Commit-ID: 7611da865c1060b2a7c87a15de663a59035747f8 Gitweb: http://git.kernel.org/tip/7611da865c1060b2a7c87a15de663a59035747f8 Author: David Daney <david.daney@xxxxxxxxxx> AuthorDate: Thu, 18 Aug 2016 15:41:58 -0700 Committer: Marc Zyngier <marc.zyngier@xxxxxxx> CommitDate: Fri, 19 Aug 2016 09:47:07 +0100 irqchip/gicv3-its: Disable the ITS before initializing it When starting a kexec/kdump kernel, the GIC ITS will already have been enabled. According to the ARM Generic Interrupt Controller Architecture Specification (GIC architecture Version 3.0 and version 4.0), writing to GITS_BASER<n> or GITS_CBASER is "UNPREDICTABLE" when the ITS is enabled. On Cavium Thunder systems, this prevents the ITS from being initializing in the kexec/kdump kernel, resulting in failure to register/enable interrupts for all devices. The fix is to disable the ITS if it is not already in the disabled state. This allows the ITS to be properly initialized and then re-enabled in the kexec/kdump kernel. Acked-by: Marc Zyngier <marc.zyngier@xxxxxxx> Signed-off-by: David Daney <david.daney@xxxxxxxxxx> Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> --- drivers/irqchip/irq-gic-v3-its.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/irqchip/irq-gic-v3-its.c b/drivers/irqchip/irq-gic-v3-its.c index 7ceaba8..36b9c28 100644 --- a/drivers/irqchip/irq-gic-v3-its.c +++ b/drivers/irqchip/irq-gic-v3-its.c @@ -1545,7 +1545,12 @@ static int its_force_quiescent(void __iomem *base) u32 val; val = readl_relaxed(base + GITS_CTLR); - if (val & GITS_CTLR_QUIESCENT) + /* + * GIC architecture specification requires the ITS to be both + * disabled and quiescent for writes to GITS_BASER<n> or + * GITS_CBASER to not have UNPREDICTABLE results. + */ + if ((val & GITS_CTLR_QUIESCENT) && !(val & GITS_CTLR_ENABLE)) return 0; /* Disable the generation of all interrupts to this ITS */ -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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