[Qemu-devel] [PATCH v6 2/6] arm: make the number of GIC interrupts configurable

[Mark Langsdorf]

Increase the maximum number of GIC interrupts for a9mp and a11mp to 1020,
and create a configurable property for each defaulting to 96 and 64
(respectively) so that device modelers can set the value appropriately
for their SoC. Other ARM processors also set their maximum number of
used IRQs appropriately.

Set the maximum theoretically number of GIC interrupts to 1020 and
update the save/restore code to only use the appropriate number for
each SoC.

Signed-off-by: Mark Langsdorf <address@hidden>
---
Changes from v5
        Clarify the commit message
        Rename GIC_NIRQ to GIC_MAXIRQ and change usage slightly
        Makes num-irq to uint32_t in all cases
        Clarify the error message
        Clarify documentation on the num-irq qdev property use in all files
Changes from v4
        None
Changes from v3
        Increase maximum number of GIC interrupts to 1020
        Remove SoC/implementation specific GIC_NIRQ #defs
        Added properties code to arm11mp
        Changed error handling for too many interrupts
        Redid save/load handling
Changes from v2
        Skipped
Changes from v1
        Increase the number of a9mp interrupts to 192
        Add a property defaulting to 96
        Add a num_irq member in the gic state structure
        Use the num_irq value as appropriate
        Add num_irq argument to gic_init()
        Add num_irq to various CPU calls to gic_init

 hw/a9mpcore.c     |   13 +++++++--
 hw/arm11mpcore.c  |   17 ++++++++----
 hw/arm_gic.c      |   68 +++++++++++++++++++++++++++++-----------------------
 hw/armv7m_nvic.c  |   30 ++++++++++++++++++-----
 hw/realview_gic.c |    7 ++++-
 5 files changed, 87 insertions(+), 48 deletions(-)

diff --git a/hw/a9mpcore.c b/hw/a9mpcore.c
index 3ef0e13..a522942 100644
--- a/hw/a9mpcore.c
+++ b/hw/a9mpcore.c
@@ -11,9 +11,8 @@
 #include "sysbus.h"
 
 /* Configuration for arm_gic.c:
- * number of external IRQ lines, max number of CPUs, how to ID current CPU
+ * max number of CPUs, how to ID current CPU
  */
-#define GIC_NIRQ 96
 #define NCPU 4
 
 static inline int
@@ -37,6 +36,7 @@ typedef struct a9mp_priv_state {
     MemoryRegion ptimer_iomem;
     MemoryRegion container;
     DeviceState *mptimer;
+    uint32_t num_irq;
 } a9mp_priv_state;
 
 static uint64_t a9_scu_read(void *opaque, target_phys_addr_t offset,
@@ -153,7 +153,7 @@ static int a9mp_priv_init(SysBusDevice *dev)
         hw_error("a9mp_priv_init: num-cpu may not be more than %d\n", NCPU);
     }
 
-    gic_init(&s->gic, s->num_cpu);
+    gic_init(&s->gic, s->num_cpu, s->num_irq);
 
     s->mptimer = qdev_create(NULL, "arm_mptimer");
     qdev_prop_set_uint32(s->mptimer, "num-cpu", s->num_cpu);
@@ -216,6 +216,13 @@ static SysBusDeviceInfo a9mp_priv_info = {
     .qdev.reset = a9mp_priv_reset,
     .qdev.props = (Property[]) {
         DEFINE_PROP_UINT32("num-cpu", a9mp_priv_state, num_cpu, 1),
+        /* The Cortex-A9MP may have anything from 0 to 224 external interrupt
+         * IRQ lines (with another 32 internal). We default to 64+32, which
+         * is the number provided by the Cortex-A9MP test chip in the 
+         * Realview PBX-A9 and Versatile Express A9 development boards.
+         * Other boards may differ and should set this property appropriately.
+         */
+        DEFINE_PROP_UINT32("num-irq", a9mp_priv_state, num_irq, 96),
         DEFINE_PROP_END_OF_LIST(),
     }
 };
diff --git a/hw/arm11mpcore.c b/hw/arm11mpcore.c
index bc0457e..37b5d58 100644
--- a/hw/arm11mpcore.c
+++ b/hw/arm11mpcore.c
@@ -10,11 +10,6 @@
 #include "sysbus.h"
 #include "qemu-timer.h"
 
