Thread (21 messages) 21 messages, 4 authors, 2018-11-26

Re: [RESEND PATCH v17 2/5] iommu/arm-smmu: Invoke pm_runtime during probe, add/remove device

From: Will Deacon <hidden>
Date: 2018-11-26 19:31:38
Also in: linux-arm-msm, linux-iommu, linux-pm, lkml

On Mon, Nov 26, 2018 at 04:56:42PM +0530, Vivek Gautam wrote:
On 11/26/2018 11:33 AM, Vivek Gautam wrote:
quoted
On 11/24/2018 12:06 AM, Will Deacon wrote:
quoted
On Thu, Nov 22, 2018 at 05:32:24PM +0530, Vivek Gautam wrote:
quoted
On Wed, Nov 21, 2018 at 11:09 PM Will Deacon [off-list ref]
wrote:
quoted
On Fri, Nov 16, 2018 at 04:54:27PM +0530, Vivek Gautam wrote:
quoted
From: Sricharan R <redacted>

The smmu device probe/remove and add/remove master device callbacks
gets called when the smmu is not linked to its master, that is
without
the context of the master device. So calling runtime apis in those
places
separately.
Global locks are also initialized before enabling runtime pm as the
runtime_resume() calls device_reset() which does tlb_sync_global()
that ultimately requires locks to be initialized.

Signed-off-by: Sricharan R <redacted>
[vivek: Cleanup pm runtime calls]
Signed-off-by: Vivek Gautam <redacted>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Tested-by: Srinivas Kandagatla <redacted>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
---
 drivers/iommu/arm-smmu.c | 101
++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 91 insertions(+), 10 deletions(-)
Given that you're doing the get/put in the TLBI ops unconditionally:
quoted
 static void arm_smmu_flush_iotlb_all(struct iommu_domain *domain)
 {
      struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+     struct arm_smmu_device *smmu = smmu_domain->smmu;

-     if (smmu_domain->tlb_ops)
+     if (smmu_domain->tlb_ops) {
+             arm_smmu_rpm_get(smmu);
smmu_domain->tlb_ops->tlb_flush_all(smmu_domain);
+             arm_smmu_rpm_put(smmu);
+     }
 }

 static void arm_smmu_iotlb_sync(struct iommu_domain *domain)
 {
      struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+     struct arm_smmu_device *smmu = smmu_domain->smmu;

-     if (smmu_domain->tlb_ops)
+     if (smmu_domain->tlb_ops) {
+             arm_smmu_rpm_get(smmu);
smmu_domain->tlb_ops->tlb_sync(smmu_domain);
+             arm_smmu_rpm_put(smmu);
+     }
Why do you need them around the map/unmap calls as well?
We still have .tlb_add_flush path?
Ok, so we could add the ops around that as well. Right now, we've got
the runtime pm hooks crossing two parts of the API.
Sure, will do that then, and remove the runtime pm hooks from map/unmap.
I missed this earlier -
We are adding runtime pm hooks in the 'iommu_ops' callbacks and not really
to
'tlb_ops'. So how the runtime pm hooks crossing the paths?
'.map/.unmap' iommu_ops don't call '.flush_iotlb_all' or '.iotlb_sync'
iommu_ops
anywhere.

E.g., only callers to domain->ops->flush_iotlb_all() are:
iommu_dma_flush_iotlb_all(), or iommu_flush_tlb_all() which are not in
map/unmap paths.
Yes, sorry, I got confused here and completely misled you. In which case,
your original patch is ok because it intercepts the core IOMMU API via
iommu_ops. Apologies.

At that level, should we also annotate arm_smmu_iova_to_phys_hard()
for the iova_to_phys() implementation?

With that detail and clock bits sorted out, we should be able to get this
queued at last.

Will
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