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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 | /* * RTC based high-frequency timer * * Copyright (C) 2000 Takashi Iwai * based on rtctimer.c by Steve Ratcliffe * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * */ #include <linux/init.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/log2.h> #include <sound/core.h> #include <sound/timer.h> #if IS_ENABLED(CONFIG_RTC) #include <linux/mc146818rtc.h> #define RTC_FREQ 1024 /* default frequency */ #define NANO_SEC 1000000000L /* 10^9 in sec */ /* * prototypes */ static int rtctimer_open(struct snd_timer *t); static int rtctimer_close(struct snd_timer *t); static int rtctimer_start(struct snd_timer *t); static int rtctimer_stop(struct snd_timer *t); /* * The hardware dependent description for this timer. */ static struct snd_timer_hardware rtc_hw = { .flags = SNDRV_TIMER_HW_AUTO | SNDRV_TIMER_HW_FIRST | SNDRV_TIMER_HW_TASKLET, .ticks = 100000000L, /* FIXME: XXX */ .open = rtctimer_open, .close = rtctimer_close, .start = rtctimer_start, .stop = rtctimer_stop, }; static int rtctimer_freq = RTC_FREQ; /* frequency */ static struct snd_timer *rtctimer; static struct tasklet_struct rtc_tasklet; static rtc_task_t rtc_task; static int rtctimer_open(struct snd_timer *t) { int err; err = rtc_register(&rtc_task); if (err < 0) return err; t->private_data = &rtc_task; return 0; } static int rtctimer_close(struct snd_timer *t) { rtc_task_t *rtc = t->private_data; if (rtc) { rtc_unregister(rtc); tasklet_kill(&rtc_tasklet); t->private_data = NULL; } return 0; } static int rtctimer_start(struct snd_timer *timer) { rtc_task_t *rtc = timer->private_data; if (snd_BUG_ON(!rtc)) return -EINVAL; rtc_control(rtc, RTC_IRQP_SET, rtctimer_freq); rtc_control(rtc, RTC_PIE_ON, 0); return 0; } static int rtctimer_stop(struct snd_timer *timer) { rtc_task_t *rtc = timer->private_data; if (snd_BUG_ON(!rtc)) return -EINVAL; rtc_control(rtc, RTC_PIE_OFF, 0); return 0; } static void rtctimer_tasklet(unsigned long data) { snd_timer_interrupt((struct snd_timer *)data, 1); } /* * interrupt */ static void rtctimer_interrupt(void *private_data) { tasklet_schedule(private_data); } /* * ENTRY functions */ static int __init rtctimer_init(void) { int err; struct snd_timer *timer; if (rtctimer_freq < 2 || rtctimer_freq > 8192 || !is_power_of_2(rtctimer_freq)) { pr_err("ALSA: rtctimer: invalid frequency %d\n", rtctimer_freq); return -EINVAL; } /* Create a new timer and set up the fields */ err = snd_timer_global_new("rtc", SNDRV_TIMER_GLOBAL_RTC, &timer); if (err < 0) return err; timer->module = THIS_MODULE; strcpy(timer->name, "RTC timer"); timer->hw = rtc_hw; timer->hw.resolution = NANO_SEC / rtctimer_freq; tasklet_init(&rtc_tasklet, rtctimer_tasklet, (unsigned long)timer); /* set up RTC callback */ rtc_task.func = rtctimer_interrupt; rtc_task.private_data = &rtc_tasklet; err = snd_timer_global_register(timer); if (err < 0) { snd_timer_global_free(timer); return err; } rtctimer = timer; /* remember this */ return 0; } static void __exit rtctimer_exit(void) { if (rtctimer) { snd_timer_global_free(rtctimer); rtctimer = NULL; } } /* * exported stuff */ module_init(rtctimer_init) module_exit(rtctimer_exit) module_param(rtctimer_freq, int, 0444); MODULE_PARM_DESC(rtctimer_freq, "timer frequency in Hz"); MODULE_LICENSE("GPL"); MODULE_ALIAS("snd-timer-" __stringify(SNDRV_TIMER_GLOBAL_RTC)); #endif /* IS_ENABLED(CONFIG_RTC) */ |