mips: Add MT halting and waking of VPEs

+ some partial support for TC's.

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>

target-mips/cpu.h

@@ -618,6 +618,14 @@ enum {
 /* Dummy exception for conditional stores.  */
 #define EXCP_SC 0x100
 
+/*
+ * This is an interrnally generated WAKE request line.
+ * It is driven by the CPU itself. Raised when the MT
+ * block wants to wake a VPE from an inactive state and
+ * cleared when VPE goes from active to inactive.
+ */
+#define CPU_INTERRUPT_WAKE CPU_INTERRUPT_TGT_INT_0
+
 int cpu_mips_exec(CPUMIPSState *s);
 CPUMIPSState *cpu_mips_init(const char *cpu_model);
 //~ uint32_t cpu_mips_get_clock (void);
@@ -658,6 +666,37 @@ static inline void cpu_set_tls(CPUState *env, target_ulong newtls)
     env->tls_value = newtls;
 }
 
+static inline int mips_vpe_active(CPUState *env)
+{
+    int active = 1;
+
+    /* Check that the VPE is enabled.  */
+    if (!(env->mvp->CP0_MVPControl & (1 << CP0MVPCo_EVP))) {
+        active = 0;
+    }
+    /* Check that the VPE is actived.  */
+    if (!(env->CP0_VPEConf0 & (1 << CP0VPEC0_VPA))) {
+        active = 0;
+    }
+
+    /* Now verify that there are active thread contexts in the VPE.
+
+       This assumes the CPU model will internally reschedule threads
+       if the active one goes to sleep. If there are no threads available
+       the active one will be in a sleeping state, and we can turn off
+       the entire VPE.  */
+    if (!(env->active_tc.CP0_TCStatus & (1 << CP0TCSt_A))) {
+        /* TC is not activated.  */
+        active = 0;
+    }
+    if (env->active_tc.CP0_TCHalt & 1) {
+        /* TC is in halt state.  */
+        active = 0;
+    }
+
+    return active;
+}
+
 static inline int cpu_has_work(CPUState *env)
 {
     int has_work = 0;
@@ -670,6 +709,18 @@ static inline int cpu_has_work(CPUState *env)
         has_work = 1;
     }
 
+    /* MIPS-MT has the ability to halt the CPU.  */
+    if (env->CP0_Config3 & (1 << CP0C3_MT)) {
+        /* The QEMU model will issue an _WAKE request whenever the CPUs
+           should be woken up.  */
+        if (env->interrupt_request & CPU_INTERRUPT_WAKE) {
+            has_work = 1;
+        }
+
+        if (!mips_vpe_active(env)) {
+            has_work = 0;
+        }
+    }
     return has_work;
 }
 

target-mips/op_helper.c

@@ -749,6 +749,46 @@ void helper_sdm (target_ulong addr, target_ulong reglist, uint32_t mem_idx)
 #endif
 
 #ifndef CONFIG_USER_ONLY
+/* SMP helpers.  */
+static int mips_vpe_is_wfi(CPUState *c)
+{
+    /* If the VPE is halted but otherwise active, it means it's waiting for
+       an interrupt.  */
+    return c->halted && mips_vpe_active(c);
+}
+
+static inline void mips_vpe_wake(CPUState *c)
+{
+    /* Dont set ->halted = 0 directly, let it be done via cpu_has_work
+       because there might be other conditions that state that c should
+       be sleeping.  */
+    cpu_interrupt(c, CPU_INTERRUPT_WAKE);
+}
+
+static inline void mips_vpe_sleep(CPUState *c)
+{
+    /* The VPE was shut off, really go to bed.
+       Reset any old _WAKE requests.  */
+    c->halted = 1;
+    cpu_reset_interrupt(c, CPU_INTERRUPT_WAKE);
+}
+
+static inline void mips_tc_wake(CPUState *c, int tc)
+{
+    /* FIXME: TC reschedule.  */
+    if (mips_vpe_active(c) && !mips_vpe_is_wfi(c)) {
+        mips_vpe_wake(c);
+    }
+}
+
+static inline void mips_tc_sleep(CPUState *c, int tc)
+{
+    /* FIXME: TC reschedule.  */
+    if (!mips_vpe_active(c)) {
+        mips_vpe_sleep(c);
+    }
+}
+
 /* tc should point to an int with the value of the global TC index.
    This function will transform it into a local index within the
    returned CPUState.
@@ -1340,6 +1380,11 @@ void helper_mtc0_tchalt (target_ulong arg1)
     env->active_tc.CP0_TCHalt = arg1 & 0x1;
 
     // TODO: Halt TC / Restart (if allocated+active) TC.
+    if (env->active_tc.CP0_TCHalt & 1) {
+        mips_tc_sleep(env, env->current_tc);
+    } else {
+        mips_tc_wake(env, env->current_tc);
+    }
 }
 
 void helper_mttc0_tchalt (target_ulong arg1)
@@ -1353,6 +1398,12 @@ void helper_mttc0_tchalt (target_ulong arg1)
         other->active_tc.CP0_TCHalt = arg1;
     else
         other->tcs[other_tc].CP0_TCHalt = arg1;
+
+    if (arg1 & 1) {
+        mips_tc_sleep(other, other_tc);
+    } else {
+        mips_tc_wake(other, other_tc);
+    }
 }
 
 void helper_mtc0_tccontext (target_ulong arg1)
@@ -1858,14 +1909,36 @@ target_ulong helper_emt(void)
 
 target_ulong helper_dvpe(void)
 {
-    // TODO
-    return 0;
+    CPUState *other_cpu = first_cpu;
+    target_ulong prev = env->mvp->CP0_MVPControl;
+
+    do {
+        /* Turn off all VPEs except the one executing the dvpe.  */
+        if (other_cpu != env) {
+            other_cpu->mvp->CP0_MVPControl &= ~(1 << CP0MVPCo_EVP);
+            mips_vpe_sleep(other_cpu);
+        }
+        other_cpu = other_cpu->next_cpu;
+    } while (other_cpu);
+    return prev;
 }
 
 target_ulong helper_evpe(void)
 {
-    // TODO
-    return 0;
+    CPUState *other_cpu = first_cpu;
+    target_ulong prev = env->mvp->CP0_MVPControl;
+
+    do {
+        if (other_cpu != env
+           /* If the VPE is WFI, dont distrub it's sleep.  */
+           && !mips_vpe_is_wfi(other_cpu)) {
+            /* Enable the VPE.  */
+            other_cpu->mvp->CP0_MVPControl |= (1 << CP0MVPCo_EVP);
+            mips_vpe_wake(other_cpu); /* And wake it up.  */
+        }
+        other_cpu = other_cpu->next_cpu;
+    } while (other_cpu);
+    return prev;
 }
 #endif /* !CONFIG_USER_ONLY */
 
@@ -2213,6 +2286,7 @@ void helper_pmon (int function)
 void helper_wait (void)
 {
     env->halted = 1;
+    cpu_reset_interrupt(env, CPU_INTERRUPT_WAKE);
     helper_raise_exception(EXCP_HLT);
 }