diff options
Diffstat (limited to 'drivers/rtc/rtc-bfin.c')
| -rw-r--r-- | drivers/rtc/rtc-bfin.c | 454 |
1 files changed, 229 insertions, 225 deletions
diff --git a/drivers/rtc/rtc-bfin.c b/drivers/rtc/rtc-bfin.c index 1aa709dda0d..fe4bdb06a55 100644 --- a/drivers/rtc/rtc-bfin.c +++ b/drivers/rtc/rtc-bfin.c @@ -1,8 +1,8 @@ /* * Blackfin On-Chip Real Time Clock Driver - * Supports BF53[123]/BF53[467]/BF54[2489] + * Supports BF51x/BF52x/BF53[123]/BF53[467]/BF54x * - * Copyright 2004-2007 Analog Devices Inc. + * Copyright 2004-2010 Analog Devices Inc. * * Enter bugs at http://blackfin.uclinux.org/ * @@ -20,9 +20,9 @@ * write would be discarded and things quickly fall apart. * * To keep this delay from significantly degrading performance (we, in theory, - * would have to sleep for up to 1 second everytime we wanted to write a + * would have to sleep for up to 1 second every time we wanted to write a * register), we only check the write pending status before we start to issue - * a new write. We bank on the idea that it doesnt matter when the sync + * a new write. We bank on the idea that it doesn't matter when the sync * happens so long as we don't attempt another write before it does. The only * time userspace would take this penalty is when they try and do multiple * operations right after another ... but in this case, they need to take the @@ -32,26 +32,35 @@ * writes to clear status registers complete immediately. */ -#include <linux/module.h> -#include <linux/kernel.h> +/* It may seem odd that there is no SWCNT code in here (which would be exposed + * via the periodic interrupt event, or PIE). Since the Blackfin RTC peripheral + * runs in units of seconds (N/HZ) but the Linux framework runs in units of HZ + * (2^N HZ), there is no point in keeping code that only provides 1 HZ PIEs. + * The same exact behavior can be accomplished by using the update interrupt + * event (UIE). Maybe down the line the RTC peripheral will suck less in which + * case we can re-introduce PIE support. + */ + #include <linux/bcd.h> -#include <linux/rtc.h> +#include <linux/completion.h> +#include <linux/delay.h> #include <linux/init.h> +#include <linux/interrupt.h> +#include <linux/kernel.h> +#include <linux/module.h> #include <linux/platform_device.h> +#include <linux/rtc.h> #include <linux/seq_file.h> -#include <linux/interrupt.h> -#include <linux/spinlock.h> -#include <linux/delay.h> +#include <linux/slab.h> #include <asm/blackfin.h> -#define stamp(fmt, args...) pr_debug("%s:%i: " fmt "\n", __FUNCTION__, __LINE__, ## args) -#define stampit() stamp("here i am") +#define dev_dbg_stamp(dev) dev_dbg(dev, "%s:%i: here i am\n", __func__, __LINE__) struct bfin_rtc { struct rtc_device *rtc_dev; struct rtc_time rtc_alarm; - spinlock_t lock; + u16 rtc_wrote_regs; }; /* Bit values for the ISTAT / ICTL registers */ @@ -72,7 +81,7 @@ struct bfin_rtc { #define SEC_BITS_OFF 0 /* Some helper functions to convert between the common RTC notion of time - * and the internal Blackfin notion that is stored in 32bits. + * and the internal Blackfin notion that is encoded in 32bits. */ static inline u32 rtc_time_to_bfin(unsigned long now) { @@ -97,7 +106,10 @@ static inline void rtc_bfin_to_tm(u32 rtc_bfin, struct rtc_time *tm) rtc_time_to_tm(rtc_bfin_to_time(rtc_bfin), tm); } -/* Wait for the previous write to a RTC register to complete. +/** + * bfin_rtc_sync_pending - make sure pending writes have complete + * + * Wait for the previous write to a RTC register to complete. * Unfortunately, we can't sleep here as that introduces a race condition when * turning on interrupt events. Consider this: * - process sets alarm @@ -112,188 +124,146 @@ static inline void rtc_bfin_to_tm(u32 rtc_bfin, struct rtc_time *tm) * If anyone can point out the obvious solution here, i'm listening :). This * shouldn't be an issue on an SMP or preempt system as this function should * only be called with the rtc lock held. + * + * Other options: + * - disable PREN so the sync happens at 32.768kHZ ... but this changes the + * inc rate for all RTC registers from 1HZ to 32.768kHZ ... + * - use the write complete IRQ */ -static void rtc_bfin_sync_pending(void) +/* +static void bfin_rtc_sync_pending_polled(void) { - stampit(); - while (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_COMPLETE)) { + while (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_COMPLETE)) if (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_PENDING)) break; - } bfin_write_RTC_ISTAT(RTC_ISTAT_WRITE_COMPLETE); } +*/ +static DECLARE_COMPLETION(bfin_write_complete); +static void bfin_rtc_sync_pending(struct device *dev) +{ + dev_dbg_stamp(dev); + while (bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_PENDING) + wait_for_completion_timeout(&bfin_write_complete, HZ * 5); + dev_dbg_stamp(dev); +} -static void rtc_bfin_reset(struct bfin_rtc *rtc) +/** + * bfin_rtc_reset - set RTC to sane/known state + * + * Initialize the RTC. Enable pre-scaler to scale RTC clock + * to 1Hz and clear interrupt/status registers. + */ +static void bfin_rtc_reset(struct device *dev, u16 rtc_ictl) { - /* Initialize the RTC. Enable pre-scaler to scale RTC clock - * to 1Hz and clear interrupt/status registers. */ - spin_lock_irq(&rtc->lock); - rtc_bfin_sync_pending(); + struct bfin_rtc *rtc = dev_get_drvdata(dev); + dev_dbg_stamp(dev); + bfin_rtc_sync_pending(dev); bfin_write_RTC_PREN(0x1); - bfin_write_RTC_ICTL(0); - bfin_write_RTC_SWCNT(0); + bfin_write_RTC_ICTL(rtc_ictl); bfin_write_RTC_ALARM(0); bfin_write_RTC_ISTAT(0xFFFF); - spin_unlock_irq(&rtc->lock); + rtc->rtc_wrote_regs = 0; } +/** + * bfin_rtc_interrupt - handle interrupt from RTC + * + * Since we handle all RTC events here, we have to make sure the requested + * interrupt is enabled (in RTC_ICTL) as the event status register (RTC_ISTAT) + * always gets updated regardless of the interrupt being enabled. So when one + * even we care about (e.g. stopwatch) goes off, we don't want to turn around + * and say that other events have happened as well (e.g. second). We do not + * have to worry about pending writes to the RTC_ICTL register as interrupts + * only fire if they are enabled in the RTC_ICTL register. + */ static