| Message ID | 20220916094152.87137-1-j@jannau.net (mailing list archive) |
|---|---|
| Headers | show |
| Series | iommu: M1 Pro/Max DART support | expand |
On 2022-09-16 10:41, Janne Grunau wrote: > Hej, > > this is the next attempt adding support for the DART found in Apple's > M1 Pro/Max/Ultra. This adds a separate io-pgtable implementation for > DART. As already mentioned in v2 the pte format is not fully compatible > with io-pgtable-arm. Especially the 2nd least significant bit is used > and is not available to tag tables/pages. > io-pgtable-dart.c is copied from io-pgtable-arm.c and support for > unused features is removed. Support for 4k IO pages is left for A7 to > A11 SoCs as there's work underway to run Linux on them. > > The incompatibilities between both Apple DART pte seems manageable in > their own io-pgtable implementation. A short list of the known > differences: > > - the physical addresses are shifted left by 4 bits and and have 2 more > bits inside the PTE entries > - the read/write protection flags are at a different position > - the subpage protection feature is now mandatory. For Linux we can > just configure it to always allow access to the entire page. > - BIT(1) tags "uncached" mappings (used for the display controller) > > There is second type of DART (t8110) present on M1 Pro/Max SoCs which > uses the same PTE format as t6000. FWIW I think there's minimal risk in queueing this up as a late addition for 6.1, lest it get forgotten again. I've not been following it since I've been busy with other things and I largely trust that DART patches are well-tested, but from a quick skim it all earns a solid "yeah, why not" from me :) Cheers, Robin. > Changes in v5: > - collected Sven's ack > - minor fixes in "iommu/io-pgtable: Move Apple DART support to its own > file" > > Changes in v4: > - split dart and io-pgtable-dart build to allow building dart as module > - add missing "SELECT IOMMU_IO_PGTABLE" > - made map/unmap_pages/iova_to_phys inon-recursive > - replace pgd concatenation with multiple table handling > - simplified config and page size checks > - collected Robin's Ack > > Changes in v3: > - move APPLE_DART to its own io-pgtable implementation, copied from > io-pgtable-arm and simplified > > Changes in v2: > - added Rob's Acked-by: > - add APPLE_DART2 io-pgtable format > > Janne Grunau (1): > iommu/io-pgtable: Move Apple DART support to its own file > > Sven Peter (4): > dt-bindings: iommu: dart: add t6000 compatible > iommu/io-pgtable: Add DART subpage protection support > iommu/io-pgtable-dart: Add DART PTE support for t6000 > iommu: dart: Support t6000 variant > > .../devicetree/bindings/iommu/apple,dart.yaml | 4 +- > MAINTAINERS | 1 + > drivers/iommu/Kconfig | 13 +- > drivers/iommu/Makefile | 1 + > drivers/iommu/apple-dart.c | 24 +- > drivers/iommu/io-pgtable-arm.c | 63 --- > drivers/iommu/io-pgtable-dart.c | 470 ++++++++++++++++++ > drivers/iommu/io-pgtable.c | 3 + > include/linux/io-pgtable.h | 1 + > 9 files changed, 512 insertions(+), 68 deletions(-) > create mode 100644 drivers/iommu/io-pgtable-dart.c >
On 16/09/2022 18.41, Janne Grunau wrote: > Hej, > > this is the next attempt adding support for the DART found in Apple's > M1 Pro/Max/Ultra. This adds a separate io-pgtable implementation for > DART. As already mentioned in v2 the pte format is not fully compatible > with io-pgtable-arm. Especially the 2nd least significant bit is used > and is not available to tag tables/pages. > io-pgtable-dart.c is copied from io-pgtable-arm.c and support for > unused features is removed. Support for 4k IO pages is left for A7 to > A11 SoCs as there's work underway to run Linux on them. > > The incompatibilities between both Apple DART pte seems manageable in > their own io-pgtable implementation. A short list of the known > differences: > > - the physical addresses are shifted left by 4 bits and and have 2 more > bits inside the PTE entries > - the read/write protection flags are at a different position > - the subpage protection feature is now mandatory. For Linux we can > just configure it to always allow access to the entire page. > - BIT(1) tags "uncached" mappings (used for the display controller) > > There is second type of DART (t8110) present on M1 Pro/Max SoCs which > uses the same PTE format as t6000. > > Changes in v5: > - collected Sven's ack > - minor fixes in "iommu/io-pgtable: Move Apple DART support to its own > file" > > Changes in v4: > - split dart and io-pgtable-dart build to allow building dart as module > - add missing "SELECT IOMMU_IO_PGTABLE" > - made map/unmap_pages/iova_to_phys inon-recursive > - replace pgd concatenation with multiple table handling > - simplified config and page size checks > - collected Robin's Ack > > Changes in v3: > - move APPLE_DART to its own io-pgtable implementation, copied from > io-pgtable-arm and simplified > > Changes in v2: > - added Rob's Acked-by: > - add APPLE_DART2 io-pgtable format > > Janne Grunau (1): > iommu/io-pgtable: Move Apple DART support to its own file > > Sven Peter (4): > dt-bindings: iommu: dart: add t6000 compatible > iommu/io-pgtable: Add DART subpage protection support > iommu/io-pgtable-dart: Add DART PTE support for t6000 > iommu: dart: Support t6000 variant > > .../devicetree/bindings/iommu/apple,dart.yaml | 4 +- > MAINTAINERS | 1 + > drivers/iommu/Kconfig | 13 +- > drivers/iommu/Makefile | 1 + > drivers/iommu/apple-dart.c | 24 +- > drivers/iommu/io-pgtable-arm.c | 63 --- > drivers/iommu/io-pgtable-dart.c | 470 ++++++++++++++++++ > drivers/iommu/io-pgtable.c | 3 + > include/linux/io-pgtable.h | 1 + > 9 files changed, 512 insertions(+), 68 deletions(-) > create mode 100644 drivers/iommu/io-pgtable-dart.c > For the whole series, modulo the trivial warning I mentioned: Acked-by: Hector Martin <marcan@marcan.st> Let's get this merged please, it's been blocking t6000 support for a long time now :) - Hector
On Fri, Sep 16, 2022 at 11:41:47AM +0200, Janne Grunau wrote: > Janne Grunau (1): > iommu/io-pgtable: Move Apple DART support to its own file > > Sven Peter (4): > dt-bindings: iommu: dart: add t6000 compatible > iommu/io-pgtable: Add DART subpage protection support > iommu/io-pgtable-dart: Add DART PTE support for t6000 > iommu: dart: Support t6000 variant Applied patches 2-5 for v6.1, thanks everyone.