1 | /* |
---|
2 | * Thread Dispatch Disable Level Methods |
---|
3 | * |
---|
4 | * COPYRIGHT (c) 1989-2011. |
---|
5 | * On-Line Applications Research Corporation (OAR). |
---|
6 | * |
---|
7 | * The license and distribution terms for this file may be |
---|
8 | * found in the file LICENSE in this distribution or at |
---|
9 | * http://www.rtems.com/license/LICENSE. |
---|
10 | * |
---|
11 | * $Id$ |
---|
12 | */ |
---|
13 | |
---|
14 | #include <rtems/system.h> |
---|
15 | #include <rtems/score/apiext.h> |
---|
16 | #include <rtems/score/context.h> |
---|
17 | #include <rtems/score/interr.h> |
---|
18 | #include <rtems/score/isr.h> |
---|
19 | #include <rtems/score/object.h> |
---|
20 | #include <rtems/score/priority.h> |
---|
21 | #include <rtems/score/states.h> |
---|
22 | #include <rtems/score/sysstate.h> |
---|
23 | #include <rtems/score/thread.h> |
---|
24 | |
---|
25 | void _Thread_Dispatch_initialization( void ) |
---|
26 | { |
---|
27 | _Thread_Dispatch_disable_level = 0; |
---|
28 | _SMP_lock_spinlock_nested_Initialize(&_Thread_Dispatch_disable_level_lock); |
---|
29 | _Thread_Dispatch_set_disable_level( 1 ); |
---|
30 | } |
---|
31 | |
---|
32 | bool _Thread_Dispatch_in_critical_section(void) |
---|
33 | { |
---|
34 | if ( _Thread_Dispatch_disable_level == 0 ) |
---|
35 | return false; |
---|
36 | |
---|
37 | return true; |
---|
38 | } |
---|
39 | |
---|
40 | uint32_t _Thread_Dispatch_get_disable_level(void) |
---|
41 | { |
---|
42 | return _Thread_Dispatch_disable_level; |
---|
43 | } |
---|
44 | |
---|
45 | uint32_t _Thread_Dispatch_increment_disable_level(void) |
---|
46 | { |
---|
47 | ISR_Level isr_level; |
---|
48 | uint32_t level; |
---|
49 | |
---|
50 | /* |
---|
51 | * Note: _SMP_lock_spinlock_nested_Obtain returns |
---|
52 | * with ISR's disabled and the isr_level that |
---|
53 | * should be restored after a short period. |
---|
54 | * |
---|
55 | * Here we obtain the lock and increment the |
---|
56 | * Thread dispatch disable level while under the |
---|
57 | * protection of the isr being off. After this |
---|
58 | * point it is safe to re-enable ISRs and allow |
---|
59 | * the dispatch disable lock to provide protection. |
---|
60 | */ |
---|
61 | |
---|
62 | isr_level = _SMP_lock_spinlock_nested_Obtain( |
---|
63 | &_Thread_Dispatch_disable_level_lock |
---|
64 | ); |
---|
65 | |
---|
66 | _Thread_Dispatch_disable_level++; |
---|
67 | level = _Thread_Dispatch_disable_level; |
---|
68 | |
---|
69 | _ISR_Enable(isr_level); |
---|
70 | |
---|
71 | return level; |
---|
72 | } |
---|
73 | |
---|
74 | uint32_t _Thread_Dispatch_decrement_disable_level(void) |
---|
75 | { |
---|
76 | ISR_Level isr_level; |
---|
77 | uint32_t level; |
---|
78 | |
---|
79 | /* First we must disable ISRs in order to protect |
---|
80 | * accesses to the dispatch disable level. |
---|
81 | */ |
---|
82 | |
---|
83 | _ISR_Disable( isr_level ); |
---|
84 | |
---|
85 | _Thread_Dispatch_disable_level--; |
---|
86 | level = _Thread_Dispatch_disable_level; |
---|
87 | |
---|
88 | |
---|
89 | /* |
---|
90 | * Note: _SMP_lock_spinlock_nested_Obtain returns with |
---|
91 | * ISR's disabled and _SMP_lock_spinlock_nested_Release |
---|
92 | * is responsable for re-enabling interrupts. |
---|
93 | */ |
---|
94 | _SMP_lock_spinlock_nested_Release( |
---|
95 | &_Thread_Dispatch_disable_level_lock, |
---|
96 | isr_level |
---|
97 | ); |
---|
98 | |
---|
99 | return level; |
---|
100 | } |
---|
101 | |
---|
102 | |
---|
103 | /* |
---|
104 | * Note this method is taking a heavy handed approach to |
---|
105 | * setting the dispatch level. This may be optimized at a |
---|
106 | * later timee, but it must be in such a way that the nesting |
---|
107 | * level is decremented by the same number as the dispatch level. |
---|
108 | * This approach is safest until we are sure the nested spinlock |
---|
109 | * is successfully working with smp isr source code. |
---|
110 | */ |
---|
111 | |
---|
112 | uint32_t _Thread_Dispatch_set_disable_level(uint32_t value) |
---|
113 | { |
---|
114 | /* |
---|
115 | * If we need the dispatch level to go higher |
---|
116 | * call increment method the desired number of times. |
---|
117 | */ |
---|
118 | |
---|
119 | while ( value > _Thread_Dispatch_disable_level ) { |
---|
120 | _Thread_Dispatch_increment_disable_level(); |
---|
121 | } |
---|
122 | |
---|
123 | /* |
---|
124 | * If we need the dispatch level to go lower |
---|
125 | * call increment method the desired number of times. |
---|
126 | */ |
---|
127 | |
---|
128 | while ( value < _Thread_Dispatch_disable_level ) { |
---|
129 | _Thread_Dispatch_decrement_disable_level(); |
---|
130 | } |
---|
131 | |
---|
132 | return value; |
---|
133 | } |
---|