From aa4d30f6618dcaf033c4294ca219ef17a6bae69f Mon Sep 17 00:00:00 2001 From: Jessica Clarke Date: Thu, 18 Jun 2020 21:23:43 +0100 Subject: [PATCH] riscv: plic: Honour source priorities The source priorities can be used to order sources with respect to other sources, not just as a way to enable/disable them based off a threshold. We must therefore always claim the highest-priority source, rather than the first source we find. Signed-off-by: Jessica Clarke Reviewed-by: Alistair Francis Message-Id: <20200618202343.20455-1-jrtc27@jrtc27.com> Signed-off-by: Alistair Francis --- hw/riscv/sifive_plic.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/hw/riscv/sifive_plic.c b/hw/riscv/sifive_plic.c index 4f216c55855d..d91e82b8ab80 100644 --- a/hw/riscv/sifive_plic.c +++ b/hw/riscv/sifive_plic.c @@ -166,6 +166,9 @@ static void sifive_plic_update(SiFivePLICState *plic) static uint32_t sifive_plic_claim(SiFivePLICState *plic, uint32_t addrid) { int i, j; + uint32_t max_irq = 0; + uint32_t max_prio = plic->target_priority[addrid]; + for (i = 0; i < plic->bitfield_words; i++) { uint32_t pending_enabled_not_claimed = (plic->pending[i] & ~plic->claimed[i]) & @@ -177,14 +180,18 @@ static uint32_t sifive_plic_claim(SiFivePLICState *plic, uint32_t addrid) int irq = (i << 5) + j; uint32_t prio = plic->source_priority[irq]; int enabled = pending_enabled_not_claimed & (1 << j); - if (enabled && prio > plic->target_priority[addrid]) { - sifive_plic_set_pending(plic, irq, false); - sifive_plic_set_claimed(plic, irq, true); - return irq; + if (enabled && prio > max_prio) { + max_irq = irq; + max_prio = prio; } } } - return 0; + + if (max_irq) { + sifive_plic_set_pending(plic, max_irq, false); + sifive_plic_set_claimed(plic, max_irq, true); + } + return max_irq; } static uint64_t sifive_plic_read(void *opaque, hwaddr addr, unsigned size)