1 /*
2 * Copyright (c) 2011 Aeroflex Gaisler
3 *
4 * BSD license:
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
12 *
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22 * THE SOFTWARE.
23 */
24
25
26 #include <asm-leon/contextswitch.h>
27 #include <asm-leon/leonbare_kernel.h>
28 #include <asm-leon/leonbare_debug.h>
29 #include <asm-leon/stack.h>
30 #include <asm-leon/leonstack.h>
31 #include <asm-leon/irq.h>
32
33 unsigned int
reschedule()34 reschedule ()
35 {
36 leonbare_sched_update ();
37 return leonbare_sched ();
38 }
39
40 unsigned int
leonbare_sched()41 leonbare_sched ()
42 {
43 unsigned int ret = 0;
44 volatile leonbare_thread_t old = LEONBARE_KR_CURRENT, new =
45 LEONBARE_KR_NEXT;
46 LBDEBUG_FNCALL;
47 LBDEBUG_HEADER_PRINTF (LBDEBUG_SCHED_NR, "switch %s[%x]->%s[%x]\n",
48 LEONBARE_TH_NAME_DBG (old), old,
49 LEONBARE_TH_NAME_DBG (new), new);
50
51 LBPASSERT ((old != new),
52 "leonbare_sched should only be called with reschedule work to do",
53 0);
54
55 LEONBARE_KR_CURRENT = new;
56
57 /* to be able to programm symetrically on kernel level each thread
58 saves it's spinlock on mutexes and kernel and irq flags in its
59 own save region. On a kernel switch they are released until the
60 thread is reawakened. Then the locks will be reaquired (and finally
61 released when the codeblock exits). The locking can be recursive. */
62 if (old->th_prot.krp_k_depth)
63 {
64 LEONBARE_SMP_SPINLOCK_RELEASE (LEONBARE_KR_LOCK);
65 }
66 if (old->th_prot.krp_m_depth)
67 {
68 LEONBARE_SMP_SPINLOCK_RELEASE (old->th_prot.krp_m);
69 }
70
71 ret = _leonbare_kernel_switchto (old, new);
72 optbarrier ();
73
74 if (new->th_prot.krp_m_depth)
75 {
76 LEONBARE_SMP_SPINLOCK_AQUIRE (new->th_prot.krp_m);
77 }
78 if (old->th_prot.krp_k_depth)
79 {
80 LEONBARE_SMP_SPINLOCK_AQUIRE (LEONBARE_KR_LOCK);
81 }
82
83 return ret;
84 }
85