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irqchip/sifive-plic: Add warning in plic_init() if handler already present

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We have two enteries (one for M-mode and another for S-mode) in the
interrupts-extended DT property of PLIC DT node for each HART. It is
expected that firmware/bootloader will set M-mode HWIRQ line of each
HART to 0xffffffff (i.e. -1) in interrupts-extended DT property
because Linux runs in S-mode only.

If firmware/bootloader is buggy then it will not correctly update
interrupts-extended DT property which might result in a plic_handler
configured twice. This patch adds a warning in plic_init() if a
plic_handler is already marked present. This warning provides us
a hint about incorrectly updated interrupts-extended DT property.

Signed-off-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
This commit is contained in:
Anup Patel 2019-02-12 18:22:44 +05:30 committed by Marc Zyngier
parent 86c7cbf1e8
commit 3fecb5aac2
1 changed files with 5 additions and 0 deletions
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5
drivers/irqchip/irq-sifive-plic.c
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@ -234,6 +234,11 @@ static int __init plic_init(struct device_node *node,
}
handler = per_cpu_ptr(&plic_handlers, cpu);
if (handler->present) {
pr_warn("handler already present for context %d.\n", i);
continue;
}
handler->present = true;
handler->hart_base =
plic_regs + CONTEXT_BASE + i * CONTEXT_PER_HART;