hw/intc: sifive_plic: Cleanup remaining functions

We can remove the original sifive_plic_irqs_pending() function and
instead just use the sifive_plic_claim() function (renamed to
sifive_plic_claimed()) to determine if any interrupts are pending.

This requires move the side effects outside of sifive_plic_claimed(),
but as they are only invoked once that isn't a problem.

We have also removed all of the old #ifdef debugging logs, so let's
cleanup the last remaining debug function while we are here.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Message-Id: <20220105213937.1113508-5-alistair.francis@opensource.wdc.com>

hw/intc/sifive_plic.c

@@ -31,8 +31,6 @@
 #include "migration/vmstate.h"
 #include "hw/irq.h"
 
-#define RISCV_DEBUG_PLIC 0
-
 static bool addr_between(uint32_t addr, uint32_t base, uint32_t num)
 {
     return addr >= base && addr - base < num;
@@ -51,47 +49,6 @@ static PLICMode char_to_mode(char c)
     }
 }
 
-static char mode_to_char(PLICMode m)
-{
-    switch (m) {
-    case PLICMode_U: return 'U';
-    case PLICMode_S: return 'S';
-    case PLICMode_H: return 'H';
-    case PLICMode_M: return 'M';
-    default: return '?';
-    }
-}
-
-static void sifive_plic_print_state(SiFivePLICState *plic)
-{
-    int i;
-    int addrid;
-
-    /* pending */
-    qemu_log("pending       : ");
-    for (i = plic->bitfield_words - 1; i >= 0; i--) {
-        qemu_log("%08x", plic->pending[i]);
-    }
-    qemu_log("\n");
-
-    /* pending */
-    qemu_log("claimed       : ");
-    for (i = plic->bitfield_words - 1; i >= 0; i--) {
-        qemu_log("%08x", plic->claimed[i]);
-    }
-    qemu_log("\n");
-
-    for (addrid = 0; addrid < plic->num_addrs; addrid++) {
-        qemu_log("hart%d-%c enable: ",
-            plic->addr_config[addrid].hartid,
-            mode_to_char(plic->addr_config[addrid].mode));
-        for (i = plic->bitfield_words - 1; i >= 0; i--) {
-            qemu_log("%08x", plic->enable[addrid * plic->bitfield_words + i]);
-        }
-        qemu_log("\n");
-    }
-}
-
 static uint32_t atomic_set_masked(uint32_t *a, uint32_t mask, uint32_t value)
 {
     uint32_t old, new, cmp = qatomic_read(a);
@@ -115,26 +72,34 @@ static void sifive_plic_set_claimed(SiFivePLICState *plic, int irq, bool level)
     atomic_set_masked(&plic->claimed[irq >> 5], 1 << (irq & 31), -!!level);
 }
 
-static int sifive_plic_irqs_pending(SiFivePLICState *plic, uint32_t addrid)
+static uint32_t sifive_plic_claimed(SiFivePLICState *plic, uint32_t addrid)
 {
+    uint32_t max_irq = 0;
+    uint32_t max_prio = plic->target_priority[addrid];
     int i, j;
+
     for (i = 0; i < plic->bitfield_words; i++) {
         uint32_t pending_enabled_not_claimed =
-            (plic->pending[i] & ~plic->claimed[i]) &
-            plic->enable[addrid * plic->bitfield_words + i];
+                        (plic->pending[i] & ~plic->claimed[i]) &
+                            plic->enable[addrid * plic->bitfield_words + i];
+
         if (!pending_enabled_not_claimed) {
             continue;
         }
+
         for (j = 0; j < 32; j++) {
             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]) {
-                return 1;
+
+            if (enabled && prio > max_prio) {
+                max_irq = irq;
+                max_prio = prio;
             }
         }
     }
-    return 0;
+
+    return max_irq;
 }
 
 static void sifive_plic_update(SiFivePLICState *plic)
@@ -145,7 +110,7 @@ static void sifive_plic_update(SiFivePLICState *plic)
     for (addrid = 0; addrid < plic->num_addrs; addrid++) {
         uint32_t hartid = plic->addr_config[addrid].hartid;
         PLICMode mode = plic->addr_config[addrid].mode;
-        int level = sifive_plic_irqs_pending(plic, addrid);
+        bool level = !!sifive_plic_claimed(plic, addrid);
 
         switch (mode) {
         case PLICMode_M:
@@ -158,41 +123,6 @@ static void sifive_plic_update(SiFivePLICState *plic)
             break;
         }
     }
-
-    if (RISCV_DEBUG_PLIC) {
-        sifive_plic_print_state(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]) &
-            plic->enable[addrid * plic->bitfield_words + i];
-        if (!pending_enabled_not_claimed) {
-            continue;
-        }
-        for (j = 0; j < 32; j++) {
-            int irq = (i << 5) + j;
-            uint32_t prio = plic->source_priority[irq];
-            int enabled = pending_enabled_not_claimed & (1 << j);
-            if (enabled && prio > max_prio) {
-                max_irq = irq;
-                max_prio = prio;
-            }
-        }
-    }
-
-    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)
@@ -223,10 +153,15 @@ static uint64_t sifive_plic_read(void *opaque, hwaddr addr, unsigned size)
         if (contextid == 0) {
             return plic->target_priority[addrid];
         } else if (contextid == 4) {
-            uint32_t value = sifive_plic_claim(plic, addrid);
+            uint32_t max_irq = sifive_plic_claimed(plic, addrid);
+
+            if (max_irq) {
+                sifive_plic_set_pending(plic, max_irq, false);
+                sifive_plic_set_claimed(plic, max_irq, true);
+            }
 
             sifive_plic_update(plic);
-            return value;
+            return max_irq;
         }
     }