Date:   Tue, 21 Mar 2023 20:21:33 +0800
From:   Cai Huoqing <cai.huoqing@linux.dev>
To:     Serge Semin <fancer.lancer@gmail.com>
Cc:     Gustavo Pimentel <gustavo.pimentel@synopsys.com>,
        Vinod Koul <vkoul@kernel.org>,
        Jingoo Han <jingoohan1@gmail.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Krzysztof =?utf-8?Q?Wilczy=C5=84ski?= <kw@linux.com>,
        Rob Herring <robh@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>,
        linux-kernel@vger.kernel.org, dmaengine@vger.kernel.org,
        linux-pci@vger.kernel.org
Subject: Re: [PATCH v7 0/5] dmaengine: dw-edma: Add support for native HDMA
Message-ID: <ZBmhTch4d2CG4TtH@chq-MS-7D45>
References: <20230315012840.6986-1-cai.huoqing@linux.dev>
 <20230320121401.zkcjbqmghzacpffh@mobilestation>
 <ZBkXEzoZZlIy18xB@chq-MS-7D45>
 <20230321083407.5gc432ttjhwbi2um@mobilestation>
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On 21 3月 23 11:34:07, Serge Semin wrote:
> On Tue, Mar 21, 2023 at 10:31:47AM +0800, Cai Huoqing wrote:
> > On 20 3月 23 15:14:01, Serge Semin wrote:
> > > Hi Cai
> > > 
> > > On Wed, Mar 15, 2023 at 09:28:31AM +0800, Cai Huoqing wrote:
> > > > Add support for HDMA NATIVE, as long the IP design has set
> > > > the compatible register map parameter-HDMA_NATIVE,
> > > > which allows compatibility for native HDMA register configuration.
> > > > 
> > > > The HDMA Hyper-DMA IP is an enhancement of the eDMA embedded-DMA IP.
> > > > And the native HDMA registers are different from eDMA,
> > > > so this patch add support for HDMA NATIVE mode.
> > > > 
> > > > HDMA write and read channels operate independently to maximize
> > > > the performance of the HDMA read and write data transfer over
> > > > the link When you configure the HDMA with multiple read channels,
> > > > then it uses a round robin (RR) arbitration scheme to select
> > > > the next read channel to be serviced.The same applies when
> > > > youhave multiple write channels.
> > > > 
> > > > The native HDMA driver also supports a maximum of 16 independent
> > > > channels (8 write + 8 read), which can run simultaneously.
> > > > Both SAR (Source Address Register) and DAR (Destination Address Register)
> > > > are aligned to byte.
> > > 
> > > It seems like we are getting towards the series finalization. I'll
> > > test it out on my HW after v8 is submitted. Meanwhile could you please
> > > clarify whether you have a real device with DW HDMA engine on board?
> > 
> 
> > Our hardware is an AI Accelerartor(PCIE Card).
> > 
> > The device pci.ids is 1d22:3864
> > in https://github.com/pciutils/pciids/blob/master/pci.ids
> > line 24737,
> > 
> > "1d22  Baidu Technology
> >         3684  Kunlun AI Accelerator
> >         3685  Kunlun2 AI Accelerator [VF]"
> > 
> > And our device driver is not ready to upstream(will cost serveral
> > 
> > months to port DRM etc.),
> 
> Ok. Thanks for clarification. Could you please add me to the Cc-list of
> the AI-accelerator patch when it's ready to be submitted for review. I am
> not that familiar with the DRM-part, but would like to have a look at
> the DMA-related code.
Sure, I'll Cc you if I send the patches.

By the way, Why use native hdma:

Our device v1 also use dw-edma. But we find that navtive HDMA work better

in SRIOV on, channel CSR can be map to every VF instead of some global

regiter must in PF. So v2 use native hdma.

Thanks,
-Cai

> 
> -Serge(y)
> 
> > 
> > but I have taken this DW eDMA core into our driver test.
> > 
> > Thanks
> > Cai-
> > 
> > > You keep submitting the DW eDMA driver core update, but there is no
> > > glue-driver or low-level device driver patch for a real device which
> > > would set the EDMA_MF_HDMA_NATIVE mapping.
> > > 
> > > -Serge(y)
> > > 
> > > > 
> > > > Cai Huoqing (2):
> > > >   dmaengine: dw-edma: Add support for native HDMA
> > > >   dmaengine: dw-edma: Optimization in dw_edma_v0_core_handle_int
> > > > 
> > > > Cai huoqing (3):
> > > >   dmaengine: dw-edma: Rename dw_edma_core_ops structure to
> > > >     dw_edma_plat_ops
> > > >   dmaengine: dw-edma: Create a new dw_edma_core_ops structure to
> > > >     abstract controller operation
> > > >   dmaengine: dw-edma: Add HDMA DebugFS support
> > > > 
> > > > v6->v7:
> > > >   [1/5]
> > > >   1.Update the commit log.
> > > >   [2/5]
> > > >   2.Revert dw_edma_core_handle_int back to dw-edma-core.h.
> > > >   3.Fix code style.
> > > >   [3/5]
> > > >   4.Move the change of register file from patch[4/5] to patch[3/5].
> > > >   5.Fix code style.
> > > > 
> > > > v6 link:
> > > >   https://lore.kernel.org/lkml/20230310032342.17395-1-cai.huoqing@linux.dev/
> > > > 
> > > >  drivers/dma/dw-edma/Makefile                 |   8 +-
> > > >  drivers/dma/dw-edma/dw-edma-core.c           |  86 ++----
> > > >  drivers/dma/dw-edma/dw-edma-core.h           |  58 ++++
> > > >  drivers/dma/dw-edma/dw-edma-pcie.c           |   4 +-
> > > >  drivers/dma/dw-edma/dw-edma-v0-core.c        |  91 ++++--
> > > >  drivers/dma/dw-edma/dw-edma-v0-core.h        |  14 +-
> > > >  drivers/dma/dw-edma/dw-hdma-v0-core.c        | 277 +++++++++++++++++++
> > > >  drivers/dma/dw-edma/dw-hdma-v0-core.h        |  17 ++
> > > >  drivers/dma/dw-edma/dw-hdma-v0-debugfs.c     | 176 ++++++++++++
> > > >  drivers/dma/dw-edma/dw-hdma-v0-debugfs.h     |  22 ++
> > > >  drivers/dma/dw-edma/dw-hdma-v0-regs.h        | 130 +++++++++
> > > >  drivers/pci/controller/dwc/pcie-designware.c |   2 +-
> > > >  include/linux/dma/edma.h                     |   7 +-
> > > >  13 files changed, 785 insertions(+), 107 deletions(-)
> > > >  create mode 100644 drivers/dma/dw-edma/dw-hdma-v0-core.c
> > > >  create mode 100644 drivers/dma/dw-edma/dw-hdma-v0-core.h
> > > >  create mode 100644 drivers/dma/dw-edma/dw-hdma-v0-debugfs.c
> > > >  create mode 100644 drivers/dma/dw-edma/dw-hdma-v0-debugfs.h
> > > >  create mode 100644 drivers/dma/dw-edma/dw-hdma-v0-regs.h
> > > > 
> > > > -- 
> > > > 2.34.1
> > > >