[PATCH V3 0/8] IOMMU probe deferral support

Sricharan R
2016-10-04T17:03:44Z

Initial post from Laurent Pinchart[1]. This is
series calls the dma ops configuration for the devices
at a generic place so that it works for all busses.
The dma_configure_ops for a device is now called during
the device_attach callback just before the probe of the
bus/driver is called. Similarly dma_deconfigure is called during
device/driver_detach path.

pci_bus_add_devices (platform/amba)(_device_create/driver_register)
| |
pci_bus_add_device (device_add/driver_register)
| |
device_attach device_initial_probe
| |
__device_attach_driver __device_attach_driver
|
driver_probe_device
|
really_probe
|
dma_configure

Similarly on the device/driver_unregister path __device_release_driver is
called which inturn calls dma_deconfigure.

If the ACPI bus code follows the same, we can add acpi_dma_configure
at the same place as of_dma_configure.

This series is based on the recently merged Generic DT bindings for
PCI IOMMUs and ARM SMMU from Robin Murphy robin.murphy@arm.com [2]

This time tested this with platform and pci device for probe deferral
and reprobe on arm64 based platform. There is an issue on the cleanup
path for arm64 though, where there is WARN_ON if the dma_ops is reset while
device is attached to an domain in arch_teardown_dma_ops.
But with iommu_groups created from the iommu driver, the device is always
attached to a domain/default_domain. So so the WARN has to be removed/handled
probably.

Previous post of this series [3].

[V3]
* Removed the patch to split dma_masks/dma_ops configuration separately
based on review comments that both masks and ops are required only
during the device probe time.

* Reworked the series based on Generic DT bindings series [2].

* Added call to iommu's remove_device in the cleanup path for arm and arm64.

* Removed the notifier trick in arm64 to handle early device registration.

* Added reset of dma_ops in cleanup path for arm based on comments.

* Fixed the pci_iommu_configure path and tested with PCI device as well.

* Fixed a bug to return the correct iommu_ops from patch 7 [4] in last post.

* Fixed few other cosmetic comments.

[V2]
* Updated the Initial post to call dma_configure/deconfigure from generic code

* Added iommu add_device callback from of_iommu_configure path

[V1]
* Initial post

[1] http://lists.linuxfoundation.org/pipermail/iommu/2015-May/013016.html
[2] http://www.spinics.net/lists/devicetree/msg142943.html
[3] https://www.mail-archive.com/iommu@lists.linux-foundation.org/msg13941.html
[4] https://www.mail-archive.com/iommu@lists.linux-foundation.org/msg13940.html

Laurent Pinchart (4):
arm: dma-mapping: Don't override dma_ops in arch_setup_dma_ops()
of: dma: Move range size workaround to of_dma_get_range()
of: dma: Make of_dma_deconfigure() public
iommu: of: Handle IOMMU lookup failure with deferred probing or error

Sricharan R (4):
drivers: platform: Configure dma operations at probe time
arm: dma-mapping: Reset the device's dma_ops
arm/arm64: dma-mapping: Call iommu's remove_device callback during
device detach
arm64: dma-mapping: Remove the notifier trick to handle early setting
of dma_ops

arch/arm/mm/dma-mapping.c | 18 ++++++++
arch/arm64/mm/dma-mapping.c | 107 +++++---------------------------------------
drivers/base/dd.c | 10 +++++
drivers/base/dma-mapping.c | 11 +++++
drivers/iommu/of_iommu.c | 47 +++++++++++++++++--
drivers/of/address.c | 20 ++++++++-
drivers/of/device.c | 34 +++++++-------
drivers/of/platform.c | 9 ----
drivers/pci/probe.c | 5 +--
include/linux/dma-mapping.h | 3 ++
include/linux/of_device.h | 7 ++-
11 files changed, 138 insertions(+), 133 deletions(-)

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