irqreturn_t bfin_rtc_interrupt(int irq, void *dev_id) { - struct platform_device *pdev = to_platform_device(dev_id); - struct bfin_rtc *rtc = platform_get_drvdata(pdev); + struct device *dev = dev_id; + struct bfin_rtc *rtc = dev_get_drvdata(dev); unsigned long events = 0; - u16 rtc_istat; + bool write_complete = false; + u16 rtc_istat, rtc_istat_clear, rtc_ictl, bits; - stampit(); - - spin_lock_irq(&rtc->lock); + dev_dbg_stamp(dev); rtc_istat = bfin_read_RTC_ISTAT(); - - if (rtc_istat & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)) { - bfin_write_RTC_ISTAT(RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY); - events |= RTC_AF | RTC_IRQF; + rtc_ictl = bfin_read_RTC_ICTL(); + rtc_istat_clear = 0; + + bits = RTC_ISTAT_WRITE_COMPLETE; + if (rtc_istat & bits) { + rtc_istat_clear |= bits; + write_complete = true; + complete(&bfin_write_complete); } - if (rtc_istat & RTC_ISTAT_STOPWATCH) { - bfin_write_RTC_ISTAT(RTC_ISTAT_STOPWATCH); - events |= RTC_PF | RTC_IRQF; - bfin_write_RTC_SWCNT(rtc->rtc_dev->irq_freq); + bits = (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY); + if (rtc_ictl & bits) { + if (rtc_istat & bits) { + rtc_istat_clear |= bits; + events |= RTC_AF | RTC_IRQF; + } } - if (rtc_istat & RTC_ISTAT_SEC) { - bfin_write_RTC_ISTAT(RTC_ISTAT_SEC); - events |= RTC_UF | RTC_IRQF; + bits = RTC_ISTAT_SEC; + if (rtc_ictl & bits) { + if (rtc_istat & bits) { + rtc_istat_clear |= bits; + events |= RTC_UF | RTC_IRQF; + } } - rtc_update_irq(rtc->rtc_dev, 1, events); - - spin_unlock_irq(&rtc->lock); + if (events) + rtc_update_irq(rtc->rtc_dev, 1, events); - return IRQ_HANDLED; + if (write_complete || events) { + bfin_write_RTC_ISTAT(rtc_istat_clear); + return IRQ_HANDLED; + } else + return IRQ_NONE; } -static int bfin_rtc_open(struct device *dev) +static void bfin_rtc_int_set(u16 rtc_int) { - struct bfin_rtc *rtc = dev_get_drvdata(dev); - int ret; - - stampit(); - - ret = request_irq(IRQ_RTC, bfin_rtc_interrupt, IRQF_DISABLED, "rtc-bfin", dev); - if (unlikely(ret)) { - dev_err(dev, "request RTC IRQ failed with %d\n", ret); - return ret; - } - - rtc_bfin_reset(rtc); - - return ret; + bfin_write_RTC_ISTAT(rtc_int); + bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() | rtc_int); } - -static void bfin_rtc_release(struct device *dev) +static void bfin_rtc_int_clear(u16 rtc_int) { - struct bfin_rtc *rtc = dev_get_drvdata(dev); - stampit(); - rtc_bfin_reset(rtc); - free_irq(IRQ_RTC, dev); + bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() & rtc_int); +} +static void bfin_rtc_int_set_alarm(struct bfin_rtc *rtc) +{ + /* Blackfin has different bits for whether the alarm is + * more than 24 hours away. + */ + bfin_rtc_int_set(rtc->rtc_alarm.tm_yday == -1 ? RTC_ISTAT_ALARM : RTC_ISTAT_ALARM_DAY); } -static int bfin_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) +static int bfin_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) { struct bfin_rtc *rtc = dev_get_drvdata(dev); - stampit(); - - switch (cmd) { - case RTC_PIE_ON: - stampit(); - spin_lock_irq(&rtc->lock); - rtc_bfin_sync_pending(); - bfin_write_RTC_ISTAT(RTC_ISTAT_STOPWATCH); - bfin_write_RTC_SWCNT(rtc->rtc_dev->irq_freq); - bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() | RTC_ISTAT_STOPWATCH); - spin_unlock_irq(&rtc->lock); - return 0; - case RTC_PIE_OFF: - stampit(); - spin_lock_irq(&rtc->lock); - rtc_bfin_sync_pending(); - bfin_write_RTC_SWCNT(0); - bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() & ~RTC_ISTAT_STOPWATCH); - spin_unlock_irq(&rtc->lock); - return 0; - - case RTC_UIE_ON: - stampit(); - spin_lock_irq(&rtc->lock); - rtc_bfin_sync_pending(); - bfin_write_RTC_ISTAT(RTC_ISTAT_SEC); - bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() | RTC_ISTAT_SEC); - spin_unlock_irq(&rtc->lock); - return 0; - case RTC_UIE_OFF: - stampit(); - spin_lock_irq(&rtc->lock); - rtc_bfin_sync_pending(); - bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() & ~RTC_ISTAT_SEC); - spin_unlock_irq(&rtc->lock); - return 0; - - case RTC_AIE_ON: { - unsigned long rtc_alarm; - u16 which_alarm; - int ret = 0; - - stampit(); - - spin_lock_irq(&rtc->lock); - - rtc_bfin_sync_pending(); - if (rtc->rtc_alarm.tm_yday == -1) { - struct rtc_time now; - rtc_bfin_to_tm(bfin_read_RTC_STAT(), &now); - now.tm_sec = rtc->rtc_alarm.tm_sec; - now.tm_min = rtc->rtc_alarm.tm_min; - now.tm_hour = rtc->rtc_alarm.tm_hour; - ret = rtc_tm_to_time(&now, &rtc_alarm); - which_alarm = RTC_ISTAT_ALARM; - } else { - ret = rtc_tm_to_time(&rtc->rtc_alarm, &rtc_alarm); - which_alarm = RTC_ISTAT_ALARM_DAY; - } - if (ret == 0) { - bfin_write_RTC_ISTAT(which_alarm); - bfin_write_RTC_ALARM(rtc_time_to_bfin(rtc_alarm)); - bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() | which_alarm); - } + dev_dbg_stamp(dev); + if (enabled) + bfin_rtc_int_set_alarm(rtc); + else + bfin_rtc_int_clear(~(RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)); - spin_unlock_irq(&rtc->lock); - - return ret; - } - case RTC_AIE_OFF: - stampit(); - spin_lock_irq(&rtc->lock); - rtc_bfin_sync_pending(); - bfin_write_RTC_ICTL(bfin_read_RTC_ICTL() & ~(RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)); - spin_unlock_irq(&rtc->lock); - return 0; - } - - return -ENOIOCTLCMD; + return 0; } static int bfin_rtc_read_time(struct device *dev, struct rtc_time *tm) { struct bfin_rtc *rtc = dev_get_drvdata(dev); - stampit(); + dev_dbg_stamp(dev); + + if (rtc->rtc_wrote_regs & 0x1) + bfin_rtc_sync_pending(dev); - spin_lock_irq(&rtc->lock); - rtc_bfin_sync_pending(); rtc_bfin_to_tm(bfin_read_RTC_STAT(), tm); - spin_unlock_irq(&rtc->lock); return 0; } @@ -304,142 +274,176 @@ static int bfin_rtc_set_time(struct device *dev, struct rtc_time *tm) int ret; unsigned long now; - stampit(); - - spin_lock_irq(&rtc->lock); + dev_dbg_stamp(dev); ret = rtc_tm_to_time(tm, &now); if (ret == 0) { - rtc_bfin_sync_pending(); + if (rtc->rtc_wrote_regs & 0x1) + bfin_rtc_sync_pending(dev); bfin_write_RTC_STAT(rtc_time_to_bfin(now)); + rtc->rtc_wrote_regs = 0x1; } - spin_unlock_irq(&rtc->lock); - return ret; } static int bfin_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct bfin_rtc *rtc = dev_get_drvdata(dev); - stampit(); - memcpy(&alrm->time, &rtc->rtc_alarm, sizeof(struct rtc_time)); - alrm->pending = !!