[MIPS] Add Goldfish target support

Basic Goldfish support for MIPS.

Also, Fix host CPU consumption when guest is idle

When the CPU is in wait state, do not wake-up if an interrupt can't be
taken. This avoid host CPU running at 100% if a device (e.g. timer) has
an interrupt line left enabled.

Also factorize code to check if interrupts are enabled in
cpu_mips_hw_interrupts_pending().

CPU consumption based on a patch from
Edgar E. Iglesias <edgar.iglesias@gmail.com>

Change-Id: Ie8371c8d0c9af1e0c8ba4cac419979350de0f5d9
Signed-off-by: yajin <yajin@mips.com.cm>
Signed-off-by: Douglas Leung <douglas@mips.com>
Signed-off-by: Bhanu Chetlapalli <bhanu@mips.com>
Signed-off-by: Chris Dearman <chris@mips.com>

1 files changed, 31 insertions, 0 deletions

diff --git a/target-mips/cpu.h b/target-mips/cpu.h
index 27bdc95..7c04fbe 100644
--- a/target-mips/cpu.h
+++ b/target-mips/cpu.h
@@ -518,6 +518,37 @@ static inline void cpu_clone_regs(CPUState *env, target_ulong newsp)
     env->active_tc.gpr[2] = 0;
 }
 
+static inline int cpu_mips_hw_interrupts_pending(CPUState *env)
+{
+    int32_t pending;
+    int32_t status;
+    int r;
+
+    if (!(env->CP0_Status & (1 << CP0St_IE)) ||
+        (env->CP0_Status & (1 << CP0St_EXL)) ||
+        (env->CP0_Status & (1 << CP0St_ERL)) ||
+        (env->hflags & MIPS_HFLAG_DM)) {
+        /* Interrupts are disabled */
+        return 0;
+    }
+
+    pending = env->CP0_Cause & CP0Ca_IP_mask;
+    status = env->CP0_Status & CP0Ca_IP_mask;
+
+    if (env->CP0_Config3 & (1 << CP0C3_VEIC)) {
+        /* A MIPS configured with a vectorizing external interrupt controller
+           will feed a vector into the Cause pending lines. The core treats
+           the status lines as a vector level, not as indiviual masks.  */
+        r = pending > status;
+    } else {
+        /* A MIPS configured with compatibility or VInt (Vectored Interrupts)
+           treats the pending lines as individual interrupt lines, the status
+           lines are individual masks.  */
+        r = pending & status;
+    }
+    return r;
+}
+
 #include "cpu-all.h"
 #include "exec-all.h"