Commit e5c59423 authored by Sascha Hauer's avatar Sascha Hauer Committed by Alexandre Belloni
Browse files

rtc: rv8803: invalidate date/time if alarm time is invalid 



RTC core never calls rv8803_set_alarm with an invalid alarm time,
so if an invalid alarm time > 0 is set, external factors must have
corrupted the RTC's alarm time and possibly other registers.

Play it safe by marking the date/time invalid, so all registers are
reinitialized on a ->set_time.

This may cause existing setups to lose time if they so far set only
date/time, but ignored that the alarm registers had an invalid date
value, e.g.:

  rtc rtc0: invalid alarm value: 2020-3-27 7:82:0

These systems will have their ->get_time return -EINVAL till
->set_time initializes the alarm value (and sets a new time).

Signed-off-by: default avatarAhmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/r/20221123095527.2771434-3-s.hauer@pengutronix.de


Signed-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 19409796

drivers/rtc/rtc-rv8803.c

+38 −7
Original line number Diff line number Diff line
@@ -70,6 +70,7 @@ struct rv8803_data { 
	struct mutex flags_lock;

	u8 ctrl;

	u8 backup;

	u8 alarm_invalid:1;

	enum rv8803_type type;

};
@@ -165,13 +166,13 @@ static int rv8803_regs_init(struct rv8803_data *rv8803) 


static int rv8803_regs_configure(struct rv8803_data *rv8803);



static int rv8803_regs_reset(struct rv8803_data *rv8803)

static int rv8803_regs_reset(struct rv8803_data *rv8803, bool full)

{

	/*

	 * The RV-8803 resets all registers to POR defaults after voltage-loss,

	 * the Epson RTCs don't, so we manually reset the remainder here.

	 */

	if (rv8803->type == rx_8803 || rv8803->type == rx_8900) {

	if (full || rv8803->type == rx_8803 || rv8803->type == rx_8900) {

		int ret = rv8803_regs_init(rv8803);

		if (ret)

			return ret;
@@ -238,6 +239,11 @@ static int rv8803_get_time(struct device *dev, struct rtc_time *tm) 
	u8 *date = date1;

	int ret, flags;



	if (rv8803->alarm_invalid) {

		dev_warn(dev, "Corruption detected, data may be invalid.\n");

		return -EINVAL;

	}



	flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);

	if (flags < 0)

		return flags;
@@ -313,12 +319,19 @@ static int rv8803_set_time(struct device *dev, struct rtc_time *tm) 
		return flags;

	}



	if (flags & RV8803_FLAG_V2F) {

		ret = rv8803_regs_reset(rv8803);

	if ((flags & RV8803_FLAG_V2F) || rv8803->alarm_invalid) {

		/*

		 * If we sense corruption in the alarm registers, but see no

		 * voltage loss flag, we can't rely on other registers having

		 * sensible values. Reset them fully.

		 */

		ret = rv8803_regs_reset(rv8803, rv8803->alarm_invalid);

		if (ret) {

			mutex_unlock(&rv8803->flags_lock);

			return ret;

		}



		rv8803->alarm_invalid = false;

	}



	ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
@@ -344,15 +357,33 @@ static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm) 
	if (flags < 0)

		return flags;



	alarmvals[0] &= 0x7f;

	alarmvals[1] &= 0x3f;

	alarmvals[2] &= 0x3f;



	if (!bcd_is_valid(alarmvals[0]) ||

	    !bcd_is_valid(alarmvals[1]) ||

	    !bcd_is_valid(alarmvals[2]))

		goto err_invalid;



	alrm->time.tm_sec  = 0;

	alrm->time.tm_min  = bcd2bin(alarmvals[0] & 0x7f);

	alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f);

	alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f);

	alrm->time.tm_min  = bcd2bin(alarmvals[0]);

	alrm->time.tm_hour = bcd2bin(alarmvals[1]);

	alrm->time.tm_mday = bcd2bin(alarmvals[2]);



	alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);

	alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled;



	if ((unsigned int)alrm->time.tm_mday > 31 ||

	    (unsigned int)alrm->time.tm_hour >= 24 ||

	    (unsigned int)alrm->time.tm_min >= 60)

		goto err_invalid;



	return 0;



err_invalid:

	rv8803->alarm_invalid = true;

	return -EINVAL;

}



static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)