Re: [PATCH 08/16] irqdomain: Add a fwnode_handle allocator

[Rafael J. Wysocki]

On Tuesday, October 06, 2015 06:36:21 PM Marc Zyngier wrote:
> In order to be able to reference an irqdomain from ACPI, we need
> to be able to create an identifier, which is usually a struct
> device_node.
> 
> This device node does't really fit the ACPI infrastructure, so
> we cunningly allocate a new structure containing a fwnode_handle,
> and return that.
> 
> This structure doesn't really point to a device (interrupt
> controllers are not "real" devices in Linux), but as we cannot
> really deny that they exist, we create them with a new fwnode_type
> (FWNODE_IRQCHIP).
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx>

This is fine by me:

Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>

[Side note: One of the patches in my linux-next branch will conflict with
the change in enum fwnode_type, but that shouldn't be a big deal.] 

> ---
>  include/linux/fwnode.h    |  1 +
>  include/linux/irqdomain.h |  2 ++
>  kernel/irq/irqdomain.c    | 51 +++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 54 insertions(+)
> 
> diff --git a/include/linux/fwnode.h b/include/linux/fwnode.h
> index 0408545..37ec668 100644
> --- a/include/linux/fwnode.h
> +++ b/include/linux/fwnode.h
> @@ -17,6 +17,7 @@ enum fwnode_type {
>  	FWNODE_OF,
>  	FWNODE_ACPI,
>  	FWNODE_PDATA,
> +	FWNODE_IRQCHIP,
>  };
>  
>  struct fwnode_handle {
> diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
> index 995d4c5..949caa7 100644
> --- a/include/linux/irqdomain.h
> +++ b/include/linux/irqdomain.h
> @@ -188,6 +188,8 @@ static inline struct device_node *irq_domain_get_of_node(struct irq_domain *d)
>  }
>  
>  #ifdef CONFIG_IRQ_DOMAIN
> +struct fwnode_handle *irq_domain_alloc_fwnode(void *data);
> +void irq_domain_free_fwnode(struct fwnode_handle *fwnode);
>  struct irq_domain *__irq_domain_add(struct fwnode_handle *fwnode, int size,
>  				    irq_hw_number_t hwirq_max, int direct_max,
>  				    const struct irq_domain_ops *ops,
> diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
> index ea62f67..6fbecae 100644
> --- a/kernel/irq/irqdomain.c
> +++ b/kernel/irq/irqdomain.c
> @@ -27,6 +27,57 @@ static int irq_domain_alloc_descs(int virq, unsigned int nr_irqs,
>  				  irq_hw_number_t hwirq, int node);
>  static void irq_domain_check_hierarchy(struct irq_domain *domain);
>  
> +struct irqchip_fwid {
> +	struct fwnode_handle fwnode;
> +	char *name;
> +	void *data;
> +};
> +
> +/**
> + * irq_domain_alloc_fwnode - Allocate a fwnode_handle suitable for
> + *                           identifying an irq domain
> + * @data: optional user-provided data
> + *
> + * Allocate a struct device_node, and return a poiner to the embedded
> + * fwnode_handle (or NULL on failure).
> + */
> +struct fwnode_handle *irq_domain_alloc_fwnode(void *data)
> +{
> +	struct irqchip_fwid *fwid;
> +	char *name;
> +
> +	fwid = kzalloc(sizeof(*fwid), GFP_KERNEL);
> +	name = kasprintf(GFP_KERNEL, "irqchip@%p", data);
> +
> +	if (!fwid || !name) {
> +		kfree(fwid);
> +		kfree(name);
> +		return NULL;
> +	}
> +
> +	fwid->name = name;
> +	fwid->data = data;
> +	fwid->fwnode.type = FWNODE_IRQCHIP;
> +	return &fwid->fwnode;
> +}
> +
> +/**
> + * irq_domain_free_fwnode - Free a non-OF-backed fwnode_handle
> + *
> + * Free a fwnode_handle allocated with irq_domain_alloc_fwnode.
> + */
> +void irq_domain_free_fwnode(struct fwnode_handle *fwnode)
> +{
> +	struct irqchip_fwid *fwid;
> +
> +	if (WARN_ON(fwnode->type != FWNODE_IRQCHIP))
> +		return;
> +
> +	fwid = container_of(fwnode, struct irqchip_fwid, fwnode);
> +	kfree(fwid->name);
> +	kfree(fwid);
> +}
> +
>  /**
>   * __irq_domain_add() - Allocate a new irq_domain data structure
>   * @of_node: optional device-tree node of the interrupt controller
> 

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