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-rw-r--r--drivers/rtc/rtc-sa1100.c161
1 files changed, 127 insertions, 34 deletions
diff --git a/drivers/rtc/rtc-sa1100.c b/drivers/rtc/rtc-sa1100.c
index e4a44b64170..88ea52b8647 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;
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-24 11:15:35 +0000