-/* ??? The MPCore TRM says the on-chip controller has 224 external IRQ lines
-   (+ 32 internal).  However my test chip only exposes/reports 32.
-   More importantly Linux falls over if more than 32 are present!  */
-#define GIC_NIRQ 64
-
 #define NCPU 4
 
 static inline int
@@ -37,6 +32,7 @@ typedef struct mpcore_priv_state {
     MemoryRegion iomem;
     MemoryRegion container;
     DeviceState *mptimer;
+    uint32_t num_irq;
 } mpcore_priv_state;
 
 /* Per-CPU private memory mapped IO.  */
@@ -132,7 +128,7 @@ static int mpcore_priv_init(SysBusDevice *dev)
 {
     mpcore_priv_state *s = FROM_SYSBUSGIC(mpcore_priv_state, dev);
 
-    gic_init(&s->gic, s->num_cpu);
+    gic_init(&s->gic, s->num_cpu, s->num_irq);
     s->mptimer = qdev_create(NULL, "arm_mptimer");
     qdev_prop_set_uint32(s->mptimer, "num-cpu", s->num_cpu);
     qdev_init_nofail(s->mptimer);
@@ -221,6 +217,15 @@ static SysBusDeviceInfo mpcore_priv_info = {
     .qdev.size  = sizeof(mpcore_priv_state),
     .qdev.props = (Property[]) {
         DEFINE_PROP_UINT32("num-cpu", mpcore_priv_state, num_cpu, 1),
+        /* The ARM11 MPCORE TRM says the on-chip controller may have
+         * anything from 0 to 224 external interrupt IRQ lines (with another
+         * 32 internal). We default to 32+32, which is the number provided by
+         * the ARM11 MPCore test chip in the Realview Versatile Express
+         * coretile. Other boards may differ and should set this property
+         * appropriately. Some Linux kernels may not boot if the hardware
+         * has more IRQ lines than the kernel expects. 
+         */
+        DEFINE_PROP_UINT32("num-irq", mpcore_priv_state, num_irq, 64),
         DEFINE_PROP_END_OF_LIST(),
     }
 };
diff --git a/hw/arm_gic.c b/hw/arm_gic.c
index 0339cf5..cf582a5 100644
--- a/hw/arm_gic.c
+++ b/hw/arm_gic.c
@@ -11,6 +11,8 @@
    controller, MPCore distributed interrupt controller and ARMv7-M
    Nested Vectored Interrupt Controller.  */
 
+/* Maximum number of possible interrupts, determined by the GIC architecture */
+#define GIC_MAXIRQ 1020
 //#define DEBUG_GIC
 
 #ifdef DEBUG_GIC
@@ -86,13 +88,13 @@ typedef struct gic_state
     int enabled;
     int cpu_enabled[NCPU];
 
-    gic_irq_state irq_state[GIC_NIRQ];
+    gic_irq_state irq_state[GIC_MAXIRQ];
 #ifndef NVIC
-    int irq_target[GIC_NIRQ];
+    int irq_target[GIC_MAXIRQ];
 #endif
     int priority1[32][NCPU];
-    int priority2[GIC_NIRQ - 32];
-    int last_active[GIC_NIRQ][NCPU];
+    int priority2[GIC_MAXIRQ - 32];
+    int last_active[GIC_MAXIRQ][NCPU];
 
     int priority_mask[NCPU];
     int running_irq[NCPU];
@@ -111,6 +113,7 @@ typedef struct gic_state
     struct gic_state *backref[NCPU];
     MemoryRegion cpuiomem[NCPU+1]; /* CPU interfaces */
 #endif
+    uint32_t num_irq;
 } gic_state;
 
