Prakash Ranjan
2020-04-20 18:36       ` Sai Prakash Ranjan
2020-04-20 16:42 ` [PATCHv3 3/6] iommu/arm-smmu: Implement iommu_ops->def_domain_type call-back Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan
2020-04-20 16:59   ` Robin Murphy
2020-04-20 16:59     ` Robin Murphy
2020-04-20 16:59     ` Robin Murphy
2020-04-20 16:42 ` [PATCHv3 4/6] iommu/arm-smmu-qcom: Request direct mapping for modem device Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan
2020-04-20 17:09   ` Robin Murphy
2020-04-20 17:09     ` Robin Murphy
2020-04-20 17:09     ` Robin Murphy
2020-04-20 18:10     ` Sai Prakash Ranjan [this message]
2020-04-20 18:10       ` Sai Prakash Ranjan
2020-04-20 18:10       ` Sai Prakash Ranjan
2020-04-20 16:42 ` [PATCHv3 5/6] dt-bindings: remoteproc: qcom: Add iommus property Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan
2020-04-20 16:42 ` [PATCHv3 6/6] arm64: dts: qcom: sdm845-cheza: " Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan
2020-04-20 16:42   ` Sai Prakash Ranjan

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