* [PATCH 3/4] ARM: mach-sa1100: Fix for a nasty initialization bug in the RTSR.
2010-03-11 20:10 [PATCH 1/4] ARM: mach-sa1100: fix checkpatch.pl issues Marcelo Roberto Jimenez
2010-03-11 20:10 ` [PATCH 2/4] ARM: mach-sa1100: Print the value of RTSR on /proc/drivers/rtc Marcelo Roberto Jimenez
@ 2010-03-11 20:10 ` Marcelo Roberto Jimenez
2010-03-11 20:10 ` [PATCH 4/4] ARM: mach-sa1100: Better use of the RTC framework for sa11xx Marcelo Roberto Jimenez
2010-03-27 22:57 ` [PATCH 1/4] ARM: mach-sa1100: fix checkpatch.pl issues Russell King - ARM Linux
3 siblings, 0 replies; 6+ messages in thread
From: Marcelo Roberto Jimenez @ 2010-03-11 20:10 UTC (permalink / raw)
To: linux-arm-kernel
This patch fixes a nasty initialization condition on the RTSR register.
Sometimes, bit 1 will wake up set, sometimes not. This can be seen
by checking the value of the RTSR by typing '$ cat /proc/driver/rtc',
which has been provided by the previous patch.
If this bit is set, the command '$ cat /dev/rtc0' will lock the system
in an endless interrupt routine calling loop.
This patch fixes the issue both at sa1100_rtc_probe(), where it avoids
a spurious interrupt from happening, and at sa1100_rtc_interrupt(),
which is the robust solution, though it does not avoid the first
spurious interrupt.
Signed-off-by: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
---
drivers/rtc/rtc-sa1100.c | 42 +++++++++++++++++++++++++++++++++++++++++-
1 files changed, 41 insertions(+), 1 deletions(-)
diff --git a/drivers/rtc/rtc-sa1100.c b/drivers/rtc/rtc-sa1100.c
index b04c837..b0985f7 100644
--- a/drivers/rtc/rtc-sa1100.c
+++ b/drivers/rtc/rtc-sa1100.c
@@ -117,7 +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)
@@ -382,6 +398,30 @@ static int sa1100_rtc_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, rtc);
+ /* 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;
}
--
1.7.0.1
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 4/4] ARM: mach-sa1100: Better use of the RTC framework for sa11xx.
2010-03-11 20:10 [PATCH 1/4] ARM: mach-sa1100: fix checkpatch.pl issues Marcelo Roberto Jimenez
2010-03-11 20:10 ` [PATCH 2/4] ARM: mach-sa1100: Print the value of RTSR on /proc/drivers/rtc Marcelo Roberto Jimenez
2010-03-11 20:10 ` [PATCH 3/4] ARM: mach-sa1100: Fix for a nasty initialization bug in the RTSR Marcelo Roberto Jimenez
@ 2010-03-11 20:10 ` Marcelo Roberto Jimenez
2010-03-27 22:57 ` [PATCH 1/4] ARM: mach-sa1100: fix checkpatch.pl issues Russell King - ARM Linux
3 siblings, 0 replies; 6+ messages in thread
From: Marcelo Roberto Jimenez @ 2010-03-11 20:10 UTC (permalink / raw)
To: linux-arm-kernel
This patch uses the RTC framework to treat some common ioctl.
In particular, it fixes the behaviour of rtc_irq_set_freq(),
which did not work as expected because the timer was not beeing
retriggered.
Signed-off-by: Marcelo Roberto Jimenez <mroberto@cpti.cetuc.puc-rio.br>
---
drivers/rtc/rtc-sa1100.c | 90 +++++++++++++++++++++++++++++++++------------
1 files changed, 66 insertions(+), 24 deletions(-)
diff --git a/drivers/rtc/rtc-sa1100.c b/drivers/rtc/rtc-sa1100.c
index b0985f7..738503c 100644
--- a/drivers/rtc/rtc-sa1100.c
+++ b/drivers/rtc/rtc-sa1100.c
@@ -42,7 +42,7 @@
#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);
@@ -156,8 +156,50 @@ 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)
+{
+ spin_lock_irq(&sa1100_rtc_lock);
+
+ OSMR1 = timer_freq / rtc->irq_freq + OSCR;
+ 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);
@@ -175,7 +217,11 @@ 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;
}
@@ -183,8 +229,10 @@ 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;
@@ -207,6 +255,7 @@ 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);
@@ -226,6 +275,9 @@ static int sa1100_rtc_open(struct device *dev)
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:
@@ -274,25 +326,6 @@ 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;
}
@@ -344,12 +377,14 @@ 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;
@@ -365,6 +400,8 @@ 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)
@@ -391,13 +428,18 @@ 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().
*
--
1.7.0.1
^ permalink raw reply related [flat|nested] 6+ messages in thread