 /* TODO: Many places that call this routine could be optimized.  */
@@ -133,7 +136,7 @@ static void gic_update(gic_state *s)
         }
         best_prio = 0x100;
         best_irq = 1023;
-        for (irq = 0; irq < GIC_NIRQ; irq++) {
+        for (irq = 0; irq < s->num_irq; irq++) {
             if (GIC_TEST_ENABLED(irq, cm) && GIC_TEST_PENDING(irq, cm)) {
                 if (GIC_GET_PRIORITY(irq, cpu) < best_prio) {
                     best_prio = GIC_GET_PRIORITY(irq, cpu);
@@ -222,7 +225,7 @@ static void gic_complete_irq(gic_state * s, int cpu, int 
irq)
     int update = 0;
     int cm = 1 << cpu;
     DPRINTF("EOI %d\n", irq);
-    if (irq >= GIC_NIRQ) {
+    if (irq >= s->num_irq) {
         /* This handles two cases:
          * 1. If software writes the ID of a spurious interrupt [ie 1023]
          * to the GICC_EOIR, the GIC ignores that write.
@@ -279,7 +282,7 @@ static uint32_t gic_dist_readb(void *opaque, 
target_phys_addr_t offset)
         if (offset == 0)
             return s->enabled;
         if (offset == 4)
-            return ((GIC_NIRQ / 32) - 1) | ((NUM_CPU(s) - 1) << 5);
+            return ((s->num_irq / 32) - 1) | ((NUM_CPU(s) - 1) << 5);
         if (offset < 0x08)
             return 0;
         if (offset >= 0x80) {
@@ -295,7 +298,7 @@ static uint32_t gic_dist_readb(void *opaque, 
target_phys_addr_t offset)
         else
             irq = (offset - 0x180) * 8;
         irq += GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         res = 0;
         for (i = 0; i < 8; i++) {
@@ -310,7 +313,7 @@ static uint32_t gic_dist_readb(void *opaque, 
target_phys_addr_t offset)
         else
             irq = (offset - 0x280) * 8;
         irq += GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         res = 0;
         mask = (irq < 32) ?  cm : ALL_CPU_MASK;
@@ -322,7 +325,7 @@ static uint32_t gic_dist_readb(void *opaque, 
target_phys_addr_t offset)
     } else if (offset < 0x400) {
         /* Interrupt Active.  */
         irq = (offset - 0x300) * 8 + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         res = 0;
         mask = (irq < 32) ?  cm : ALL_CPU_MASK;
@@ -334,14 +337,14 @@ static uint32_t gic_dist_readb(void *opaque, 
target_phys_addr_t offset)
     } else if (offset < 0x800) {
         /* Interrupt Priority.  */
         irq = (offset - 0x400) + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         res = GIC_GET_PRIORITY(irq, cpu);
 #ifndef NVIC
     } else if (offset < 0xc00) {
         /* Interrupt CPU Target.  */
         irq = (offset - 0x800) + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         if (irq >= 29 && irq <= 31) {
             res = cm;
@@ -351,7 +354,7 @@ static uint32_t gic_dist_readb(void *opaque, 
target_phys_addr_t offset)
     } else if (offset < 0xf00) {
         /* Interrupt Configuration.  */
         irq = (offset - 0xc00) * 2 + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         res = 0;
         for (i = 0; i < 4; i++) {
@@ -426,7 +429,7 @@ static void gic_dist_writeb(void *opaque, 
target_phys_addr_t offset,
     } else if (offset < 0x180) {
         /* Interrupt Set Enable.  */
         irq = (offset - 0x100) * 8 + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         if (irq < 16)
           value = 0xff;
@@ -451,7 +454,7 @@ static void gic_dist_writeb(void *opaque, 
target_phys_addr_t offset,
     } else if (offset < 0x200) {
         /* Interrupt Clear Enable.  */
         irq = (offset - 0x180) * 8 + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         if (irq < 16)
           value = 0;
@@ -468,7 +471,7 @@ static void gic_dist_writeb(void *opaque, 
target_phys_addr_t offset,
     } else if (offset < 0x280) {
         /* Interrupt Set Pending.  */
         irq = (offset - 0x200) * 8 + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         if (irq < 16)
           irq = 0;
@@ -481,7 +484,7 @@ static void gic_dist_writeb(void *opaque, 
target_phys_addr_t offset,
     } else if (offset < 0x300) {
         /* Interrupt Clear Pending.  */
         irq = (offset - 0x280) * 8 + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         for (i = 0; i < 8; i++) {
             /* ??? This currently clears the pending bit for all CPUs, even
@@ -497,7 +500,7 @@ static void gic_dist_writeb(void *opaque, 
target_phys_addr_t offset,
     } else if (offset < 0x800) {
         /* Interrupt Priority.  */
         irq = (offset - 0x400) + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         if (irq < 32) {
             s->priority1[irq][cpu] = value;
@@ -508,7 +511,7 @@ static void gic_dist_writeb(void *opaque, 
target_phys_addr_t offset,
     } else if (offset < 0xc00) {
         /* Interrupt CPU Target.  */
         irq = (offset - 0x800) + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         if (irq < 29)
             value = 0;
@@ -518,7 +521,7 @@ static void gic_dist_writeb(void *opaque, 
target_phys_addr_t offset,
     } else if (offset < 0xf00) {
         /* Interrupt Configuration.  */
         irq = (offset - 0xc00) * 4 + GIC_BASE_IRQ;
-        if (irq >= GIC_NIRQ)
+        if (irq >= s->num_irq)
             goto bad_reg;
         if (irq < 32)
             value |= 0xaa;
@@ -699,7 +702,7 @@ static const MemoryRegionOps gic_cpu_ops = {
 static void gic_reset(gic_state *s)
 {
     int i;
-    memset(s->irq_state, 0, GIC_NIRQ * sizeof(gic_irq_state));
+    memset(s->irq_state, 0, GIC_MAXIRQ * sizeof(gic_irq_state));
     for (i = 0 ; i < NUM_CPU(s); i++) {
         s->priority_mask[i] = 0xf0;
         s->current_pending[i] = 1023;
@@ -735,17 +738,17 @@ static void gic_save(QEMUFile *f, void *opaque)
         qemu_put_be32(f, s->cpu_enabled[i]);
         for (j = 0; j < 32; j++)
             qemu_put_be32(f, s->priority1[j][i]);
-        for (j = 0; j < GIC_NIRQ; j++)
+        for (j = 0; j < s->num_irq; j++)
             qemu_put_be32(f, s->last_active[j][i]);
         qemu_put_be32(f, s->priority_mask[i]);
         qemu_put_be32(f, s->running_irq[i]);
         qemu_put_be32(f, s->running_priority[i]);
         qemu_put_be32(f, s->current_pending[i]);
     }
-    for (i = 0; i < GIC_NIRQ - 32; i++) {
+    for (i = 0; i < s->num_irq - 32; i++) {
         qemu_put_be32(f, s->priority2[i]);
     }
-    for (i = 0; i < GIC_NIRQ; i++) {
+    for (i = 0; i < s->num_irq; i++) {
 #ifndef NVIC
         qemu_put_be32(f, s->irq_target[i]);
 #endif
@@ -772,17 +775,17 @@ static int gic_load(QEMUFile *f, void *opaque, int 
version_id)
         s->cpu_enabled[i] = qemu_get_be32(f);
         for (j = 0; j < 32; j++)
             s->priority1[j][i] = qemu_get_be32(f);
-        for (j = 0; j < GIC_NIRQ; j++)
+        for (j = 0; j < s->num_irq; j++)
             s->last_active[j][i] = qemu_get_be32(f);
         s->priority_mask[i] = qemu_get_be32(f);
         s->running_irq[i] = qemu_get_be32(f);
         s->running_priority[i] = qemu_get_be32(f);
         s->current_pending[i] = qemu_get_be32(f);
     }
-    for (i = 0; i < GIC_NIRQ - 32; i++) {
+    for (i = 0; i < s->num_irq - 32; i++) {
         s->priority2[i] = qemu_get_be32(f);
     }
-    for (i = 0; i < GIC_NIRQ; i++) {
+    for (i = 0; i < s->num_irq; i++) {
 #ifndef NVIC
         s->irq_target[i] = qemu_get_be32(f);
 #endif
@@ -798,9 +801,9 @@ static int gic_load(QEMUFile *f, void *opaque, int 
version_id)
 }
 
