On Fri, Nov 5, 2021 at 3:18 PM guoren@kernel.org wrote:
From: Guo Ren guoren@linux.alibaba.com
When using "devm_request_threaded_irq(,,,,IRQF_ONESHOT,,)" in the driver, only the first interrupt could be handled, and continue irq is blocked by hw. Because the riscv plic couldn't complete masked irq source which has been disabled in enable register. The bug was firstly reported in [1].
Here is the description of Interrupt Completion in PLIC spec [2]:
The PLIC signals it has completed executing an interrupt handler by writing the interrupt ID it received from the claim to the claim/complete register. The PLIC does not check whether the completion ID is the same as the last claim ID for that target. If the completion ID does not match an interrupt source that is currently enabled for the target, the ^^ ^^^^^^^^^ ^^^^^^^ completion is silently ignored.
[1] http://lists.infradead.org/pipermail/linux-riscv/2021-July/007441.html [2] https://github.com/riscv/riscv-plic-spec/blob/8bc15a35d07c9edf7b5d23fec97283...
Fixes: bb0fed1c60cc ("irqchip/sifive-plic: Switch to fasteoi flow") Reported-by: Vincent Pelletier plr.vincent@gmail.com Tested-by: Nikita Shubin nikita.shubin@maquefel.me Signed-off-by: Guo Ren guoren@linux.alibaba.com
Looks good to me.
Reviewed-by: Anup Patel anup@brainfault.org
Regards, Anup
Cc: stable@vger.kernel.org Cc: Anup Patel anup@brainfault.org Cc: Thomas Gleixner tglx@linutronix.de Cc: Marc Zyngier maz@kernel.org Cc: Palmer Dabbelt palmer@dabbelt.com Cc: Atish Patra atish.patra@wdc.com Cc: Nikita Shubin nikita.shubin@maquefel.me Cc: incent Pelletier plr.vincent@gmail.com
Changes since V7:
- Add Fixes tag
- Add Tested-by
- Add Cc stable
Changes since V6:
- Propagate to plic_irq_eoi for all riscv,plic by Nikita Shubin
- Remove thead related codes
Changes since V5:
- Move back to mask/unmask
- Fixup the problem in eoi callback
- Remove allwinner,sun20i-d1 IRQCHIP_DECLARE
- Rewrite comment log
Changes since V4:
- Update comment by Anup
Changes since V3:
- Rename "c9xx" to "c900"
- Add sifive_plic_chip and thead_plic_chip for difference
Changes since V2:
- Add a separate compatible string "thead,c9xx-plic"
- set irq_mask/unmask of "plic_chip" to NULL and point irq_enable/disable of "plic_chip" to plic_irq_mask/unmask
- Add a detailed comment block in plic_init() about the differences in Claim/Completion process of RISC-V PLIC and C9xx PLIC.
drivers/irqchip/irq-sifive-plic.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/irqchip/irq-sifive-plic.c b/drivers/irqchip/irq-sifive-plic.c index cf74cfa82045..259065d271ef 100644 --- a/drivers/irqchip/irq-sifive-plic.c +++ b/drivers/irqchip/irq-sifive-plic.c @@ -163,7 +163,13 @@ static void plic_irq_eoi(struct irq_data *d) { struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM);
if (irqd_irq_masked(d)) {
plic_irq_unmask(d);
writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM);
plic_irq_mask(d);
} else {
writel(d->hwirq, handler->hart_base + CONTEXT_CLAIM);
}
}
static struct irq_chip plic_chip = {
2.25.1