(bfin_read_RTC_ICTL() & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)); + dev_dbg_stamp(dev); + alrm->time = rtc->rtc_alarm; + bfin_rtc_sync_pending(dev); + alrm->enabled = !!(bfin_read_RTC_ICTL() & (RTC_ISTAT_ALARM | RTC_ISTAT_ALARM_DAY)); return 0; } static int bfin_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) { struct bfin_rtc *rtc = dev_get_drvdata(dev); - stampit(); - memcpy(&rtc->rtc_alarm, &alrm->time, sizeof(struct rtc_time)); + unsigned long rtc_alarm; + + dev_dbg_stamp(dev); + + if (rtc_tm_to_time(&alrm->time, &rtc_alarm)) + return -EINVAL; + + rtc->rtc_alarm = alrm->time; + + bfin_rtc_sync_pending(dev); + bfin_write_RTC_ALARM(rtc_time_to_bfin(rtc_alarm)); + if (alrm->enabled) + bfin_rtc_int_set_alarm(rtc); + return 0; } static int bfin_rtc_proc(struct device *dev, struct seq_file *seq) { -#define yesno(x) (x ? "yes" : "no") +#define yesno(x) ((x) ? "yes" : "no") u16 ictl = bfin_read_RTC_ICTL(); - stampit(); - seq_printf(seq, "alarm_IRQ\t: %s\n", yesno(ictl & RTC_ISTAT_ALARM)); - seq_printf(seq, "wkalarm_IRQ\t: %s\n", yesno(ictl & RTC_ISTAT_ALARM_DAY)); - seq_printf(seq, "seconds_IRQ\t: %s\n", yesno(ictl & RTC_ISTAT_SEC)); - seq_printf(seq, "periodic_IRQ\t: %s\n", yesno(ictl & RTC_ISTAT_STOPWATCH)); -#ifdef DEBUG - seq_printf(seq, "RTC_STAT\t: 0x%08X\n", bfin_read_RTC_STAT()); - seq_printf(seq, "RTC_ICTL\t: 0x%04X\n", bfin_read_RTC_ICTL()); - seq_printf(seq, "RTC_ISTAT\t: 0x%04X\n", bfin_read_RTC_ISTAT()); - seq_printf(seq, "RTC_SWCNT\t: 0x%04X\n", bfin_read_RTC_SWCNT()); - seq_printf(seq, "RTC_ALARM\t: 0x%08X\n", bfin_read_RTC_ALARM()); - seq_printf(seq, "RTC_PREN\t: 0x%04X\n", bfin_read_RTC_PREN()); -#endif - return 0; -} - -static int bfin_irq_set_freq(struct device *dev, int freq) -{ - struct bfin_rtc *rtc = dev_get_drvdata(dev); - stampit(); - rtc->rtc_dev->irq_freq = freq; + dev_dbg_stamp(dev); + seq_printf(seq, + "alarm_IRQ\t: %s\n" + "wkalarm_IRQ\t: %s\n" + "seconds_IRQ\t: %s\n", + yesno(ictl & RTC_ISTAT_ALARM), + yesno(ictl & RTC_ISTAT_ALARM_DAY), + yesno(ictl & RTC_ISTAT_SEC)); return 0; +#undef yesno } static struct rtc_class_ops bfin_rtc_ops = { - .open = bfin_rtc_open, - .release = bfin_rtc_release, - .ioctl = bfin_rtc_ioctl, .read_time = bfin_rtc_read_time, .set_time = bfin_rtc_set_time, .read_alarm = bfin_rtc_read_alarm, .set_alarm = bfin_rtc_set_alarm, .proc = bfin_rtc_proc, - .irq_set_freq = bfin_irq_set_freq, + .alarm_irq_enable = bfin_rtc_alarm_irq_enable, }; -static int __devinit bfin_rtc_probe(struct platform_device *pdev) +static int bfin_rtc_probe(struct platform_device *pdev) { struct bfin_rtc *rtc; - int ret = 0; + struct device *dev = &pdev->dev; + int ret; + unsigned long timeout = jiffies + HZ; - stampit(); + dev_dbg_stamp(dev); - rtc = kzalloc(sizeof(*rtc), GFP_KERNEL); + /* Allocate memory for our RTC struct */ + rtc = devm_kzalloc(dev, sizeof(*rtc), GFP_KERNEL); if (unlikely(!rtc)) return -ENOMEM; + platform_set_drvdata(pdev, rtc); + device_init_wakeup(dev, 1); + + /* Register our RTC with the RTC framework */ + rtc->rtc_dev = devm_rtc_device_register(dev, pdev->name, &bfin_rtc_ops, + THIS_MODULE); + if (unlikely(IS_ERR(rtc->rtc_dev))) + return PTR_ERR(rtc->rtc_dev); + + /* Grab the IRQ and init the hardware */ + ret = devm_request_irq(dev, IRQ_RTC, bfin_rtc_interrupt, 0, + pdev->name, dev); + if (unlikely(ret)) + dev_err(&pdev->dev, + "unable to request IRQ; alarm won't work, " + "and writes will be delayed\n"); + + /* sometimes the bootloader touched things, but the write complete was not + * enabled, so let's just do a quick timeout here since the IRQ will not fire ... + */ + while (bfin_read_RTC_ISTAT() & RTC_ISTAT_WRITE_PENDING) + if (time_after(jiffies, timeout)) + break; + bfin_rtc_reset(dev, RTC_ISTAT_WRITE_COMPLETE); + bfin_write_RTC_SWCNT(0); - spin_lock_init(&rtc->lock); + return 0; +} - rtc->rtc_dev = rtc_device_register(pdev->name, &pdev->dev, &bfin_rtc_ops, THIS_MODULE); - if (unlikely(IS_ERR(rtc))) { - ret = PTR_ERR(rtc->rtc_dev); - goto err; - } - rtc->rtc_dev->irq_freq = 0; - rtc->rtc_dev->max_user_freq = (2 << 16); /* stopwatch is an unsigned 16 bit reg */ +static int bfin_rtc_remove(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; - platform_set_drvdata(pdev, rtc); + bfin_rtc_reset(dev, 0); return 0; - -err: - kfree(rtc); - return ret; } -static int __devexit bfin_rtc_remove(struct platform_device *pdev) +#ifdef CONFIG_PM_SLEEP +static int bfin_rtc_suspend(struct device *dev) { - struct bfin_rtc *rtc = platform_get_drvdata(pdev); + dev_dbg_stamp(dev); - rtc_device_unregister(rtc->rtc_dev); - platform_set_drvdata(pdev, NULL); - kfree(rtc); + if (device_may_wakeup(dev)) { + enable_irq_wake(IRQ_RTC); + bfin_rtc_sync_pending(dev); + } else + bfin_rtc_int_clear(0); return 0; } +static int bfin_rtc_resume(struct device *dev) +{ + dev_dbg_stamp(dev); + + if (device_may_wakeup(dev)) + disable_irq_wake(IRQ_RTC); + + /* + * Since only some of the RTC bits are maintained externally in the + * Vbat domain, we need to wait for the RTC MMRs to be synced into + * the core after waking up. This happens every RTC 1HZ. Once that + * has happened, we can go ahead and re-enable the important write + * complete interrupt event. + */ + while (!(bfin_read_RTC_ISTAT() & RTC_ISTAT_SEC)) + continue; + bfin_rtc_int_set(RTC_ISTAT_WRITE_COMPLETE); + + return 0; +} +#endif + +static SIMPLE_DEV_PM_OPS(bfin_rtc_pm_ops, bfin_rtc_suspend, bfin_rtc_resume); + static struct platform_driver bfin_rtc_driver = { .driver = { .name = "rtc-bfin", .owner = THIS_MODULE, + .pm = &bfin_rtc_pm_ops, }, .probe = bfin_rtc_probe, - .remove = __devexit_p(bfin_rtc_remove), + .remove = bfin_rtc_remove, }; -static int __init bfin_rtc_init(void) -{ - stampit(); - return platform_driver_register(&bfin_rtc_driver); -} - -static void __exit bfin_rtc_exit(void) -{ - platform_driver_unregister(&bfin_rtc_driver); -} - -module_init(bfin_rtc_init); -module_exit(bfin_rtc_exit); +module_platform_driver(bfin_rtc_driver); MODULE_DESCRIPTION("Blackfin On-Chip Real Time Clock Driver"); MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>"); MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:rtc-bfin"); |