Subject: [PATCH v7 0/9] Fix broken DMAFLUSHP on Rockchips platform

From: [email-masked] (Vinod Koul)
Date: Mon, 8 Feb 2016 08:41:34 +0530

On Mon, Feb 01, 2016 at 02:56:54PM +0800, Caesar Wang wrote:
> Hello Vinod,
> 
> Is there any chance apply the DMA patches?:-)

I was waiting for any ACKs on ARM patches before I merge this series.

> ? 2016?01?22? 19:06, Caesar Wang ??:
> >This series patches are apply on linus master branch.
> >Okay, this series patches verified on my github.
> >(https://github.com/Caesar-github/rockchip/commits/for-dma-tests)
> >
> >Linux version 4.4.0+ (wxt at ubuntu)  (Ubuntu/Linaro 4.7.3-12ubuntu1) ) #14
> >SMP Fri Jan 22 18:13:12 CST 2016
> >
> >The perious version 6 from Shawn.
> >(http://www.spinics.net/lists/dmaengine/msg06606.html)
> >I pick them up to go on upstream since Shawn hasn't much time to track them.
> >----
> >
> >The purpose of the DMAFLUSHP instruction:
> >- Tell the peripheral to clear its status and control registers.
> >- Send a message to the peripheral to resend its level status.
> >
> >There are 3 timings described in PL330 Technical Reference Manual:
> >- Timing 1: Burst request, can work well without DMAFLUSHP.
> >- Timing 2: Single and burst request, DMAC will ignore the single
> >             transfer request. This timing happens if there are single
> >             and burst request.
> >- Timing 3: Single transfers for a burst request, DMAC should signals
> >             datype to request the peripheral to flush the contents of
> >             any control registers. This timing happens if there is
> >             not enough MFIFO to places the burst data.
> >
> >A peripheral may signal a DMA request during the execution of
> >DMAFLUSHP instruction, that cause DMA request being ignored by DMAC.
> >
> >But DMAC and all peripherals on RK3X SoCs DO NOT support DMAFLUSHP.
> >It can't send a message to the peripheral to resend DMA request,
> >and the peripheral can't acknowledge a flush request from DMAC.
> >So all DMA requests should NOT be ignored by DMAC, and DMAC will not
> >notify the peripheral to flush.
> >
> >To fix this problem, we need:
> >- Do NOT execute DMAFLUSHP instruction.
> >- Timing 2 and timing 3 should not happen.
> >
> >Because on RK3X SoCs, there are 6 or below  channels and 32 MFIFO depth
> >for DMAC_BUS, and 8 channels and 64 MFIFO depth for DMAC_PERI, it is
> >impossible to hit the timing 3 if burst length is equal or less than 4.
> >
> >Since the request type signal by the peripheral can only be set by
> >software. We can set Rockchip Soc's GRF_PERIDMAC_CON0[2:1] to select single
> >or burst request, if it is set b01,  all of the peripharals will signal a brust
> >request. So the timing 2 will not happen, too.
> >
> >So DMAC on RK3X can support single or burst transfer, but can't support
> >mixed transfer.
> >
> >Because burst transfer is more efficient than single transfer, this is
> >confirmed by our ASIC team, who strongly suggest to use burst transfer.
> >And this is confirmed by Addy's test on RK3288-Pink2 board, the speed of
> >spi flash burst transfer will increase about two times than single transfer.
> >Also, I have tested dw_mmc with pl330 on RK3188 platform to double confirm
> >the result. That means burst transfer is reansonable.
> >
> >So we need a quirk not to execute DMAFLUSHP instruction and to use burst
> >transfer.
> >
> >Note:
> >- The Rockchip Soc default value of GRF_PERIDMAC_CON0[2:1] is b01. To
> >   support brust transfer, these bits should not be changed in bootloader.
