Re: [PATCH v2] mtd: mtk-quadspi: add support for DMA reading

[Chuanhong Guo]

Hi all!

On Sat, Feb 8, 2020 at 4:41 PM Chuanhong Guo <gch981213@xxxxxxxxx> wrote:
>
> PIO reading mode on this controller is pretty inefficient
> (one cmd+addr+dummy sequence reads only one byte)
> This patch adds support for reading using DMA mode which increases
> reading speed from 1MB/s to 4MB/s
>
> DMA busy checking is implemented with readl_poll_timeout because
> I don't have access to IRQ-related docs. The speed increment comes
> from those saved cmd+addr+dummy clocks.
>
> This controller requires that DMA source/destination address and
> reading length should be 16-byte aligned. We use a bounce buffer if
> one of them is not aligned, read more than what we need, and copy
> data from corresponding buffer offset.
>
> Signed-off-by: Chuanhong Guo <gch981213@xxxxxxxxx>

This patch is deprecated. I wrote a new spi-mem driver for this
controller:
https://patchwork.ozlabs.org/project/linux-mtd/list/?series=158701
and will be focus on getting that one merged instead.
-- 
Regards,
Chuanhong Guo