Re: [PATCH v23 1/2] mailbox/pcc: support mailbox management of the shared buffer

[Simon Horman <horms@kernel.org>]

On Mon, Jul 14, 2025 at 08:10:07PM -0400, admiyo@os.amperecomputing.com wrote:
> From: Adam Young <admiyo@os.amperecomputing.com>
> 
> Define a new, optional, callback that allows the driver to
> specify how the return data buffer is allocated.  If that callback
> is set,  mailbox/pcc.c is now responsible for reading from and
> writing to the PCC shared buffer.
> 
> This also allows for proper checks of the Commnand complete flag
> between the PCC sender and receiver.

Command

> 
> For Type 4 channels, initialize the command complete flag prior
> to accepting messages.
> 
> Since the mailbox does not know what memory allocation scheme
> to use for response messages, the client now has an optional
> callback that allows it to allocate the buffer for a response
> message.
> 
> When an outbound message is written to the buffer, the mailbox
> checks for the flag indicating the client wants an tx complete
> notification via IRQ.  Upon receipt of the interrupt It will
> pair it with the outgoing message. The expected use is to
> free the kernel memory buffer for the previous outgoing message.
> 
> Signed-off-by: Adam Young <admiyo@os.amperecomputing.com>

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