On Thursday 24 July 2014 01:19 PM, Jassi Brar wrote: > On 23 July 2014 20:40, Linus Walleij <linus.walleij@xxxxxxxxxx> wrote: >> On Wed, Jul 16, 2014 at 12:43 PM, Grygorii Strashko >> <grygorii.strashko@xxxxxx> wrote: >> >>> From: Murali Karicheri <m-karicheri2@xxxxxx> >>> >>> On Keystone SOCs, ARM host can send interrupts to DSP cores using the >>> DSP GPIO controller IP. Each DSP GPIO controller provides 28 IRQ signals for >>> each DSP core. This is one of the component used by the IPC mechanism used >>> on Keystone SOCs. >>> >>> Keystone 2 DSP GPIO controller has specific features: >>> - each GPIO can be configured only as output pin; >>> - setting GPIO value to 1 causes IRQ generation on target DSP core; >>> - reading pin value returns 0 - if IRQ was handled or 1 - IRQ is still >>> pending. >>> >>> Signed-off-by: Murali Karicheri <m-karicheri2@xxxxxx> >>> Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx> >> >> Pardon me. How is this GENERAL PURPOSE Input/Output? >> >> It seems very very much SPECIAL PURPOSE to me, it's like >> you're just shoehorning some IPC mechanism into the GPIO >> subsystem, and this may be because the datasheet calls it >> GPIO when it's not. >> >> What other stuff than DSP is connected to these lines, and is it >> really even external lines? Aren't these just polysilicon rails >> pretty much hammered to be used by the DSP and nothing else. >> >> What is the difference between this and a mailbox IRQ line >> and the kind of stuff handled by drivers/mailbox? >> >> I'd like Suman and Jassi to have a look at this to see if it's >> actually a mailbox before we proceed. >> > The controller seems like most others, only incapable of reading > signals (output only). > The userspace driving those signals to communicate with a DSP isn't > enough to call it a mailbox usecase, because on a different board the > userspace may drive those signals to control LEDs :) > Exactly !! And that was my point. Thanks for echo. Regards, Santosh -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
