[Qemu-devel] [PATCH 4/4] hw/arm: Correctly disable FPU/DSP for some ARMSSE-based boards

[Peter Maydell]

The SSE-200 hardware has configurable integration settings which
determine whether its two CPUs have the FPU and DSP:
 * CPU0_FPU (default 0)
 * CPU0_DSP (default 0)
 * CPU1_FPU (default 1)
 * CPU1_DSP (default 1)

Similarly, the IoTKit has settings for its single CPU:
 * CPU0_FPU (default 1)
 * CPU0_DSP (default 1)

Of our four boards that use either the IoTKit or the SSE-200:
 * mps2-an505, mps2-an521 and musca-a use the default settings
 * musca-b1 enables FPU and DSP on both CPUs

Currently QEMU models all these boards using CPUs with
both FPU and DSP enabled. This means that we are incorrect
for mps2-an521 and musca-a, which should not have FPU or DSP
on CPU0.

Create QOM properties on the ARMSSE devices corresponding to the
default h/w integration settings, and make the Musca-B1 board
enable FPU and DSP on both CPUs. This fixes the mps2-an521
and musca-a behaviour, and leaves the musca-b1 and mps2-an505
behaviour unchanged.

Signed-off-by: Peter Maydell <address@hidden>
---
 include/hw/arm/armsse.h |  7 +++++
 hw/arm/armsse.c         | 58 ++++++++++++++++++++++++++++++++---------
 hw/arm/musca.c          |  8 ++++++
 3 files changed, 61 insertions(+), 12 deletions(-)

diff --git a/include/hw/arm/armsse.h b/include/hw/arm/armsse.h
index 81e082cccf8..84080c22993 100644
--- a/include/hw/arm/armsse.h
+++ b/include/hw/arm/armsse.h
@@ -50,6 +50,11 @@
  *    address of each SRAM bank (and thus the total amount of internal SRAM)
  *  + QOM property "init-svtor" sets the initial value of the CPU SVTOR 
register
  *    (where it expects to load the PC and SP from the vector table on reset)
+ *  + QOM properties "CPU0_FPU", "CPU0_DSP", "CPU1_FPU" and "CPU1_DSP" which
+ *    set whether the CPUs have the FPU and DSP features present. The default
+ *    (matching the hardware) is that for CPU0 in an IoTKit and CPU1 in an
+ *    SSE-200 both are present; CPU0 in an SSE-200 has neither.
+ *    Since the IoTKit has only one CPU, it does not have the CPU1_* 
properties.
  *  + Named GPIO inputs "EXP_IRQ" 0..n are the expansion interrupts for CPU 0,
  *    which are wired to its NVIC lines 32 .. n+32
  *  + Named GPIO inputs "EXP_CPU1_IRQ" 0..n are the expansion interrupts for
@@ -208,6 +213,8 @@ typedef struct ARMSSE {
     uint32_t mainclk_frq;
     uint32_t sram_addr_width;
     uint32_t init_svtor;
+    bool cpu_fpu[SSE_MAX_CPUS];
+    bool cpu_dsp[SSE_MAX_CPUS];
 } ARMSSE;
 
 typedef struct ARMSSEInfo ARMSSEInfo;
diff --git a/hw/arm/armsse.c b/hw/arm/armsse.c
index 76cc6905798..e138aee673f 100644
--- a/hw/arm/armsse.c
+++ b/hw/arm/armsse.c
@@ -37,6 +37,33 @@ struct ARMSSEInfo {
     bool has_cachectrl;
     bool has_cpusecctrl;
     bool has_cpuid;
+    Property *props;
+};
+
+static Property iotkit_properties[] = {
+    DEFINE_PROP_LINK("memory", ARMSSE, board_memory, TYPE_MEMORY_REGION,
+                     MemoryRegion *),
+    DEFINE_PROP_UINT32("EXP_NUMIRQ", ARMSSE, exp_numirq, 64),
+    DEFINE_PROP_UINT32("MAINCLK", ARMSSE, mainclk_frq, 0),
+    DEFINE_PROP_UINT32("SRAM_ADDR_WIDTH", ARMSSE, sram_addr_width, 15),
+    DEFINE_PROP_UINT32("init-svtor", ARMSSE, init_svtor, 0x10000000),
+    DEFINE_PROP_BOOL("CPU0_FPU", ARMSSE, cpu_fpu[0], true),
+    DEFINE_PROP_BOOL("CPU0_DSP", ARMSSE, cpu_dsp[0], true),
+    DEFINE_PROP_END_OF_LIST()
+};
+
+static Property armsse_properties[] = {
+    DEFINE_PROP_LINK("memory", ARMSSE, board_memory, TYPE_MEMORY_REGION,
+                     MemoryRegion *),
+    DEFINE_PROP_UINT32("EXP_NUMIRQ", ARMSSE, exp_numirq, 64),
+    DEFINE_PROP_UINT32("MAINCLK", ARMSSE, mainclk_frq, 0),
+    DEFINE_PROP_UINT32("SRAM_ADDR_WIDTH", ARMSSE, sram_addr_width, 15),
+    DEFINE_PROP_UINT32("init-svtor", ARMSSE, init_svtor, 0x10000000),
+    DEFINE_PROP_BOOL("CPU0_FPU", ARMSSE, cpu_fpu[0], false),
+    DEFINE_PROP_BOOL("CPU0_DSP", ARMSSE, cpu_dsp[0], false),
+    DEFINE_PROP_BOOL("CPU1_FPU", ARMSSE, cpu_fpu[1], true),
+    DEFINE_PROP_BOOL("CPU1_DSP", ARMSSE, cpu_dsp[1], true),
+    DEFINE_PROP_END_OF_LIST()
 };
 
