irqchip: Support Aspeed IRQ controller

Signed-off-by Joel Stanley <[email protected]>

---
v2:
Fix device tree binding example, thanks Baruch and Arnd for pointing this out

 .../interrupt-controller/aspeed,ast2400-vic.txt    | 24 ++++++++++++++++++++++
 1 file changed, 24 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/aspeed,ast2400-vic.txt

Documentation/devicetree/bindings/interrupt-controller/aspeed,ast2400-vic.txt new file +3 -0

new file mode 100644
index 000000000000..86dede1755a2
@@ -0,0 +1,24 @@
+Aspeed Vectored Interrupt Controller
+
+These bindings are for the Aspeed AST2400 interrupt controller register layout.

Documentation/devicetree/bindings/interrupt-controller/aspeed,ast2400-vic.txt new file +6 -0

+      compatible = "aspeed,ast2400-vic";
+      interrupt-controller;
+      #interrupt-cells = <1>;
+      valid-sources = < 0xffffffff 0x0007ffff>;
+      reg = <0x1e6c0080 0x80>;
+ };

Signature · 6 lines

2.8.1

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Quoted 3 lines

+- interrupt-controller : Identifies the node as an interrupt controller
+- #interrupt-cells : Specifies the number of cells needed to encode an

+? interrupt source. The value shall be 1.

No need for level vs. edge flags?

Quoted 1 line

+- valid-sources : bitmask of valid irq sources

Drop this. Either all interrupt controllers need this or none of? them do. The valid sources are the ones described in the DT.

Documentation/devicetree/bindings/interrupt-controller/aspeed,ast2400-vic.txt line 18

Quoted 4 lines

Documentation/devicetree/bindings/interrupt-controller/aspeed,ast2400-vic.txt new file +4 -0

+
+Example:
+
+ vic: interrupt-controller {

Needs a unit address.

Quoted 13 lines

+????? compatible = "aspeed,ast2400-vic";
+????? interrupt-controller;
+????? #interrupt-cells = <1>;
+????? valid-sources = < 0xffffffff 0x0007ffff>;
+????? reg = <0x1e6c0080 0x80>;
+ };
--?
2.8.1
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Quoted 5 lines · Rob Herring

Quoted 3 lines

+- interrupt-controller : Identifies the node as an interrupt controller
+- #interrupt-cells : Specifies the number of cells needed to encode an
+  interrupt source. The value shall be 1.

No need for level vs. edge flags?

That's an open question. Most interrupts are fixed. A handful of GPIOs can be configured either way. For now I am relying on uboot setting up the right config for them and I read it back at boot time, but we could make it part of the binding I suppose.

Quoted 5 lines

Quoted 2 lines

+- valid-sources : bitmask of valid irq sources

Drop this. Either all interrupt controllers need this or none of them do. The valid sources are the ones described in the DT.

Looking at the code (I wrote that ages ago), this is only used for:

Quoted 7 lines · Benjamin Herrenschmidt

Quoted 5 lines · Rob Herring

Quoted 3 lines

+- interrupt-controller : Identifies the node as an interrupt controller
+- #interrupt-cells : Specifies the number of cells needed to encode an
+  interrupt source. The value shall be 1.

No need for level vs. edge flags?

Quoted 4 lines

That's an open question. Most interrupts are fixed. A handful of GPIOs can be configured either way. For now I am relying on uboot setting up the right config for them and I read it back at boot time, but we could make it part of the binding I suppose.

It is almost standard to just use 2 cells here even if reserved for future use. Especially since the IP block seems to have registers to control that.

Quoted 9 lines · Rob Herring

Quoted 7 lines · Benjamin Herrenschmidt

Quoted 5 lines · Rob Herring

Quoted 3 lines

+- interrupt-controller : Identifies the node as an interrupt controller
+- #interrupt-cells : Specifies the number of cells needed to encode an
+  interrupt source. The value shall be 1.

No need for level vs. edge flags?

Quoted 8 lines

Quoted 4 lines

That's an open question. Most interrupts are fixed. A handful of GPIOs can be configured either way. For now I am relying on uboot setting up the right config for them and I read it back at boot time, but we could make it part of the binding I suppose.

It is almost standard to just use 2 cells here even if reserved for future use. Especially since the IP block seems to have registers to control that.

Yep, makes sense. I've added this to the bindings document.

I was trying to use the second cell in our driver:

  static struct irq_domain_ops avic_dom_ops = {
          .map = avic_map,
         .xlate = irq_domain_xlate_twocell,
  };

So we have irq_domain_xlate_twocell to parse the device tree and
grabs the type property from the second cell.

In avic_map we set the irq handler:

         if (vic->edge_sources[sidx] & sbit) {
                 /* TODO: Check aginst type from dt and warn if not edge */
                 irq_set_chip_and_handler(irq, &avic_chip, handle_edge_irq);
         } else {
                 /* TODO: Check aginst type from dt and warn if not level */
                 irq_set_chip_and_handler(irq, &avic_chip, handle_level_irq);
         }

However, we don't have the type here, so we can't use it to check that we're setting the correct edge/level callback (or use it to set the register in the future if we want to use the device tree to override the bootloader settings).

I had a look at some other drivers and they don't seem to use the dt property when mapping the irq. What am I missing here?

Hello All,

This adds support for the IRQ controller found in the Aspeed ast2400 and ast2500 BMC SoCs.

It's been tested on the ast2400 in an OpenPower Palmetto system, and on the ast2500-edk developer kit.

V2 has a fix for the compatible string in the device tree bindings.

V3 drops the valid-sources bitmasks and adds a unit address to the example in the bindings

Cheers,

Joel

Benjamin Herrenschmidt (1):
irqchip: Add irq controller for Aspeed

Joel Stanley (1):
doc/devicetree: Add Aspeed VIC bindings

 .../interrupt-controller/aspeed,ast2400-vic.txt    |  22 ++
 drivers/irqchip/Makefile                           |   1 +
 drivers/irqchip/irq-aspeed-vic.c                   | 230 +++++++++++++++++++++
 3 files changed, 253 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/interrupt-controller/aspeed,ast2400-vic.txt
 create mode 100644 drivers/irqchip/irq-aspeed-vic.c