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 struct leonbare_kernel leonbare_kernel;
34
35 /*
36 * queue 0: [ <acc=2>],
37 * queue 1: [ <acc=10>, <acc=8>,<acc=8>,<acc=1> ],
38 * queue 2: [ ... ],
39 * ...
40 * queue n: [ ... ]
41 *
42 * Seach through ready queue [0 - LEONBARE_RUNQ_READY_NR-1] for the
43 * first thread in a queue'ss head to discover
44 * leonbare_thread_tick_callback() will put threads that have their th_caccount
45 * consumed into the prepare-run queues. th_caccount is already initialized
46 * to the value for the next schedule round. So all there is to do is to
47 * move the to prepare-run queues to run queues [0 - LEONBARE_RUNQ_READY_NR-1].
48 * return the first thread in any queue, similary to leonbare_sched_next().
49 * Using LEONBARE_KR_RUNQ_WHICH and leonbare_thread.th_runq_which one can
50 * determine weather the thread is in a runqueue or a prepare-runqueue:
51 * LEONBARE_KR_RUNQ_WHICH == leonbare_thread.th_runq_which : thread in runqueue
52 * LEONBARE_KR_RUNQ_WHICH != leonbare_thread.th_runq_which : thread in prepare-runqueue
53 * after a leonbare_thread_tick_callback() or a run queue change, call
54 * leonbare_sched_update() to update LEONBARE_KR_NEXT and
55 * LEONBARE_KR_NEED_SCHEDULE
56 */
57 int
leonbare_sched_update()58 leonbare_sched_update ()
59 {
60 int idx;
61 leonbare_thread_t n = 0;
62 int i = 0;
63 LEONBARE_VERIFYIRQDISABLED ();
64 LEONBARE_VERIFYSCHED ();
65 for (i = 0; i < LEONBARE_RUNQ_READY_NR; i++)
66 {
67 leonbare_thread_t c;
68 if (!LBTAILQ_EMPTY (LEONBARE_KR_RUNQ (i)))
69 {
70 n = LBTAILQ_FIRST (LEONBARE_KR_RUNQ (i));
71 break;
72 }
73 }
74 if (!n)
75 {
76 for (idx = 0; idx < LEONBARE_RUNQ_READY_NR; idx++)
77 {
78 struct leonbare_thread_queue *h0 =
79 (struct leonbare_thread_queue *) LEONBARE_KR_RUNQ (idx);
80 struct leonbare_thread_queue *h1 = (struct leonbare_thread_queue *)
81 LEONBARE_KR_RUNQ (idx + LEONBARE_RUNQ_PREPARE_IDX);
82 if (LBTAILQ_EMPTY (h1))
83 {
84 LBTAILQ_INIT (h0);
85 }
86 else
87 {
88 *h0 = *h1;
89 if (LBTAILQ_FIRST (h0))
90 {
91 LBTAILQ_FIRST (h0)->th_runq.tqe_prev = &(h0)->tqh_first;
92 }
93 if (!n)
94 {
95 n = LBTAILQ_FIRST (h0);
96 }
97 }
98 }
99 for (idx = 0; idx < LEONBARE_RUNQ_READY_NR; idx++)
100 {
101 LBTAILQ_INIT (LEONBARE_KR_RUNQ (idx + LEONBARE_RUNQ_PREPARE_IDX));
102 }
103 LEONBARE_KR_RUNQ_WHICH++;
104 LEONBARE_VERIFYSCHED ();
105 LEONBARE_PRINTQUEUES ();
106 }
107 LEONBARE_KR_NEXT = n;
108 return (LEONBARE_KR_NEED_SCHEDULE);
109 }
110
111 /* called in the timer irq handling. Decrements the
112 * th_caccount field. On consumption of th_caccount the
113 * thread will be removed from the ready queue nad placed into the
114 * prepare-runqueue for later readdition by leonbare_sched_readyprepare()
115 * called from gettimeofday.c's installed ticker_callback callback
116 * leonbare_thread_tick_callback() might change the kernel state in which case
117 * state on return from leonbare_thread_tick_callback() leonbare_thread_schedule_callback()
118 * will be called from rtrap_fast.S .
