Date: Thu, 11 Jan 2024 15:14:18 +0200
From: Oded Gabbay <ogabbay@...nel.org>
To: Tomeu Vizoso <tomeu@...euvizoso.net>,
 Cancan Chang <Cancan.Chang@...ogic.com>
Cc: Jagan Teki <jagan@...eble.ai>, linux-media <linux-media@...r.kernel.org>,
 linux-kernel <linux-kernel@...r.kernel.org>, Dave Airlie
 <airlied@...hat.com>, Daniel Vetter <daniel.vetter@...ll.ch>
Subject: Re: kernel.org 6.5.4 , NPU driver, --not support (RFC)

On 11/01/2024 10:04, Tomeu Vizoso wrote:
> Hi Oded,
> 
> Out of curiosity, did you end up taking a look at Amlogic's driver?
> 
> Cheers,
> 
> Tomeu
Hi Tomeu,
Yes, I have looked at the driver's code. It was not an in-depth review, 
but I tried to mainly understand the features the driver provide to the 
user and how much complex it is.

 From what I could see, this is a full-fledged accelerator which 
requires command submission/completion handling, memory management, 
information and debug capabilities and more.

Therefore, I do think the correct place is in the accel sub-system, 
which will require you to convert the driver to use drm (we can discuss 
exactly what is the level of integration required).

As I said, I didn't do a full-fledged review, but please note the driver 
has a lot of OS-wrapper code, which is not acceptable in the Linux 
kernel, so you will have to clean all the up.

