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Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/module.h>#include <linux/of.h>#include <linux/rtc.h>#include <linux/kdev_t.h>#include <linux/idr.h>#include <linux/slab.h>#include <linux/workqueue.h>
#include "rtc-core.h"
static DEFINE_IDA(rtc_ida);
static void rtc_device_release(struct device *dev){ struct rtc_device *rtc = to_rtc_device(dev); struct timerqueue_head *head = &rtc->timerqueue; struct timerqueue_node *node;
mutex_lock(&rtc->ops_lock); while ((node = timerqueue_getnext(head))) timerqueue_del(head, node); mutex_unlock(&rtc->ops_lock);
cancel_work_sync(&rtc->irqwork);
ida_free(&rtc_ida, rtc->id); mutex_destroy(&rtc->ops_lock); kfree(rtc);}
#ifdef CONFIG_RTC_HCTOSYS_DEVICE/* Result of the last RTC to system clock attempt. */int rtc_hctosys_ret = -ENODEV;
/* IMPORTANT: the RTC only stores whole seconds. It is arbitrary * whether it stores the most close value or the value with partial * seconds truncated. However, it is important that we use it to store * the truncated value. This is because otherwise it is necessary, * in an rtc sync function, to read both xtime.tv_sec and * xtime.tv_nsec. On some processors (i.e. ARM), an atomic read * of >32bits is not possible. So storing the most close value would * slow down the sync API. So here we have the truncated value and * the best guess is to add 0.5s. */
static void rtc_hctosys(struct rtc_device *rtc){ int err; struct rtc_time tm; struct timespec64 tv64 = { .tv_nsec = NSEC_PER_SEC >> 1, };
err = rtc_read_time(rtc, &tm); if (err) { dev_err(rtc->dev.parent, "hctosys: unable to read the hardware clock\n"); goto err_read; }
tv64.tv_sec = rtc_tm_to_time64(&tm);
#if BITS_PER_LONG == 32 if (tv64.tv_sec > INT_MAX) { err = -ERANGE; goto err_read; }#endif
err = do_settimeofday64(&tv64);
dev_info(rtc->dev.parent, "setting system clock to %ptR UTC (%lld)\n", &tm, (long long)tv64.tv_sec);
err_read: rtc_hctosys_ret = err;}#endif
#if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)/* * On suspend(), measure the delta between one RTC and the * system's wall clock; restore it on resume(). */
static struct timespec64 old_rtc, old_system, old_delta;
static int rtc_suspend(struct device *dev){ struct rtc_device *rtc = to_rtc_device(dev); struct rtc_time tm; struct timespec64 delta, delta_delta; int err;
if (timekeeping_rtc_skipsuspend()) return 0;
if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) return 0;
/* snapshot the current RTC and system time at suspend*/ err = rtc_read_time(rtc, &tm); if (err < 0) { pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); return 0; }
ktime_get_real_ts64(&old_system); old_rtc.tv_sec = rtc_tm_to_time64(&tm);
/* * To avoid drift caused by repeated suspend/resumes, * which each can add ~1 second drift error, * try to compensate so the difference in system time * and rtc time stays close to constant. */ delta = timespec64_sub(old_system, old_rtc); delta_delta = timespec64_sub(delta, old_delta); if (delta_delta.tv_sec < -2 || delta_delta.tv_sec >= 2) { /* * if delta_delta is too large, assume time correction * has occurred and set old_delta to the current delta. */ old_delta = delta; } else { /* Otherwise try to adjust old_system to compensate */ old_system = timespec64_sub(old_system, delta_delta); }
return 0;}
static int rtc_resume(struct device *dev){ struct rtc_device *rtc = to_rtc_device(dev); struct rtc_time tm; struct timespec64 new_system, new_rtc; struct timespec64 sleep_time; int err;
if (timekeeping_rtc_skipresume()) return 0;
rtc_hctosys_ret = -ENODEV; if (strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE) != 0) return 0;
/* snapshot the current rtc and system time at resume */ ktime_get_real_ts64(&new_system); err = rtc_read_time(rtc, &tm); if (err < 0) { pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev)); return 0; }
new_rtc.tv_sec = rtc_tm_to_time64(&tm); new_rtc.tv_nsec = 0;
if (new_rtc.tv_sec < old_rtc.tv_sec) { pr_debug("%s: time travel!\n", dev_name(&rtc->dev)); return 0; }
