[PATCH 05/13 v2] irqchip/gic: assign irqchip dynamically

[PATCH 05/13 v2] irqchip/gic: assign irqchip dynamically

[Linus Walleij]

Instead of having the irqchip being a static struct, make it part
of the per-instance data so we can assign it a dynamic name. This
has the usable side effect of displaying the GIC with an instance
number as GIC0, GIC1 ... GICn in /proc/interrupts, which is helpful
when debugging cascaded GICs, such as on the ARM PB11MPCore.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
ChangeLog v1->v2:
- Keep the static structs around, just delete the .name
  field assign them to the chips at registration time, updating
  the name field with the instance number.
- Also enumerate the EOIMODE1 sub-chips.

Marc: can't test the EOIMODE1 thing, it's far above me, but it
"should work". Is it correct that there is one unique and coupled
EOIMODE1 instance per GIC instance like this?
---
 drivers/irqchip/irq-gic.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
index bd021e1e4847..8c93ff80ec52 100644
--- a/drivers/irqchip/irq-gic.c
+++ b/drivers/irqchip/irq-gic.c
@@ -58,6 +58,8 @@ union gic_base {
 };
 
 struct gic_chip_data {
+	struct irq_chip chip;
+	struct irq_chip eoimode1_chip;
 	union gic_base dist_base;
 	union gic_base cpu_base;
 #ifdef CONFIG_CPU_PM
@@ -370,7 +372,6 @@ static void gic_handle_cascade_irq(struct irq_desc *desc)
 }
 
 static struct irq_chip gic_chip = {
-	.name			= "GIC",
 	.irq_mask		= gic_mask_irq,
 	.irq_unmask		= gic_unmask_irq,
 	.irq_eoi		= gic_eoi_irq,
@@ -386,7 +387,6 @@ static struct irq_chip gic_chip = {
 };
 
 static struct irq_chip gic_eoimode1_chip = {
-	.name			= "GICv2",
 	.irq_mask		= gic_eoimode1_mask_irq,
 	.irq_unmask		= gic_unmask_irq,
 	.irq_eoi		= gic_eoimode1_eoi_irq,
@@ -880,11 +880,12 @@ void __init gic_init_physaddr(struct device_node *node)
 static int gic_irq_domain_map(struct irq_domain *d, unsigned int irq,
 				irq_hw_number_t hw)
 {
-	struct irq_chip *chip = &gic_chip;
+	struct gic_chip_data *gic = d->host_data;
+	struct irq_chip *chip = &gic->chip;
 
 	if (static_key_true(&supports_deactivate)) {
 		if (d->host_data == (void *)&gic_data[0])
-			chip = &gic_eoimode1_chip;
+			chip = &gic->eoimode1_chip;
 	}
 
 	if (hw < 32) {
@@ -989,6 +990,13 @@ static void __init __gic_init_bases(unsigned int gic_nr, int irq_start,
 	BUG_ON(gic_nr >= MAX_GIC_NR);
 
 	gic = &gic_data[gic_nr];
+
+	/* Initialize irq_chip */
+	gic->chip = gic_chip;
+	gic->eoimode1_chip = gic_eoimode1_chip;
+	gic->chip.name = kasprintf(GFP_KERNEL, "GIC%d", gic_nr);
+	gic->eoimode1_chip.name = kasprintf(GFP_KERNEL, "GICv2%d", gic_nr);
+
 #ifdef CONFIG_GIC_NON_BANKED
 	if (percpu_offset) { /* Frankein-GIC without banked registers... */
 		unsigned int cpu;
-- 
2.4.3

[PATCH 05/13 v2] irqchip/gic: assign irqchip dynamically

[Marc Zyngier]

Hi Linus,

Sorry for the delay, I just enjoyed two weeks off, and I'm slowly making
my way through my exploding Inbox...

On 23/10/15 10:04, Linus Walleij wrote:
> Instead of having the irqchip being a static struct, make it part
> of the per-instance data so we can assign it a dynamic name. This
> has the usable side effect of displaying the GIC with an instance
> number as GIC0, GIC1 ... GICn in /proc/interrupts, which is helpful
> when debugging cascaded GICs, such as on the ARM PB11MPCore.
> 
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Jason Cooper <jason@lakedaemon.net>
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
> ---
> ChangeLog v1->v2:
> - Keep the static structs around, just delete the .name
>   field assign them to the chips at registration time, updating
>   the name field with the instance number.
> - Also enumerate the EOIMODE1 sub-chips.
> 
> Marc: can't test the EOIMODE1 thing, it's far above me, but it
> "should work". Is it correct that there is one unique and coupled
> EOIMODE1 instance per GIC instance like this?

I'm afraid you misinterpreted the EOIMODE==1 thing. The GIC can either
be EOIMODE==0 (which is what most people are using on 32bit when not
booting at HYP), or EOIMODE==1 (most 64bit systems). For systems with
multiple GICs, the secondary GICs are always EOIMODE==0.

So you should only have a single irqchip structure in gic_chip_data, and
populate it depending on the case you're in:

- gic_nr == 0 && static_key_true(&supports_deactivate) -> EOIMODE==1
- otherwise EOIMODE==0.

Does this make more sense?

Thanks,

	M.
-- 
Jazz is not dead. It just smells funny...

[PATCH 05/13 v2] irqchip/gic: assign irqchip dynamically

[Linus Walleij]

On Mon, Nov 2, 2015 at 10:53 AM, Marc Zyngier <marc.zyngier@arm.com> wrote:
> On 23/10/15 10:04, Linus Walleij wrote:

>> Marc: can't test the EOIMODE1 thing, it's far above me, but it
>> "should work". Is it correct that there is one unique and coupled
>> EOIMODE1 instance per GIC instance like this?
>
> I'm afraid you misinterpreted the EOIMODE==1 thing. The GIC can either
> be EOIMODE==0 (which is what most people are using on 32bit when not
> booting at HYP), or EOIMODE==1 (most 64bit systems). For systems with
> multiple GICs, the secondary GICs are always EOIMODE==0.

So it's an either-or thing not both-and. OK that's the missing piece,
thanks Marc, I'll fix up the patch.

Yours,
Linus Walleij