Re: [PATCH 03/12] irqdomain: Support for static IRQ mapping andassociation.

[Benjamin Herrenschmidt]

On Fri, 2012-06-15 at 23:01 -0600, Grant Likely wrote:
> From: Paul Mundt <lethal@xxxxxxxxxxxx>
> 
> This adds a new strict mapping API for supporting creation of linux IRQs
> at existing positions within the domain. The new routines are as follows:
> 
> For dynamic allocation and insertion to specified ranges:
> 
> 	- irq_create_identity_mapping()
> 	- irq_create_strict_mappings()

How does that differ from NOMAP ? Any reason to add that rather than use
NOMAP and some offset built into the PIC driver ?

Cheers,
Ben.

> These will allocate and associate a range of linux IRQs at the specified
> location. This can be used by controllers that have their own static linux IRQ
> definitions to map a hwirq range to, as well as for platforms that wish to
> establish 1:1 identity mapping between linux and hwirq space.
> 
> For insertion to specified ranges by platforms that do their own irq_desc
> management:
> 
> 	- irq_domain_associate()
> 	- irq_domain_associate_many()
> 
> These in turn call back in to the domain's ->map() routine, for further
> processing by the platform. Disassociation of IRQs get handled through
> irq_dispose_mapping() as normal.
> 
> With these in place it should be possible to begin migration of legacy IRQ
> domains to linear ones, without requiring special handling for static vs
> dynamic IRQ definitions in DT vs non-DT paths. This also makes it possible
> for domains with static mappings to adopt whichever tree model best fits
> their needs, rather than simply restricting them to linear revmaps.
> 
> Signed-off-by: Paul Mundt <lethal@xxxxxxxxxxxx>
> [grant.likely: Reorganized irq_domain_associate{,_many} to have all logic in one place]
> [grant.likely: Add error checking for unallocated irq_descs at associate time]
> Signed-off-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
> Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Rob Herring <rob.herring@xxxxxxxxxxx>
> ---
>  include/linux/irqdomain.h |   19 ++++++++
>  kernel/irq/irqdomain.c    |  106 +++++++++++++++++++++++++++++++++++----------
>  2 files changed, 102 insertions(+), 23 deletions(-)
> 
> diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
> index 5abb533..3425631 100644
> --- a/include/linux/irqdomain.h
> +++ b/include/linux/irqdomain.h
> @@ -144,12 +144,31 @@ static inline struct irq_domain *irq_domain_add_legacy_isa(
>  
>  extern void irq_domain_remove(struct irq_domain *host);
>  
> +extern int irq_domain_associate_many(struct irq_domain *domain,
> +				     unsigned int irq_base,
> +				     irq_hw_number_t hwirq_base, int count);
> +static inline int irq_domain_associate(struct irq_domain *domain, unsigned int irq,
> +					irq_hw_number_t hwirq)
> +{
> +	return irq_domain_associate_many(domain, irq, hwirq, 1);
> +}
> +
>  extern unsigned int irq_create_mapping(struct irq_domain *host,
>  				       irq_hw_number_t hwirq);
>  extern void irq_dispose_mapping(unsigned int virq);
>  extern unsigned int irq_find_mapping(struct irq_domain *host,
>  				     irq_hw_number_t hwirq);
>  extern unsigned int irq_create_direct_mapping(struct irq_domain *host);
> +extern int irq_create_strict_mappings(struct irq_domain *domain,
> +				      unsigned int irq_base,
> +				      irq_hw_number_t hwirq_base, int count);
> +
> +static inline int irq_create_identity_mapping(struct irq_domain *host,
> +					      irq_hw_number_t hwirq)
> +{
> +	return irq_create_strict_mappings(host, hwirq, hwirq, 1);
> +}
> +
>  extern void irq_radix_revmap_insert(struct irq_domain *host, unsigned int virq,
>  				    irq_hw_number_t hwirq);
>  extern unsigned int irq_radix_revmap_lookup(struct irq_domain *host,
> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> index 5c36722..1a8f3d2 100644
> --- a/kernel/irq/irqdomain.c
> +++ b/kernel/irq/irqdomain.c
> @@ -379,34 +379,56 @@ static void irq_domain_disassociate_many(struct irq_domain *domain,
>  	}
>  }
>  
> -static int irq_setup_virq(struct irq_domain *domain, unsigned int virq,
> -			    irq_hw_number_t hwirq)
> +int irq_domain_associate_many(struct irq_domain *domain, unsigned int irq_base,
> +			      irq_hw_number_t hwirq_base, int count)
>  {
