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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4 18/18] xen/arm: IRQ: Handle multiple action per IRQ
>>> On 22.04.14 at 14:58, <julien.grall@xxxxxxxxxx> wrote:
> On ARM, it may happen (eg ARM SMMU) to setup multiple handler for the same
> interrupt.
>
> To be able to use multiple action, the driver has to explicitly call
> {setup,request}_irq with IRQF_SHARED as 2nd parameter.
>
> The behavior stays the same on x86, e.g only one action is handled.
>
> Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
For the non-ARM part:
Acked-by: Jan Beulich <jbeulich@xxxxxxxx>
> ---
> Changes in v4:
> - Go back to a single custom linked list. The double linked-list
> doesn't fit the requirements (i.e browsing safely without look) and
> the llist.h from Linux doesn't allow use to delete a node in the
> middle
> of the list.
>
> Changes in v3:
> - Drop {setup,request}_irq_flags, the current function has been
> extended on an earlier patch.
> - Rename IRQ_SHARED into IRQF_SHARED
>
> Changes in v2:
> - Explain design choice
> - Introduce CONFIG_IRQ_HAS_MULTIPLE_ACTION
> - Use list instead of custom pointer
> - release_irq should not shutdown the IRQ at the beginning
> - Add IRQ_SHARED flags
> - Introduce request_irq_flags and setup_irq_flags
> - Fix compilation on x86. Some code are creating the irqaction
> via = { ... } so the "next" field should be moved
> toward the end
> ---
> xen/arch/arm/irq.c | 79
> +++++++++++++++++++++++++++++++++---------
> xen/include/asm-arm/config.h | 2 ++
> xen/include/xen/irq.h | 4 +++
> 3 files changed, 68 insertions(+), 17 deletions(-)
>
> diff --git a/xen/arch/arm/irq.c b/xen/arch/arm/irq.c
> index 1bc960d..d05c0be 100644
> --- a/xen/arch/arm/irq.c
> +++ b/xen/arch/arm/irq.c
> @@ -155,7 +155,6 @@ int request_irq(unsigned int irq, unsigned int irqflags,
> void do_IRQ(struct cpu_user_regs *regs, unsigned int irq, int is_fiq)
> {
> struct irq_desc *desc = irq_to_desc(irq);
> - struct irqaction *action = desc->action;
>
> /* TODO: perfc_incr(irqs); */
>
> @@ -166,7 +165,7 @@ void do_IRQ(struct cpu_user_regs *regs, unsigned int irq,
> int is_fiq)
> spin_lock(&desc->lock);
> desc->handler->ack(desc);
>
> - if ( action == NULL )
> + if ( !desc->action )
> {
> printk("Unknown %s %#3.3x\n",
> is_fiq ? "FIQ" : "IRQ", irq);
> @@ -198,12 +197,21 @@ void do_IRQ(struct cpu_user_regs *regs, unsigned int
> irq, int is_fiq)
>
> desc->status |= IRQ_INPROGRESS;
>
> - action = desc->action;
> while ( desc->status & IRQ_PENDING )
> {
> + struct irqaction *action;
> +
> desc->status &= ~IRQ_PENDING;
> + action = desc->action;
> +
> spin_unlock_irq(&desc->lock);
> - action->handler(irq, action->dev_id, regs);
> +
> + do
> + {
> + action->handler(irq, action->dev_id, regs);
> + action = action->next;
> + } while ( action );
> +
> spin_lock_irq(&desc->lock);
> }
>
> @@ -220,34 +228,71 @@ void release_irq(unsigned int irq, const void *dev_id)
> {
> struct irq_desc *desc;
> unsigned long flags;
> - struct irqaction *action;
> + struct irqaction *action, **action_ptr;
>
> desc = irq_to_desc(irq);
>
> spin_lock_irqsave(&desc->lock,flags);
>
> - desc->handler->shutdown(desc);
> + action_ptr = &desc->action;
> + for ( ;; )
> + {
