[PATCH 2/3] dt-bindings: Add io-tlb-segsize property for restricted-dma-pool

From: Hsin-Yi Wang
Date: Tue Nov 23 2021 - 06:21:24 EST


Add a io-tlb-segsize property that each restricted-dma-pool can set its
own io_tlb_segsize since some use cases require slabs larger than default
value (128).

Signed-off-by: Hsin-Yi Wang <hsinyi@xxxxxxxxxxxx>
---
.../bindings/reserved-memory/shared-dma-pool.yaml | 8 ++++++++
1 file changed, 8 insertions(+)

diff --git a/Documentation/devicetree/bindings/reserved-memory/shared-dma-pool.yaml b/Documentation/devicetree/bindings/reserved-memory/shared-dma-pool.yaml
index a4bf757d6881de..6198bf6b76f0b2 100644
--- a/Documentation/devicetree/bindings/reserved-memory/shared-dma-pool.yaml
+++ b/Documentation/devicetree/bindings/reserved-memory/shared-dma-pool.yaml
@@ -56,6 +56,14 @@ properties:
If this property is present, then Linux will use the region for
the default pool of the consistent DMA allocator.

+ io-tlb-segsize:
+ type: u32
+ description: >
+ Each restricted-dma-pool can use this property to set its own
+ io_tlb_segsize. If not set, it will use the default value
+ IO_TLB_SEGSIZE defined in include/linux/swiotlb.h. The value has
+ to be a power of 2, otherwise it will fall back to IO_TLB_SEGSIZE.
+
unevaluatedProperties: false

examples:
--
2.34.0.rc2.393.gf8c9666880-goog