Date: Thu, 15 Jan 2015 08:31:35 -0800 From: Nathan Whitehorn <nwhitehorn@freebsd.org> To: freebsd-arm@freebsd.org Subject: Re: interrupt framework Message-ID: <54B7EB67.6010702@freebsd.org> In-Reply-To: <CAFHCsPX5kG_v-F-cjpyMQsT_b386eok=mqWW0%2BEUb_4-_1Otnw@mail.gmail.com> References: <CAFHCsPX5kG_v-F-cjpyMQsT_b386eok=mqWW0%2BEUb_4-_1Otnw@mail.gmail.com>
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On 01/15/15 05:51, Svatopluk Kraus wrote: > Hi community, > > I and Michal Meloun have done some work on ARM interrupt framework and > this is the result. > > We've started with intrng project with Ian's WIP changes, have looked > at Andrew's ARM64 git repository, and this is how we think an > interrupt framework should look like. We've implemented it with > removable interrupt controllers in mind (PCI world). It's not finished > from this point of view, however some functions are more complex > because of it. > > It's tested on pandaboard and only GIC is implemented now. There is no > problem to implement it to other controllers. We are open to questions > and can finish our work considering any comments. Whoever is waiting > for ARM interrupt framework as we were, you are welcome to test it. > Whoever is welcome. The patches are done against FreeBSD-11-current > revision 277210. There are two new files. > > ARM_INTRNG option must be added to board configuration file for new framework. > > There are still some things not implemented and some things which > should be discussed like PPI support. For example, how to enable PPI > interrupt on other CPUs when they are already running? > > We keep in mind that an interrupt framework should be helpfull but > general enough to not dictate interrupt controlles too much. Thus we > try to keep some things as much separated as possible. Each interrupt > is represented by an interrupt source (ISRC) in the framework. An ISRC > is described by an interrupt number which is much more an unique > resource handle - totally independent on internal representation of > interrupts in any interrupt controller. This is a good design. > An interrupt is described by cells in FDT world. The cells can be > decoded only by associated interrupt controller and as such, they are > transparent for interrupt framework. The framework provides > arm_fdt_map_irq() function which maps this transparent cells to an > interrupt number. It creates an ISRC, saves cells on it, and once when > associated interrupt controller is registered, it provides the ISRC > with cells into the controller. > > It's a controller responsibility to save an ISRC associated with > cells. An ISRC is transparent for any controller. However, an > controller can set/get its data to/from an ISRC. Further, an > controller should set a name to an ISRC according to internal > representation of associated interrupt. I'm assuming you are referring to arm_describe_irq? I had three comments on that: 1. Can you please make it part of the same API as ofw_bus_map_irq() rather than an out-of-band thing? This will let other platforms use it. 2. Once you've done that, you can remove all the #ifdef from simplebus. I would strongly prefer it not gain platform-specific #ifdef. 3. We should not be adding new things to machine/fdt.h unless they are really internal platforms APIs for reading the FDT. And even then, the header should probably disappear soon. FDT_MAP_IRQ() is used only in arm/intr.c, for example, and should be replaced by a direct invocation of arm_fdt_map_intr(). arm_describe_irq() should not join it there. > An controller interrupt dispatch function can call framework only if > it has associated ISRC to received interrupt. > > For legacy reason, there is arm_namespace_map_irq() function. An > interrupt is described by namespace type and a number from the > namespace. It's intented for use with no FDT drivers. Now, it's used > for mapping an IPI on a controller. > > We think that it's better to call chained controllers (with filter > only) without MI interrupt framework overhead, so we implemented > shortcut. It could be utilized by INTR_SOLO flag during > bus_setup_intr(). Can you describe the shortcut? We never ended up needing something like this on PowerPC. > Only an interrupt controller can really know its position in interrupt > controller's tree. So root controller must claim itself as a root. In > FDT world, according to ePAPR approved version 1.1 from 08 April 2011, > page 30: > > "The root of the interrupt tree is determined when traversal of the > interrupt tree reaches an interrupt controller node without an > interrupts property and thus no explicit interrupt parent." > > Thus there are no need for any non-standard things in DTS files. Right, this is what we did on PPC. -Nathan > Svata > > > _______________________________________________ > freebsd-arm@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-arm > To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org"
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