[PATCH v2] irqchip: armada: Fix chained per-cpu interrupts

[gregory.clement@free-electrons.com (Gregory CLEMENT)]

Hi Maxime,

On 03/03/2015 11:27, Maxime Ripard wrote:
> On the Cortex-A9-based Armada SoCs, the MPIC is not the primary interrupt
> controller. Yet, it still has to handle some per-cpu interrupt.
> 
> To do so, it is chained with the GIC using a per-cpu interrupt. However, the
> current code only call irq_set_chained_handler, which is called and enable that
> interrupt only on the boot CPU, which means that the parent per-CPU interrupt
> is never unmasked on the secondary CPUs, preventing the per-CPU interrupt to
> actually work as expected.
> 
> This was not seen until now since the only MPIC PPI users were the Marvell
> timers that were not working, but not used either since the system use the ARM
> TWD by default, and the ethernet controllers, that are faking there interrupts
> as SPI, and don't really expect to have interrupts on the secondary cores
> anyway.
> 
> Add a CPU notifier that will enable the PPI on the secondary cores when they
> are brought up.

Acked-by: Gregory CLEMENT <gregory.clement@free-electrons.com>


Thanks,

Gregory

> 
> Cc: <stable@vger.kernel.org> # 3.15+
> Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
> ---
> Changes from v1:
>   - Renamed the function and notifier names
> 
>  drivers/irqchip/irq-armada-370-xp.c | 21 ++++++++++++++++++++-
>  1 file changed, 20 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/irqchip/irq-armada-370-xp.c b/drivers/irqchip/irq-armada-370-xp.c
> index 463c235acbdc..4387dae14e45 100644
> --- a/drivers/irqchip/irq-armada-370-xp.c
> +++ b/drivers/irqchip/irq-armada-370-xp.c
> @@ -69,6 +69,7 @@ static void __iomem *per_cpu_int_base;
>  static void __iomem *main_int_base;
>  static struct irq_domain *armada_370_xp_mpic_domain;
>  static u32 doorbell_mask_reg;
> +static int parent_irq;
>  #ifdef CONFIG_PCI_MSI
>  static struct irq_domain *armada_370_xp_msi_domain;
>  static DECLARE_BITMAP(msi_used, PCI_MSI_DOORBELL_NR);
> @@ -356,6 +357,7 @@ static int armada_xp_mpic_secondary_init(struct notifier_block *nfb,
>  {
>  	if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
>  		armada_xp_mpic_smp_cpu_init();
> +
>  	return NOTIFY_OK;
>  }
>  
> @@ -364,6 +366,20 @@ static struct notifier_block armada_370_xp_mpic_cpu_notifier = {
>  	.priority = 100,
>  };
>  
> +static int mpic_cascaded_secondary_init(struct notifier_block *nfb,
> +					unsigned long action, void *hcpu)
> +{
> +	if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
> +		enable_percpu_irq(parent_irq, IRQ_TYPE_NONE);
> +
> +	return NOTIFY_OK;
> +}
> +
> +static struct notifier_block mpic_cascaded_cpu_notifier = {
> +	.notifier_call = mpic_cascaded_secondary_init,
> +	.priority = 100,
> +};
> +
>  #endif /* CONFIG_SMP */
>  
>  static struct irq_domain_ops armada_370_xp_mpic_irq_ops = {
> @@ -539,7 +555,7 @@ static int __init armada_370_xp_mpic_of_init(struct device_node *node,
>  					     struct device_node *parent)
>  {
>  	struct resource main_int_res, per_cpu_int_res;
> -	int parent_irq, nr_irqs, i;
> +	int nr_irqs, i;
>  	u32 control;
>  
>  	BUG_ON(of_address_to_resource(node, 0, &main_int_res));
> @@ -587,6 +603,9 @@ static int __init armada_370_xp_mpic_of_init(struct device_node *node,
>  		register_cpu_notifier(&armada_370_xp_mpic_cpu_notifier);
>  #endif
>  	} else {
> +#ifdef CONFIG_SMP
> +		register_cpu_notifier(&mpic_cascaded_cpu_notifier);
> +#endif
>  		irq_set_chained_handler(parent_irq,
>  					armada_370_xp_mpic_handle_cascade_irq);
>  	}
> 


-- 
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com