armv7m: Split systick out from NVIC

The SysTick timer isn't really part of the NVIC proper;
we just modelled it that way back when we couldn't
easily have devices that only occupied a small chunk
of a memory region. Split it out into its own device.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 1487604965-23220-10-git-send-email-peter.maydell@linaro.org
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>

2 files changed, 37 insertions, 7 deletions

diff --git a/include/hw/arm/armv7m_nvic.h b/include/hw/arm/armv7m_nvic.h
index 39b94ee08e..1d145fb75f 100644
--- a/include/hw/arm/armv7m_nvic.h
+++ b/include/hw/arm/armv7m_nvic.h
@@ -12,6 +12,7 @@
 
 #include "target/arm/cpu.h"
 #include "hw/sysbus.h"
+#include "hw/timer/armv7m_systick.h"
 
 #define TYPE_NVIC "armv7m_nvic"
 
@@ -48,19 +49,14 @@ typedef struct NVICState {
     unsigned int vectpending; /* highest prio pending enabled exception */
     int exception_prio; /* group prio of the highest prio active exception */
 
-    struct {
-        uint32_t control;
-        uint32_t reload;
-        int64_t tick;
-        QEMUTimer *timer;
-    } systick;
-
     MemoryRegion sysregmem;
     MemoryRegion container;
 
     uint32_t num_irq;
     qemu_irq excpout;
     qemu_irq sysresetreq;
+
+    SysTickState systick;
 } NVICState;
 
 #endif
diff --git a/include/hw/timer/armv7m_systick.h b/include/hw/timer/armv7m_systick.h
new file mode 100644
index 0000000000..cca04defd8
--- /dev/null
+++ b/include/hw/timer/armv7m_systick.h
@@ -0,0 +1,34 @@
+/*
+ * ARMv7M SysTick timer
+ *
+ * Copyright (c) 2006-2007 CodeSourcery.
+ * Written by Paul Brook
+ * Copyright (c) 2017 Linaro Ltd
+ * Written by Peter Maydell
+ *
+ * This code is licensed under the GPL (version 2 or later).
+ */
+
+#ifndef HW_TIMER_ARMV7M_SYSTICK_H
+#define HW_TIMER_ARMV7M_SYSTICK_H
+
+#include "hw/sysbus.h"
+
+#define TYPE_SYSTICK "armv7m_systick"
+
+#define SYSTICK(obj) OBJECT_CHECK(SysTickState, (obj), TYPE_SYSTICK)
+
+typedef struct SysTickState {
+    /*< private >*/
+    SysBusDevice parent_obj;
+    /*< public >*/
+
+    uint32_t control;
+    uint32_t reload;
+    int64_t tick;
+    QEMUTimer *timer;
+    MemoryRegion iomem;
+    qemu_irq irq;
+} SysTickState;
+
+#endif