@@ -428,23 +428,26 @@ properties:
snps,pbl:
description:
- Programmable Burst Length (tx and rx)
+ Programmable Burst Length (tx and rx). Note some of these values
+ can be still invalid due to HW limitations connected with the data
+ bus width and the FIFOs depth, so a total length of a single DMA
+ burst shouldn't exceed half the FIFO depth.
$ref: /schemas/types.yaml#/definitions/uint32
- enum: [2, 4, 8]
+ enum: [1, 2, 4, 8, 16, 32]
snps,txpbl:
description:
Tx Programmable Burst Length. If set, DMA tx will use this
value rather than snps,pbl.
$ref: /schemas/types.yaml#/definitions/uint32
- enum: [2, 4, 8]
+ enum: [1, 2, 4, 8, 16, 32]
snps,rxpbl:
description:
Rx Programmable Burst Length. If set, DMA rx will use this
value rather than snps,pbl.
$ref: /schemas/types.yaml#/definitions/uint32
- enum: [2, 4, 8]
+ enum: [1, 2, 4, 8, 16, 32]
snps,no-pbl-x8:
$ref: /schemas/types.yaml#/definitions/flag
In accordance with [1] the permitted PBL values can be set as one of [1, 2, 4, 8, 16, 32]. The rest of the values result in undefined behavior. At the same time some of the permitted values can be also invalid depending on the controller FIFOs size and the data bus width. Due to having too many variables all the possible PBL property constraints can't be implemented in the bindings schema, let's extend the set of permitted PBL values to be as much as the configuration register supports leaving the undefined behaviour cases for developers to handle. [1] DesignWare Cores Ethernet MAC Universal Databook, Revision 3.73a, October 2013, p. 380. Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru> Reviewed-by: Rob Herring <robh@kernel.org> --- Changelog v1: - Use correct syntax of the JSON pointers, so the later would begin with a '/' after the '#'. --- Documentation/devicetree/bindings/net/snps,dwmac.yaml | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-)