diff mbox series

rtc: pcf2127: handle timestamp interrupts

Message ID 20210429144758.4552-1-ykaukab@suse.de
State Changes Requested
Headers show
Series rtc: pcf2127: handle timestamp interrupts | expand

Commit Message

Mian Yousaf Kaukab April 29, 2021, 2:47 p.m. UTC
commit 03623b4b041c ("rtc: pcf2127: add tamper detection support")
added support for timestamp interrupts. However they are not being
handled in the irq handler. If a timestamp interrupt occurs it
results in kernel disabling the interrupt and displaying the call
trace:

[  121.145580] irq 78: nobody cared (try booting with the "irqpoll" option)
...
[  121.238087] [<00000000c4d69393>] irq_default_primary_handler threaded [<000000000a90d25b>] pcf2127_rtc_irq [rtc_pcf2127]
[  121.248971] Disabling IRQ #78

Handle timestamp interrupts in pcf2127_rtc_irq(). Display a message
in kernel log when a timestamp interrupt occurs. Don’t check for
TSF1 and TSF2 flags in timestamp0_show() as they are cleared in the
IRQ handler now.

Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
---
 drivers/rtc/rtc-pcf2127.c | 34 +++++++++++++++++++++++++---------
 1 file changed, 25 insertions(+), 9 deletions(-)

Comments

Alexandre Belloni April 29, 2021, 9:25 p.m. UTC | #1
Hello,

On 29/04/2021 16:47:58+0200, Mian Yousaf Kaukab wrote:
> commit 03623b4b041c ("rtc: pcf2127: add tamper detection support")
> added support for timestamp interrupts. However they are not being
> handled in the irq handler. If a timestamp interrupt occurs it
> results in kernel disabling the interrupt and displaying the call
> trace:
> 
> [  121.145580] irq 78: nobody cared (try booting with the "irqpoll" option)
> ...
> [  121.238087] [<00000000c4d69393>] irq_default_primary_handler threaded [<000000000a90d25b>] pcf2127_rtc_irq [rtc_pcf2127]
> [  121.248971] Disabling IRQ #78
> 
> Handle timestamp interrupts in pcf2127_rtc_irq(). Display a message
> in kernel log when a timestamp interrupt occurs. Don’t check for
> TSF1 and TSF2 flags in timestamp0_show() as they are cleared in the
> IRQ handler now.

This breaks an important functionality (as I already replied to a
previous fix a while ago) as then there is no way to know whether the
timestamp is bogus or if an event really happened. Please fix properly.

> 
> Signed-off-by: Mian Yousaf Kaukab <ykaukab@suse.de>
> ---
>  drivers/rtc/rtc-pcf2127.c | 34 +++++++++++++++++++++++++---------
>  1 file changed, 25 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
> index d13c20a2adf7..0dbc0473cc68 100644
> --- a/drivers/rtc/rtc-pcf2127.c
> +++ b/drivers/rtc/rtc-pcf2127.c
> @@ -94,6 +94,13 @@
>  #define PCF2127_WD_VAL_MAX		255
>  #define PCF2127_WD_VAL_DEFAULT		60
>  
> +/* Mask for currently enabled interrupts */
> +#define PCF2127_CTRL1_IRQ_MASK (PCF2127_BIT_CTRL1_TSF1)
> +#define PCF2127_CTRL2_IRQ_MASK ( \
> +		PCF2127_BIT_CTRL2_AF | \
> +		PCF2127_BIT_CTRL2_WDTF | \
> +		PCF2127_BIT_CTRL2_TSF2)
> +
>  struct pcf2127 {
>  	struct rtc_device *rtc;
>  	struct watchdog_device wdd;
> @@ -437,20 +444,33 @@ static int pcf2127_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
>  static irqreturn_t pcf2127_rtc_irq(int irq, void *dev)
>  {
>  	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
> -	unsigned int ctrl2 = 0;
> +	unsigned int ctrl1, ctrl2;
>  	int ret = 0;
>  
> +	ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL1, &ctrl1);
> +	if (ret)
> +		return IRQ_NONE;
> +
>  	ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
>  	if (ret)
>  		return IRQ_NONE;
>  
> -	if (!(ctrl2 & PCF2127_BIT_CTRL2_AF))
> +	if (!(ctrl1 & PCF2127_CTRL1_IRQ_MASK || ctrl2 & PCF2127_CTRL2_IRQ_MASK))
>  		return IRQ_NONE;
>  
> -	regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
> -		     ctrl2 & ~(PCF2127_BIT_CTRL2_AF | PCF2127_BIT_CTRL2_WDTF));
> +	if (ctrl1 & PCF2127_CTRL1_IRQ_MASK)
> +		regmap_write(pcf2127->regmap, PCF2127_REG_CTRL1,
> +			ctrl1 & ~PCF2127_CTRL1_IRQ_MASK);
>  
> -	rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
> +	if (ctrl2 & PCF2127_CTRL2_IRQ_MASK)
> +		regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
> +			ctrl2 & ~PCF2127_CTRL2_IRQ_MASK);
> +
> +	if (ctrl1 & PCF2127_BIT_CTRL1_TSF1 || ctrl2 & PCF2127_BIT_CTRL2_TSF2)
> +		dev_info(dev, "timestamp interrupt generated");
> +

Please do not add random strings in the kernel, this will probably never
be seen by any real user.

