1 /*
2  * ARM CMSDK APB dual-timer emulation
3  *
4  * Copyright (c) 2018 Linaro Limited
5  * Written by Peter Maydell
6  *
7  *  This program is free software; you can redistribute it and/or modify
8  *  it under the terms of the GNU General Public License version 2 or
9  *  (at your option) any later version.
10  */
11 
12 /*
13  * This is a model of the "APB dual-input timer" which is part of the Cortex-M
14  * System Design Kit (CMSDK) and documented in the Cortex-M System
15  * Design Kit Technical Reference Manual (ARM DDI0479C):
16  * https://developer.arm.com/products/system-design/system-design-kits/cortex-m-system-design-kit
17  *
18  * QEMU interface:
19  *  + QOM property "pclk-frq": frequency at which the timer is clocked
20  *  + sysbus MMIO region 0: the register bank
21  *  + sysbus IRQ 0: combined timer interrupt TIMINTC
22  *  + sysbus IRO 1: timer block 1 interrupt TIMINT1
23  *  + sysbus IRQ 2: timer block 2 interrupt TIMINT2
24  */
25 
26 #ifndef CMSDK_APB_DUALTIMER_H
27 #define CMSDK_APB_DUALTIMER_H
28 
29 #include "hw/sysbus.h"
30 #include "hw/ptimer.h"
31 
32 #define TYPE_CMSDK_APB_DUALTIMER "cmsdk-apb-dualtimer"
33 #define CMSDK_APB_DUALTIMER(obj) OBJECT_CHECK(CMSDKAPBDualTimer, (obj), \
34                                               TYPE_CMSDK_APB_DUALTIMER)
35 
36 typedef struct CMSDKAPBDualTimer CMSDKAPBDualTimer;
37 
38 /* One of the two identical timer modules in the dual-timer module */
39 typedef struct CMSDKAPBDualTimerModule {
40     CMSDKAPBDualTimer *parent;
41     struct ptimer_state *timer;
42     qemu_irq timerint;
43     /*
44      * We must track the guest LOAD and VALUE register state by hand
45      * rather than leaving this state only in the ptimer limit/count,
46      * because if CONTROL.SIZE is 0 then only the low 16 bits of the
47      * counter actually counts, but the high half is still guest
48      * accessible.
49      */
50     uint32_t load;
51     uint32_t value;
52     uint32_t control;
53     uint32_t intstatus;
54 } CMSDKAPBDualTimerModule;
55 
56 #define CMSDK_APB_DUALTIMER_NUM_MODULES 2
57 
58 struct CMSDKAPBDualTimer {
59     /*< private >*/
60     SysBusDevice parent_obj;
61 
62     /*< public >*/
63     MemoryRegion iomem;
64     qemu_irq timerintc;
65     uint32_t pclk_frq;
66 
67     CMSDKAPBDualTimerModule timermod[CMSDK_APB_DUALTIMER_NUM_MODULES];
68     uint32_t timeritcr;
69     uint32_t timeritop;
70 };
71 
72 #endif
73