diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-07 03:50:35 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2011-01-07 03:50:35 +0300 |
commit | 3c0cb7c31c206aaedb967e44b98442bbeb17a6c4 (patch) | |
tree | 3ecba45d7ffae4fba4a5aafaef4af5b0b1105bde /drivers/rtc | |
parent | f70f5b9dc74ca7d0a64c4ead3fb28da09dc1b234 (diff) | |
parent | 404a02cbd2ae8bf256a2fa1169bdfe86bb5ebb34 (diff) | |
download | linux-3c0cb7c31c206aaedb967e44b98442bbeb17a6c4.tar.xz |
Merge branch 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm
* 'devel' of master.kernel.org:/home/rmk/linux-2.6-arm: (416 commits)
ARM: DMA: add support for DMA debugging
ARM: PL011: add DMA burst threshold support for ST variants
ARM: PL011: Add support for transmit DMA
ARM: PL011: Ensure IRQs are disabled in UART interrupt handler
ARM: PL011: Separate hardware FIFO size from TTY FIFO size
ARM: PL011: Allow better handling of vendor data
ARM: PL011: Ensure error flags are clear at startup
ARM: PL011: include revision number in boot-time port printk
ARM: vexpress: add sched_clock() for Versatile Express
ARM i.MX53: Make MX53 EVK bootable
ARM i.MX53: Some bug fix about MX53 MSL code
ARM: 6607/1: sa1100: Update platform device registration
ARM: 6606/1: sa1100: Fix platform device registration
ARM i.MX51: rename IPU irqs
ARM i.MX51: Add ipu clock support
ARM: imx/mx27_3ds: Add PMIC support
ARM: DMA: Replace page_to_dma()/dma_to_page() with pfn_to_dma()/dma_to_pfn()
mx51: fix usb clock support
MX51: Add support for usb host 2
arch/arm/plat-mxc/ehci.c: fix errors/typos
...
Diffstat (limited to 'drivers/rtc')
-rw-r--r-- | drivers/rtc/rtc-sa1100.c | 161 |
1 files changed, 127 insertions, 34 deletions
diff --git a/drivers/rtc/rtc-sa1100.c b/drivers/rtc/rtc-sa1100.c index e4a44b641702..88ea52b8647a 100644 --- a/drivers/rtc/rtc-sa1100.c +++ b/drivers/rtc/rtc-sa1100.c @@ -39,10 +39,10 @@ #include <mach/regs-ost.h> #endif -#define RTC_DEF_DIVIDER 32768 - 1 +#define RTC_DEF_DIVIDER (32768 - 1) #define RTC_DEF_TRIM 0 -static unsigned long rtc_freq = 1024; +static const unsigned long RTC_FREQ = 1024; static unsigned long timer_freq; static struct rtc_time rtc_alarm; static DEFINE_SPINLOCK(sa1100_rtc_lock); @@ -61,7 +61,8 @@ static inline int rtc_periodic_alarm(struct rtc_time *tm) * Calculate the next alarm time given the requested alarm time mask * and the current time. */ -static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, struct rtc_time *alrm) +static void rtc_next_alarm_time(struct rtc_time *next, struct rtc_time *now, + struct rtc_time *alrm) { unsigned long next_time; unsigned long now_time; @@ -116,7 +117,23 @@ static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) rtsr = RTSR; /* clear interrupt sources */ RTSR = 0; - RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2); + /* Fix for a nasty initialization problem the in SA11xx RTSR register. + * See also the comments in sa1100_rtc_probe(). */ + if (rtsr & (RTSR_ALE | RTSR_HZE)) { + /* This is the original code, before there was the if test + * above. This code does not clear interrupts that were not + * enabled. */ + RTSR = (RTSR_AL | RTSR_HZ) & (rtsr >> 2); + } else { + /* For some reason, it is possible to enter this routine + * without interruptions enabled, it has been tested with + * several units (Bug in SA11xx chip?). + * + * This situation leads to an infinite "loop" of interrupt + * routine calling and as a result the processor seems to + * lock on its first call to open(). */ + RTSR = RTSR_AL | RTSR_HZ; + } /* clear alarm interrupt if it has occurred */ if (rtsr & RTSR_AL) @@ -139,8 +156,58 @@ static irqreturn_t sa1100_rtc_interrupt(int