 #if NCPU > 1
-static void gic_init(gic_state *s, int num_cpu)
+static void gic_init(gic_state *s, int num_cpu, int num_irq)
 #else
-static void gic_init(gic_state *s)
+static void gic_init(gic_state *s, int num_irq)
 #endif
 {
     int i;
@@ -808,7 +811,12 @@ static void gic_init(gic_state *s)
 #if NCPU > 1
     s->num_cpu = num_cpu;
 #endif
-    qdev_init_gpio_in(&s->busdev.qdev, gic_set_irq, GIC_NIRQ - 32);
+    s->num_irq = num_irq + GIC_BASE_IRQ;
+    if (s->num_irq > GIC_MAXIRQ) {
+        hw_error("requested %u interrupt lines exceeds GIC maximum %d\n",
+                 num_irq, GIC_MAXIRQ);
+    }
+    qdev_init_gpio_in(&s->busdev.qdev, gic_set_irq, s->num_irq - 32);
     for (i = 0; i < NUM_CPU(s); i++) {
         sysbus_init_irq(&s->busdev, &s->parent_irq[i]);
     }
diff --git a/hw/armv7m_nvic.c b/hw/armv7m_nvic.c
index bf8c3c5..44932c8 100644
--- a/hw/armv7m_nvic.c
+++ b/hw/armv7m_nvic.c
@@ -15,9 +15,6 @@
 #include "arm-misc.h"
 #include "exec-memory.h"
 
