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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: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Link: https://lore.kernel.org/r/20221123095527.2771434-3-s.hauer@pengutronix.de
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Sascha Hauer 2022-11-23 10:55:27 +01:00 committed by Alexandre Belloni
parent 1940979657
commit e5c594233f
1 changed files with 38 additions and 7 deletions
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45
drivers/rtc/rtc-rv8803.c
View File

@ -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)