[v5,3/6] irqchip: gic: Support hierarchy irq domain.

Add support to use gic as a parent for stacked irq domain.

Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
---
 drivers/irqchip/Kconfig   |  1 +
 drivers/irqchip/irq-gic.c | 90 +++++++++++++++++++++++++++++++++--------------
 2 files changed, 65 insertions(+), 26 deletions(-)

On 2014/10/29 18:00, Yingjoe Chen wrote:
> Add support to use gic as a parent for stacked irq domain.
> 
> Signed-off-by: Yingjoe Chen <yingjoe.chen@mediatek.com>
> ---
>  drivers/irqchip/Kconfig   |  1 +
>  drivers/irqchip/irq-gic.c | 90 +++++++++++++++++++++++++++++++++--------------
>  2 files changed, 65 insertions(+), 26 deletions(-)
> 
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index b21f12f..7f34138 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -5,6 +5,7 @@ config IRQCHIP
>  config ARM_GIC
>  	bool
>  	select IRQ_DOMAIN
> +	select IRQ_DOMAIN_HIERARCHY
>  	select MULTI_IRQ_HANDLER
>  
>  config GIC_NON_BANKED
> diff --git a/drivers/irqchip/irq-gic.c b/drivers/irqchip/irq-gic.c
> index 38493ff..6f39bef 100644
> --- a/drivers/irqchip/irq-gic.c
> +++ b/drivers/irqchip/irq-gic.c
> @@ -786,19 +786,17 @@ 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)
>  {
> +	irq_domain_set_hwirq_and_chip(d, irq, hw, &gic_chip, d->host_data);
>  	if (hw < 32) {
>  		irq_set_percpu_devid(irq);
> -		irq_set_chip_and_handler(irq, &gic_chip,
> -					 handle_percpu_devid_irq);
> +		irq_set_handler(irq, handle_percpu_devid_irq);
Hi Joe,
	This may trigger a warning when dealing with hierarchy
irqdomain as below. It's because the child domain hasn't set
irq_data->chip yet when parent domain's gic_irq_domain_map() gets
called. We may need to relax the WARNING_ON() in  __irq_set_handler().
    WARN_ON(desc->irq_data.chip == &no_irq_chip)

