On Fri, Sep 23, 2022 at 02:35:52PM +0200, Thierry Reding wrote: > From: Thierry Reding <treding@xxxxxxxxxx> > > Hi, > > This version has several fixes over the previous v8, which can be found > here: > > https://lore.kernel.org/all/20220905170833.396892-1-thierry.reding@xxxxxxxxx/ > > An example is included in the DT bindings, but here is an extract of > what I've used to test this: > > reserved-memory { > #address-cells = <2>; > #size-cells = <2>; > ranges; > > /* > * Creates an identity mapping for the framebuffer that > * the firmware has setup to scan out a bootsplash from. > */ > fb: framebuffer@92cb2000 { > reg = <0x0 0x92cb2000 0x0 0x00800000>; > iommu-addresses = <&dc0 0x0 0x92cb2000 0x0 0x00800000>; > }; > > /* > * Creates a reservation in the IOVA space to prevent > * any buffers from being mapped to that region. Note > * that on Tegra the range is actually quite different > * from this, but it would conflict with the display > * driver that I tested this against, so this is just > * a dummy region for testing. > */ > adsp: reservation-adsp { > iommu-addresses = <&dc0 0x0 0x90000000 0x0 0x00010000>; > }; > }; > > host1x@50000000 { > dc@54200000 { > memory-region = <&fb>, <&adsp>; > }; > }; > > This is abbreviated a little to focus on the essentials. Note also that > the ADSP reservation is not actually used on this device and the driver > for this doesn't exist yet, but I wanted to include this variant for > testing, because we'll want to use these bindings for the reservation > use-case as well at some point. > > I've also been able to make use of this binding and the IOMMU code in > conjunction with the simple-framebuffer driver to hand over a display > configuration set up by UEFI to the Linux kernel. > > Janne has confirmed[0] this to be suitable for indirect mappings as > well, though these patches don't implement that feature yet. Potential > extensions to this have been discussed but are not yet included at this > time to not further complicate things. > > Thierry > > [0]: https://lore.kernel.org/all/20220909144504.GA4024@xxxxxxxxxx/ > > Navneet Kumar (1): > iommu/tegra-smmu: Support managed domains > > Thierry Reding (4): > dt-bindings: reserved-memory: Document iommu-addresses > iommu: Implement of_iommu_get_resv_regions() > iommu: dma: Use of_iommu_get_resv_regions() > iommu/tegra-smmu: Add support for reserved regions > > .../reserved-memory/reserved-memory.yaml | 70 ++++++++++++ > drivers/iommu/dma-iommu.c | 3 + > drivers/iommu/of_iommu.c | 104 ++++++++++++++++++ > drivers/iommu/tegra-smmu.c | 86 ++++++++++++--- > include/linux/of_iommu.h | 8 ++ > 5 files changed, 254 insertions(+), 17 deletions(-) Joerg, if there are no further concerns on this, can you pick this up once v6.1-rc1 is released? Thanks, Thierry
Attachment:
signature.asc
Description: PGP signature