Thanks,
Oded

> 
> On Sat, Oct 7, 2023 at 8:37 AM Cancan Chang <Cancan.Chang@...ogic.com> wrote:
>>
>> Oded,
>>         You can get the driver code from  github link： https://github.com/OldDaddy9/driver
>>          e.g.  git clone https://github.com/OldDaddy9/driver.git
>>
>> ________________________________________
>> 发件人: Oded Gabbay <ogabbay@...nel.org>
>> 发送时间: 2023年10月3日 18:52
>> 收件人: Cancan Chang
>> 抄送: Jagan Teki; linux-media; linux-kernel; Dave Airlie; Daniel Vetter
>> 主题: Re: kernel.org 6.5.4 , NPU driver, --not support (RFC)
>>
>> [ EXTERNAL EMAIL ]
>>
>> On Thu, Sep 28, 2023 at 11:16 AM Cancan Chang <Cancan.Chang@...ogic.com> wrote:
>>>
>>> “What happens if you call this again without waiting for the previous
>>> inference to complete ?”
>>>     --- There is a work-queue in the driver to manage inference tasks.
>>>           When two consecutive inference tasks occur, the second inference task will be add to
>>>           the "pending list". While the previous inference task ends, the second inference task will
>>>           switch to the "scheduled list", and be executed.
>>>           Each inference task has an id,  "inferece" and "wait until finish" are paired.
>>>
>>>           thanks
>> Thanks for the clarification.
>> I'll wait for your driver's code link. It doesn't have to be a patch
>> series at this point. A link to a git repo is enough.
>> I just want to do a quick pass.
>>
>> Thanks,
>> Oded
>>
>>
>>
>>>
>>> ________________________________________
>>> 发件人: Oded Gabbay <ogabbay@...nel.org>
>>> 发送时间: 2023年9月28日 15:40
>>> 收件人: Cancan Chang
>>> 抄送: Jagan Teki; linux-media; linux-kernel; Dave Airlie; Daniel Vetter
>>> 主题: Re: kernel.org 6.5.4 , NPU driver, --not support (RFC)
>>>
>>> [ EXTERNAL EMAIL ]
>>>
>>> On Thu, Sep 28, 2023 at 10:25 AM Cancan Chang <Cancan.Chang@...ogic.com> wrote:
>>>>
>>>> “Could you please post a link to the driver's source code ?
>>>> In addition, could you please elaborate which userspace libraries
>>>> exists that work with your driver ? Are any of them open-source ?”
>>>> --- We will prepare the adla driver link after the holiday on October 6th.
>>>>       It's a pity that there is no open-source userspace library.
>>>>       But you can probably understand it through a workflow, which can be simplified as:
>>>>       1. create model context
>>>>            ret = ioctl(context->fd, ADLAK_IOCTL_REGISTER_NETWORK, &desc);
>>>>       2.  set inputs
>>>>       3.  inference
>>>>             ret = ioctl(context->fd, ADLAK_IOCTL_INVOKE, &invoke_dec);
>>> What happens if you call this again without waiting for the previous
>>> inference to complete ?
>>> Oded
>>>>       4.  wait for the inference to complete
>>>>             ret = ioctl(context->fd, ADLAK_IOCTL_WAIT_UNTIL_FINISH, &stat_req_desc);
>>>>       5.  destroy model context
>>>>             ret = ioctl(context->fd, ADLAK_IOCTL_DESTROY_NETWORK, &submit_del);
>>>>
>>>>
>>>>        thanks
>>>>
>>>>
>>>> ________________________________________
>>>> 发件人: Oded Gabbay <ogabbay@...nel.org>
>>>> 发送时间: 2023年9月28日 13:28
>>>> 收件人: Cancan Chang
>>>> 抄送: Jagan Teki; linux-media; linux-kernel; Dave Airlie; Daniel Vetter
>>>> 主题: Re: kernel.org 6.5.4 , NPU driver, --not support (RFC)
>>>>
>>>> [ EXTERNAL EMAIL ]
>>>>
>>>> On Wed, Sep 27, 2023 at 10:01 AM Cancan Chang <Cancan.Chang@...ogic.com> wrote:
>>>>>
>>>>> “Or do you handle one cmd at a time, where the user sends a cmd buffer
>>>>> to the driver and the driver then submit it by writing to a couple of
>>>>> registers and polls on some status register until its done, or waits
>>>>> for an interrupt to mark it as done ?”
>>>>>    --- yes， user sends a cmd buffer to driver, and driver triggers hardware by writing to register,
>>>>>          and then, waits for an interrupt to mark it  as done.
>>>>>
>>>>>      My current driver is very different from drm, so I want to know if I have to switch to drm？
>>>> Could you please post a link to the driver's source code ?
>>>> In addition, could you please elaborate which userspace libraries
>>>> exists that work with your driver ? Are any of them open-source ?
>>>>
>>>>>      Maybe I can refer to /driver/accel/habanalabs.
>>>> That's definitely a possibility.
>>>>
>>>> Oded
>>>>>
>>>>> thanks
>>>>>
>>>>> ________________________________________
>>>>> 发件人: Oded Gabbay <ogabbay@...nel.org>
>>>>> 发送时间: 2023年9月26日 20:54
>>>>> 收件人: Cancan Chang
>>>>> 抄送: Jagan Teki; linux-media; linux-kernel; Dave Airlie; Daniel Vetter
>>>>> 主题: Re: kernel.org 6.5.4 , NPU driver, --not support (RFC)
>>>>>
>>>>> [ EXTERNAL EMAIL ]
>>>>>
>>>>> On Mon, Sep 25, 2023 at 12:29 PM Cancan Chang <Cancan.Chang@...ogic.com> wrote:
>>>>>>
>>>>>> Thank you for your reply from Jagan & Oded.
>>>>>>
>>>>>> It is very appropritate for my driver to be placed in driver/accel.
>>>>>>
