[PATCH 1/3] rtc: mxc: fix possible race condition

[PATCH 1/3] rtc: mxc: fix possible race condition

[Alexandre Belloni]

The IRQ is requested before the struct rtc is allocated and registered, but
this struct is used in the IRQ handler. This may lead to a NULL pointer
dereference.

Switch to devm_rtc_allocate_device/rtc_register_device to allocate the rtc
struct before requesting the IRQ.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-mxc.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/drivers/rtc/rtc-mxc.c b/drivers/rtc/rtc-mxc.c
index 708b9e9b86a6..d9a038afedf0 100644
--- a/drivers/rtc/rtc-mxc.c
+++ b/drivers/rtc/rtc-mxc.c
@@ -340,6 +340,13 @@ static int mxc_rtc_probe(struct platform_device *pdev)
 	if (IS_ERR(pdata->ioaddr))
 		return PTR_ERR(pdata->ioaddr);
 
+	rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(rtc))
+		return PTR_ERR(rtc);
+
+	pdata->rtc = rtc;
+	rtc->ops = &mxc_rtc_ops;
+
 	pdata->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
 	if (IS_ERR(pdata->clk_ipg)) {
 		dev_err(&pdev->dev, "unable to get ipg clock!\n");
@@ -402,14 +409,9 @@ static int mxc_rtc_probe(struct platform_device *pdev)
 			dev_err(&pdev->dev, "failed to enable irq wake\n");
 	}
 
-	rtc = devm_rtc_device_register(&pdev->dev, pdev->name, &mxc_rtc_ops,
-				  THIS_MODULE);
-	if (IS_ERR(rtc)) {
-		ret = PTR_ERR(rtc);
+	ret = rtc_register_device(rtc);
+	if (ret)
 		goto exit_put_clk_ref;
-	}
-
-	pdata->rtc = rtc;
 
 	return 0;
 
-- 
2.20.1

[PATCH 2/3] rtc: mxc: set range

[Alexandre Belloni]

Let the core handle the range, and in particular the imx1 offsetting. This
has the benefit of extending the range of the RTC further than 365 days and
making .read_time useful again on imx1.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-mxc.c | 30 +++++++++++++++++-------------
 1 file changed, 17 insertions(+), 13 deletions(-)

diff --git a/drivers/rtc/rtc-mxc.c b/drivers/rtc/rtc-mxc.c
index d9a038afedf0..31d3f375bc0f 100644
--- a/drivers/rtc/rtc-mxc.c
+++ b/drivers/rtc/rtc-mxc.c
@@ -256,19 +256,6 @@ static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm)
  */
 static int mxc_rtc_set_mmss(struct device *dev, time64_t time)
 {
-	struct rtc_plat_data *pdata = dev_get_drvdata(dev);
-
-	/*
-	 * TTC_DAYR register is 9-bit in MX1 SoC, save time and day of year only
-	 */
-	if (is_imx1_rtc(pdata)) {
-		struct rtc_time tm;
-
-		rtc_time64_to_tm(time, &tm);
-		tm.tm_year = 70;
-		time = rtc_tm_to_time64(&tm);
-	}
-
 	/* Avoid roll-over from reading the different registers */
 	do {
 		set_alarm_or_time(dev, MXC_RTC_TIME, time);
@@ -346,6 +333,23 @@ static int mxc_rtc_probe(struct platform_device *pdev)
 
 	pdata->rtc = rtc;
 	rtc->ops = &mxc_rtc_ops;
+	if (is_imx1_rtc(pdata)) {
+		struct rtc_time tm;
+
+		/* 9bit days + hours minutes seconds */
+		rtc->range_max = (1 << 9) * 86400 - 1;
+
+		/*
+		 * Set the start date as beginning of the current year. This can
+		 * be overridden using device tree.
+		 */
+		rtc_time64_to_tm(ktime_get_real_seconds(), &tm);
+		rtc->start_secs =  mktime64(tm.tm_year, 1, 1, 0, 0, 0);
+		rtc->set_start_time = true;
+	} else {
+		/* 16bit days + hours minutes seconds */
+		rtc->range_max = (1 << 16) * 86400ULL - 1;
+	}
 
 	pdata->clk_ipg = devm_clk_get(&pdev->dev, "ipg");
 	if (IS_ERR(pdata->clk_ipg)) {
-- 
2.20.1

[PATCH 3/3] rtc: mxc: use .set_time

[Alexandre Belloni]

Use .set_time instead of the deprecated .set_mmss64.

Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
---
 drivers/rtc/rtc-mxc.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-mxc.c b/drivers/rtc/rtc-mxc.c
index 31d3f375bc0f..e697e96612bb 100644
--- a/drivers/rtc/rtc-mxc.c
+++ b/drivers/rtc/rtc-mxc.c
@@ -254,8 +254,10 @@ static int mxc_rtc_read_time(struct device *dev, struct rtc_time *tm)
 /*
  * This function sets the internal RTC time based on tm in Gregorian date.
  */
-static int mxc_rtc_set_mmss(struct device *dev, time64_t time)
+static int mxc_rtc_set_time(struct device *dev, struct rtc_time *tm)
 {
+	time64_t time = rtc_tm_to_time64(tm);
+
 	/* Avoid roll-over from reading the different registers */
 	do {
 		set_alarm_or_time(dev, MXC_RTC_TIME, time);
@@ -298,7 +300,7 @@ static int mxc_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 /* RTC layer */
 static const struct rtc_class_ops mxc_rtc_ops = {
 	.read_time		= mxc_rtc_read_time,
-	.set_mmss64		= mxc_rtc_set_mmss,
+	.set_time		= mxc_rtc_set_time,
 	.read_alarm		= mxc_rtc_read_alarm,
 	.set_alarm		= mxc_rtc_set_alarm,
 	.alarm_irq_enable	= mxc_rtc_alarm_irq_enable,
-- 
2.20.1