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author | Valentin Caron <valentin.caron@foss.st.com> | 2023-07-05 20:43:56 +0300 |
---|---|---|
committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2023-07-28 00:03:34 +0300 |
commit | 46828a5f89044b8e057f6bbb50ae2bac926a0fa2 (patch) | |
tree | cb4c6df28593e63df98fb226fa3da34df28f2673 | |
parent | fb9a7e5360dc8089097337a9685f6fed350a310f (diff) | |
download | linux-46828a5f89044b8e057f6bbb50ae2bac926a0fa2.tar.xz |
rtc: stm32: fix issues of stm32_rtc_valid_alrm function
stm32_rtc_valid_alrm function has some issues :
- arithmetical operations are impossible on BCD values
- "cur_mon + 1" can overflow
- the use case with the next month, the same day/hour/minutes went wrong
To solve that, we prefer to use timestamp comparison.
e.g. : On 5 Dec. 2021, the alarm limit is 5 Jan. 2022 (+31 days)
On 31 Jan 2021, the alarm limit is 28 Feb. 2022 (+28 days)
Signed-off-by: Valentin Caron <valentin.caron@foss.st.com>
Link: https://lore.kernel.org/r/20230705174357.353616-7-valentin.caron@foss.st.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
-rw-r--r-- | drivers/rtc/rtc-stm32.c | 61 |
1 files changed, 33 insertions, 28 deletions
diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c index 17e549806784..836d39a124dd 100644 --- a/drivers/rtc/rtc-stm32.c +++ b/drivers/rtc/rtc-stm32.c @@ -90,6 +90,9 @@ /* Max STM32 RTC register offset is 0x3FC */ #define UNDEF_REG 0xFFFF +/* STM32 RTC driver time helpers */ +#define SEC_PER_DAY (24 * 60 * 60) + struct stm32_rtc; struct stm32_rtc_registers { @@ -427,40 +430,42 @@ static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) return 0; } -static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm) +static int stm32_rtc_valid_alrm(struct device *dev, struct rtc_time *tm) { - const struct stm32_rtc_registers *regs = &rtc->data->regs; - int cur_day, cur_mon, cur_year, cur_hour, cur_min, cur_sec; - unsigned int tr = readl_relaxed(rtc->base + regs->tr); - unsigned int dr = readl_relaxed(rtc->base + regs->dr); - - cur_day = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT; - cur_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT; - cur_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT; - cur_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT; - cur_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT; - cur_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT; + static struct rtc_time now; + time64_t max_alarm_time64; + int max_day_forward; + int next_month; + int next_year; /* * Assuming current date is M-D-Y H:M:S. * RTC alarm can't be set on a specific month and year. * So the valid alarm range is: * M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S - * with a specific case for December... */ - if ((((tm->tm_year > cur_year) && - (tm->tm_mon == 0x1) && (cur_mon == 0x12)) || - ((tm->tm_year == cur_year) && - (tm->tm_mon <= cur_mon + 1))) && - ((tm->tm_mday > cur_day) || - ((tm->tm_mday == cur_day) && - ((tm->tm_hour > cur_hour) || - ((tm->tm_hour == cur_hour) && (tm->tm_min > cur_min)) || - ((tm->tm_hour == cur_hour) && (tm->tm_min == cur_min) && - (tm->tm_sec >= cur_sec)))))) - return 0; + stm32_rtc_read_time(dev, &now); + + /* + * Find the next month and the year of the next month. + * Note: tm_mon and next_month are from 0 to 11 + */ + next_month = now.tm_mon + 1; + if (next_month == 12) { + next_month = 0; + next_year = now.tm_year + 1; + } else { + next_year = now.tm_year; + } - return -EINVAL; + /* Find the maximum limit of alarm in days. */ + max_day_forward = rtc_month_days(now.tm_mon, now.tm_year) + - now.tm_mday + + min(rtc_month_days(next_month, next_year), now.tm_mday); + + /* Convert to timestamp and compare the alarm time and its upper limit */ + max_alarm_time64 = rtc_tm_to_time64(&now) + max_day_forward * SEC_PER_DAY; + return rtc_tm_to_time64(tm) <= max_alarm_time64 ? 0 : -EINVAL; } static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) @@ -471,17 +476,17 @@ static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) unsigned int cr, isr, alrmar; int ret = 0; - tm2bcd(tm); - /* * RTC alarm can't be set on a specific date, unless this date is * up to the same day of month next month. */ - if (stm32_rtc_valid_alrm(rtc, tm) < 0) { + if (stm32_rtc_valid_alrm(dev, tm) < 0) { dev_err(dev, "Alarm can be set only on upcoming month.\n"); return -EINVAL; } + tm2bcd(tm); + alrmar = 0; /* tm_year and tm_mon are not used because not supported by RTC */ alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) & |