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c8410c0f81
Iommu framework introduce default_domain for automatic attach which we were not interesting before, now rockchip iommu driver following this way that make things different: iommu_detach_device function is not able to disable iommu anymore. It just do following things either: 1. Just return Like Vcodec/ISP who does not allocate new domain 2. Attach default_domain Like vop who allocate new domain by vop driver We have no way to temporary disable iommu,to fix this issue, master driver need to attach a NULL domain,also master driver need more step: 1. iommu_attach_device(NULL, dev) -> disable iommu 2. iommu_detach_device(NULL, dev) -> attach default_domain Above two steps must comes in pairs. Following order called by driver is not permitted: 1. iommu_attach_device(domain, dev) 2. iommu_attach_device(NULL, dev) 3. iommu_detach_device(NULL, dev) 4. iommu_detach_device(domain, dev) Correct is: 1. iommu_attach_device(domain, dev) 2. iommu_detach_device(domain, dev) 3. iommu_attach_device(NULL, dev) 4. iommu_detach_device(NULL, dev) Change-Id: I12b1e27e5119fb1abd05ccce57c9e941f03e9498 Signed-off-by: Simon Xue <xxm@rock-chips.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.