> +	if (ctrl2 & PCF2127_BIT_CTRL2_AF)
> +		rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
>  
>  	pcf2127_wdt_active_ping(&pcf2127->wdd);
>  
> @@ -524,10 +544,6 @@ static ssize_t timestamp0_show(struct device *dev,
>  	if (ret)
>  		return ret;
>  
> -	if (!(data[PCF2127_REG_CTRL1] & PCF2127_BIT_CTRL1_TSF1) &&
> -	    !(data[PCF2127_REG_CTRL2] & PCF2127_BIT_CTRL2_TSF2))
> -		return 0;
> -
>  	tm.tm_sec = bcd2bin(data[PCF2127_REG_TS_SC] & 0x7F);
>  	tm.tm_min = bcd2bin(data[PCF2127_REG_TS_MN] & 0x7F);
>  	tm.tm_hour = bcd2bin(data[PCF2127_REG_TS_HR] & 0x3F);
> -- 
> 2.26.2
>
diff mbox series

Patch

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index d13c20a2adf7..0dbc0473cc68 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -94,6 +94,13 @@ 
 #define PCF2127_WD_VAL_MAX		255
 #define PCF2127_WD_VAL_DEFAULT		60
 
+/* Mask for currently enabled interrupts */
+#define PCF2127_CTRL1_IRQ_MASK (PCF2127_BIT_CTRL1_TSF1)
+#define PCF2127_CTRL2_IRQ_MASK ( \
+		PCF2127_BIT_CTRL2_AF | \
+		PCF2127_BIT_CTRL2_WDTF | \
+		PCF2127_BIT_CTRL2_TSF2)
+
 struct pcf2127 {
 	struct rtc_device *rtc;
 	struct watchdog_device wdd;
@@ -437,20 +444,33 @@  static int pcf2127_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 static irqreturn_t pcf2127_rtc_irq(int irq, void *dev)
 {
 	struct pcf2127 *pcf2127 = dev_get_drvdata(dev);
-	unsigned int ctrl2 = 0;
+	unsigned int ctrl1, ctrl2;
 	int ret = 0;
 
+	ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL1, &ctrl1);
+	if (ret)
+		return IRQ_NONE;
+
 	ret = regmap_read(pcf2127->regmap, PCF2127_REG_CTRL2, &ctrl2);
 	if (ret)
 		return IRQ_NONE;
 
-	if (!(ctrl2 & PCF2127_BIT_CTRL2_AF))
+	if (!(ctrl1 & PCF2127_CTRL1_IRQ_MASK || ctrl2 & PCF2127_CTRL2_IRQ_MASK))
 		return IRQ_NONE;
 
-	regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
-		     ctrl2 & ~(PCF2127_BIT_CTRL2_AF | PCF2127_BIT_CTRL2_WDTF));
+	if (ctrl1 & PCF2127_CTRL1_IRQ_MASK)
+		regmap_write(pcf2127->regmap, PCF2127_REG_CTRL1,
+			ctrl1 & ~PCF2127_CTRL1_IRQ_MASK);
 
-	rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
+	if (ctrl2 & PCF2127_CTRL2_IRQ_MASK)
+		regmap_write(pcf2127->regmap, PCF2127_REG_CTRL2,
+			ctrl2 & ~PCF2127_CTRL2_IRQ_MASK);
+
+	if (ctrl1 & PCF2127_BIT_CTRL1_TSF1 || ctrl2 & PCF2127_BIT_CTRL2_TSF2)
+		dev_info(dev, "timestamp interrupt generated");
+
+	if (ctrl2 & PCF2127_BIT_CTRL2_AF)
+		rtc_update_irq(pcf2127->rtc, 1, RTC_IRQF | RTC_AF);
 
 	pcf2127_wdt_active_ping(&pcf2127->wdd);
 
@@ -524,10 +544,6 @@  static ssize_t timestamp0_show(struct device *dev,
 	if (ret)
 		return ret;
 
-	if (!(data[PCF2127_REG_CTRL1] & PCF2127_BIT_CTRL1_TSF1) &&
-	    !(data[PCF2127_REG_CTRL2] & PCF2127_BIT_CTRL2_TSF2))
-		return 0;
-
 	tm.tm_sec = bcd2bin(data[PCF2127_REG_TS_SC] & 0x7F);
 	tm.tm_min = bcd2bin(data[PCF2127_REG_TS_MN] & 0x7F);
 	tm.tm_hour = bcd2bin(data[PCF2127_REG_TS_HR] & 0x3F);