[RFC PATCH v2 15/15] hw/mips/itu: Pass SAAR using QOM link property

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

QOM objects shouldn't access each other internals fields
except using the QOM API.

mips_cps_realize() instantiates a TYPE_MIPS_ITU object, and
directly sets the 'saar' pointer:

   if (saar_present) {
       s->itu.saar = &env->CP0_SAAR;
   }

In order to avoid that, pass the MIPS_CPU object via a QOM
link property, and set the 'saar' pointer in mips_itu_realize().

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
RFC because not tested.
---
 hw/mips/cps.c              | 23 ++++++-----------------
 hw/misc/mips_itu.c         | 26 ++++++++++++++++++--------
 include/hw/misc/mips_itu.h |  5 ++---
 3 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/hw/mips/cps.c b/hw/mips/cps.c
index 38acc57468..2b5269ebf1 100644
--- a/hw/mips/cps.c
+++ b/hw/mips/cps.c
@@ -66,20 +66,17 @@ static bool cpu_mips_itu_supported(CPUMIPSState *env)
 static void mips_cps_realize(DeviceState *dev, Error **errp)
 {
     MIPSCPSState *s = MIPS_CPS(dev);
-    CPUMIPSState *env;
-    MIPSCPU *cpu;
-    int i;
     target_ulong gcr_base;
     bool itu_present = false;
-    bool saar_present = false;
 
     if (!clock_get(s->clock)) {
         error_setg(errp, "CPS input clock is not connected to an output clock");
         return;
     }
 
-    for (i = 0; i < s->num_vp; i++) {
-        cpu = MIPS_CPU(object_new(s->cpu_type));
+    for (int i = 0; i < s->num_vp; i++) {
+        MIPSCPU *cpu = MIPS_CPU(object_new(s->cpu_type));
+        CPUMIPSState *env = &cpu->env;
 
         /* All VPs are halted on reset. Leave powering up to CPC. */
         if (!object_property_set_bool(OBJECT(cpu), "start-powered-off", true,
@@ -97,7 +94,6 @@ static void mips_cps_realize(DeviceState *dev, Error **errp)
         cpu_mips_irq_init_cpu(cpu);
         cpu_mips_clock_init(cpu);
 
-        env = &cpu->env;
         if (cpu_mips_itu_supported(env)) {
             itu_present = true;
             /* Attach ITC Tag to the VP */
@@ -107,22 +103,15 @@ static void mips_cps_realize(DeviceState *dev, Error **errp)
         qemu_register_reset(main_cpu_reset, cpu);
     }
 
-    cpu = MIPS_CPU(first_cpu);
-    env = &cpu->env;
-    saar_present = (bool)env->saarp;
-
     /* Inter-Thread Communication Unit */
     if (itu_present) {
         object_initialize_child(OBJECT(dev), "itu", &s->itu, TYPE_MIPS_ITU);
+        object_property_set_link(OBJECT(&s->itu), "cpu[0]",
+                                 OBJECT(first_cpu), &error_abort);
         object_property_set_uint(OBJECT(&s->itu), "num-fifo", 16,
                                 &error_abort);
         object_property_set_uint(OBJECT(&s->itu), "num-semaphores", 16,
                                 &error_abort);
-        object_property_set_bool(OBJECT(&s->itu), "saar-present", saar_present,
-                                 &error_abort);
-        if (saar_present) {
-            s->itu.saar = &env->CP0_SAAR;
-        }
         if (!sysbus_realize(SYS_BUS_DEVICE(&s->itu), errp)) {
             return;
         }
@@ -158,7 +147,7 @@ static void mips_cps_realize(DeviceState *dev, Error **errp)
                             sysbus_mmio_get_region(SYS_BUS_DEVICE(&s->gic), 0));
 
