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From: Robin Murphy <robin.murphy@arm.com>
To: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>,
	Rob Clark <robdclark@gmail.com>
Cc: linux-arm-msm@vger.kernel.org, iommu@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] iomm/arm-smmu: Add stall implementation hook
Date: Thu, 7 May 2020 15:56:28 +0100	[thread overview]
Message-ID: <80a3b07d-f3a7-07c4-4e8f-76e28563027c@arm.com> (raw)
In-Reply-To: <fad5dc096a2bd9404341ba8738ba8fc9@codeaurora.org>

On 2020-05-07 1:06 pm, Sai Prakash Ranjan wrote:
[...]
> We could have our own context fault handler in QCOM implementation,
> but that would just be duplicating things from arm-smmu context fault
> handler. So I did not think it makes much sense to have our own
> fault handler in qcom impl just for enabling stall model.

Hmm, it's probably worth thinking ahead a bit here, to the "actually 
doing things with stalls" plan. I don't have a clear picture off-hand of 
how well the new device fault handler API might fit into arm-smmu - at 
the very least trying to make it truly generic implies having to play 
nasty tricks with disable_irq() for the general case given the "IRQ may 
remain asserted while SS is active" possibility, and that isn't 
particularly inviting. Not to mention tying it into the 
pretend-auxdomain stuff that *is* rather dependent on the qcom impl. If 
it turns out that you'll eventually have to reimplement the IRQ handler 
anyway for all that, then starting off down that route *might* work out 
cleaner and less hassle overall.

Robin.
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  reply	other threads:[~2020-05-07 14:56 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-21 20:20 [PATCH] iomm/arm-smmu: Add stall implementation hook Sai Prakash Ranjan
2020-05-07 10:14 ` Sai Prakash Ranjan
2020-05-07 10:55   ` Robin Murphy
2020-05-07 12:06     ` Sai Prakash Ranjan
2020-05-07 14:56       ` Robin Murphy [this message]
2020-05-07 12:53     ` Will Deacon
2020-05-08 15:32       ` Rob Clark
2020-05-08 15:40         ` Rob Clark
2020-05-11 17:30           ` Jordan Crouse
2020-05-18 15:45             ` Will Deacon
2020-05-19  9:26               ` Sai Prakash Ranjan
2020-05-19 15:11                 ` Rob Clark
2020-05-20  9:32                   ` Sai Prakash Ranjan
2020-05-20 12:59                     ` Will Deacon

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