> + action = *action_ptr;
> + if ( !action )
> + {
> + printk(XENLOG_WARNING "Trying to free already-free IRQ %u\n",
> irq);
> + spin_unlock_irqrestore(&desc->lock, flags);
> + return;
> + }
> +
> + if ( action->dev_id == dev_id )
> + break;
> +
> + action_ptr = &action->next;
> + }
> +
> + /* Found it - remove it from the action list */
> + *action_ptr = action->next;
>
> - action = desc->action;
> - desc->action = NULL;
> - desc->status &= ~IRQ_GUEST;
> + /* If this was the last action, shut down the IRQ */
> + if ( !desc->action )
> + {
> + desc->handler->shutdown(desc);
> + desc->status &= ~IRQ_GUEST;
> + }
>
> spin_unlock_irqrestore(&desc->lock,flags);
>
> /* Wait to make sure it's not being used on another CPU */
> do { smp_mb(); } while ( desc->status & IRQ_INPROGRESS );
>
> - if ( action && action->free_on_release )
> + if ( action->free_on_release )
> xfree(action);
> }
>
> -static int __setup_irq(struct irq_desc *desc, struct irqaction *new)
> +static int __setup_irq(struct irq_desc *desc, unsigned int irqflags,
> + struct irqaction *new)
> {
> - if ( desc->action != NULL )
> - return -EBUSY;
> + bool_t shared = !!(irqflags & IRQF_SHARED);
> +
> + ASSERT(new != NULL);
> +
> + /* Sanity checks:
> + * - if the IRQ is marked as shared
> + * - dev_id is not NULL when IRQF_SHARED is set
> + */
> + if ( desc->action != NULL && (!(desc->status & IRQF_SHARED) || !shared) )
> + return -EINVAL;
> + if ( shared && new->dev_id == NULL )
> + return -EINVAL;
> +
> + if ( shared )
> + desc->status |= IRQF_SHARED;
>
> - desc->action = new;
> - dsb(sy);
> + new->next = desc->action;
> + dsb(ish);
> + desc->action = new;
> + dsb(ish);
>
> return 0;
> }
> @@ -275,7 +320,7 @@ int setup_irq(unsigned int irq, unsigned int irqflags,
> struct irqaction *new)
>
> disabled = (desc->action == NULL);
>
> - rc = __setup_irq(desc, new);
> + rc = __setup_irq(desc, irqflags, new);
> if ( rc )
> goto err;
>
> @@ -340,7 +385,7 @@ int route_dt_irq_to_guest(struct domain *d, const struct
> dt_irq *irq,
> goto out;
> }
>
> - retval = __setup_irq(desc, action);
> + retval = __setup_irq(desc, 0, action);
> if ( retval )
> goto out;
>
> diff --git a/xen/include/asm-arm/config.h b/xen/include/asm-arm/config.h
> index ef291ff..1c3abcf 100644
> --- a/xen/include/asm-arm/config.h
> +++ b/xen/include/asm-arm/config.h
> @@ -37,6 +37,8 @@
>
> #define CONFIG_VIDEO 1
>
> +#define CONFIG_IRQ_HAS_MULTIPLE_ACTION 1
> +
> #define OPT_CONSOLE_STR "dtuart"
>
> #ifdef MAX_PHYS_CPUS
> diff --git a/xen/include/xen/irq.h b/xen/include/xen/irq.h
> index f9a18d8..40c0f3f 100644
> --- a/xen/include/xen/irq.h
> +++ b/xen/include/xen/irq.h
> @@ -14,6 +14,9 @@ struct irqaction {
> const char *name;
> void *dev_id;
> bool_t free_on_release;
> +#ifdef CONFIG_IRQ_HAS_MULTIPLE_ACTION
> + struct irqaction *next;
> +#endif
> };
>
> /*
> @@ -27,6 +30,7 @@ struct irqaction {
> #define IRQ_MOVE_PENDING (1u<<5) /* IRQ is migrating to another CPUs */
> #define IRQ_PER_CPU (1u<<6) /* IRQ is per CPU */
> #define IRQ_GUEST_EOI_PENDING (1u<<7) /* IRQ was disabled, pending a guest
> EOI */
> +#define IRQF_SHARED (1<<8) /* IRQ is shared */
>
> /* Special IRQ numbers. */
> #define AUTO_ASSIGN_IRQ (-1)
> --
> 1.7.10.4
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