> -----Original Message----- > From: linux-omap-owner@xxxxxxxxxxxxxxx > [mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of Ohad Ben-Cohen > Sent: Thursday, June 24, 2010 3:23 PM > To: Kanigeri, Hari > Cc: linux-omap@xxxxxxxxxxxxxxx; Hiroshi Doyu; Ramirez Luna, Omar > Subject: Re: [PATCH 3/4] omap mailbox: remove mbox_configured scheme > > On Thu, Jun 24, 2010 at 6:10 PM, Kanigeri, Hari > <h-kanigeri2@xxxxxx> wrote: > > Ohad, > > > >> mbox_configured is global and therefore does not support > concurrent > >> usage of multiple mailbox instances. > > > > -- Why do you say that it doesn't support concurrent usage > of multiple mailbox instances ? If you take example of OMAP4, > we have 2 mailbox instances, one talking to DSP and other to > Ducati and they should be supported concurrently. > > > Interesting. was this actually tested and found working ? > I think by supporting multiple instances, what Hari meant was that, for DSP and Ducati 2 different struct omap_mbox * are returned. They still can maintain their own callback function (http://dev.omapzoom.org/?p=tisyslink/kernel-syslink.git;a=blob;f=arch/arm/mach-omap2/mailbox.c;h=a23c7edf1e84ab4fa51e56d0c2daf2922084751a;hb=438f7a6a3cced478eb121426201206f6205fbbdc#l327 for Ducati and http://dev.omapzoom.org/?p=tisyslink/kernel-syslink.git;a=blob;f=arch/arm/mach-omap2/mailbox.c;h=a23c7edf1e84ab4fa51e56d0c2daf2922084751a;hb=438f7a6a3cced478eb121426201206f6205fbbdc#l334 for DSP). The "mbox_configured" was a means to reference count for one instance of the struct omap_mbox * . > AFAICT (I don't have OMAP4, this is just by looking at the > code) this doesn't work: > mbox_configured will prevent omap2_mbox_startup from being > invoked more than once. This means that > omap2_mbox_enable_irq(mbox, IRQ_RX) will only be called once > too, which seems like a problem if you want to start > receiving RX interrupts from both mbox instances at the same time. > > To fix that I guess we should decouple the RX interrupt > enabling from the mbox startup function. I can write > something, but I'd need your help to test it on OMAP4 :) > > > > > If you remove the mbox_configured variable, then the mailbox module > > would shut down once the first instance calls the > omap_mbox_put function. > > Also interesting point. > > So you use mbox_configures as a reference counter to allow > concurrent multiple senders to the same mbox instance. > > I will update the previous patch (that introduced the > atomic_t reference counter) to reflect this use case, thanks! > > > > > Thank you, > > Best regards, > > Hari > > > -- > To unsubscribe from this list: send the line "unsubscribe > linux-omap" in the body of a message to > majordomo@xxxxxxxxxxxxxxx More majordomo info at > http://vger.kernel.org/majordomo-info.html > Thank you and Regards Subbu-- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
