[PATCH] ARM: Tegra: dt: Set up an OF IRQ translation range

[PATCH] ARM: Tegra: dt: Set up an OF IRQ translation range

[Stephen Warren]

Without this, none of the devicetree devices in tegra-harmony.dts can
map interrupts, and the system fails to boot.

Signed-off-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
---
Note: This patch is based on Grant's latest
git://git.secretlab.ca/git/linux-2.6 devicetree/test
plus all the Tegra fixes I recently posted to linaro-dev, which in
particular move tegra-harmony.dts to a different location.

Question: It seems like the call to of_irq_domain_add_simple should be
part of arch/arm/common/gic.c:gic_init(), rather than each SoC's DT board
file having to do this. However, that'd require gic_init having an OF
device node to pass to of_irq_domain_add_simple.

Question 2: Should the range of IRQ numbers cover just the IRQs directly
managed by the GIC itself, or cover the entire range of IRQ numbers for
the SoC? Put another way, should it include mappings for a GPIO controller
then aggregates interrupts from N GPIOs into 1 or M GIC interrupts, or not?
Put yet another way, should the code pass INT_MAIN_NR or NR_IRQS for Tegra?
I suspect the former, and that child interrupt devices should themselves
call of_irq_domain_add_simple to set up their mappings?

Question 3: I'm not sure "arm,gic" is the correct sanctioned compatible value?

 arch/arm/boot/dts/tegra-harmony.dts |    2 ++
 arch/arm/mach-tegra/board-dt.c      |   13 +++++++++++++
 2 files changed, 15 insertions(+), 0 deletions(-)

diff --git a/arch/arm/boot/dts/tegra-harmony.dts b/arch/arm/boot/dts/tegra-harmony.dts
index 6fe09d7..1972f61 100644
--- a/arch/arm/boot/dts/tegra-harmony.dts
+++ b/arch/arm/boot/dts/tegra-harmony.dts
@@ -26,8 +26,10 @@
 		ranges;
 
 		intc: intc {
+			compatible = "arm,gic";
 			interrupt-controller;
 			#interrupt-cells = <1>;
+			reg = <0x50041000 0x1000 0x50040100 0x100 >;
 		};
 	};
 
diff --git a/arch/arm/mach-tegra/board-dt.c b/arch/arm/mach-tegra/board-dt.c
index aa37783..894c7a3 100644
--- a/arch/arm/mach-tegra/board-dt.c
+++ b/arch/arm/mach-tegra/board-dt.c
@@ -22,7 +22,9 @@
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
 #include <linux/of.h>
+#include <linux/of_address.h>
 #include <linux/of_fdt.h>
+#include <linux/of_irq.h>
 #include <linux/of_platform.h>
 #include <linux/pda_power.h>
 #include <linux/io.h>
@@ -137,8 +139,19 @@ static struct of_device_id tegra_dt_match_table[] __initdata = {
 	{}
 };
 
+struct of_device_id gic_match[] = {
+	{ .compatible = "arm,gic", }, {}
+};
+
 static void __init tegra_dt_init(void)
 {
+	struct device_node *node;
+
+	node = of_find_matching_node_by_address(NULL, gic_match,
+						TEGRA_ARM_INT_DIST_BASE);
+	if (node)
+		of_irq_domain_add_simple(node, INT_GIC_BASE, INT_MAIN_NR);
+
 	/*
 	 * Before registering devices; tell Linux about which device nodes
 	 * are intended to be registered so that it doesn't create devices
-- 
1.7.0.4

Re: [PATCH] ARM: Tegra: dt: Set up an OF IRQ translation range

[Grant Likely]

On Fri, Apr 29, 2011 at 04:31:33PM -0600, Stephen Warren wrote:
> Without this, none of the devicetree devices in tegra-harmony.dts can
> map interrupts, and the system fails to boot.
> 
> Signed-off-by: Stephen Warren <swarren-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org>
> ---
> Note: This patch is based on Grant's latest
> git://git.secretlab.ca/git/linux-2.6 devicetree/test
> plus all the Tegra fixes I recently posted to linaro-dev, which in
> particular move tegra-harmony.dts to a different location.
> 
> Question: It seems like the call to of_irq_domain_add_simple should be
> part of arch/arm/common/gic.c:gic_init(), rather than each SoC's DT board
> file having to do this. However, that'd require gic_init having an OF
> device node to pass to of_irq_domain_add_simple.