irq, void *dev_id) return IRQ_HANDLED; } +static int sa1100_irq_set_freq(struct device *dev, int freq) +{ + if (freq < 1 || freq > timer_freq) { + return -EINVAL; + } else { + struct rtc_device *rtc = (struct rtc_device *)dev; + + rtc->irq_freq = freq; + + return 0; + } +} + static int rtc_timer1_count; +static int sa1100_irq_set_state(struct device *dev, int enabled) +{ + spin_lock_irq(&sa1100_rtc_lock); + if (enabled) { + struct rtc_device *rtc = (struct rtc_device *)dev; + + OSMR1 = timer_freq / rtc->irq_freq + OSCR; + OIER |= OIER_E1; + rtc_timer1_count = 1; + } else { + OIER &= ~OIER_E1; + } + spin_unlock_irq(&sa1100_rtc_lock); + + return 0; +} + +static inline int sa1100_timer1_retrigger(struct rtc_device *rtc) +{ + unsigned long diff; + unsigned long period = timer_freq / rtc->irq_freq; + + spin_lock_irq(&sa1100_rtc_lock); + + do { + OSMR1 += period; + diff = OSMR1 - OSCR; + /* If OSCR > OSMR1, diff is a very large number (unsigned + * math). This means we have a lost interrupt. */ + } while (diff > period); + OIER |= OIER_E1; + + spin_unlock_irq(&sa1100_rtc_lock); + + return 0; +} + static irqreturn_t timer1_interrupt(int irq, void *dev_id) { struct platform_device *pdev = to_platform_device(dev_id); @@ -158,7 +225,11 @@ static irqreturn_t timer1_interrupt(int irq, void *dev_id) rtc_update_irq(rtc, rtc_timer1_count, RTC_PF | RTC_IRQF); if (rtc_timer1_count == 1) - rtc_timer1_count = (rtc_freq * ((1 << 30) / (timer_freq >> 2))); + rtc_timer1_count = + (rtc->irq_freq * ((1 << 30) / (timer_freq >> 2))); + + /* retrigger. */ + sa1100_timer1_retrigger(rtc); return IRQ_HANDLED; } @@ -166,8 +237,10 @@ static irqreturn_t timer1_interrupt(int irq, void *dev_id) static int sa1100_rtc_read_callback(struct device *dev, int data) { if (data & RTC_PF) { + struct rtc_device *rtc = (struct rtc_device *)dev; + /* interpolate missed periods and set match for the next */ - unsigned long period = timer_freq / rtc_freq; + unsigned long period = timer_freq / rtc->irq_freq; unsigned long oscr = OSCR; unsigned long osmr1 = OSMR1; unsigned long missed = (oscr - osmr1)/period; @@ -178,7 +251,7 @@ static int sa1100_rtc_read_callback(struct device *dev, int data) * Here we compare (match - OSCR) 8 instead of 0 -- * see comment in pxa_timer_interrupt() for explanation. */ - while( (signed long)((osmr1 = OSMR1) - OSCR) <= 8 ) { + while ((signed long)((osmr1 = OSMR1) - OSCR) <= 8) { data += 0x100; OSSR = OSSR_M1; /* clear match on timer 1 */ OSMR1 = osmr1 + period; @@ -190,25 +263,29 @@ static int sa1100_rtc_read_callback(struct device *dev, int data) static int sa1100_rtc_open(struct device *dev) { int ret; + struct rtc_device *rtc = (struct rtc_device *)dev; ret = request_irq(IRQ_RTC1Hz, sa1100_rtc_interrupt, IRQF_DISABLED, - "rtc 1Hz", dev); + "rtc 1Hz", dev); if (ret) { dev_err(dev, "IRQ %d already in use.\n", IRQ_RTC1Hz); goto fail_ui; } ret = request_irq(IRQ_RTCAlrm, sa1100_rtc_interrupt, IRQF_DISABLED, - "rtc Alrm", dev); + "rtc Alrm", dev); if (ret) { dev_err(dev, "IRQ %d already in use.\n", IRQ_RTCAlrm); goto fail_ai; } ret = request_irq(IRQ_OST1, timer1_interrupt, IRQF_DISABLED, - "rtc timer", dev); + "rtc timer", dev); if (ret) { dev_err(dev, "IRQ %d already in use.