     /* Global Configuration Registers */
-    gcr_base = env->CP0_CMGCRBase << 4;
+    gcr_base = MIPS_CPU(first_cpu)->env.CP0_CMGCRBase << 4;
 
     object_initialize_child(OBJECT(dev), "gcr", &s->gcr, TYPE_MIPS_GCR);
     object_property_set_uint(OBJECT(&s->gcr), "num-vp", s->num_vp,
diff --git a/hw/misc/mips_itu.c b/hw/misc/mips_itu.c
index a06cdd10ea..0eda302db4 100644
--- a/hw/misc/mips_itu.c
+++ b/hw/misc/mips_itu.c
@@ -93,10 +93,10 @@ void itc_reconfigure(MIPSITUState *tag)
     uint64_t size = (1 * KiB) + (am[1] & ITC_AM1_ADDR_MASK_MASK);
     bool is_enabled = (am[0] & ITC_AM0_EN_MASK) != 0;
 
-    if (tag->saar_present) {
-        address = ((*(uint64_t *) tag->saar) & 0xFFFFFFFFE000ULL) << 4;
-        size = 1ULL << ((*(uint64_t *) tag->saar >> 1) & 0x1f);
-        is_enabled = *(uint64_t *) tag->saar & 1;
+    if (tag->saar) {
+        address = (tag->saar[0] & 0xFFFFFFFFE000ULL) << 4;
+        size = 1ULL << ((tag->saar[0] >> 1) & 0x1f);
+        is_enabled = tag->saar[0] & 1;
     }
 
     memory_region_transaction_begin();
@@ -157,7 +157,7 @@ static inline ITCView get_itc_view(hwaddr addr)
 static inline int get_cell_stride_shift(const MIPSITUState *s)
 {
     /* Minimum interval (for EntryGain = 0) is 128 B */
-    if (s->saar_present) {
+    if (s->saar) {
         return 7 + ((s->icr0 >> ITC_ICR0_BLK_GRAIN) &
                     ITC_ICR0_BLK_GRAIN_MASK);
     } else {
@@ -515,6 +515,7 @@ static void mips_itu_init(Object *obj)
 static void mips_itu_realize(DeviceState *dev, Error **errp)
 {
     MIPSITUState *s = MIPS_ITU(dev);
+    CPUMIPSState *env;
 
     if (s->num_fifo > ITC_FIFO_NUM_MAX) {
         error_setg(errp, "Exceed maximum number of FIFO cells: %d",
@@ -526,6 +527,15 @@ static void mips_itu_realize(DeviceState *dev, Error **errp)
                    s->num_semaphores);
         return;
     }
+    if (!s->cpu0) {
+        error_setg(errp, "Missing 'cpu[0]' property");
+        return;
+    }
+
+    env = &s->cpu0->env;
+    if (env->saarp) {
+        s->saar = env->CP0_SAAR;
+    }
 
     s->cell = g_new(ITCStorageCell, get_num_cells(s));
 }
@@ -534,8 +544,8 @@ static void mips_itu_reset(DeviceState *dev)
 {
     MIPSITUState *s = MIPS_ITU(dev);
 
-    if (s->saar_present) {
-        *(uint64_t *) s->saar = 0x11 << 1;
+    if (s->saar) {
+        s->saar[0] = 0x11 << 1;
         s->icr0 = get_num_cells(s) << ITC_ICR0_CELL_NUM;
     } else {
         s->ITCAddressMap[0] = 0;
@@ -553,7 +563,7 @@ static Property mips_itu_properties[] = {
                       ITC_FIFO_NUM_MAX),
     DEFINE_PROP_UINT32("num-semaphores", MIPSITUState, num_semaphores,
                       ITC_SEMAPH_NUM_MAX),
-    DEFINE_PROP_BOOL("saar-present", MIPSITUState, saar_present, false),
+    DEFINE_PROP_LINK("cpu[0]", MIPSITUState, cpu0, TYPE_MIPS_CPU, MIPSCPU *),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/include/hw/misc/mips_itu.h b/include/hw/misc/mips_itu.h
index ab6d286c38..35218b2d14 100644
--- a/include/hw/misc/mips_itu.h
+++ b/include/hw/misc/mips_itu.h
@@ -72,9 +72,8 @@ struct MIPSITUState {
     uint64_t icr0;
 
     /* SAAR */
-    bool saar_present;
-    void *saar;
-
+    uint64_t *saar;
+    MIPSCPU *cpu0;
 };
 
 /* Get ITC Configuration Tag memory region. */
-- 
2.38.1