1 /*
2  * QTest testcase for the CMSDK APB watchdog device
3  *
4  * Copyright (c) 2021 Linaro Limited
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the
8  * Free Software Foundation; either version 2 of the License, or
9  * (at your option) any later version.
10  *
11  * This program is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14  * for more details.
15  */
16 
17 #include "qemu/osdep.h"
18 #include "qemu/bitops.h"
19 #include "libqtest-single.h"
20 
21 /*
22  * lm3s811evb watchdog; at board startup this runs at 200MHz / 16 == 12.5MHz,
23  * which is 80ns per tick.
24  */
25 #define WDOG_BASE 0x40000000
26 
27 #define WDOGLOAD 0
28 #define WDOGVALUE 4
29 #define WDOGCONTROL 8
30 #define WDOGINTCLR 0xc
31 #define WDOGRIS 0x10
32 #define WDOGMIS 0x14
33 #define WDOGLOCK 0xc00
34 
35 #define SSYS_BASE 0x400fe000
36 #define RCC 0x60
37 #define SYSDIV_SHIFT 23
38 #define SYSDIV_LENGTH 4
39 
40 static void test_watchdog(void)
41 {
42     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
43 
44     writel(WDOG_BASE + WDOGCONTROL, 1);
45     writel(WDOG_BASE + WDOGLOAD, 1000);
46 
47     /* Step to just past the 500th tick */
48     clock_step(500 * 80 + 1);
49     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
50     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 500);
51 
52     /* Just past the 1000th tick: timer should have fired */
53     clock_step(500 * 80);
54     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 1);
55     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 0);
56 
57     /* VALUE reloads at following tick */
58     clock_step(80);
59     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 1000);
60 
61     /* Writing any value to WDOGINTCLR clears the interrupt and reloads */
62     clock_step(500 * 80);
63     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 500);
64     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 1);
65     writel(WDOG_BASE + WDOGINTCLR, 0);
66     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 1000);
67     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
68 }
69 
70 static void test_clock_change(void)
71 {
72     uint32_t rcc;
73 
74     /*
75      * Test that writing to the stellaris board's RCC register to
76      * change the system clock frequency causes the watchdog
77      * to change the speed it counts at.
78      */
79     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
80 
81     writel(WDOG_BASE + WDOGCONTROL, 1);
82     writel(WDOG_BASE + WDOGLOAD, 1000);
83 
84     /* Step to just past the 500th tick */
85     clock_step(80 * 500 + 1);
86     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
87     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 500);
88 
89     /* Rewrite RCC.SYSDIV from 16 to 8, so the clock is now 40ns per tick */
90     rcc = readl(SSYS_BASE + RCC);
91     g_assert_cmpuint(extract32(rcc, SYSDIV_SHIFT, SYSDIV_LENGTH), ==, 0xf);
92     rcc = deposit32(rcc, SYSDIV_SHIFT, SYSDIV_LENGTH, 7);
93     writel(SSYS_BASE + RCC, rcc);
94 
95     /* Just past the 1000th tick: timer should have fired */
96     clock_step(40 * 500);
97     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 1);
98 
99     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 0);
100 
101     /* VALUE reloads at following tick */
102     clock_step(41);
103     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 1000);
104 
105     /* Writing any value to WDOGINTCLR clears the interrupt and reloads */
106     clock_step(40 * 500);
107     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 500);
108     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 1);
109     writel(WDOG_BASE + WDOGINTCLR, 0);
110     g_assert_cmpuint(readl(WDOG_BASE + WDOGVALUE), ==, 1000);
111     g_assert_cmpuint(readl(WDOG_BASE + WDOGRIS), ==, 0);
112 }
113 
114 int main(int argc, char **argv)
115 {
116     int r;
117 
118     g_test_init(&argc, &argv, NULL);
119 
120     qtest_start("-machine lm3s811evb");
121 
122     qtest_add_func("/cmsdk-apb-watchdog/watchdog", test_watchdog);
123     qtest_add_func("/cmsdk-apb-watchdog/watchdog_clock_change",
124                    test_clock_change);
125 
126     r = g_test_run();
127 
128     qtest_end();
129 
130     return r;
131 }
132