[PATCH v2 02/13] dmaengine: pl330: Add quirk 'arm,pl330-periph-burst'
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
> 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,
> 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.
Below looks fine, pls reorder the series and have binding patch come
first and then the use of binding. Below looks fine though
More information about the Linux-rockchip