xref: /openbmc/qemu/hw/xtensa/pic_cpu.c (revision 1f7685fa)
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 "qemu/osdep.h"
29 #include "hw/hw.h"
30 #include "qemu/log.h"
31 #include "qemu/timer.h"
32 
33 void xtensa_advance_ccount(CPUXtensaState *env, uint32_t d)
34 {
35     uint32_t old_ccount = env->sregs[CCOUNT] + 1;
36 
37     env->sregs[CCOUNT] += d;
38 
39     if (xtensa_option_enabled(env->config, XTENSA_OPTION_TIMER_INTERRUPT)) {
40         int i;
41         for (i = 0; i < env->config->nccompare; ++i) {
42             if (env->sregs[CCOMPARE + i] - old_ccount < d) {
43                 xtensa_timer_irq(env, i, 1);
44             }
45         }
46     }
47 }
48 
49 void check_interrupts(CPUXtensaState *env)
50 {
51     CPUState *cs = CPU(xtensa_env_get_cpu(env));
52     int minlevel = xtensa_get_cintlevel(env);
53     uint32_t int_set_enabled = env->sregs[INTSET] & env->sregs[INTENABLE];
54     int level;
55 
56     /* If the CPU is halted advance CCOUNT according to the QEMU_CLOCK_VIRTUAL time
57      * elapsed since the moment when it was advanced last time.
58      */
59     if (cs->halted) {
60         int64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
61 
62         xtensa_advance_ccount(env,
63                 muldiv64(now - env->halt_clock,
64                     env->config->clock_freq_khz, 1000000));
65         env->halt_clock = now;
66     }
67     for (level = env->config->nlevel; level > minlevel; --level) {
68         if (env->config->level_mask[level] & int_set_enabled) {
69             env->pending_irq_level = level;
70             cpu_interrupt(cs, CPU_INTERRUPT_HARD);
71             qemu_log_mask(CPU_LOG_INT,
72                     "%s level = %d, cintlevel = %d, "
73                     "pc = %08x, a0 = %08x, ps = %08x, "
74                     "intset = %08x, intenable = %08x, "
75                     "ccount = %08x\n",
76                     __func__, level, xtensa_get_cintlevel(env),
77                     env->pc, env->regs[0], env->sregs[PS],
78                     env->sregs[INTSET], env->sregs[INTENABLE],
79                     env->sregs[CCOUNT]);
80             return;
81         }
82     }
83     env->pending_irq_level = 0;
84     cpu_reset_interrupt(cs, CPU_INTERRUPT_HARD);
85 }
86 
87 static void xtensa_set_irq(void *opaque, int irq, int active)
88 {
89     CPUXtensaState *env = opaque;
90 
91     if (irq >= env->config->ninterrupt) {
92         qemu_log("%s: bad IRQ %d\n", __func__, irq);
93     } else {
94         uint32_t irq_bit = 1 << irq;
95 
96         if (active) {
97             env->sregs[INTSET] |= irq_bit;
98         } else if (env->config->interrupt[irq].inttype == INTTYPE_LEVEL) {
99             env->sregs[INTSET] &= ~irq_bit;
100         }
101 
102         check_interrupts(env);
103     }
104 }
105 
106 void xtensa_timer_irq(CPUXtensaState *env, uint32_t id, uint32_t active)
107 {
108     qemu_set_irq(env->irq_inputs[env->config->timerint[id]], active);
109 }
110 
111 void xtensa_rearm_ccompare_timer(CPUXtensaState *env)
112 {
113     int i;
114     uint32_t wake_ccount = env->sregs[CCOUNT] - 1;
115 
116     for (i = 0; i < env->config->nccompare; ++i) {
117         if (env->sregs[CCOMPARE + i] - env->sregs[CCOUNT] <
118                 wake_ccount - env->sregs[CCOUNT]) {
119             wake_ccount = env->sregs[CCOMPARE + i];
120         }
121     }
122     env->wake_ccount = wake_ccount;
123     timer_mod(env->ccompare_timer, env->halt_clock +
124             muldiv64(wake_ccount - env->sregs[CCOUNT],
125                 1000000, env->config->clock_freq_khz));
126 }
127 
128 static void xtensa_ccompare_cb(void *opaque)
129 {
130     XtensaCPU *cpu = opaque;
131     CPUXtensaState *env = &cpu->env;
132     CPUState *cs = CPU(cpu);
133 
134     if (cs->halted) {
135         env->halt_clock = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
136         xtensa_advance_ccount(env, env->wake_ccount - env->sregs[CCOUNT]);
137         if (!cpu_has_work(cs)) {
138             env->sregs[CCOUNT] = env->wake_ccount + 1;
139             xtensa_rearm_ccompare_timer(env);
140         }
141     }
142 }
143 
144 void xtensa_irq_init(CPUXtensaState *env)
145 {
146     XtensaCPU *cpu = xtensa_env_get_cpu(env);
147 
148     env->irq_inputs = (void **)qemu_allocate_irqs(
149             xtensa_set_irq, env, env->config->ninterrupt);
150     if (xtensa_option_enabled(env->config, XTENSA_OPTION_TIMER_INTERRUPT) &&
151             env->config->nccompare > 0) {
152         env->ccompare_timer =
153             timer_new_ns(QEMU_CLOCK_VIRTUAL, &xtensa_ccompare_cb, cpu);
154     }
155 }
156 
157 void *xtensa_get_extint(CPUXtensaState *env, unsigned extint)
158 {
159     if (extint < env->config->nextint) {
160         unsigned irq = env->config->extint[extint];
161         return env->irq_inputs[irq];
162     } else {
163         qemu_log("%s: trying to acquire invalid external interrupt %d\n",
164                 __func__, extint);
165         return NULL;
166     }
167 }
168