AW: CAN driver implementation for Xilinx Zynq

[Carlo.Brokering at dlr.de]

Hello Prashanth S,

 

the design for the rx data path including the RxFIFO looks promising. If nobody is working on it yet, I would try to implement it. You said it still needs to be approved - who do I have to contact for this?

 

I think you misunderstood me about the ioctl api. My main question was why command and buffer are not passed to the dev_ioctl here:

 

bus->can_dev_ops->dev_ioctl(bus->priv, NULL, 0);

 

Regards

Carlo Brokering

 

Von: Prashanth S <fishesprashanth at gmail.com> 
Gesendet: Mittwoch, 1. März 2023 11:53
An: Brokering, Carlo <Carlo.Brokering at dlr.de>
Cc: devel at rtems.org
Betreff: Re: CAN driver implementation for Xilinx Zynq

 

Hello @Carlo Brokering,

 

> As part of an internship at the German Aerospace Center, I am currently working on the implementation of a CAN driver for a Xilinx

> Zynq SoC. For this I used the existing CAN framework /dev/can/can.h. A merge request will follow soon.

All the best for your Internship.

> 

>
> Here's what I'd like to add to the framework if it hasn't already been done:
>
> * RxFIFO. Currently can_bus_read only stores the latest CAN message in can_bus->can_rx_msg.

> There is a FIXME note on this in can.c, line 188, but I couldn't find an implementation of it.

Currently, the CAN framework has minimal rx support. The design of the rx data path in the CAN Framework is ready (You could use that design if approved or you can have your own design).

 

Note: The tx data path has been implemented, it supports multiple open among different tasks, configurable buffers.

>
> * ioctl functionality. can_bus_ioctl does not forward the commands and arguments to can_dev_ops->dev_ioctl.

> Is there a reason for that? I propose a command enum that would provide consistency.

The bsp CAN driver should register the ioctl api with the CAN Framework for device specific commands (To add commands for hardware independent functionality the commands can be added before "if (bus == NULL || bus->can_dev_ops->dev_ioctl == NULL)" statement.

 

struct can_dev_ops dev_ops (.dev_ioctl member should be registered).

> 

>
> @Prashanth S (fishesprashanth at gmail.com <mailto:fishesprashanth at gmail.com> ) have you already worked on these points?

 

For the overview of the CAN framework, tx, rx, data paths you can refer the docs files in the gitlab link (.puml version of the docs are also available if you needed (https://gitlab.com/slpp95prashanth/gsoc-2022/-/commit/f42e192afefdd94a66456181f9d169f0728d5b4f)).

 

You can use the gitlab https://gitlab.com/slpp95prashanth/gsoc-2022/-/tree/can-bsp-docs/can-docs link for the design documents.

 

Regards

Prashanth S

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