block/export: Add query-block-exports
[qemu.git] / include / hw / timer / armv7m_systick.h
1 /*
2 * ARMv7M SysTick timer
3 *
4 * Copyright (c) 2006-2007 CodeSourcery.
5 * Written by Paul Brook
6 * Copyright (c) 2017 Linaro Ltd
7 * Written by Peter Maydell
8 *
9 * This code is licensed under the GPL (version 2 or later).
10 */
11
12 #ifndef HW_TIMER_ARMV7M_SYSTICK_H
13 #define HW_TIMER_ARMV7M_SYSTICK_H
14
15 #include "hw/sysbus.h"
16 #include "qom/object.h"
17
18 #define TYPE_SYSTICK "armv7m_systick"
19
20 OBJECT_DECLARE_SIMPLE_TYPE(SysTickState, SYSTICK)
21
22 struct SysTickState {
23 /*< private >*/
24 SysBusDevice parent_obj;
25 /*< public >*/
26
27 uint32_t control;
28 uint32_t reload;
29 int64_t tick;
30 QEMUTimer *timer;
31 MemoryRegion iomem;
32 qemu_irq irq;
33 };
34
35 /*
36 * Multiplication factor to convert from system clock ticks to qemu timer
37 * ticks. This should be set (by board code, usually) to a value
38 * equal to NANOSECONDS_PER_SECOND / frq, where frq is the clock frequency
39 * in Hz of the CPU.
40 *
41 * This value is used by the systick device when it is running in
42 * its "use the CPU clock" mode (ie when SYST_CSR.CLKSOURCE == 1) to
43 * set how fast the timer should tick.
44 *
45 * TODO: we should refactor this so that rather than using a global
46 * we use a device property or something similar. This is complicated
47 * because (a) the property would need to be plumbed through from the
48 * board code down through various layers to the systick device
49 * and (b) the property needs to be modifiable after realize, because
50 * the stellaris board uses this to implement the behaviour where the
51 * guest can reprogram the PLL registers to downclock the CPU, and the
52 * systick device needs to react accordingly. Possibly this should
53 * be deferred until we have a good API for modelling clock trees.
54 */
55 extern int system_clock_scale;
56
57 #endif