------------[ cut here ]------------
WARNING: CPU: 2 PID: 912 at kernel/irq/chip.c:734
__irq_set_handler+0x138/0x13c()
Modules linked in: mlx4_core(+) rtc_efi efivarfs
CPU: 2 PID: 912 Comm: modprobe Not tainted 3.18.0-rc3-p2v5+ #53
Call trace:
[<fffffe00000963d4>] dump_backtrace+0x0/0x16c
[<fffffe0000096550>] show_stack+0x10/0x1c
[<fffffe000067545c>] dump_stack+0x74/0x98
[<fffffe00000b205c>] warn_slowpath_common+0x84/0xac
[<fffffe00000b2148>] warn_slowpath_null+0x14/0x20
[<fffffe00000ed968>] __irq_set_handler+0x134/0x13c
[<fffffe000042af14>] gic_irq_domain_map+0x4c/0xac
[<fffffe000042afd4>] gic_irq_domain_alloc+0x60/0x88
[<fffffe000042b374>] gicv2m_domain_alloc+0x30/0xa8
[<fffffe00000efc1c>] __irq_domain_alloc_irqs+0x144/0x30c
[<fffffe000042b58c>] gicv2m_setup_msi_irq+0xc0/0x118
[<fffffe000044548c>] arch_setup_msi_irq+0x34/0x60
[<fffffe0000445544>] arch_setup_msi_irqs+0x50/0xb0
[<fffffe0000445e3c>] pci_enable_msix+0x310/0x39c
[<fffffe0000445efc>] pci_enable_msix_range+0x34/0x9c
>  		set_irq_flags(irq, IRQF_VALID | IRQF_NOAUTOEN);
>  	} else {
> -		irq_set_chip_and_handler(irq, &gic_chip,
> -					 handle_fasteoi_irq);
> +		irq_set_handler(irq, handle_fasteoi_irq);
>  		set_irq_flags(irq, IRQF_VALID | IRQF_PROBE);
>  
>  		gic_routable_irq_domain_ops->map(d, irq, hw);
>  	}
> -	irq_set_chip_data(irq, d->host_data);
>  	return 0;
>  }
>  
> @@ -814,8 +812,6 @@ static int gic_irq_domain_xlate(struct irq_domain *d,
>  {
>  	unsigned long ret = 0;
>  
> -	if (d->of_node != controller)
> -		return -EINVAL;
>  	if (intsize < 3)
>  		return -EINVAL;
>  
> @@ -858,6 +854,42 @@ static struct notifier_block gic_cpu_notifier = {
>  };
>  #endif
>  
> +static int gic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
> +				unsigned int nr_irqs, void *arg)
> +{
> +	int i, ret;
> +	irq_hw_number_t hwirq;
> +	unsigned int type = IRQ_TYPE_NONE;
> +	struct of_phandle_args *irq_data = arg;
> +
> +	ret = gic_irq_domain_xlate(domain, irq_data->np, irq_data->args,
> +				   irq_data->args_count, &hwirq, &type);
> +	if (ret)
> +		return ret;
> +
> +	for (i = 0; i < nr_irqs; i++)
> +		gic_irq_domain_map(domain, virq+i, hwirq+i);
> +
> +	return 0;
> +}
> +
> +static void gic_irq_domain_free(struct irq_domain *domain, unsigned int virq,
> +				unsigned int nr_irqs)
> +{
> +	int i;
> +
> +	for (i = 0; i < nr_irqs; i++) {
> +		irq_set_handler(virq + i, NULL);
> +		irq_domain_set_hwirq_and_chip(domain, virq + i, 0, NULL, NULL);
> +	}
> +}
> +
> +static const struct irq_domain_ops gic_irq_domain_hierarchy_ops = {
> +	.xlate = gic_irq_domain_xlate,
> +	.alloc = gic_irq_domain_alloc,
> +	.free = gic_irq_domain_free,
> +};
> +
>  static const struct irq_domain_ops gic_irq_domain_ops = {
>  	.map = gic_irq_domain_map,
>  	.unmap = gic_irq_domain_unmap,
> @@ -948,18 +980,6 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
>  		gic_cpu_map[i] = 0xff;
>  
>  	/*
> -	 * For primary GICs, skip over SGIs.
> -	 * For secondary GICs, skip over PPIs, too.
> -	 */
> -	if (gic_nr == 0 && (irq_start & 31) > 0) {
> -		hwirq_base = 16;
> -		if (irq_start != -1)
> -			irq_start = (irq_start & ~31) + 16;
> -	} else {
> -		hwirq_base = 32;
> -	}
> -
> -	/*
>  	 * Find out how many interrupts are supported.
>  	 * The GIC only supports up to 1020 interrupt sources.
>  	 */
> @@ -969,10 +989,32 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
>  		gic_irqs = 1020;
>  	gic->gic_irqs = gic_irqs;
>  
> -	gic_irqs -= hwirq_base; /* calculate # of irqs to allocate */
> +	if (node) {		/* DT case */
> +		const struct irq_domain_ops *ops =
> +					&gic_irq_domain_hierarchy_ops;
> +
> +		if (!of_property_read_u32(node, "arm,routable-irqs",
> +					  &nr_routable_irqs)) {
> +			ops = &gic_irq_domain_ops;
> +			gic_irqs = nr_routable_irqs;
> +		}
> +
> +		gic->domain = irq_domain_add_linear(node, gic_irqs, ops, gic);
> +	} else {		/* Non-DT case */
> +		/*
> +		 * For primary GICs, skip over SGIs.
> +		 * For secondary GICs, skip over PPIs, too.
> +		 */
> +		if (gic_nr == 0 && (irq_start & 31) > 0) {
> +			hwirq_base = 16;
> +			if (irq_start != -1)
> +				irq_start = (irq_start & ~31) + 16;
> +		} else {
> +			hwirq_base = 32;
> +		}
> +
> +		gic_irqs -= hwirq_base; /* calculate # of irqs to allocate */
>  
> -	if (of_property_read_u32(node, "arm,routable-irqs",
> -				 &nr_routable_irqs)) {
>  		irq_base = irq_alloc_descs(irq_start, 16, gic_irqs,
>  					   numa_node_id());
>  		if (IS_ERR_VALUE(irq_base)) {
> @@ -983,10 +1025,6 @@ void __init gic_init_bases(unsigned int gic_nr, int irq_start,
>  
>  		gic->domain = irq_domain_add_legacy(node, gic_irqs, irq_base,
>  					hwirq_base, &gic_irq_domain_ops, gic);
> -	} else {
> -		gic->domain = irq_domain_add_linear(node, nr_routable_irqs,
> -						    &gic_irq_domain_ops,
> -						    gic);
>  	}
>  
>  	if (WARN_ON(!gic->domain))
> 
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