I agree.  We could add a variant of gic_init that accepts a device
node so that it can take care of setting up a simple domain.  I've
actually got a patch that I've been working on that embeds
of_irq_domain in struct gic_chip_data() so that it has direct access
to the hw context, which may end up being a cleaner overall solution.

> Question 2: Should the range of IRQ numbers cover just the IRQs directly
> managed by the GIC itself, or cover the entire range of IRQ numbers for
> the SoC? Put another way, should it include mappings for a GPIO controller
> then aggregates interrupts from N GPIOs into 1 or M GIC interrupts, or not?
> Put yet another way, should the code pass INT_MAIN_NR or NR_IRQS for Tegra?
> I suspect the former, and that child interrupt devices should themselves
> call of_irq_domain_add_simple to set up their mappings?

If you're talking about GPIOs, then probably not since you'll want
your GPIO controller described using a different node from the irq
controller.  If all of the irqs will be described using a single node,
then it makes sense to have a separate of_irq_domain registration for
each node (otherwise you have to jump through all kinds of hoops to
make it work).

>From an SoC perspective, if the chip is documented as having a single
flat irq numberspace, even if it is implemented by multiple gics, then
it makes a certain amount of sense to describe the whole irq complex
with a single node and of_irq_domain().  The flip side is that Russell
wants, and I agree, to have a common binding as must as possible for
all the different irq controllers that are out there; particularly in
light of the irq_chip_generic work that Thomas is carving out.

> 
> Question 3: I'm not sure "arm,gic" is the correct sanctioned compatible value?

I really prefer to name stuff like this after the specific
implementation, like "nvidia,tegra250-gic", with a possible
'compatible' string of the arm logic core: "arm,gic".  Also, I'd be a
lot happier if I knew more about how different versions of the gic
spec are handled, and if some of that version information could be
encoded in the compatible value.

g.

> 
>  arch/arm/boot/dts/tegra-harmony.dts |    2 ++
>  arch/arm/mach-tegra/board-dt.c      |   13 +++++++++++++
>  2 files changed, 15 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/boot/dts/tegra-harmony.dts b/arch/arm/boot/dts/tegra-harmony.dts
> index 6fe09d7..1972f61 100644
> --- a/arch/arm/boot/dts/tegra-harmony.dts
> +++ b/arch/arm/boot/dts/tegra-harmony.dts
> @@ -26,8 +26,10 @@
>  		ranges;
>  
>  		intc: intc {
> +			compatible = "arm,gic";
>  			interrupt-controller;
>  			#interrupt-cells = <1>;
> +			reg = <0x50041000 0x1000 0x50040100 0x100 >;
>  		};
>  	};
>  
> diff --git a/arch/arm/mach-tegra/board-dt.c b/arch/arm/mach-tegra/board-dt.c
> index aa37783..894c7a3 100644
> --- a/arch/arm/mach-tegra/board-dt.c
> +++ b/arch/arm/mach-tegra/board-dt.c
> @@ -22,7 +22,9 @@
>  #include <linux/clk.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/of.h>
> +#include <linux/of_address.h>
>  #include <linux/of_fdt.h>
> +#include <linux/of_irq.h>
>  #include <linux/of_platform.h>
>  #include <linux/pda_power.h>
>  #include <linux/io.h>
> @@ -137,8 +139,19 @@ static struct of_device_id tegra_dt_match_table[] __initdata = {
>  	{}
>  };
>  
> +struct of_device_id gic_match[] = {
> +	{ .compatible = "arm,gic", }, {}
> +};
> +
>  static void __init tegra_dt_init(void)
>  {
> +	struct device_node *node;
> +
> +	node = of_find_matching_node_by_address(NULL, gic_match,
> +						TEGRA_ARM_INT_DIST_BASE);
> +	if (node)
> +		of_irq_domain_add_simple(node, INT_GIC_BASE, INT_MAIN_NR);
> +
>  	/*
>  	 * Before registering devices; tell Linux about which device nodes
>  	 * are intended to be registered so that it doesn't create devices
> -- 
> 1.7.0.4
>