quoted

Okay, so each child device may allocate a buffer like this during probe():
priv->xmit_buf = devm_kcalloc(dev, MAX_PACKET_SZ, sizeof(unsigned char),
GFP_KERNEL), right?

basically yes, probably devm_kzalloc() or embed it into the priv struct
directly with ____cacheline_aligned:

| https://elixir.bootlin.com/linux/v6.11.5/source/drivers/net/can/spi/mcp251xfd/mcp251xfd.h#L498

The size of the driver's RX and TX buffers depend on what they want to
send and expect to receive. The next step would be to create structs the
describe the RX and TX buffers for each driver. If you have a common
header between each driver, create that first.

regards,
Marc

Understood, I'll make these modifications in the next patch.

Thanks,
Ming