1 /******************************************************************************
2 * *
3 * License Agreement *
4 * *
5 * Copyright (c) 2003 Altera Corporation, San Jose, California, USA. *
6 * All rights reserved. *
7 * *
8 * Permission is hereby granted, free of charge, to any person obtaining a *
9 * copy of this software and associated documentation files (the "Software"), *
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13 * Software is furnished to do so, subject to the following conditions: *
14 * *
15 * The above copyright notice and this permission notice shall be included in *
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27 * Altera does not recommend, suggest or require that this reference design *
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29 ******************************************************************************/
30
31 #include "altera_avalon_sysid.h"
32 #include "altera_avalon_sysid_regs.h"
33 #include "alt_types.h"
34 #include <io.h>
35
36 /*
37 * This component is special: there's only one of it.
38 * Therefore we can dispense with a bunch of complexity
39 * normally associated with components, such as specialized
40 * structs containing parameter info, and instead use that
41 * info by name directly out of system.h. A downside of this
42 * approach is that each time the system is regenerated, and
43 * system.h changes, this file must be recompiled. Fortunately
44 * this file is, and is likely to remain, quite small.
45 */
46 #include "system.h"
47
48 #ifdef SYSID_BASE
49 /*
50 * return values:
51 * 0 if the hardware and software appear to be in sync
52 * 1 if software appears to be older than hardware
53 * -1 if hardware appears to be older than software
54 */
55
alt_avalon_sysid_test(void)56 alt_32 alt_avalon_sysid_test(void)
57 {
58 /* Read the hardware-tag, aka value0, from the hardware. */
59 alt_u32 hardware_id = IORD_ALTERA_AVALON_SYSID_ID(SYSID_BASE);
60
61 /* Read the time-of-generation, aka value1, from the hardware register. */
62 alt_u32 hardware_timestamp = IORD_ALTERA_AVALON_SYSID_TIMESTAMP(SYSID_BASE);
63
64 /* Return 0 if the hardware and software appear to be in sync. */
65 if ((SYSID_TIMESTAMP == hardware_timestamp) && (SYSID_ID == hardware_id))
66 {
67 return 0;
68 }
69
70 /*
71 * Return 1 if software appears to be older than hardware (that is,
72 * the value returned by the hardware is larger than that recorded by
73 * the generator function).
74 * If the hardware time happens to match the generator program's value
75 * (but the hardware tag, value0, doesn't match or 0 would have been
76 * returned above), return an arbitrary value, let's say -1.
77 */
78 return ((alt_32)(hardware_timestamp - SYSID_TIMESTAMP)) > 0 ? 1 : -1;
79 }
80 #endif
81
