[PATCH v2 1/1] hw/intc: resample level IRQ on PLIC completion

From: lanxiaoyun1 <[email protected]>

When an interrupt completion message is received, if the interrupt is
level-triggered and still asserted, forward a new interrupt request to
the PLIC core.

This updates the SiFive PLIC IRQ handling so completion rechecks the
current source level and reasserts pending state when the input remains
high, matching the RISC-V PLIC specification.

Signed-off-by: lanxiaoyun1 <[email protected]>
---
 hw/intc/sifive_plic.c         | 5 ++++-
 include/hw/intc/sifive_plic.h | 1 +
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/hw/intc/sifive_plic.c b/hw/intc/sifive_plic.c
index 9c84ff06a9..3927684bcf 100644
--- a/hw/intc/sifive_plic.c
+++ b/hw/intc/sifive_plic.c
@@ -246,6 +246,7 @@ static void sifive_plic_write(void *opaque, hwaddr addr, uint64_t value,
         } else if (contextid == 4) {
             if (value < plic->num_sources) {
                 sifive_plic_set_claimed(plic, value, false);
+                sifive_plic_set_pending(plic, value, !!plic->source[value]);
                 sifive_plic_update(plic);
             }
         } else {
@@ -276,6 +277,7 @@ static void sifive_plic_reset(DeviceState *dev)
     int i;
 
     memset(s->source_priority, 0, sizeof(uint32_t) * s->num_sources);
+    memset(s->source, 0, sizeof(uint32_t) * s->num_sources);
     memset(s->target_priority, 0, sizeof(uint32_t) * s->num_addrs);
     memset(s->pending, 0, sizeof(uint32_t) * s->bitfield_words);
     memset(s->claimed, 0, sizeof(uint32_t) * s->bitfield_words);
@@ -353,7 +355,7 @@ static void parse_hart_config(SiFivePLICState *plic)
 static void sifive_plic_irq_request(void *opaque, int irq, int level)
 {
     SiFivePLICState *s = opaque;
-
+    s->source[irq] = !!level;
     if (level > 0) {
         sifive_plic_set_pending(s, irq, true);
         sifive_plic_update(s);
@@ -379,6 +381,7 @@ static void sifive_plic_realize(DeviceState *dev, Error **errp)
     s->bitfield_words = (s->num_sources + 31) >> 5;
     s->num_enables = s->bitfield_words * s->num_addrs;
     s->source_priority = g_new0(uint32_t, s->num_sources);
+    s->source = g_new0(uint32_t, s->num_sources);
     s->target_priority = g_new(uint32_t, s->num_addrs);
     s->pending = g_new0(uint32_t, s->bitfield_words);
     s->claimed = g_new0(uint32_t, s->bitfield_words);
diff --git a/include/hw/intc/sifive_plic.h b/include/hw/intc/sifive_plic.h
index 32973dbf28..627a418ba1 100644
--- a/include/hw/intc/sifive_plic.h
+++ b/include/hw/intc/sifive_plic.h
@@ -54,6 +54,7 @@ struct SiFivePLICState {
     uint32_t num_enables;
     PLICAddr *addr_config;
     uint32_t *source_priority;
+    uint32_t *source;
     uint32_t *target_priority;
     uint32_t *pending;
     uint32_t *claimed;
-- 
2.43.0