[PATCHv3 00/14] drivers: mailbox: framework creation

[jaswinder.singh@linaro.org (Jassi Brar)]

Hi Loic,

On 24 April 2013 13:09, Loic PALLARDY <loic.pallardy@st.com> wrote:
> Hi Jassi, Suman,
>
> Yes, the xxx_no_irq API has been introduced to answer some STE
> requirements. It must be possible to send some message under atomic
> context for different reasons (latency, during idle/suspend procedures...).
> This is not the best way to do, but the goal was to preserve TI legacy
> in a first step. As explained by Suman, this patch series is coming from
> the original TI mailbox framework and is modified step by step to fit
> with all platforms.
>
IMHO a better way is to introduce a clean generically designed API and
convert the existing drivers one at time. Let the TI drivers work as
such for a while until someone converts them to the common API.
Cloning and then complete organ transplantation seems a very
inefficient way to have something new ;)

>>>
>>> (d) The 'struct mailbox_msg' should be just an opaque void* - the client/protocol
>>> driver typecasts to void* the IPC controller specific message structure. API
>>> shouldn't aim the impossible of providing a generic message format.
>>
>> The size parameter would still be needed. Depending on the h/w, it can be just an u32 or a series of bytes, and even in the latter case, it is not guaranteed that all messages transmitted will occupy the entire h/w shared memory data packet. I can see the current header field getting absorbed into the opaque void * structure for the ST mailbox driver. The size and ptr together provide a very generic message format.
> That's something we discussed with Suman. The mailbox framework should
> be independent from message format. Since mailbox could be base don a
> shared mem or an hw fifo, message size is mandatory to transmit the
> right number of data.
>
I too believe the "mailbox framework should be independent from
message format" but _also_ that .size doesn't have to be a part of the
standard format.
Maybe it will help if I know what you guys mean by "shared mem" or an
"hw fifo" mailbox?

Thanks
-Jassi