Jean-Philippe Brucker bcfced1580 iommu/arm-smmu: Fix polling of command queue ... When the SMMUv3 driver attempts to send a command, it adds an entry to the command queue. This is a circular buffer, where both the producer and consumer have a wrap bit. When producer.index == consumer.index and producer.wrap == consumer.wrap, the list is empty. When producer.index == consumer.index and producer.wrap != consumer.wrap, the list is full. If the list is full when the driver needs to add a command, it waits for the SMMU to consume one command, and advance the consumer pointer. The problem is that we currently rely on "X before Y" operation to know if entries have been consumed, which is a bit fiddly since it only makes sense when the distance between X and Y is less than or equal to the size of the queue. At the moment when the list is full, we use "Consumer before Producer + 1", which is out of range and returns a value opposite to what we expect: when the queue transitions to not full, we stay in the polling loop and time out, printing an error. Given that the actual bug was difficult to determine, simplify the polling logic by relying exclusively on queue_full and queue_empty, that don't have this range constraint. Polling the queue is now straightforward: * When we want to add a command and the list is full, wait until it isn't full and retry. * After adding a sync, wait for the list to be empty before returning. Suggested-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com>		2016-09-16 09:34:13 +01:00
..
amd_iommu_init.c
amd_iommu_proto.h
amd_iommu_types.h	iommu/amd: Use container_of to get dma_ops_domain	2016-07-14 10:21:57 +02:00
amd_iommu_v2.c	IOMMU Updates for Linux v4.8	2016-08-01 07:25:10 -04:00
amd_iommu.c	dma-mapping: use unsigned long for dma_attrs	2016-08-04 08:50:07 -04:00
arm-smmu-v3.c	iommu/arm-smmu: Fix polling of command queue	2016-09-16 09:34:13 +01:00
arm-smmu.c	iommu/arm-smmu: Support v7s context format	2016-09-16 09:34:13 +01:00
dma-iommu.c	iommu/dma: Respect IOMMU aperture when allocating	2016-08-10 12:02:02 +02:00
dmar.c	IOMMU Updates for Linux v4.8	2016-08-01 07:25:10 -04:00
exynos-iommu.c
fsl_pamu_domain.c
fsl_pamu_domain.h
fsl_pamu.c
fsl_pamu.h
intel_irq_remapping.c
intel-iommu.c	dma-mapping: use unsigned long for dma_attrs	2016-08-04 08:50:07 -04:00
intel-svm.c	mm: do not pass mm_struct into handle_mm_fault	2016-07-26 16:19:19 -07:00
io-pgtable-arm-v7s.c	iommu/io-pgtable-arm-v7s: Fix attributes when splitting blocks	2016-08-19 09:40:16 +01:00
io-pgtable-arm.c
io-pgtable.c
io-pgtable.h
iommu-sysfs.c
iommu-traces.c
iommu.c	Merge branches 'x86/amd', 'x86/vt-d', 'arm/exynos', 'arm/mediatek', 'arm/msm', 'arm/rockchip', 'arm/smmu' and 'core' into next	2016-07-26 16:02:37 +02:00
iova.c
ipmmu-vmsa.c
irq_remapping.c
irq_remapping.h
Kconfig	Merge branches 'x86/amd', 'x86/vt-d', 'arm/exynos', 'arm/mediatek', 'arm/msm', 'arm/rockchip', 'arm/smmu' and 'core' into next	2016-07-26 16:02:37 +02:00
Makefile	Merge branches 'x86/amd', 'x86/vt-d', 'arm/exynos', 'arm/mediatek', 'arm/msm', 'arm/rockchip', 'arm/smmu' and 'core' into next	2016-07-26 16:02:37 +02:00
msm_iommu_hw-8xxx.h
msm_iommu.c
msm_iommu.h
mtk_iommu_v1.c
mtk_iommu.c
mtk_iommu.h	iommu/mediatek: Mark static functions in headers inline	2016-08-09 15:46:46 +02:00
of_iommu.c
omap-iommu-debug.c
omap-iommu.c
omap-iommu.h
omap-iopgtable.h
rockchip-iommu.c
s390-iommu.c
tegra-gart.c
tegra-smmu.c