On Fri, Feb 23, 2018 at 5:22 AM, Jordan Crouse <jcrouse@xxxxxxxxxxxxxx> wrote: > On Wed, Feb 07, 2018 at 04:01:19PM +0530, Vivek Gautam wrote: >> From: Sricharan R <sricharan@xxxxxxxxxxxxxx> >> >> 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. >> >> Signed-off-by: Sricharan R <sricharan@xxxxxxxxxxxxxx> >> [vivek: Cleanup pm runtime calls] >> Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx> >> --- >> drivers/iommu/arm-smmu.c | 42 ++++++++++++++++++++++++++++++++++++++---- >> 1 file changed, 38 insertions(+), 4 deletions(-) >> >> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c >> index 9e2f917e16c2..c024f69c1682 100644 >> --- a/drivers/iommu/arm-smmu.c >> +++ b/drivers/iommu/arm-smmu.c >> @@ -913,11 +913,15 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) >> struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain); >> struct arm_smmu_device *smmu = smmu_domain->smmu; >> struct arm_smmu_cfg *cfg = &smmu_domain->cfg; >> - int irq; >> + int ret, irq; >> >> if (!smmu || domain->type == IOMMU_DOMAIN_IDENTITY) >> return; >> >> + ret = pm_runtime_get_sync(smmu->dev); >> + if (ret) >> + return; >> + >> /* >> * Disable the context bank and free the page tables before freeing >> * it. >> @@ -932,6 +936,8 @@ static void arm_smmu_destroy_domain_context(struct iommu_domain *domain) >> >> free_io_pgtable_ops(smmu_domain->pgtbl_ops); >> __arm_smmu_free_bitmap(smmu->context_map, cfg->cbndx); >> + >> + pm_runtime_put_sync(smmu->dev); >> } >> >> static struct iommu_domain *arm_smmu_domain_alloc(unsigned type) >> @@ -1407,14 +1413,22 @@ static int arm_smmu_add_device(struct device *dev) >> while (i--) >> cfg->smendx[i] = INVALID_SMENDX; >> >> - ret = arm_smmu_master_alloc_smes(dev); >> + ret = pm_runtime_get_sync(smmu->dev); >> if (ret) >> goto out_cfg_free; > > Hey Vivek, I just hit a problem with this on sdm845. It turns out that > pm_runtime_get_sync() returns a positive 1 if the device is already active. > > I hit this in the GPU code. The a6xx has two platform devices that each use a > different sid on the iommu. The GPU is probed normally from a platform driver > and it in turn initializes the GMU device by way of a phandle. > > Because the GMU isn't probed with a platform driver we need to call > of_dma_configure() on the device to set up the IOMMU for the device which ends > up calling through this path and we discover that the smmu->dev is already > powered (pm_runtime_get_sync returns 1). > > I'm not immediately sure if this is a bug on sdm845 or not because a cursory > inspection says that the SMMU device shouldn't be powered at this time but there > might be a connection that I'm not seeing. Obviously if the SMMU was left > powered thats a bad thing. But putting that aside it is obvious that this > code should be accommodating of the possibility that the device is already > powered, and so this should be > > if (ret < 0) > goto out_cfg_free; Right, as Tomasz also pointed, we should surely check the negative value of pm_runtime_get_sync(). >From your description, it may be that the GPU has turned on the smmu, and then once if goes and probes the GMU, the GMU device also wants to turn-on the same smmu device. But that's already active. So pm_runtime_get_sync() returns 1. Am i making sense? regards Vivek > > With that the GPU/GMU successfully comes up on Sean Paul's display testing > branch. > > Jordan > > -- > The Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, > a Linux Foundation Collaborative Project > -- > To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
