[PATCHv2 2/4] mailbox: Introduce a new common API

[Jassi Brar]

On Thu, May 9, 2013 at 10:10 PM, Suman Anna <s-anna at ti.com> wrote:
> On 05/09/2013 11:41 AM, Jassi Brar wrote:
>> On 9 May 2013 22:01, Suman Anna <s-anna at ti.com> wrote:
>>> Hi Jassi,
>>>
>>> On 05/06/2013 02:24 AM, Jassi Brar wrote:
>>>> +++ b/include/linux/mailbox_client.h
>>>> @@ -0,0 +1,85 @@
>>>> +/*
>>>> + * This program is free software; you can redistribute it and/or modify
>>>> + * it under the terms of the GNU General Public License version 2 as
>>>> + * published by the Free Software Foundation.
>>>> + */
>>>> +
>>>> +#ifndef __MAILBOX_CLIENT_H
>>>> +#define __MAILBOX_CLIENT_H
>>>> +
>>>> +#include <linux/mailbox.h>
>>>> +
>>>> +/**
>>>> + * struct ipc_client - User of a mailbox
>>>> + * @chan_name: the "controller:channel" this client wants
>>>> + * @rxcb: atomic callback to provide client the data received
>>>> + * @txcb: atomic callback to tell client of data transmission
>>>> + * @tx_block: if the ipc_send_message should block until data is transmitted
>>>> + * @tx_tout: Max block period in ms before TX is assumed failure
>>>> + * @knows_txdone: if the client could run the TX state machine. Usually if
>>>> + *    the client receives some ACK packet for transmission. Unused if the
>>>> + *    controller already has TX_Done/RTR IRQ.
>>>> + * @cntlr_data: Optional controller specific parameters during channel request
>>>> + */
>>>> +struct ipc_client {
>>>> +     char *chan_name;
>>>> +     void (*rxcb)(void *data);
>>>> +     void (*txcb)(request_token_t t, enum xfer_result r);
>>>
>>> We have to introduce a callback data pointer, so that the calling
>>> clients can retrieve a context object variable or some other useful
>>> data within the callback functions, just like most normal callback
>>> function declarations and registrations do.
>>>
>> I meant the request_token_t for the purpose. That's how we do with DMAEngine.
>
> I faced this issue on the rxcb while adopting the
> omap_rproc_mbox_callback. omap_remoteproc is a common driver for all the
> OMAP co-processors and there can be multiple instances, providing the
> same set of features. Look at the code in
> drivers/remoteproc/omap_remoteproc.c and you will get the idea. But in
> general, the users registering callback functions would prefer to get
> some context pointer back.
>
Of course they do. The request_token_t returned corresponds to the
request they submit via ipc_send_message.

Perhaps we should change the following

   void ipc_link_txdone(struct ipc_link *link, enum xfer_result r)
to
   void ipc_link_txdone(struct ipc_link *link, enum xfer_result r, void *data)

So that the API could pass that onto clients ?

regards,
jassi