119 */
120 int
leonbare_thread_tick_callback()121 leonbare_thread_tick_callback ()
122 {
123 LEONBARE_PROTECT_DECL (flags);
124 unsigned int r;
125 volatile leonbare_thread_t c = LEONBARE_KR_CURRENT;
126 leonbare_thread_t i;
127 LBDEBUG_FNCALL;
128 if (c && LEONBARE_KR_IS_PREEMPTION)
129 {
130
131 LEONBARE_PROTECT_KERNEL_START ();
132 {
133
134 LEONBARE_VERIFYIRQDISABLED ();
135 LEONBARE_VERIFYSCHED ();
136
137 if ((--c->th_caccount) < 0)
138 {
139 LBDEBUG_HEADER_PRINTF (LBDEBUG_QUEUE_NR, "remove %s(%x)\n",
140 LEONBARE_TH_NAME_DBG (c), c);
141 LBTAILQ_REMOVE (LEONBARE_KR_RUNQ (c->th_runq_idx), c, th_runq);
142 LBTAILQ_INSERT_TAIL (LEONBARE_KR_RUNQ
143 (c->th_runq_idx + LEONBARE_RUNQ_PREPARE_IDX),
144 c, th_runq);
145 c->th_caccount = c->th_account;
146 c->th_runq_which++;
147 }
148 else
149 {
150 /* todo: round robbin scheme */
151 }
152 }
153 LEONBARE_PROTECT_KERNEL_END ();
154 }
155 r = leonbare_sched_update ();
156 return r;
157 }
158
159 /* called from rtrap_fast.S's installed schedule_callback callback */
160 int
leonbare_thread_schedule_callback(struct leonbare_pt_regs * ptregs)161 leonbare_thread_schedule_callback (struct leonbare_pt_regs *ptregs)
162 {
163 unsigned int retval;
164 LBDEBUG_FNCALL;
165 if (LEONBARE_KR_IS_IN_KERNEL == 0 && LEONBARE_KR_NEED_SCHEDULE)
166 {
167
168 leonbare_sched ();
169
170 //KERNEL_ENTER;
171 //KERNEL_EXIT(LEONBARE_KR_NEED_SCHEDULE, retval);
172 }
173 LBDEBUG_FNEXIT;
174 }
175
176
177 struct leonbare_thread _thread_main;
178 int
leonbare_thread_init()179 leonbare_thread_init ()
180 {
181 int i;
182 LBDEBUG_FNCALL;
183
184 memset ((void *) &_thread_main, 0, sizeof (_thread_main));
185 _thread_main.th_reentp = _impure_ptr;
186 _thread_main.th_name = "<main>";
187 _thread_main.th_runq_idx = 0;
188 _thread_main.th_pri_idx = 0;
189 _thread_main.th_account = 0;
190
191 LBTAILQ_INIT (LEONBARE_KR_ALLQ);
192 for (i = 0; i < LEONBARE_RUNQ_NR; i++)
193 {
194 LBTAILQ_INIT (LEONBARE_KR_RUNQ (i));
195 }
196 LBTAILQ_INIT (LEONBARE_KR_ALLM);
197
198 /* queues */
199 LBTAILQ_INSERT_TAIL (LEONBARE_KR_ALLQ, &_thread_main, th_allq);
200
201 /* inseart into ready queue 0 at head */
202 LBTAILQ_INSERT_HEAD (LEONBARE_KR_RUNQ (_thread_main.th_runq_idx),
203 &_thread_main, th_runq);
204
205 LEONBARE_KR_CURRENT = &_thread_main;
206 LEONBARE_KR_IS_IN_KERNEL = 0;
207
208 leonbare_init_ticks ();
209 schedule_callback = (schedulehandler) leonbare_thread_schedule_callback;
210 ticker_callback = (tickerhandler) leonbare_thread_tick_callback;
211
212 /* disable later */
213 LEONBARE_KR_IS_PREEMPTION = 1;
214
215
216 LBDEBUG_FNEXIT;
217 }
218