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| author | Tomer Tayar | 2019-06-16 15:48:29 +0200 |
|---|---|---|
| committer | Oded Gabbay | 2019-06-16 15:48:29 +0200 |
| commit | 4a0ce7764b09044fdb5f92dcf03ec5d8657296f4 (patch) | |
| tree | 009d171c57d8625736a2709c9fe30c45a02666a8 /Documentation/ABI | |
| parent | habanalabs: add WARN in case of bad MMU mapping (diff) | |
| download | kernel-qcow2-linux-4a0ce7764b09044fdb5f92dcf03ec5d8657296f4.tar.gz kernel-qcow2-linux-4a0ce7764b09044fdb5f92dcf03ec5d8657296f4.tar.xz kernel-qcow2-linux-4a0ce7764b09044fdb5f92dcf03ec5d8657296f4.zip | |
habanalabs: Allow accessing host mapped addresses via debugfs
Allows using the addr/data32 debugfs nodes to access a device VA of a
host mapped memory when the IOMMU is disabled.
Due to the possible large amount of a user host mapped memory, the
driver doesn't maintain a database with the host addresses per device VA.
When the IOMMU is disabled, this missing info is being overcome by
simply using phys_to_virt(). However, this is not useful when the IOMMU
is enabled, and thus the enforced limitation.
Signed-off-by: Tomer Tayar <ttayar@habana.ai>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/debugfs-driver-habanalabs | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/Documentation/ABI/testing/debugfs-driver-habanalabs b/Documentation/ABI/testing/debugfs-driver-habanalabs index 2f5b80be07a3..18191c2becab 100644 --- a/Documentation/ABI/testing/debugfs-driver-habanalabs +++ b/Documentation/ABI/testing/debugfs-driver-habanalabs @@ -3,7 +3,10 @@ Date: Jan 2019 KernelVersion: 5.1 Contact: oded.gabbay@gmail.com Description: Sets the device address to be used for read or write through - PCI bar. The acceptable value is a string that starts with "0x" + PCI bar, or the device VA of a host mapped memory to be read or + written directly from the host. The latter option is allowed + only when the IOMMU is disabled. + The acceptable value is a string that starts with "0x" What: /sys/kernel/debug/habanalabs/hl<n>/command_buffers Date: Jan 2019 @@ -33,10 +36,12 @@ Contact: oded.gabbay@gmail.com Description: Allows the root user to read or write directly through the device's PCI bar. Writing to this file generates a write transaction while reading from the file generates a read - transcation. This custom interface is needed (instead of using + transaction. This custom interface is needed (instead of using the generic Linux user-space PCI mapping) because the DDR bar is very small compared to the DDR memory and only the driver can - move the bar before and after the transaction + move the bar before and after the transaction. + If the IOMMU is disabled, it also allows the root user to read + or write from the host a device VA of a host mapped memory What: /sys/kernel/debug/habanalabs/hl<n>/device Date: Jan 2019 |