diff options
author | Sekhar Nori <nsekhar@ti.com> | 2015-12-15 19:56:12 +0530 |
---|---|---|
committer | Thomas Gleixner <tglx@linutronix.de> | 2016-01-06 11:35:13 +0100 |
commit | d3b421cd07e4c0d4d6c0bbd55ca169c054fc081d (patch) | |
tree | fc3e082b4bd7aaf798c495db3a2d5f838e2dea0d /drivers/irqchip/irq-omap-intc.c | |
parent | 1fd9a71076ccbcf731cf02408122600a6f2b5d17 (diff) | |
download | linux-d3b421cd07e4c0d4d6c0bbd55ca169c054fc081d.tar.bz2 |
irqchip/omap-intc: Add support for spurious irq handling
Under some conditions, irq sorting procedure used by INTC can go wrong
resulting in a spurious irq getting reported.
If this condition is not handled, it results in endless stream of:
unexpected IRQ trap at vector 00
messages from ack_bad_irq()
Handle the spurious interrupt condition in omap-intc driver to prevent this.
Measurements using kernel function profiler on AM335x EVM running at 720MHz
show that after this patch omap_intc_handle_irq() takes about 37.4us against
34us before this patch.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Cc: John Ogness <john.ogness@linutronix.de>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Jason Cooper <jason@lakedaemon.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/9c78a6db02ac55f7af7371b417b6e414d2c3095b.1450188128.git.nsekhar@ti.com
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'drivers/irqchip/irq-omap-intc.c')
-rw-r--r-- | drivers/irqchip/irq-omap-intc.c | 27 |
1 files changed, 26 insertions, 1 deletions
diff --git a/drivers/irqchip/irq-omap-intc.c b/drivers/irqchip/irq-omap-intc.c index ed25175ae9fa..9d1bcfc33e4c 100644 --- a/drivers/irqchip/irq-omap-intc.c +++ b/drivers/irqchip/irq-omap-intc.c @@ -47,6 +47,7 @@ #define INTC_ILR0 0x0100 #define ACTIVEIRQ_MASK 0x7f /* omap2/3 active interrupt bits */ +#define SPURIOUSIRQ_MASK (0x1ffffff << 7) #define INTCPS_NR_ILR_REGS 128 #define INTCPS_NR_MIR_REGS 4 @@ -329,11 +330,35 @@ static int __init omap_init_irq(u32 base, struct device_node *node) static asmlinkage void __exception_irq_entry omap_intc_handle_irq(struct pt_regs *regs) { + extern unsigned long irq_err_count; u32 irqnr; irqnr = intc_readl(INTC_SIR); + + /* + * A spurious IRQ can result if interrupt that triggered the + * sorting is no longer active during the sorting (10 INTC + * functional clock cycles after interrupt assertion). Or a + * change in interrupt mask affected the result during sorting + * time. There is no special handling required except ignoring + * the SIR register value just read and retrying. + * See section 6.2.5 of AM335x TRM Literature Number: SPRUH73K + * + * Many a times, a spurious interrupt situation has been fixed + * by adding a flush for the posted write acking the IRQ in + * the device driver. Typically, this is going be the device + * driver whose interrupt was handled just before the spurious + * IRQ occurred. Pay attention to those device drivers if you + * run into hitting the spurious IRQ condition below. + */ + if (unlikely((irqnr & SPURIOUSIRQ_MASK) == SPURIOUSIRQ_MASK)) { + pr_err_once("%s: spurious irq!\n", __func__); + irq_err_count++; + omap_ack_irq(NULL); + return; + } + irqnr &= ACTIVEIRQ_MASK; - WARN_ONCE(!irqnr, "Spurious IRQ ?\n"); handle_domain_irq(domain, irqnr, regs); } |