On 8/23/2013 7:08 PM, Santosh Shilimkar wrote: > On Friday 23 August 2013 04:14 AM, Sekhar Nori wrote: >> On Friday 23 August 2013 12:23 PM, Sricharan R wrote: >>> On Friday 23 August 2013 12:06 PM, Sekhar Nori wrote: >>>> On Friday 23 August 2013 11:41 AM, Sricharan R wrote: >>>>> Hi, >>>>> On Friday 23 August 2013 10:17 AM, Rajendra Nayak wrote: >>>>>> On Thursday 22 August 2013 05:03 PM, Sricharan R wrote: >>>>>>> maps crossbar number<-> to interrupt number and >>>>>>> calls request_irq(int_no, crossbar_handler,..) >>>>>> So will this mapping happen based on some data passed from DT or >>>>>> just based on whats available when the device does a request_irq()? >>>>>> >>>>>> If its based on whats available then I see an issue when you need >>>>>> to remap something thats already mapped by default (and not used) >>>>>> since you run out of all free ones. >>>>> Yes, when done based on what is available then there is a >>>>> problem when we run out of free ones because we do not >>>>> know which one to replace. I was thinking of something like >>>>> this, >>>>> 1) DT would give a list of all free ones, and also if some are >>>>> mapped as default and not used, mark those also as free. >>>>> >>>>> 2) While mapping see if it has a default mapping and use it. >>>>> otherwise, pick from free list. >>>> Since the entire DT is available to you at boot time, you should be able >>>> to find each node where interrupt-parent = <&crossbar> and then allocate >>>> one of 0-160 GIC interrupt numbers for that node, no? Where would there >>>> be a need for default mapping and remapping? From one the mails in the >>>> thread the crossbar is completely flexible - any of the 320 crossbar >>>> interrupts can be mapped to any of the 160 GIC interrupts. >>>> >>>> Any GIC interrupts left after this boot-time scan can be added to an >>>> unused list for use with runtime DT fragments (when that support comes). >>>> >>>> Sorry if I misunderstood, but above proposal sounds like maintaining a >>>> separate free interrupt lines list in DT. That will quickly go out of sync. >>> Say, peripheral x uses crossbar 1 and specifies this in DT. >>> During boot crossbar 1 gets mapped int 10. So if by default >>> some other crossbar has its interrupt mapped to 10, >>> then it should be removed. Instead clear all crossbar registers >>> once and mark all as free, then allocate only during request. >>> Correct ?. In this the free no need to maintain any list. >> >> Right, so in my suggestion there is nothing like a "default mapping" and >> entire 160 GIC interrupt number space is up for grabs. I think this will >> be much simpler to write and maintain. >> >> If you really want to maintain default mapping as far as possible, you >> can do two passes on the crossbar interrupt numbers requested. Once to >> assign the default map - for numbers less that 160 - and then look at >> the free GIC interrupt slots and use those for numbers greater than 160. >> > The whole point we are moving to domain is not have any default > mapping(connection done) at DT level. Rather DT only specifies the > peripherals and their cross-bar connection ID(i.e cross-bar IRQ line). > This will be the driver input as a IRQ line from DT. The cross-bar > driver needs to map any of the free list available on *request* only. Right, the mapping can be done on request. That will be cleaner. Thanks, Sekhar -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