/* calculate the RTC time delta (sleep time)*/ sleep_time = timespec64_sub(new_rtc, old_rtc);
/* * Since these RTC suspend/resume handlers are not called * at the very end of suspend or the start of resume, * some run-time may pass on either sides of the sleep time * so subtract kernel run-time between rtc_suspend to rtc_resume * to keep things accurate. */ sleep_time = timespec64_sub(sleep_time, timespec64_sub(new_system, old_system));
if (sleep_time.tv_sec >= 0) timekeeping_inject_sleeptime64(&sleep_time); rtc_hctosys_ret = 0; return 0;}
static SIMPLE_DEV_PM_OPS(rtc_class_dev_pm_ops, rtc_suspend, rtc_resume);#define RTC_CLASS_DEV_PM_OPS (&rtc_class_dev_pm_ops)#else#define RTC_CLASS_DEV_PM_OPS NULL#endif
const struct class rtc_class = { .name = "rtc", .pm = RTC_CLASS_DEV_PM_OPS,};
/* Ensure the caller will set the id before releasing the device */static struct rtc_device *rtc_allocate_device(void){ struct rtc_device *rtc;
rtc = kzalloc_obj(*rtc); if (!rtc) return NULL;
device_initialize(&rtc->dev);
/* * Drivers can revise this default after allocating the device. * The default is what most RTCs do: Increment seconds exactly one * second after the write happened. This adds a default transport * time of 5ms which is at least halfways close to reality. */ rtc->set_offset_nsec = NSEC_PER_SEC + 5 * NSEC_PER_MSEC;
rtc->irq_freq = 1; rtc->max_user_freq = 64; rtc->dev.class = &rtc_class; rtc->dev.groups = rtc_get_dev_attribute_groups(); rtc->dev.release = rtc_device_release;
mutex_init(&rtc->ops_lock); spin_lock_init(&rtc->irq_lock); init_waitqueue_head(&rtc->irq_queue);
/* Init timerqueue */ timerqueue_init_head(&rtc->timerqueue); INIT_WORK(&rtc->irqwork, rtc_timer_do_work); /* Init aie timer */ rtc_timer_init(&rtc->aie_timer, rtc_aie_update_irq, rtc); /* Init uie timer */ rtc_timer_init(&rtc->uie_rtctimer, rtc_uie_update_irq, rtc); /* Init pie timer */ hrtimer_setup(&rtc->pie_timer, rtc_pie_update_irq, CLOCK_MONOTONIC, HRTIMER_MODE_REL); rtc->pie_enabled = 0;
set_bit(RTC_FEATURE_ALARM, rtc->features); set_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
return rtc;}
static int rtc_device_get_id(struct device *dev){ int of_id = -1, id = -1;
if (dev->of_node) of_id = of_alias_get_id(dev->of_node, "rtc"); else if (dev->parent && dev->parent->of_node) of_id = of_alias_get_id(dev->parent->of_node, "rtc");
if (of_id >= 0) { id = ida_alloc_range(&rtc_ida, of_id, of_id, GFP_KERNEL); if (id < 0) dev_warn(dev, "/aliases ID %d not available\n", of_id); }
if (id < 0) id = ida_alloc(&rtc_ida, GFP_KERNEL);
return id;}
static void rtc_device_get_offset(struct rtc_device *rtc){ time64_t range_secs; u32 start_year; int ret;
/* * If RTC driver did not implement the range of RTC hardware device, * then we can not expand the RTC range by adding or subtracting one * offset. */ if (rtc->range_min == rtc->range_max) return;
ret = device_property_read_u32(rtc->dev.parent, "start-year", &start_year); if (!ret) { rtc->start_secs = mktime64(start_year, 1, 1, 0, 0, 0); rtc->set_start_time = true; }
/* * If user did not implement the start time for RTC driver, then no * need to expand the RTC range. */ if (!rtc->set_start_time) return;
range_secs = rtc->range_max - rtc->range_min + 1;
/* * If the start_secs is larger than the maximum seconds (rtc->range_max) * supported by RTC hardware or the maximum seconds of new expanded * range (start_secs + rtc->range_max - rtc->range_min) is less than * rtc->range_min, which means the minimum seconds (rtc->range_min) of * RTC hardware will be mapped to start_secs by adding one offset, so * the offset seconds calculation formula should be: * rtc->offset_secs = rtc->start_secs - rtc->range_min; * * If the start_secs is larger than the minimum seconds (rtc->range_min) * supported by RTC hardware, then there is one region is overlapped * between the original RTC hardware range and the new expanded range, * and this overlapped region do not need to be mapped into the new * expanded range due to it is valid for RTC device. So the minimum * seconds of RTC hardware (rtc->range_min) should be mapped to * rtc->range_max + 1, then the offset seconds formula should be: * rtc->offset_secs = rtc->range_max - rtc->range_min + 1; * * If the start_secs is less than the minimum seconds (rtc->range_min), * which is similar to case 2. So the start_secs should be mapped to * start_secs + rtc->range_max - rtc->range_min + 1, then the * offset seconds formula should be: * rtc->offset_secs = -(rtc->range_max - rtc->range_min + 1); * * Otherwise the offset seconds should be 0. */ if ((rtc->start_secs >= 0 && rtc->start_secs > rtc->range_max) || rtc->start_secs + range_secs - 1 < rtc->range_min) rtc->offset_secs = rtc->start_secs - rtc->range_min; else if (rtc->start_secs > rtc->range_min) rtc->offset_secs = range_secs; else if (rtc->start_secs < rtc->range_min) rtc->offset_secs = -range_secs; else rtc->offset_secs = 0;}
static void devm_rtc_unregister_device(void *data){ struct rtc_device *rtc = data;
mutex_lock(&rtc->ops_lock); /* * Remove innards of this RTC, then disable it, before * letting any rtc_class_open() users access it again */ rtc_proc_del_device(rtc); if (!test_bit(RTC_NO_CDEV, &rtc->flags)) cdev_device_del(&rtc->char_dev, &rtc->dev); rtc->ops = NULL; mutex_unlock(&rtc->ops_lock);}
static void devm_rtc_release_device(void *res){ struct rtc_device *rtc = res;
put_device(&rtc->dev);}
struct rtc_device *devm_rtc_allocate_device(struct device *dev){ struct rtc_device *rtc; int id, err;
id = rtc_device_get_id(dev); if (id < 0) return ERR_PTR(id);
rtc = rtc_allocate_device(); if (!rtc) { ida_free(&rtc_ida, id); return ERR_PTR(-ENOMEM); }
rtc->id = id; rtc->dev.parent = dev; err = devm_add_action_or_reset(dev, devm_rtc_release_device, rtc); if (err) return ERR_PTR(err);
err = dev_set_name(&rtc->dev, "rtc%d", id); if (err) return ERR_PTR(err);
return rtc;}EXPORT_SYMBOL_GPL(devm_rtc_allocate_device);
int __devm_rtc_register_device(struct module *owner, struct rtc_device *rtc){ struct rtc_wkalrm alrm; int err;
if (!rtc->ops) { dev_dbg(&rtc->dev, "no ops set\n"); return -EINVAL; }
if (!rtc->ops->set_alarm) clear_bit(RTC_FEATURE_ALARM, rtc->features);
if (rtc->ops->set_offset) set_bit(RTC_FEATURE_CORRECTION, rtc->features);
rtc->owner = owner; rtc_device_get_offset(rtc);
/* Check to see if there is an ALARM already set in hw */ err = __rtc_read_alarm(rtc, &alrm); if (!err) rtc_initialize_alarm(rtc, &alrm);
rtc_dev_prepare(rtc);
err = cdev_device_add(&rtc->char_dev, &rtc->dev); if (err) { set_bit(RTC_NO_CDEV, &rtc->flags); dev_warn(rtc->dev.parent, "failed to add char device %d:%d\n", MAJOR(rtc->dev.devt), rtc->id); } else { dev_dbg(rtc->dev.parent, "char device (%d:%d)\n", MAJOR(rtc->dev.devt), rtc->id); }
rtc_proc_add_device(rtc);
dev_info(rtc->dev.parent, "registered as %s\n", dev_name(&rtc->dev));
#ifdef CONFIG_RTC_HCTOSYS_DEVICE if (!strcmp(dev_name(&rtc->dev), CONFIG_RTC_HCTOSYS_DEVICE)) rtc_hctosys(rtc);#endif
return devm_add_action_or_reset(rtc->dev.parent, devm_rtc_unregister_device, rtc);}EXPORT_SYMBOL_GPL(__devm_rtc_register_device);
/** * devm_rtc_device_register - resource managed rtc_device_register() * @dev: the device to register * @name: the name of the device (unused) * @ops: the rtc operations structure * @owner: the module owner * * @return a struct rtc on success, or an ERR_PTR on error * * Managed rtc_device_register(). The rtc_device returned from this function * are automatically freed on driver detach. * This function is deprecated, use devm_rtc_allocate_device and * rtc_register_device instead */struct rtc_device *devm_rtc_device_register(struct device *dev, const char *name, const struct rtc_class_ops *ops, struct module *owner){ struct rtc_device *rtc; int err;
rtc = devm_rtc_allocate_device(dev); if (IS_ERR(rtc)) return rtc;
rtc->ops = ops;
err = __devm_rtc_register_device(owner, rtc); if (err) return ERR_PTR(err);
return rtc;}EXPORT_SYMBOL_GPL(devm_rtc_device_register);
static int __init rtc_init(void){ int err;
err = class_register(&rtc_class); if (err) return err;
rtc_dev_init();
return 0;}subsys_initcall(rtc_init);