On 05/05/2023 11:44, Joy Chakraborty wrote: > On Thu, May 4, 2023 at 8:38 PM Krzysztof Kozlowski > <krzysztof.kozlowski@xxxxxxxxxx> wrote: >> >> On 04/05/2023 16:57, Joy Chakraborty wrote: >>> Add 2 new quirks added to the driver "arm,pl330-optimize-dev2mem-axsize" >>> and "arm,pl330-periph-single-dregs" >> >> This we can see from the diff. You need to answer why? >> > > Sure will change it to: > " > Addition of following quirks : > - "arm,pl330-periph-use-diff-axsize" > AxSize of transactions to peripherals are limited by the peripheral > address width which inturn limits the AxSize used for transactions > towards memory. > This quirk will make transactions to memory use the maximum > possible bus width(AxSize), store data in MFIFO and use narrow > multi-beat transactions to move data to peripherals. > This only applies to transfers between memory and peripherals where > bus widths available are different for memory and the peripheral. > - "arm,pl330-periph-complete-with-singles" : > When transfer sizes are not a multiple of a block of burst > transfers (AxLen * AxSize configured at the peripheral), certain > peripherals might choose not to set the burst request at the > peripheral request interface of the DMA. > This quirk moves the remaining bytes to the peripheral using single > transactions. > " This does not answer why. You just copied again the patch contents. > >>> >>> Signed-off-by: Joy Chakraborty <joychakr@xxxxxxxxxx> >>> --- >>> Documentation/devicetree/bindings/dma/arm,pl330.yaml | 8 ++++++++ >>> 1 file changed, 8 insertions(+) >>> >>> diff --git a/Documentation/devicetree/bindings/dma/arm,pl330.yaml b/Documentation/devicetree/bindings/dma/arm,pl330.yaml >>> index 4a3dd6f5309b..0499a7fba88d 100644 >>> --- a/Documentation/devicetree/bindings/dma/arm,pl330.yaml >>> +++ b/Documentation/devicetree/bindings/dma/arm,pl330.yaml >>> @@ -53,6 +53,14 @@ properties: >>> type: boolean >>> description: quirk for performing burst transfer only >>> >>> + arm,pl330-optimize-dev2mem-axsize: >>> + type: boolean >>> + description: quirk for optimizing AxSize used between dev<->mem >> >> This tells me nothing... Neither what it is about nor why this is >> property of a board or PL330 hardware implementation. Please describe >> hardware, not drivers. >> > > Will change the name to "arm,pl330-periph-use-diff-axsize" and add description: > " > Quirk to use different AxSize for bursts while accessing source and > destination when moving data between memory and peripheral. > Maximum possible bus width is used as AxSize for transactions towards > memory and transactions towards peripherals use AxSize as per > peripheral address width. > " Still no answer. Why this is property of a board or PL330 hardware implementation? I also asked to describe hardware but I still see "quirk to ...". We use "quirk" as concept in Linux driver. Describe the hardware, not Linux driver. > >>> + >>> + arm,pl330-periph-single-dregs: >>> + type: boolean >>> + description: quirk for using dma-singles for peripherals in _dregs() >> >> Same concerns. >> > > Will change the name to "arm,pl330-periph-complete-with-singles" and > add description: > " > Quirk to use dma singles n times instead of an n beat burst to > complete a transfer when the transfer size is not a multiple of the No, how you wrote it sounds like driver. Don't add driver quirks to DT. Best regards, Krzysztof
