linux_dsm_epyc7002/Documentation/devicetree/bindings/interrupt-controller/brcm,bcm7120-l2-intc.txt
Kevin Cernekee c76acf4dff irqchip: bcm7120-l2: Extend driver to support 64+ bit controllers
Most implementations of the bcm7120-l2 controller only have a single
32-bit enable word + 32-bit status word.  But some instances have added
more enable/status pairs in order to support 64+ IRQs (which are all
ORed into one parent IRQ input).  Make the following changes to allow
the driver to support this:

 - Extend DT bindings so that multiple words can be specified for the
   reg property, various masks, etc.

 - Add loops to the probe/handle functions to deal with each word
   separately

 - Allocate 1 generic-chip for every 32 IRQs, so we can still use the
   clr/set helper functions

 - Update the documentation

This uses one domain per bcm7120-l2 DT node.  If the DT node defines
multiple enable/status pairs (i.e. >=64 IRQs) then the driver will
create a single IRQ domain with 2+ generic chips.  Multiple generic chips
are required because the generic-chip code can only handle one
enable/status register pair per instance.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Link: https://lkml.kernel.org/r/1415342669-30640-12-git-send-email-cernekee@gmail.com
Signed-off-by: Jason Cooper <jason@lakedaemon.net>
2014-11-09 04:03:13 +00:00

97 lines
3.7 KiB
Plaintext

Broadcom BCM7120-style Level 2 interrupt controller
This interrupt controller hardware is a second level interrupt controller that
is hooked to a parent interrupt controller: e.g: ARM GIC for ARM-based
platforms. It can be found on BCM7xxx products starting with BCM7120.
Such an interrupt controller has the following hardware design:
- outputs multiple interrupts signals towards its interrupt controller parent
- controls how some of the interrupts will be flowing, whether they will
directly output an interrupt signal towards the interrupt controller parent,
or if they will output an interrupt signal at this 2nd level interrupt
controller, in particular for UARTs
- typically has one 32-bit enable word and one 32-bit status word, but on
some hardware may have more than one enable/status pair
- no atomic set/clear operations
- not all bits within the interrupt controller actually map to an interrupt
The typical hardware layout for this controller is represented below:
2nd level interrupt line Outputs for the parent controller (e.g: ARM GIC)
0 -----[ MUX ] ------------|==========> GIC interrupt 75
\-----------\
|
1 -----[ MUX ] --------)---|==========> GIC interrupt 76
\------------|
|
2 -----[ MUX ] --------)---|==========> GIC interrupt 77
\------------|
|
3 ---------------------|
4 ---------------------|
5 ---------------------|
7 ---------------------|---|===========> GIC interrupt 66
9 ---------------------|
10 --------------------|
11 --------------------/
6 ------------------------\
|===========> GIC interrupt 64
8 ------------------------/
12 ........................ X
13 ........................ X (not connected)
..
31 ........................ X
Required properties:
- compatible: should be "brcm,bcm7120-l2-intc"
- reg: specifies the base physical address and size of the registers;
multiple pairs may be specified, with the first pair handling IRQ offsets
0..31 and the second pair handling 32..63
- interrupt-controller: identifies the node as an interrupt controller
- #interrupt-cells: specifies the number of cells needed to encode an interrupt
source, should be 1.
- interrupt-parent: specifies the phandle to the parent interrupt controller
this one is cascaded from
- interrupts: specifies the interrupt line(s) in the interrupt-parent controller
node, valid values depend on the type of parent interrupt controller
- brcm,int-map-mask: 32-bits bit mask describing how many and which interrupts
are wired to this 2nd level interrupt controller, and how they match their
respective interrupt parents. Should match exactly the number of interrupts
specified in the 'interrupts' property, multiplied by the number of
enable/status register pairs implemented by this controller. For
multiple parent IRQs with multiple enable/status words, this looks like:
<irq0_w0 irq0_w1 irq1_w0 irq1_w1 ...>
Optional properties:
- brcm,irq-can-wake: if present, this means the L2 controller can be used as a
wakeup source for system suspend/resume.
- brcm,int-fwd-mask: if present, a bit mask to configure the interrupts which
have a mux gate, typically UARTs. Setting these bits will make their
respective interrupt outputs bypass this 2nd level interrupt controller
completely; it is completely transparent for the interrupt controller
parent. This should have one 32-bit word per enable/status pair.
Example:
irq0_intc: interrupt-controller@f0406800 {
compatible = "brcm,bcm7120-l2-intc";
interrupt-parent = <&intc>;
#interrupt-cells = <1>;
reg = <0xf0406800 0x8>;
interrupt-controller;
interrupts = <0x0 0x42 0x0>, <0x0 0x40 0x0>;
brcm,int-map-mask = <0xeb8>, <0x140>;
brcm,int-fwd-mask = <0x7>;
};