[PATCH v2 02/13] dmaengine: pl330: Add quirk 'arm,pl330-periph-burst'
Vinod Koul
vkoul at kernel.org
Wed Jun 24 04:19:29 EDT 2020
On 09-06-20, 09:14, Sugar Zhang wrote:
> This patch adds the qurik to use busrt transfers only
s/busrt/burst
> for pl330 controller, even for request with a length of 1.
>
> Although, the correct way should be: if the peripheral request
> length is 1, the peripheral should use SINGLE request, and then
> notify the dmac using SINGLE mode by src/dst_maxburst with 1.
>
> For example, on the Rockchip SoCs, all the peripherals can use
> SINGLE or BURST request by setting GRF registers. it is possible
> that if these peripheral drivers are used only for Rockchip SoCs.
> Unfortunately, it's not, such as dw uart, which is used so widely,
> and we can't set src/dst_maxburst according to the SoCs' specific
> to compatible with all the other SoCs.
>
> So, for convenience, all the peripherals are set as BURST request
> by default on the Rockchip SoCs. even for request with a length of 1.
> the current pl330 driver will perform SINGLE transfer if the client's
> maxburst is 1, which still should be working according to chapter 2.6.6
> of datasheet which describe how DMAC performs SINGLE transfers for
> a BURST request. unfortunately, it's broken on the Rockchip SoCs,
s/unfortunately/Unfortunately
> which support only matching transfers, such as BURST transfer for
> BURST request, SINGLE transfer for SINGLE request.
>
> Finaly, we add the quirk to specify pl330 to use burst transfers only.
s/Finaly/Finally
Below looks fine, pls reorder the series and have binding patch come
first and then the use of binding. Below looks fine though
--
~Vinod
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