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

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.deSigned-off-by: default avatarAlexandre Belloni <alexandre.belloni@bootlin.com>
parent 19409796
...@@ -70,6 +70,7 @@ struct rv8803_data { ...@@ -70,6 +70,7 @@ struct rv8803_data {
struct mutex flags_lock; struct mutex flags_lock;
u8 ctrl; u8 ctrl;
u8 backup; u8 backup;
u8 alarm_invalid:1;
enum rv8803_type type; enum rv8803_type type;
}; };
...@@ -165,13 +166,13 @@ static int rv8803_regs_init(struct rv8803_data *rv8803) ...@@ -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_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 RV-8803 resets all registers to POR defaults after voltage-loss,
* the Epson RTCs don't, so we manually reset the remainder here. * 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); int ret = rv8803_regs_init(rv8803);
if (ret) if (ret)
return ret; return ret;
...@@ -238,6 +239,11 @@ static int rv8803_get_time(struct device *dev, struct rtc_time *tm) ...@@ -238,6 +239,11 @@ static int rv8803_get_time(struct device *dev, struct rtc_time *tm)
u8 *date = date1; u8 *date = date1;
int ret, flags; 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); flags = rv8803_read_reg(rv8803->client, RV8803_FLAG);
if (flags < 0) if (flags < 0)
return flags; return flags;
...@@ -313,12 +319,19 @@ static int rv8803_set_time(struct device *dev, struct rtc_time *tm) ...@@ -313,12 +319,19 @@ static int rv8803_set_time(struct device *dev, struct rtc_time *tm)
return flags; return flags;
} }
if (flags & RV8803_FLAG_V2F) { if ((flags & RV8803_FLAG_V2F) || rv8803->alarm_invalid) {
ret = rv8803_regs_reset(rv8803); /*
* 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) { if (ret) {
mutex_unlock(&rv8803->flags_lock); mutex_unlock(&rv8803->flags_lock);
return ret; return ret;
} }
rv8803->alarm_invalid = false;
} }
ret = rv8803_write_reg(rv8803->client, RV8803_FLAG, ret = rv8803_write_reg(rv8803->client, RV8803_FLAG,
...@@ -344,15 +357,33 @@ static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm) ...@@ -344,15 +357,33 @@ static int rv8803_get_alarm(struct device *dev, struct rtc_wkalrm *alrm)
if (flags < 0) if (flags < 0)
return flags; 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_sec = 0;
alrm->time.tm_min = bcd2bin(alarmvals[0] & 0x7f); alrm->time.tm_min = bcd2bin(alarmvals[0]);
alrm->time.tm_hour = bcd2bin(alarmvals[1] & 0x3f); alrm->time.tm_hour = bcd2bin(alarmvals[1]);
alrm->time.tm_mday = bcd2bin(alarmvals[2] & 0x3f); alrm->time.tm_mday = bcd2bin(alarmvals[2]);
alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE); alrm->enabled = !!(rv8803->ctrl & RV8803_CTRL_AIE);
alrm->pending = (flags & RV8803_FLAG_AF) && alrm->enabled; 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; return 0;
err_invalid:
rv8803->alarm_invalid = true;
return -EINVAL;
} }
static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) static int rv8803_set_alarm(struct device *dev, struct rtc_wkalrm *alrm)
......
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