xref: /openbmc/qemu/hw/xtensa/pic_cpu.c (revision 14a650ec)
1 /*
2  * Copyright (c) 2011, Max Filippov, Open Source and Linux Lab.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions are met:
7  *     * Redistributions of source code must retain the above copyright
8  *       notice, this list of conditions and the following disclaimer.
9  *     * Redistributions in binary form must reproduce the above copyright
10  *       notice, this list of conditions and the following disclaimer in the
11  *       documentation and/or other materials provided with the distribution.
12  *     * Neither the name of the Open Source and Linux Lab nor the
13  *       names of its contributors may be used to endorse or promote products
14  *       derived from this software without specific prior written permission.
15  *
16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19  * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
20  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
22  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
23  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
25  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26  */
27 
28 #include "hw/hw.h"
29 #include "qemu/log.h"
30 #include "qemu/timer.h"
31 
32 void xtensa_advance_ccount(CPUXtensaState *env, uint32_t d)
33 {
34     uint32_t old_ccount = env->sregs[CCOUNT];
35 
36     env->sregs[CCOUNT] += d;
37 
38     if (xtensa_option_enabled(env->config, XTENSA_OPTION_TIMER_INTERRUPT)) {
39         int i;
40         for (i = 0; i < env->config->nccompare; ++i) {
41             if (env->sregs[CCOMPARE + i] - old_ccount <= d) {
42                 xtensa_timer_irq(env, i, 1);
43             }
44         }
45     }
46 }
47 
48 void check_interrupts(CPUXtensaState *env)
49 {
50     CPUState *cs = CPU(xtensa_env_get_cpu(env));
51     int minlevel = xtensa_get_cintlevel(env);
52     uint32_t int_set_enabled = env->sregs[INTSET] & env->sregs[INTENABLE];
53     int level;
54 
55     /* If the CPU is halted advance CCOUNT according to the QEMU_CLOCK_VIRTUAL time
56      * elapsed since the moment when it was advanced last time.
57      */
58     if (cs->halted) {
59         int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
60 
61         xtensa_advance_ccount(env,
62                 muldiv64(now - env->halt_clock,
63                     env->config->clock_freq_khz, 1000000));
64         env->halt_clock = now;
65     }
66     for (level = env->config->nlevel; level > minlevel; --level) {
67         if (env->config->level_mask[level] & int_set_enabled) {
68             env->pending_irq_level = level;
69             cpu_interrupt(cs, CPU_INTERRUPT_HARD);
70             qemu_log_mask(CPU_LOG_INT,
71                     "%s level = %d, cintlevel = %d, "
72                     "pc = %08x, a0 = %08x, ps = %08x, "
73                     "intset = %08x, intenable = %08x, "
74                     "ccount = %08x\n",
75                     __func__, level, xtensa_get_cintlevel(env),
76                     env->pc, env->regs[0], env->sregs[PS],
77                     env->sregs[INTSET], env->sregs[INTENABLE],
78                     env->sregs[CCOUNT]);
79             return;
80         }
81     }
82     env->pending_irq_level = 0;
83     cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
84 }
85 
86 static void xtensa_set_irq(void *opaque, int irq, int active)
87 {
88     CPUXtensaState *env = opaque;
89 
90     if (irq >= env->config->ninterrupt) {
91         qemu_log("%s: bad IRQ %d\n", __func__, irq);
92     } else {
93         uint32_t irq_bit = 1 << irq;
94 
95         if (active) {
96             env->sregs[INTSET] |= irq_bit;
97         } else if (env->config->interrupt[irq].inttype == INTTYPE_LEVEL) {
98             env->sregs[INTSET] &= ~irq_bit;
99         }
100 
101         check_interrupts(env);
102     }
103 }
104 
105 void xtensa_timer_irq(CPUXtensaState *env, uint32_t id, uint32_t active)
106 {
107     qemu_set_irq(env->irq_inputs[env->config->timerint[id]], active);
108 }
109 
110 void xtensa_rearm_ccompare_timer(CPUXtensaState *env)
111 {
112     int i;
113     uint32_t wake_ccount = env->sregs[CCOUNT] - 1;
114 
115     for (i = 0; i < env->config->nccompare; ++i) {
116         if (env->sregs[CCOMPARE + i] - env->sregs[CCOUNT] <
117                 wake_ccount - env->sregs[CCOUNT]) {
118             wake_ccount = env->sregs[CCOMPARE + i];
119         }
120     }
121     env->wake_ccount = wake_ccount;
122     timer_mod(env->ccompare_timer, env->halt_clock +
123             muldiv64(wake_ccount - env->sregs[CCOUNT],
124                 1000000, env->config->clock_freq_khz));
125 }
126 
127 static void xtensa_ccompare_cb(void *opaque)
128 {
129     XtensaCPU *cpu = opaque;
130     CPUXtensaState *env = &cpu->env;
131     CPUState *cs = CPU(cpu);
132 
133     if (cs->halted) {
134         env->halt_clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
135         xtensa_advance_ccount(env, env->wake_ccount - env->sregs[CCOUNT]);
136         if (!cpu_has_work(cs)) {
137             env->sregs[CCOUNT] = env->wake_ccount + 1;
138             xtensa_rearm_ccompare_timer(env);
139         }
140     }
141 }
142 
143 void xtensa_irq_init(CPUXtensaState *env)
144 {
145     XtensaCPU *cpu = xtensa_env_get_cpu(env);
146 
147     env->irq_inputs = (void **)qemu_allocate_irqs(
148             xtensa_set_irq, env, env->config->ninterrupt);
149     if (xtensa_option_enabled(env->config, XTENSA_OPTION_TIMER_INTERRUPT) &&
150             env->config->nccompare > 0) {
151         env->ccompare_timer =
152             timer_new_ns(QEMU_CLOCK_VIRTUAL, &xtensa_ccompare_cb, cpu);
153     }
154 }
155 
156 void *xtensa_get_extint(CPUXtensaState *env, unsigned extint)
157 {
158     if (extint < env->config->nextint) {
159         unsigned irq = env->config->extint[extint];
160         return env->irq_inputs[irq];
161     } else {
162         qemu_log("%s: trying to acquire invalid external interrupt %d\n",
163                 __func__, extint);
164         return NULL;
165     }
166 }
167