hw/arm/xlnx-versal: add support for multiple GICs

The Versal SoC contains two GICs: one GICv3 in the APU and one GICv2 in
the RPU (currently not instantiated). To prepare for the GICv2
instantiation, add support for multiple GICs when connecting interrupts.

When a GIC is created, the first-cpu-index property is set on it, and a
pointer to the GIC is stored in the intc array. When connecting an IRQ,
a TYPE_SPLIT_IRQ device is created with its num-lines property set to
the number of GICs in the SoC. The split device is used to fan out the
IRQ to all the GICs.

Signed-off-by: Luc Michel <luc.michel@amd.com>
Reviewed-by: Francisco Iglesias <francisco.iglesias@amd.com>
Reviewed-by: Edgar E. Iglesias <edgar.iglesias@amd.com>
Tested-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-id: 20250926070806.292065-25-luc.michel@amd.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 52 insertions, 4 deletions

diff --git a/hw/arm/xlnx-versal.c b/hw/arm/xlnx-versal.c
index e03411bc21..9256eceffc 100644
--- a/hw/arm/xlnx-versal.c
+++ b/hw/arm/xlnx-versal.c
@@ -45,6 +45,7 @@
 #include "hw/misc/xlnx-versal-crl.h"
 #include "hw/intc/arm_gicv3_common.h"
 #include "hw/intc/arm_gicv3_its_common.h"
+#include "hw/core/split-irq.h"
 
 #define XLNX_VERSAL_ACPU_TYPE ARM_CPU_TYPE_NAME("cortex-a72")
 #define XLNX_VERSAL_RCPU_TYPE ARM_CPU_TYPE_NAME("cortex-r5f")
@@ -318,6 +319,43 @@ static inline Object *versal_get_child_idx(Versal *s, const char *child,
 }
 
 /*
+ * The SoC embeds multiple GICs. They all receives the same IRQ lines at the
+ * same index. This function creates a TYPE_SPLIT_IRQ device to fan out the
+ * given IRQ input to all the GICs.
+ *
+ * The TYPE_SPLIT_IRQ devices lie in the /soc/irq-splits QOM container
+ */
+static qemu_irq versal_get_gic_irq(Versal *s, int irq_idx)
+{
+    DeviceState *split;
+    Object *container = versal_get_child(s, "irq-splits");
+    int idx = FIELD_EX32(irq_idx, VERSAL_IRQ, IRQ);
+    g_autofree char *name = g_strdup_printf("irq[%d]", idx);
+
+    split = DEVICE(object_resolve_path_at(container, name));
+
+    if (split == NULL) {
+        size_t i;
+
+        split = qdev_new(TYPE_SPLIT_IRQ);
+        qdev_prop_set_uint16(split, "num-lines", s->intc->len);
+        object_property_add_child(container, name, OBJECT(split));
+        qdev_realize_and_unref(split, NULL, &error_abort);
+
+        for (i = 0; i < s->intc->len; i++) {
+            DeviceState *gic;
+
+            gic = g_array_index(s->intc, DeviceState *, i);
+            qdev_connect_gpio_out(split, i, qdev_get_gpio_in(gic, idx));
+        }
+    } else {
+        g_assert(FIELD_EX32(irq_idx, VERSAL_IRQ, ORED));
+    }
+
+    return qdev_get_gpio_in(split, 0);
+}
+
+/*
  * When the R_VERSAL_IRQ_ORED flag is set on an IRQ descriptor, this function is
  * used to return the corresponding or gate input IRQ. The or gate is created if
  * not already existant.
@@ -353,12 +391,10 @@ static qemu_irq versal_get_irq(Versal *s, int irq_idx)
 {
     qemu_irq irq;
     bool ored;
-    DeviceState *gic;
 
     ored = FIELD_EX32(irq_idx, VERSAL_IRQ, ORED);
 
-    gic = DEVICE(versal_get_child_idx(s, "apu-gic", 0));
-    irq = qdev_get_gpio_in(gic, FIELD_EX32(irq_idx, VERSAL_IRQ, IRQ));
+    irq = versal_get_gic_irq(s, irq_idx);
 
     if (ored) {
         irq = versal_get_irq_or_gate_in(s, irq_idx, irq);
@@ -501,6 +537,7 @@ static void versal_create_gic_its(Versal *s,
 static DeviceState *versal_create_gic(Versal *s,
                                       const VersalCpuClusterMap *map,
                                       MemoryRegion *mr,
+                                      int first_cpu_idx,
                                       size_t num_cpu)
 {
     DeviceState *dev;
@@ -525,6 +562,7 @@ static DeviceState *versal_create_gic(Versal *s,
     qdev_prop_set_bit(dev, "has-security-extensions", true);
     qdev_prop_set_bit(dev, "has-lpi", map->gic.has_its);
     object_property_set_link(OBJECT(dev), "sysmem", OBJECT(mr), &error_abort);
+    qdev_prop_set_uint32(dev, "first-cpu-index", first_cpu_idx);
 
     sysbus_realize_and_unref(sbd, &error_fatal);
 
@@ -551,6 +589,8 @@ static DeviceState *versal_create_gic(Versal *s,
 
     versal_create_gic_its(s, map, dev, mr, node);
 
+    g_array_append_val(s->intc, dev);
+
     return dev;
 }
 
@@ -608,9 +648,11 @@ static inline void versal_create_and_connect_gic(Versal *s,
                                                  size_t num_cpu)
 {
     DeviceState *gic;
+    int first_cpu_idx;
     size_t i;
 
-    gic = versal_create_gic(s, map, mr, num_cpu);
+    first_cpu_idx = CPU(cpus[0])->cpu_index;
+    gic = versal_create_gic(s, map, mr, first_cpu_idx, num_cpu);
 
     for (i = 0; i < num_cpu; i++) {
         connect_gic_to_cpu(map, gic, cpus[i], i, num_cpu);
@@ -1540,6 +1582,10 @@ static void versal_realize(DeviceState *dev, Error **errp)
     s->phandle.gic = qemu_fdt_alloc_phandle(s->cfg.fdt);
 
     container = object_new(TYPE_CONTAINER);
+    object_property_add_child(OBJECT(s), "irq-splits", container);
+    object_unref(container);
+
+    container = object_new(TYPE_CONTAINER);
     object_property_add_child(OBJECT(s), "irq-or-gates", container);
     object_unref(container);
 
@@ -1720,6 +1766,7 @@ static void versal_base_init(Object *obj)
     memory_region_init(&s->mr_ps, obj, "mr-ps-switch", UINT64_MAX);
     memory_region_init_alias(&s->lpd.rpu.mr_ps_alias, OBJECT(s),
                              "mr-rpu-ps-alias", &s->mr_ps, 0, UINT64_MAX);
+    s->intc = g_array_new(false, false, sizeof(DeviceState *));
 
     num_can = versal_get_map(s)->num_canfd;
     s->cfg.canbus = g_new0(CanBusState *, num_can);
@@ -1737,6 +1784,7 @@ static void versal_base_finalize(Object *obj)
 {
     Versal *s = XLNX_VERSAL_BASE(obj);
 
+    g_array_free(s->intc, true);
     g_free(s->cfg.canbus);
 }