-/* 32 internal lines (16 used for system exceptions) plus 64 external
-   interrupt lines.  */
-#define GIC_NIRQ 96
 #define NCPU 1
 #define NVIC 1
 
@@ -41,6 +38,7 @@ typedef struct {
         int64_t tick;
         QEMUTimer *timer;
     } systick;
+    uint32_t num_irq;
 } nvic_state;
 
 /* qemu timers run at 1GHz.   We want something closer to 1MHz.  */
@@ -125,7 +123,7 @@ static uint32_t nvic_readl(void *opaque, uint32_t offset)
 
     switch (offset) {
     case 4: /* Interrupt Control Type.  */
-        return (GIC_NIRQ / 32) - 1;
+        return (s->num_irq / 32) - 1;
     case 0x10: /* SysTick Control and Status.  */
         val = s->systick.control;
         s->systick.control &= ~SYSTICK_COUNTFLAG;
@@ -169,7 +167,7 @@ static uint32_t nvic_readl(void *opaque, uint32_t offset)
         if (s->gic.current_pending[0] != 1023)
             val |= (s->gic.current_pending[0] << 12);
         /* ISRPENDING */
-        for (irq = 32; irq < GIC_NIRQ; irq++) {
+        for (irq = 32; irq < s->num_irq; irq++) {
             if (s->gic.irq_state[irq].pending) {
                 val |= (1 << 22);
                 break;
@@ -384,16 +382,34 @@ static int armv7m_nvic_init(SysBusDevice *dev)
 {
     nvic_state *s= FROM_SYSBUSGIC(nvic_state, dev);
 
-    gic_init(&s->gic);
+   /* 32 internal lines (16 used for system exceptions) plus 64 external
+    * interrupt lines.  */
+    gic_init(&s->gic, 96);
     memory_region_add_subregion(get_system_memory(), 0xe000e000, 
&s->gic.iomem);
     s->systick.timer = qemu_new_timer_ns(vm_clock, systick_timer_tick, s);
     vmstate_register(&dev->qdev, -1, &vmstate_nvic, s);
     return 0;
 }
 
+static SysBusDeviceInfo armv7m_nvic_priv_info = {
+    .init = armv7m_nvic_init,
+    .qdev.name  = "armv7m_nvic",
+    .qdev.size  = sizeof(nvic_state),
+    .qdev.vmsd = &vmstate_nvic,
+    .qdev.props = (Property[]) {
+        /* The ARM v7m may have anything from 0 to 496 external interrupt
+         * IRQ lines (with another 32 hidden internal exception lines). We
+         * default to 64+32
+         * Other boards may differ and should set this property appropriately.
+         */
+        DEFINE_PROP_UINT32("num-irq", nvic_state, num_irq, 64),
+        DEFINE_PROP_END_OF_LIST(),
+    }
+};
+
 static void armv7m_nvic_register_devices(void)
 {
-    sysbus_register_dev("armv7m_nvic", sizeof(nvic_state), armv7m_nvic_init);
+    sysbus_register_withprop(&armv7m_nvic_priv_info);
 }
 
 device_init(armv7m_nvic_register_devices)
diff --git a/hw/realview_gic.c b/hw/realview_gic.c
index 8c4d509..7342ede 100644
--- a/hw/realview_gic.c
+++ b/hw/realview_gic.c
@@ -9,7 +9,6 @@
 
 #include "sysbus.h"
 
-#define GIC_NIRQ 96
 #define NCPU 1
 
 /* Only a single "CPU" interface is present.  */
@@ -37,7 +36,11 @@ static int realview_gic_init(SysBusDevice *dev)
 {
     RealViewGICState *s = FROM_SYSBUSGIC(RealViewGICState, dev);
 
-    gic_init(&s->gic);
+    /* The GICs on the RealView boards have a fixed nonconfigurable
+     * number of interrupt lines, so we don't need to expose this as
+     * a qdev property.
+     */
+    gic_init(&s->gic, 96);
     realview_gic_map_setup(s);
     sysbus_init_mmio(dev, &s->container);
     return 0;
-- 
1.7.5.4