Lines Matching +full:interrupt +full:- +full:map
2 The irq_domain interrupt number mapping library
7 This is simple when there is only one interrupt controller, but in
8 systems with multiple interrupt controllers the kernel must ensure
9 that each one gets assigned non-overlapping allocations of Linux
12 The number of interrupt controllers registered as unique irqchips
15 mechanisms as the IRQ core system by modelling their interrupt
16 handlers as irqchips, i.e. in effect cascading interrupt controllers.
18 Here the interrupt number loose all kind of correspondence to
19 hardware interrupt numbers: whereas in the past, IRQ numbers could
21 interrupt controller (i.e. the component actually fireing the
22 interrupt line to the CPU) nowadays this number is just a number.
24 For this reason we need a mechanism to separate controller-local
25 interrupt numbers, called hardware irq's, from Linux IRQ numbers.
29 the controller-local IRQ (hwirq) number into the Linux IRQ number
34 preferred over interrupt controller drivers open coding their own
44 An interrupt controller driver creates and registers an irq_domain by
55 the hwirq, and call the .map() callback so the driver can perform any
61 - irq_resolve_mapping() returns a pointer to the irq_desc structure
64 - irq_find_mapping() returns a Linux IRQ number for a given domain and
66 - irq_linear_revmap() is now identical to irq_find_mapping(), and is
68 - generic_handle_domain_irq() handles an interrupt described by a
70 - handle_domain_irq() does the same thing for root interrupt
75 compatible with a RCU read-side critical section.
83 callbacks) then it can be directly obtained from irq_data->hwirq.
90 Which reverse map type should be used depends on the use case. Each
91 of the reverse map types are described below:
94 ------
101 The linear reverse map maintains a fixed size table indexed by the
105 The Linear map is a good choice when the maximum number of hwirqs is
107 map are fixed time lookup for IRQ numbers, and irq_descs are only
108 allocated for in-use IRQs. The disadvantage is that the table must be
112 equivalent, except for the first argument is different - the former
116 The majority of drivers should use the linear map.
119 ----
126 The irq_domain maintains a radix tree map from hwirq numbers to Linux
130 The tree map is a good choice if the hwirq number can be very large
136 equivalent, except for the first argument is different - the former
142 No Map
143 ------
149 The No Map mapping is to be used when the hwirq number is
153 IRQ number and call the .map() callback so that driver can program the
161 ------
183 The legacy map assumes a contiguous range of IRQ numbers has already
186 visa-versa. The disadvantage is that it requires the interrupt
190 The legacy map should only be used if fixed IRQ mappings must be
191 supported. For example, ISA controllers would use the legacy map for
192 mapping Linux IRQs 0-15 so that existing ISA drivers get the correct IRQ
199 descriptors will be allocated on-the-fly for it, and if no range is
214 equivalent, except for the first argument is different - the former
219 --------------------
221 On some architectures, there may be multiple interrupt controllers
222 involved in delivering an interrupt from the device to the target CPU.
223 Let's look at a typical interrupt delivering path on x86 platforms::
225 Device --> IOAPIC -> Interrupt remapping Controller -> Local APIC -> CPU
227 There are three interrupt controllers involved:
230 2) Interrupt remapping controller
235 interrupt controller and those irq_domains are organized into hierarchy.
243 Interrupt Remapping irq_domain (manage irq_remapping entries)
250 1) irq_domain_alloc_irqs(): allocate IRQ descriptors and interrupt
252 2) irq_domain_free_irqs(): free IRQ descriptors and interrupt controller
254 3) irq_domain_activate_irq(): activate interrupt controller hardware to
255 deliver the interrupt.
256 4) irq_domain_deactivate_irq(): deactivate interrupt controller hardware
257 to stop delivering the interrupt.
270 irq_domain structure is built for each interrupt controller, and an
277 With stacked irq_chip, interrupt controller driver only needs to deal
282 For an interrupt controller driver to support hierarchy irq_domain, it
288 3) Optionally implement an irq_chip to manage the interrupt controller
290 4) No need to implement irq_domain_ops.map and irq_domain_ops.unmap,