From: Will Deacon Date: Thu, 5 Apr 2012 18:42:10 +0000 (+0100) Subject: ARM: 7377/1: vic: re-read status register before dispatching each IRQ handler X-Git-Tag: upstream/snapshot3+hdmi~7633^2~10 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=34af657916332e89564566bc8d35e3e06cc0c236;p=platform%2Fadaptation%2Frenesas_rcar%2Frenesas_kernel.git ARM: 7377/1: vic: re-read status register before dispatching each IRQ handler handle_IRQ may briefly cause interrupts to be re-enabled during soft IRQ processing on the exit path, leading to nested handling of VIC interrupts. Since the current code does not re-read the VIC_IRQ_STATUS register, this can lead to multiple invocations of the same interrupt handler and spurious interrupts to be reported. This patch changes the VIC interrupt dispatching code to re-read the status register each time, avoiding duplicate invocations of the same handler. Acked-and-Tested-by: H Hartley Sweeten Reviewed-by: Jamie Iles Signed-off-by: Will Deacon Signed-off-by: Russell King --- diff --git a/arch/arm/common/vic.c b/arch/arm/common/vic.c index 7a66311..7e288f9 100644 --- a/arch/arm/common/vic.c +++ b/arch/arm/common/vic.c @@ -427,19 +427,18 @@ int __init vic_of_init(struct device_node *node, struct device_node *parent) /* * Handle each interrupt in a single VIC. Returns non-zero if we've - * handled at least one interrupt. This does a single read of the - * status register and handles all interrupts in order from LSB first. + * handled at least one interrupt. This reads the status register + * before handling each interrupt, which is necessary given that + * handle_IRQ may briefly re-enable interrupts for soft IRQ handling. */ static int handle_one_vic(struct vic_device *vic, struct pt_regs *regs) { u32 stat, irq; int handled = 0; - stat = readl_relaxed(vic->base + VIC_IRQ_STATUS); - while (stat) { + while ((stat = readl_relaxed(vic->base + VIC_IRQ_STATUS))) { irq = ffs(stat) - 1; handle_IRQ(irq_find_mapping(vic->domain, irq), regs); - stat &= ~(1 << irq); handled = 1; }