>>>>>> My accelerator is named ADLA(Amlogic Deep Learning Accelerator).
>>>>>> It is an IP in SOC,mainly used for neural network models acceleration.
>>>>>> It will split and compile the neural network model into a private format cmd buffer,
>>>>>> and submit this cmd buffer to ADLA hardware. It is not programmable device.
>>>>> What exactly does it mean to "submit this cmd buffer to ADLA hardware" ?
>>>>>
>>>>> Does your h/w provides queues for the user/driver to put their
>>>>> workloads/cmd-bufs on them ? And does it provide some completion queue
>>>>> to notify when the work is completed?
>>>>>
>>>>> Or do you handle one cmd at a time, where the user sends a cmd buffer
>>>>> to the driver and the driver then submit it by writing to a couple of
>>>>> registers and polls on some status register until its done, or waits
>>>>> for an interrupt to mark it as done ?
>>>>>
>>>>>>
>>>>>> ADLA includes four hardware engines:
>>>>>> RS engines             : working for the reshape operators
>>>>>> MAC engines         : working for the convolution operators
>>>>>> DW engines           : working for the planer & Elementwise operators
>>>>>> Activation engines : working for activation operators(ReLu,tanh..)
>>>>>>
>>>>>> By the way, my IP is mainly used for SOC, and the current driver registration is through the platform_driver,
>>>>>> is it necessary to switch to drm?
>>>>> This probably depends on the answer to my question above. btw, there
>>>>> are drivers in drm that handle IPs that are part of an SOC, so
>>>>> platform_driver is supported.
>>>>>
>>>>> Oded
>>>>>
>>>>>>
>>>>>> thanks.
>>>>>>
>>>>>> ________________________________________
>>>>>> 发件人: Oded Gabbay <ogabbay@...nel.org>
>>>>>> 发送时间: 2023年9月22日 23:08
>>>>>> 收件人: Jagan Teki
>>>>>> 抄送: Cancan Chang; linux-media; linux-kernel; Dave Airlie; Daniel Vetter
>>>>>> 主题: Re: kernel.org 6.5.4 , NPU driver, --not support (RFC)
>>>>>>
>>>>>> [你通常不会收到来自 ogabbay@...nel.org 的电子邮件。请访问 https://aka.ms/LearnAboutSenderIdentification，以了解这一点为什么很重要]
>>>>>>
>>>>>> [ EXTERNAL EMAIL ]
>>>>>>
>>>>>> On Fri, Sep 22, 2023 at 12:38 PM Jagan Teki <jagan@...eble.ai> wrote:
>>>>>>>
>>>>>>> On Fri, 22 Sept 2023 at 15:04, Cancan Chang <Cancan.Chang@...ogic.com> wrote:
>>>>>>>>
>>>>>>>> Dear Media Maintainers:
>>>>>>>>       Thanks for your attention. Before describing my problem，let me introduce to you what I  mean by NPU.
>>>>>>>>       NPU is Neural Processing Unit, It is designed for deep learning acceleration, It is also called TPU, APU ..
>>>>>>>>
>>>>>>>>       The real problems:
>>>>>>>>        When I was about to upstream my NPU driver codes to linux mainline, i meet two problems:
>>>>>>>>          1.  According to my research, There is no NPU module path in the linux (base on linux 6.5.4) , I have searched all linux projects and found no organization or comany that has submitted NPU code. Is there a path prepared for NPU driver currently?
>>>>>>>>          2.   If there is no NPU driver path currently, I am going to put my NPU driver code in the drivers/media/platform/amlogic/ , because my NPU driver belongs to amlogic. and amlogic NPU is mainly used for AI vision applications. Is this plan suitabe for you?
>>>>>>>
>>>>>>> If I'm correct about the discussion with Oded Gabby before. I think
>>>>>>> the drivers/accel/ is proper for AI Accelerators including NPU.
>>>>>>>
>>>>>>> + Oded in case he can comment.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Jagan.
>>>>>> Thanks Jagan for adding me to this thread. Adding Dave & Daniel as well.
>>>>>>
>>>>>> Indeed, the drivers/accel is the place for Accelerators, mainly for
>>>>>> AI/Deep-Learning accelerators.
>>>>>> We currently have 3 drivers there already.
>>>>>>
>>>>>> The accel subsystem is part of the larger drm subsystem. Basically, to
>>>>>> get into accel, you need to integrate your driver with the drm at the
>>>>>> basic level (registering a device, hooking up with the proper
>>>>>> callbacks). ofc the more you use code from drm, the better.
>>>>>> You can take a look at the drivers under accel for some examples on
>>>>>> how to do that.
>>>>>>
>>>>>> Could you please describe in a couple of sentences what your
>>>>>> accelerator does, which engines it contains, how you program it. i.e.
>>>>>> Is it a fixed-function device where you write to a couple of registers
>>>>>> to execute workloads, or is it a fully programmable device where you
>>>>>> load compiled code into it (GPU style) ?
>>>>>>
>>>>>> For better background on the accel subsystem, please read the following:
>>>>>> https://docs.kernel.org/accel/introduction.html
>>>>>> This introduction also contains links to other important email threads
>>>>>> and to Dave Airlie's BOF summary in LPC2022.
>>>>>>
>>>>>> Thanks,
>>>>>> Oded

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