\n", IRQ_OST1); goto fail_pi; } + rtc->max_user_freq = RTC_FREQ; + sa1100_irq_set_freq(dev, RTC_FREQ); + return 0; fail_pi: @@ -236,7 +313,7 @@ static void sa1100_rtc_release(struct device *dev) static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { - switch(cmd) { + switch (cmd) { case RTC_AIE_OFF: spin_lock_irq(&sa1100_rtc_lock); RTSR &= ~RTSR_ALE; @@ -257,25 +334,6 @@ static int sa1100_rtc_ioctl(struct device *dev, unsigned int cmd, RTSR |= RTSR_HZE; spin_unlock_irq(&sa1100_rtc_lock); return 0; - case RTC_PIE_OFF: - spin_lock_irq(&sa1100_rtc_lock); - OIER &= ~OIER_E1; - spin_unlock_irq(&sa1100_rtc_lock); - return 0; - case RTC_PIE_ON: - spin_lock_irq(&sa1100_rtc_lock); - OSMR1 = timer_freq / rtc_freq + OSCR; - OIER |= OIER_E1; - rtc_timer1_count = 1; - spin_unlock_irq(&sa1100_rtc_lock); - return 0; - case RTC_IRQP_READ: - return put_user(rtc_freq, (unsigned long *)arg); - case RTC_IRQP_SET: - if (arg < 1 || arg > timer_freq) - return -EINVAL; - rtc_freq = arg; - return 0; } return -ENOIOCTLCMD; } @@ -327,12 +385,15 @@ static int sa1100_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) static int sa1100_rtc_proc(struct device *dev, struct seq_file *seq) { + struct rtc_device *rtc = (struct rtc_device *)dev; + seq_printf(seq, "trim/divider\t: 0x%08x\n", (u32) RTTR); seq_printf(seq, "update_IRQ\t: %s\n", (RTSR & RTSR_HZE) ? "yes" : "no"); seq_printf(seq, "periodic_IRQ\t: %s\n", (OIER & OIER_E1) ? "yes" : "no"); - seq_printf(seq, "periodic_freq\t: %ld\n", rtc_freq); + seq_printf(seq, "periodic_freq\t: %d\n", rtc->irq_freq); + seq_printf(seq, "RTSR\t\t: 0x%08x\n", (u32)RTSR); return 0; } @@ -347,6 +408,8 @@ static const struct rtc_class_ops sa1100_rtc_ops = { .read_alarm = sa1100_rtc_read_alarm, .set_alarm = sa1100_rtc_set_alarm, .proc = sa1100_rtc_proc, + .irq_set_freq = sa1100_irq_set_freq, + .irq_set_state = sa1100_irq_set_state, }; static int sa1100_rtc_probe(struct platform_device *pdev) @@ -364,7 +427,8 @@ static int sa1100_rtc_probe(struct platform_device *pdev) */ if (RTTR == 0) { RTTR = RTC_DEF_DIVIDER + (RTC_DEF_TRIM << 16); - dev_warn(&pdev->dev, "warning: initializing default clock divider/trim value\n"); + dev_warn(&pdev->dev, "warning: " + "initializing default clock divider/trim value\n"); /* The current RTC value probably doesn't make sense either */ RCNR = 0; } @@ -372,13 +436,42 @@ static int sa1100_rtc_probe(struct platform_device *pdev) device_init_wakeup(&pdev->dev, 1); rtc = rtc_device_register(pdev->name, &pdev->dev, &sa1100_rtc_ops, - THIS_MODULE); + THIS_MODULE); if (IS_ERR(rtc)) return PTR_ERR(rtc); platform_set_drvdata(pdev, rtc); + /* Set the irq_freq */ + /*TODO: Find out who is messing with this value after we initialize + * it here.*/ + rtc->irq_freq = RTC_FREQ; + + /* Fix for a nasty initialization problem the in SA11xx RTSR register. + * See also the comments in sa1100_rtc_interrupt(). + * + * Sometimes bit 1 of the RTSR (RTSR_HZ) will wake up 1, which means an + * interrupt pending, even though interrupts were never enabled. + * In this case, this bit it must be reset before enabling + * interruptions to avoid a nonexistent interrupt to occur. + * + * In principle, the same problem would apply to bit 0, although it has + * never been observed to happen. + * + * This issue is addressed both here and in sa1100_rtc_interrupt(). + * If the issue is not addressed here, in the times when the processor + * wakes up with the bit set there will be one spurious interrupt. + * + * The issue is also dealt with in sa1100_rtc_interrupt() to be on the + * safe side, once the condition that lead to this strange + * initialization is unknown and could in principle happen during + * normal processing. + * + * Notice that clearing bit 1 and 0 is accomplished by writting ONES to + * the corresponding bits in RTSR. */ + RTSR = RTSR_AL | RTSR_HZ; + return 0; } @@ -386,7 +479,7 @@ static int sa1100_rtc_remove(struct platform_device *pdev) { struct rtc_device *rtc = platform_get_drvdata(pdev); - if (rtc) + if (rtc) rtc_device_unregister(rtc); return 0; |