> -	struct irq_data *irq_data = irq_get_irq_data(virq);
> +	unsigned int virq = irq_base;
> +	irq_hw_number_t hwirq = hwirq_base;
> +	int i;
>  
> -	irq_data->hwirq = hwirq;
> -	irq_data->domain = domain;
> -	if (domain->ops->map(domain, virq, hwirq)) {
> -		pr_debug("irq-%i==>hwirq-0x%lx mapping failed\n", virq, hwirq);
> -		irq_data->domain = NULL;
> -		irq_data->hwirq = 0;
> -		return -1;
> -	}
> +	for (i = 0; i < count; i++) {
> +		struct irq_data *irq_data = irq_get_irq_data(virq + i);
>  
> -	switch (domain->revmap_type) {
> -	case IRQ_DOMAIN_MAP_LINEAR:
> -		if (hwirq < domain->revmap_data.linear.size)
> -			domain->revmap_data.linear.revmap[hwirq] = virq;
> -		break;
> -	case IRQ_DOMAIN_MAP_TREE:
> -		irq_radix_revmap_insert(domain, virq, hwirq);
> -		break;
> -	}
> +		if (WARN(!irq_data, "error: irq_desc not allocated; "
> +			 "irq=%i hwirq=0x%x\n", virq + i, (int)hwirq + i))
> +			return -EINVAL;
> +		if (WARN(irq_data->domain, "error: irq_desc already associated; "
> +			 "irq=%i hwirq=0x%x\n", virq + i, (int)hwirq + i))
> +			return -EINVAL;
> +	};
>  
> -	irq_clear_status_flags(virq, IRQ_NOREQUEST);
> +	for (i = 0; i < count; i++, virq++, hwirq++) {
> +		struct irq_data *irq_data = irq_get_irq_data(virq);
> +
> +		irq_data->hwirq = hwirq;
> +		irq_data->domain = domain;
> +		if (domain->ops->map(domain, virq, hwirq)) {
> +			pr_debug("irq-%i==>hwirq-0x%lx mapping failed\n", virq, hwirq);
> +			irq_data->domain = NULL;
> +			irq_data->hwirq = 0;
> +			goto err_unmap;
> +		}
> +
> +		switch (domain->revmap_type) {
> +		case IRQ_DOMAIN_MAP_LINEAR:
> +			if (hwirq < domain->revmap_data.linear.size)
> +				domain->revmap_data.linear.revmap[hwirq] = virq;
> +			break;
> +		case IRQ_DOMAIN_MAP_TREE:
> +			irq_radix_revmap_insert(domain, virq, hwirq);
> +			break;
> +		}
> +
> +		irq_clear_status_flags(virq, IRQ_NOREQUEST);
> +	}
>  
>  	return 0;
> +
> + err_unmap:
> +	irq_domain_disassociate_many(domain, irq_base, i);
> +	return -EINVAL;
>  }
> +EXPORT_SYMBOL_GPL(irq_domain_associate_many);
>  
>  /**
>   * irq_create_direct_mapping() - Allocate an irq for direct mapping
> @@ -439,7 +461,7 @@ unsigned int irq_create_direct_mapping(struct irq_domain *domain)
>  	}
>  	pr_debug("create_direct obtained virq %d\n", virq);
>  
> -	if (irq_setup_virq(domain, virq, virq)) {
> +	if (irq_domain_associate(domain, virq, virq)) {
>  		irq_free_desc(virq);
>  		return 0;
>  	}
> @@ -500,7 +522,7 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
>  		return 0;
>  	}
>  
> -	if (irq_setup_virq(domain, virq, hwirq)) {
> +	if (irq_domain_associate(domain, virq, hwirq)) {
>  		irq_free_desc(virq);
>  		return 0;
>  	}
> @@ -512,6 +534,44 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
>  }
>  EXPORT_SYMBOL_GPL(irq_create_mapping);
>  
> +/**
> + * irq_create_strict_mappings() - Map a range of hw irqs to fixed linux irqs
> + * @domain: domain owning the interrupt range
> + * @irq_base: beginning of linux IRQ range
> + * @hwirq_base: beginning of hardware IRQ range
> + * @count: Number of interrupts to map
> + *
> + * This routine is used for allocating and mapping a range of hardware
> + * irqs to linux irqs where the linux irq numbers are at pre-defined
> + * locations. For use by controllers that already have static mappings
> + * to insert in to the domain.
> + *
> + * Non-linear users can use irq_create_identity_mapping() for IRQ-at-a-time
> + * domain insertion.
> + *
> + * 0 is returned upon success, while any failure to establish a static
> + * mapping is treated as an error.
> + */
> +int irq_create_strict_mappings(struct irq_domain *domain, unsigned int irq_base,
> +			       irq_hw_number_t hwirq_base, int count)
> +{
> +	int ret;
> +
> +	ret = irq_alloc_descs(irq_base, irq_base, count,
> +			      of_node_to_nid(domain->of_node));
> +	if (unlikely(ret < 0))
> +		return ret;
> +
> +	ret = irq_domain_associate_many(domain, irq_base, hwirq_base, count);
> +	if (unlikely(ret < 0)) {
> +		irq_free_descs(irq_base, count);
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(irq_create_strict_mappings);
> +
>  unsigned int irq_create_of_mapping(struct device_node *controller,
>  				   const u32 *intspec, unsigned int intsize)
>  {


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