> >
> >Todo:
> >remove the patches releated to i2s, that will send them at later.
> >- https://patchwork.kernel.org/patch/7399581/
> >- https://patchwork.kernel.org/patch/7399671/
> >
> >
> >Changes in v7:
> >- As vinod comments, fix the subsystem name.
> >- modify the subject to be better match.
> >- fix the subsystem.
> >- fix the subject.
> >- fix the subject.
> >
> >Changes in v6:
> >- remove expose quirk and add dma max_burst caps for clients
> >- remove expose quirks and add max_burst for dmaengine
> >- remove quirks and get dma caps in order to limit burst
> >
> >Changes in v5:
> >- add Mark's tag for spi changes
> >- remove unnecessary whitespace change
> >- use switch statement for i2s quirk
> >
> >Changes in v4:
> >- remove spi & i2s dts changes and query quirk from dmaengine API
> >   suggeseted by Mark.
> >- fix typo
> >- Add dmaengine_get_quirk hook and implement it for pl330
> >
> >Changes in v3:
> >- add Sunny's tag
> >- add more rockchip drivers' changes in this patchset
> >- add Reviewed-by: Sonny Rao <[email-masked]>
> >- add Reviewed-by: Sonny Rao <[email-masked]>
> >- add Reviewed-by: Sonny Rao <[email-masked]>
> >
> >Changes in v2:
> >- amend the author
> >- reorder the patches suggested by Doug
> >- add Reviewed-by: Doug Anderson <[email-masked]> for
> >   rk3288.dtsi patch and arm-pl330.txt patch
> >- add Reviewed-by: Doug Anderson <[email-masked]>
> >- amend the author
> >- fix Olof's mail address
> >- amend the author
> >- add Reviewed-by: Doug Anderson <[email-masked]>
> >- amend Olof's mail address
> >
> >Changes in v1:
> >- rename broken-no-flushp to "arm,pl330-broken-no-flushp" suggested
> >   by Krzysztof.
> >- add From original author.
> >- remove Sunny's tag
> >- rename broken-no-flushp to "arm,pl330-broken-no-flushp" suggested
> >   by Krzysztof.
> >- rename broken-no-flushp to "arm,pl330-broken-no-flushp" suggested
> >   by Krzysztof.
> >- remove Sunny's tag
> >- rename broken-no-flushp to "arm,pl330-broken-no-flushp" suggested
> >   by Krzysztof.
> >   - remove Sunny's tag
> >- rename broken-no-flushp to "arm,pl330-broken-no-flushp" suggested
> >   by Krzysztof.
> >
> >Addy Ke (3):
> >   dmaengine: pl330: add quirk for broken no flushp
> >   ARM: dts: Add arm, pl330-broken-no-flushp quirk for rk3288 platform
> >   spi: rockchip: modify DMA max burst to 1
> >
> >Boojin Kim (1):
> >   dmaengine: pl330: support burst mode for dev-to-mem and mem-to-dev
> >     transmit
> >
> >Caesar Wang (1):
> >   ARM: dts: add pl330-broken-no-flushp quirk for rk3036 SoCs
> >
> >Shawn Lin (4):
> >   dt/bindings: arm-pl330: add description of arm, pl330-broken-no-flushp
> >   ARM: dts: Add arm, pl330-broken-no-flushp quirk for rk3xxx platform
> >   dmaengine: core: expose max burst capability to clients
> >   dmaengine: pl330: add max burst for dmaengine
> >
> >  .../devicetree/bindings/dma/arm-pl330.txt          |   1 +
> >  arch/arm/boot/dts/rk3036.dtsi                      |   1 +
> >  arch/arm/boot/dts/rk3288.dtsi                      |   3 +
> >  arch/arm/boot/dts/rk3xxx.dtsi                      |   3 +
> >  drivers/dma/dmaengine.c                            |   1 +
> >  drivers/dma/pl330.c                                | 106 +++++++++++++++------
> >  drivers/spi/spi-rockchip.c                         |  12 ++-
> >  include/linux/dmaengine.h                          |   4 +
> >  8 files changed, 99 insertions(+), 32 deletions(-)
> >
> 
> 
> -- 
> Thanks,
> Caesar
> 

-- 
~Vinod