lkml.org 
[lkml]   [2014]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC 1/6] mailbox: add core framework
On Mon, Feb 10, 2014 at 11:52:05AM -0600, Rob Herring wrote:
> On Mon, Feb 10, 2014 at 8:11 AM, Arnd Bergmann <arnd@arndb.de> wrote:
> > On Friday 07 February 2014 16:50:14 Courtney Cavin wrote:
[..]
> >> +int mbox_channel_notify(struct mbox_channel *chan,
> >> + const void *data, unsigned int len)
> >> +{
> >> + return atomic_notifier_call_chain(&chan->notifier, len, (void *)data);
> >> +}
> >> +EXPORT_SYMBOL(mbox_channel_notify);
> >
> > What is the reason to use a notifier chain here? Isn't a simple
> > callback function pointer enough? I would expect that each mailbox
> > can have exactly one consumer, not multiple ones.
>
> It probably can be a callback, but there can be multiple consumers. It
> was only a notifier on the pl320 as there was no framework at the time
> and to avoid creating custom interfaces between drivers. On highbank
> for example, we can asynchronously receive the events for temperature
> change, power off, and reset. So either there needs to be an event
> demux somewhere or callbacks have to return whether they handled an
> event or not.

I'm not familiar with highbank IPC, but with these requirements should
the mailbox core even bother with asynchronous notifier chain? It
sounds like a better fit might be for the mailbox core to implement a
proper adapter-specific irqdomain and used a chained irq handler to
demux (or have consumers request with IRQF_SHARED in the shared case).

--
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
hosted by The Linux Foundation


\
 
 \ /
  Last update: 2014-02-10 21:01    [W:0.106 / U:2.328 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site