[PATCH V3 16/16] irqchip: crossbar: allow for quirky hardware with direct hardwiring of GIC

Hi Jason,

On Saturday 21 June 2014 08:27 AM, Jason Cooper wrote:

On Mon, Jun 16, 2014 at 04:53:16PM +0530, Sricharan R wrote:

quoted

From: Nishanth Menon <nm@ti.com>

On certain platforms such as DRA7, SPIs 0, 1, 2, 3, 5, 6, 10, 131,
132, 133 are direct wired to hardware blocks bypassing crossbar.
This quirky implementation is *NOT* supposed to be the expectation
of crossbar hardware usage. However, these are already marked in our
description of the hardware with SKIP and RESERVED where appropriate.

Unfortunately, we need to be able to refer to these hardwired IRQs.
So, to request these, crossbar driver can use the existing information
from it's table that these SKIP/RESERVED maps are direct wired sources
and generic allocation/programming of crossbar should be avoided.

Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Sricharan R <redacted>
---
 .../devicetree/bindings/arm/omap/crossbar.txt      |   12 ++++++++++--
 drivers/irqchip/irq-crossbar.c                     |   20 ++++++++++++++++++--
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/arm/omap/crossbar.txt b/Documentation/devicetree/bindings/arm/omap/crossbar.txt
index 8210ea4..438ccab 100644
--- a/Documentation/devicetree/bindings/arm/omap/crossbar.txt
+++ b/Documentation/devicetree/bindings/arm/omap/crossbar.txt

@@ -42,8 +42,10 @@ Documentation/devicetree/bindings/arm/gic.txt for further details.
 
 An interrupt consumer on an SoC using crossbar will use:
 	interrupts = <GIC_SPI request_number interrupt_level>
-request number shall be between 0 to that described by
-"ti,max-crossbar-sources"
+When the request number is between 0 to that described by
+"ti,max-crossbar-sources", it is assumed to be a crossbar mapping. If the
+request_number is greater than "ti,max-crossbar-sources", then it is mapped as a
+quirky hardware mapping direct to GIC.
 
 Example:
 	device_x at 0x4a023000 {

@@ -51,3 +53,9 @@ Example:
 		interrupts = <GIC_SPI 8 IRQ_TYPE_LEVEL_HIGH>;
 		...
 	};
+
+	device_y at 0x4a033000 {
+		/* Direct mapped GIC SPI 1 used */
+		interrupts = <GIC_SPI 401 IRQ_TYPE_LEVEL_HIGH>;

Ideally, I'd like to see a macro here so that it's clear that we crossed
a magic threshold. eg:

#define MAX_SOURCES     400
#define DIRECT_IRQ(irq) (MAX_SOURCES + irq)
...
		interrupts = <GIC_SPI DIRECT_IRQ(1) IRQ_TYPE_LEVEL_HIGH>;

and, then:

		ti,max-crossbar-sources = <MAX_SOURCES>;

 Ok, thats more good for readability. Will add that macro then.

Regards,
 Sricharan