driver: can: add new filter to match CAN-FD frames

[congnguyenhuu]

Add support FD frame filter to configure type frame for each Rx msg to receive corresponding frames (classic, FD frames).

I have a PR #52450 which introduces support for NXP S32 CANEXCEL, it need to implement this.

[henrikbrixandersen]

Still evaluating the idea of this API change, but if we are to add it we need the existing in-tree CAN-FD driver (yes, there's only one: Bosch M_CAN) adapted to support this and a test case added to prove it.

[congnguyenhuu]

Member

Still evaluating the idea of this API change, but if we are to add it we need the existing in-tree CAN-FD driver (yes, there's only one: Bosch M_CAN) adapted to support this and a test case added to prove it.

I think we should only add the filter type frame to can drivers which require eg. NXP S32 CANEXCEL. I see Bosch M_CAN doesn't require this.
So I added a Kconfig to enable filter type frame. We can use if driver require. And I modified the test canfd to support this.
But now I don't have any board (run CAN-FD over Bosch M_CAN) to check it. Anyone have board, pls help me run it?

[henrikbrixandersen]

I think we should only add the filter type frame to can drivers which require eg. NXP S32 CANEXCEL.

No. That will lead to different APIs for different CAN controllers, making it difficult to write portable application code. This is not an acceptable solution.

I see Bosch M_CAN doesn't require this.

It doesn't require it, but it could support it.

The above is exactly why I still hesitate in accepting this API change. We need to think carefully about user applications, portability, and support from more than just one driver/hardware peripheral.

[congnguyenhuu]

No. That will lead to different APIs for different CAN controllers, making it difficult to write portable application code. This is not an acceptable solution.

But in Bosch M_CAN driver, mcan filter no has field to configure filter type frame.

struct can_mcan_std_filter {
	volatile uint32_t id2  : 11; /* ID2 for dual or range, mask otherwise */
	volatile uint32_t res  :  5;
	volatile uint32_t id1  : 11;
	volatile uint32_t sfce :  3; /* Filter config */
	volatile uint32_t sft  :  2; /* Filter type */
} __packed __aligned(4);

[henrikbrixandersen]

But in Bosch M_CAN driver, mcan filter no has field to configure filter type frame.

It doesn't have a field for RTR either, but that is handled in software. Something similar can be done for FDF.

[congnguyenhuu]

It doesn't have a field for RTR either, but that is handled in software. Something similar can be done for FDF.

Great ! I handled in software as you said.

[henrikbrixandersen]

You need to update can_utils_filter_match() in drivers/can/can_utils.h to handle the new flag as well.

[congnguyenhuu]

You need to update can_utils_filter_match() in drivers/can/can_utils.h to handle the new flag as well.

I updated for handling it

[henrikbrixandersen]

Thanks! Looks good. Apologies for the review delay.

[congnguyenhuu]

Thanks! Looks good. Apologies for the review delay.

Thank you.

[martinjaeger]

Looks good. Thanks for the fix.