[PATCH AUTOSEL 5.2 19/42] rtc: snvs: fix possible race condition

[PATCH AUTOSEL 5.2 19/42] rtc: snvs: fix possible race condition

[Sasha Levin]

From: Anson Huang <Anson.Huang@nxp.com>

[ Upstream commit 6fd4fe9b496d9ba3382992ff4fde3871d1b6f63d ]

The RTC IRQ is requested before the struct rtc_device is allocated,
this may lead to a NULL pointer dereference in IRQ handler.

To fix this issue, allocating the rtc_device struct before requesting
the RTC IRQ using devm_rtc_allocate_device, and use rtc_register_device
to register the RTC device.

Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Dong Aisheng <aisheng.dong@nxp.com>
Link: https://lore.kernel.org/r/20190716071858.36750-1-Anson.Huang@nxp.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/rtc/rtc-snvs.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/rtc/rtc-snvs.c b/drivers/rtc/rtc-snvs.c
index 7ee673a25fd0a..4f9a107a04277 100644
--- a/drivers/rtc/rtc-snvs.c
+++ b/drivers/rtc/rtc-snvs.c
@@ -279,6 +279,10 @@ static int snvs_rtc_probe(struct platform_device *pdev)
 	if (!data)
 		return -ENOMEM;
 
+	data->rtc = devm_rtc_allocate_device(&pdev->dev);
+	if (IS_ERR(data->rtc))
+		return PTR_ERR(data->rtc);
+
 	data->regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "regmap");
 
 	if (IS_ERR(data->regmap)) {
@@ -343,10 +347,9 @@ static int snvs_rtc_probe(struct platform_device *pdev)
 		goto error_rtc_device_register;
 	}
 
-	data->rtc = devm_rtc_device_register(&pdev->dev, pdev->name,
-					&snvs_rtc_ops, THIS_MODULE);
-	if (IS_ERR(data->rtc)) {
-		ret = PTR_ERR(data->rtc);
+	data->rtc->ops = &snvs_rtc_ops;
+	ret = rtc_register_device(data->rtc);
+	if (ret) {
 		dev_err(&pdev->dev, "failed to register rtc: %d\n", ret);
 		goto error_rtc_device_register;
 	}
-- 
2.20.1

[PATCH AUTOSEL 5.2 20/42] rtc: pcf85363/pcf85263: fix regmap error in set_time

[Sasha Levin]

From: Biwen Li <biwen.li@nxp.com>

[ Upstream commit 7ef66122bdb3b839e9f51b76d7e600b6e21ef648 ]

Issue:
    - # hwclock -w
      hwclock: RTC_SET_TIME: Invalid argument

Why:
    - Relative commit: 8b9f9d4dc511 ("regmap: verify if register is
      writeable before writing operations"), this patch
      will always check for unwritable registers, it will compare reg
      with max_register in regmap_writeable.

    - The pcf85363/pcf85263 has the capability of address wrapping
      which means if you access an address outside the allowed range
      (0x00-0x2f) hardware actually wraps the access to a lower address.
      The rtc-pcf85363 driver will use this feature to configure the time
      and execute 2 actions in the same i2c write operation (stopping the
      clock and configure the time). However the driver has also
      configured the `regmap maxregister` protection mechanism that will
      block accessing addresses outside valid range (0x00-0x2f).

How:
    - Split of writing regs to two parts, first part writes control
      registers about stop_enable and resets, second part writes
      RTC time and date registers.

Signed-off-by: Biwen Li <biwen.li@nxp.com>
Link: https://lore.kernel.org/r/20190829021418.4607-1-biwen.li@nxp.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/rtc/rtc-pcf85363.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-pcf85363.c b/drivers/rtc/rtc-pcf85363.c
index a075e77617dcb..3450d615974d5 100644
--- a/drivers/rtc/rtc-pcf85363.c
+++ b/drivers/rtc/rtc-pcf85363.c
@@ -166,7 +166,12 @@ static int pcf85363_rtc_set_time(struct device *dev, struct rtc_time *tm)
 	buf[DT_YEARS] = bin2bcd(tm->tm_year % 100);
 
 	ret = regmap_bulk_write(pcf85363->regmap, CTRL_STOP_EN,
-				tmp, sizeof(tmp));
+				tmp, 2);
+	if (ret)
+		return ret;
+
+	ret = regmap_bulk_write(pcf85363->regmap, DT_100THS,
+				buf, sizeof(tmp) - 2);
 	if (ret)
 		return ret;
 
-- 
2.20.1