target/xtensa: add MX interrupt controller

MX interrupt controller is a collection of the following devices
accessible through the external registers interface:
- interrupt distributor can route each external IRQ line to the
  corresponding external IRQ pin of selected subset of connected xtensa
  cores. It has per-CPU and per-IRQ enable signals and per-IRQ software
  assert signals;
- IPI controller has 16 per-CPU IPI signals that may be routed to a
  combination of 3 designated external IRQ pins of connected xtensa
  cores;
- cache coherecy register controls core L1 cache participation in the
  SMP cluster cache coherency protocol;
- runstall register lets BSP core stall and unstall AP cores.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

include/hw/xtensa/mx_pic.h

@@ -0,0 +1,44 @@
+/*
+ * Copyright (c) 2013 - 2019, Max Filippov, Open Source and Linux Lab.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the Open Source and Linux Lab nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef _XTENSA_MX_PIC_H
+#define _XTENSA_MX_PIC_H
+
+#include "exec/memory.h"
+#include "hw/irq.h"
+
+struct XtensaMxPic;
+typedef struct XtensaMxPic XtensaMxPic;
+
+XtensaMxPic *xtensa_mx_pic_init(unsigned n_extint);
+void xtensa_mx_pic_reset(void *opaque);
+MemoryRegion *xtensa_mx_pic_register_cpu(XtensaMxPic *mx,
+                                         qemu_irq *irq,
+                                         qemu_irq runstall);
+qemu_irq *xtensa_mx_pic_get_extints(XtensaMxPic *mx);
+
+#endif