[Qemu-devel] [PATCH V2] Target-arm: Add the Cortex-M4 CPU

["Aurelio C. Remonda" <aurelioremonda@gmail.com>]

* Changes in V2: Add the ARM_FEATURE_THUMB_DSP in a separate patch.
This patch adds the Cortex-M4 CPU. The M4 is basically the same as the M3,
the main differences being the DSP instructions and an optional FPU.
I created an ARM_FEATURE_THUMB_DSP to be added to any non-M thumb2-compatible
CPU that uses DSP instructions, and I manually added it to the M4 in its initfn.

Signed-off-by: Aurelio C. Remonda <aurelioremonda@gmail.com>
---
 target-arm/cpu.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/target-arm/cpu.c b/target-arm/cpu.c
index 4a888ab..537e6ee 100644
--- a/target-arm/cpu.c
+++ b/target-arm/cpu.c
@@ -533,6 +533,10 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
     if (arm_feature(env, ARM_FEATURE_CBAR_RO)) {
         set_feature(env, ARM_FEATURE_CBAR);
     }
+    if (arm_feature(env, ARM_FEATURE_THUMB2) &&
+        !arm_feature(env, ARM_FEATURE_M)) {
+        set_feature(env, ARM_FEATURE_THUMB_DSP);
+    }
 
     if (cpu->reset_hivecs) {
             cpu->reset_sctlr |= (1 << 13);
@@ -782,6 +786,22 @@ static void cortex_m3_initfn(Object *obj)
     set_feature(&cpu->env, ARM_FEATURE_M);
     cpu->midr = 0x410fc231;
 }
+static void cortex_m4_initfn(Object *obj)
+{
+    ARMCPU *cpu = ARM_CPU(obj);
+    set_feature(&cpu->env, ARM_FEATURE_V7);
+    set_feature(&cpu->env, ARM_FEATURE_M);
+    set_feature(&cpu->env, ARM_FEATURE_THUMB_DSP);
+    cpu->midr = 0x410fc240;
+    /* Main id register CPUID bit assignments
+     * Bits    NAME        Function
+     * [31:24] IMPLEMENTER Indicates implementor: 0x41 = ARM
+     * [23:20] VARIANT     Indicates processor revision: 0x0 = Revision 0
+     * [19:16] (Constant)  Reads as 0xF
+     * [15:4]  PARTNO      Indicates part number: 0xC24 = Cortex-M4
+     * [3:0]   REVISION    Indicates patch release: 0x0 = Patch 0.
+     */
+}
 
 static void arm_v7m_class_init(ObjectClass *oc, void *data)
 {
@@ -1185,6 +1205,8 @@ static const ARMCPUInfo arm_cpus[] = {
     { .name = "arm11mpcore", .initfn = arm11mpcore_initfn },
     { .name = "cortex-m3",   .initfn = cortex_m3_initfn,
                              .class_init = arm_v7m_class_init },
+    { .name = "cortex-m4",   .initfn = cortex_m4_initfn,
+                             .class_init = arm_v7m_class_init },
     { .name = "cortex-a8",   .initfn = cortex_a8_initfn },
     { .name = "cortex-a9",   .initfn = cortex_a9_initfn },
     { .name = "cortex-a15",  .initfn = cortex_a15_initfn },
1.9.1