From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753357AbaBYQcA (ORCPT ); Tue, 25 Feb 2014 11:32:00 -0500 Received: from mail-wi0-f178.google.com ([209.85.212.178]:59104 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752827AbaBYQb7 (ORCPT ); Tue, 25 Feb 2014 11:31:59 -0500 From: Jean-Jacques Hiblot To: tglx@linutronix.de, linus.walleij@linaro.org Cc: grant.likely@linaro.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Jean-Jacques Hiblot Subject: [PATCH] irq: Consider a negative return value of irq_startup() as an error Date: Tue, 25 Feb 2014 17:28:39 +0100 Message-Id: <1393345719-3707-1-git-send-email-jjhiblot@traphandler.com> X-Mailer: git-send-email 1.9.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The irq_startup() function returns the return value of the irq_startup callback of the underlying irq_chip. Currently this value only tells if the interrupt is pending, but we can make it also return an error code when it fails. Signed-off-by: Jean-Jacques Hiblot --- Hi Thomas, This patch updates the semantic of the return value of the irq_startup() callback of an irq_chip : a negative value indicates an error. The purpose is to make __setup_irq() fail if the irq_chip can't startup the interrupt. I checked in the kernel for drivers impacted by this. It turns out that most of the implementation of irq_startup() return 0. The only drivers that return non-zero values are: * arch/x86/kernel/apic/io_apic.c: returns 1 when an interrupt is pending * drivers/pinctrl/pinctrl-adi2.c: may return -ENODEV. GPIO-based irq_chip could use this feature because an output gpio can't be used as an interrupt, and thus a call to irq_startup() is likely to fail. You can check out http://www.spinics.net/lists/arm-kernel/msg302713.html for a reference. Regards, Jean-Jacques include/linux/irq.h | 2 ++ kernel/irq/autoprobe.c | 2 +- kernel/irq/manage.c | 4 +++- 3 files changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/irq.h b/include/linux/irq.h index 7dc1003..d566855 100644 --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -282,6 +282,8 @@ static inline irq_hw_number_t irqd_to_hwirq(struct irq_data *d) * * @name: name for /proc/interrupts * @irq_startup: start up the interrupt (defaults to ->enable if NULL) + * negative return values indicate an error, otherwise the + * return values indicates if an interrupt is pending * @irq_shutdown: shut down the interrupt (defaults to ->disable if NULL) * @irq_enable: enable the interrupt (defaults to chip->unmask if NULL) * @irq_disable: disable the interrupt diff --git a/kernel/irq/autoprobe.c b/kernel/irq/autoprobe.c index 0119b9d..64794fa 100644 --- a/kernel/irq/autoprobe.c +++ b/kernel/irq/autoprobe.c @@ -70,7 +70,7 @@ unsigned long probe_irq_on(void) raw_spin_lock_irq(&desc->lock); if (!desc->action && irq_settings_can_probe(desc)) { desc->istate |= IRQS_AUTODETECT | IRQS_WAITING; - if (irq_startup(desc, false)) + if (irq_startup(desc, false) > 0) desc->istate |= IRQS_PENDING; } raw_spin_unlock_irq(&desc->lock); diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c index 481a13c..58c6be0 100644 --- a/kernel/irq/manage.c +++ b/kernel/irq/manage.c @@ -1116,7 +1116,9 @@ __setup_irq(unsigned int irq, struct irq_desc *desc, struct irqaction *new) desc->istate |= IRQS_ONESHOT; if (irq_settings_can_autoenable(desc)) - irq_startup(desc, true); + ret = irq_startup(desc, true); + if (ret < 0) + goto out_mask; else /* Undo nested disables: */ desc->depth = 1; -- 1.9.0