 static const ARMSSEInfo armsse_variants[] = {
@@ -52,6 +79,7 @@ static const ARMSSEInfo armsse_variants[] = {
         .has_cachectrl = false,
         .has_cpusecctrl = false,
         .has_cpuid = false,
+        .props = iotkit_properties,
     },
     {
         .name = TYPE_SSE200,
@@ -65,6 +93,7 @@ static const ARMSSEInfo armsse_variants[] = {
         .has_cachectrl = true,
         .has_cpusecctrl = true,
         .has_cpuid = true,
+        .props = armsse_properties,
     },
 };
 
@@ -532,6 +561,20 @@ static void armsse_realize(DeviceState *dev, Error **errp)
                 return;
             }
         }
+        if (!s->cpu_fpu[i]) {
+            object_property_set_bool(cpuobj, false, "vfp", &err);
+            if (err) {
+                error_propagate(errp, err);
+                return;
+            }
+        }
+        if (!s->cpu_dsp[i]) {
+            object_property_set_bool(cpuobj, false, "dsp", &err);
+            if (err) {
+                error_propagate(errp, err);
+                return;
+            }
+        }
 
         if (i > 0) {
             memory_region_add_subregion_overlap(&s->cpu_container[i], 0,
@@ -1221,16 +1264,6 @@ static const VMStateDescription armsse_vmstate = {
     }
 };
 
-static Property armsse_properties[] = {
-    DEFINE_PROP_LINK("memory", ARMSSE, board_memory, TYPE_MEMORY_REGION,
-                     MemoryRegion *),
-    DEFINE_PROP_UINT32("EXP_NUMIRQ", ARMSSE, exp_numirq, 64),
-    DEFINE_PROP_UINT32("MAINCLK", ARMSSE, mainclk_frq, 0),
-    DEFINE_PROP_UINT32("SRAM_ADDR_WIDTH", ARMSSE, sram_addr_width, 15),
-    DEFINE_PROP_UINT32("init-svtor", ARMSSE, init_svtor, 0x10000000),
-    DEFINE_PROP_END_OF_LIST()
-};
-
 static void armsse_reset(DeviceState *dev)
 {
     ARMSSE *s = ARMSSE(dev);
@@ -1243,13 +1276,14 @@ static void armsse_class_init(ObjectClass *klass, void 
*data)
     DeviceClass *dc = DEVICE_CLASS(klass);
     IDAUInterfaceClass *iic = IDAU_INTERFACE_CLASS(klass);
     ARMSSEClass *asc = ARMSSE_CLASS(klass);
+    const ARMSSEInfo *info = data;
 
     dc->realize = armsse_realize;
     dc->vmsd = &armsse_vmstate;
-    dc->props = armsse_properties;
+    dc->props = info->props;
     dc->reset = armsse_reset;
     iic->check = armsse_idau_check;
-    asc->info = data;
+    asc->info = info;
 }
 
 static const TypeInfo armsse_info = {
diff --git a/hw/arm/musca.c b/hw/arm/musca.c
index 23aff43f4bc..736f37b774c 100644
--- a/hw/arm/musca.c
+++ b/hw/arm/musca.c
@@ -385,6 +385,14 @@ static void musca_init(MachineState *machine)
     qdev_prop_set_uint32(ssedev, "init-svtor", mmc->init_svtor);
     qdev_prop_set_uint32(ssedev, "SRAM_ADDR_WIDTH", mmc->sram_addr_width);
     qdev_prop_set_uint32(ssedev, "MAINCLK", SYSCLK_FRQ);
+    /*
+     * Musca-A takes the default SSE-200 FPU/DSP settings (ie no for
+     * CPU0 and yes for CPU1); Musca-B1 explicitly enables them for CPU0.
+     */
+    if (mmc->type == MUSCA_B1) {
+        qdev_prop_set_bit(ssedev, "CPU0_FPU", true);
+        qdev_prop_set_bit(ssedev, "CPU0_DSP", true);
+    }
     object_property_set_bool(OBJECT(&mms->sse), true, "realized",
                              &error_fatal);
 
-- 
2.20.1