From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: [PATCH v7 6/6] xen/arm: IRQ: Handle multiple action per IRQ Date: Fri, 16 May 2014 15:40:32 +0100 Message-ID: <1400251232-7695-7-git-send-email-julien.grall@linaro.org> References: <1400251232-7695-1-git-send-email-julien.grall@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta3.messagelabs.com ([195.245.230.39]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1WlJJX-0005Nz-6a for xen-devel@lists.xenproject.org; Fri, 16 May 2014 14:40:47 +0000 Received: by mail-ee0-f44.google.com with SMTP id c41so1619927eek.17 for ; Fri, 16 May 2014 07:40:45 -0700 (PDT) In-Reply-To: <1400251232-7695-1-git-send-email-julien.grall@linaro.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xenproject.org Cc: stefano.stabellini@citrix.com, Julien Grall , tim@xen.org, ian.campbell@citrix.com, Jan Beulich List-Id: xen-devel@lists.xenproject.org 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 Acked-by: Jan Beulich Acked-by: Ian Campbell --- 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 1b62d83..3a9a688 100644 --- a/xen/arch/arm/irq.c +++ b/xen/arch/arm/irq.c @@ -171,7 +171,6 @@ 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); */ @@ -182,7 +181,7 @@ 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); @@ -214,12 +213,21 @@ 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); } @@ -236,34 +244,71 @@ 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; } @@ -291,7 +336,7 @@ 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; @@ -355,7 +400,7 @@ int route_irq_to_guest(struct domain *d, unsigned int 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