linux/drivers/rtc/rtc-snvs.c, branch v5.3

rtc: snvs: Use __maybe_unused instead of #if CONFIG_PM_SLEEP

2019-05-08T20:14:36Z

Use __maybe_unused for power management related functions instead of #if CONFIG_PM_SLEEP to simply the code. Signed-off-by: Anson Huang Reviewed-by: Dong Aisheng Signed-off-by: Alexandre Belloni

rtc: snvs: use devm_platform_ioremap_resource() to simplify code

2019-04-04T08:07:11Z

Use the new helper devm_platform_ioremap_resource() which wraps the platform_get_resource() and devm_ioremap_resource() together, to simplify the code. Signed-off-by: Anson Huang Signed-off-by: Alexandre Belloni

rtc: snvs: use dev_pm_set_wake_irq() to simplify code

2019-04-04T08:07:11Z

With calling dev_pm_set_wake_irq() to set SNVS RTC as wakeup source for suspend, generic wake irq mechanism will automatically enable it as wakeup source when suspend, then the suspend/resume callback which are ONLY for enabling/disabling irq wake can be removed, it simplifies the code. Signed-off-by: Anson Huang Signed-off-by: Alexandre Belloni

rtc: snvs: make sure clock is enabled for interrupt handle

2019-02-05T22:11:31Z

During system suspend, the SNVS RTC's clock will be disabled in noirq suspend phase, but SNVS RTC's alarm interrupt could still arrive, system will hang if SNVS RTC driver tries to access register without clock enabled, this patch fixes the issue of this scenario. Signed-off-by: Anson Huang Signed-off-by: Alexandre Belloni

rtc: snvs: Add timeouts to avoid kernel lockups

2018-07-11T18:41:09Z

In order to read correctly from asynchronously updated RTC registers, it's necessary to read repeatedly until their values do not change from read to read. It's also necessary to wait for three RTC clock ticks for certain operations. There are no timeouts in this code and these operations could possibly loop forever. To avoid kernel hangs, put in timeouts. The iMX7d can be configured to stop the SRTC on a tamper event, which will lockup the kernel inside this driver as described above. These hangs can happen when running under qemu, which doesn't emulate the SNVS RTC, though currently the driver will refuse to load on qemu due to a timeout in the driver probe method. It could also happen if the SRTC block where somehow placed into reset or the slow speed clock that drives the SRTC counter (but not the CPU) were to stop. The symptoms on a two core iMX7d are a work queue hang on rtc_timer_do_work(), which eventually blocks a systemd fsnotify operation that triggers a work queue flush, causing systemd to hang and thus causing all services that should be started by systemd, like a console getty, to fail to start or stop. Also optimize the wait code to wait less. It only needs to wait for the clock to advance three ticks, not to see it change three times. Cc: Alexandre Belloni Cc: Alessandro Zummo Cc: Fabio Estevam Cc: Shawn Guo Cc: Bryan O'Donoghue Signed-off-by: Trent Piepho Signed-off-by: Alexandre Belloni

rtc: snvs: Switch to SPDX identifier

2018-05-22T07:47:15Z

Adopt the SPDX license identifier headers to ease license compliance management. Signed-off-by: Fabio Estevam Signed-off-by: Alexandre Belloni

rtc: snvs: Fix usage of snvs_rtc_enable

2018-04-03T14:43:36Z

commit 179a502f8c46 ("rtc: snvs: add Freescale rtc-snvs driver") introduces the SNVS RTC driver with a function snvs_rtc_enable(). snvs_rtc_enable() can return an error on the enable path however this driver does not currently trap that failure on the probe() path and consequently if enabling the RTC fails we encounter a later error spinning forever in rtc_write_sync_lp(). [ 36.093481] [] (__irq_svc) from [] (_raw_spin_unlock_irqrestore+0x34/0x44) [ 36.102122] [] (_raw_spin_unlock_irqrestore) from [] (regmap_read+0x4c/0x5c) [ 36.110938] [] (regmap_read) from [] (rtc_write_sync_lp+0x6c/0x98) [ 36.118881] [] (rtc_write_sync_lp) from [] (snvs_rtc_alarm_irq_enable+0x40/0x4c) [ 36.128041] [] (snvs_rtc_alarm_irq_enable) from [] (rtc_timer_do_work+0xd8/0x1a8) [ 36.137291] [] (rtc_timer_do_work) from [] (process_one_work+0x28c/0x76c) [ 36.145840] [] (process_one_work) from [] (worker_thread+0x34/0x58c) [ 36.153961] [] (worker_thread) from [] (kthread+0x138/0x150) [ 36.161388] [] (kthread) from [] (ret_from_fork+0x14/0x20) [ 36.168635] rcu_sched kthread starved for 2602 jiffies! g496 c495 f0x2 RCU_GP_WAIT_FQS(3) ->state=0x0 ->cpu=0 [ 36.178564] rcu_sched R running task 0 8 2 0x00000000 [ 36.185664] [] (__schedule) from [] (schedule+0x3c/0xa0) [ 36.192739] [] (schedule) from [] (schedule_timeout+0x78/0x4e0) [ 36.200422] [] (schedule_timeout) from [] (rcu_gp_kthread+0x648/0x1864) [ 36.208800] [] (rcu_gp_kthread) from [] (kthread+0x138/0x150) [ 36.216309] [] (kthread) from [] (ret_from_fork+0x14/0x20) This patch fixes by parsing the result of rtc_write_sync_lp() and propagating both in the probe and elsewhere. If the RTC doesn't start we don't proceed loading the driver and don't get into this loop mess later on. Fixes: 179a502f8c46 ("rtc: snvs: add Freescale rtc-snvs driver") Signed-off-by: Bryan O'Donoghue Acked-by: Shawn Guo Signed-off-by: Alexandre Belloni

rtc: snvs: fix an incorrect check of return value

2017-05-04T22:43:50Z

Function devm_regmap_init_mmio() returns an ERR_PTR on error. However, in function snvs_rtc_probe() its return value is checked against NULL. This patch fixes it by checking the return value with IS_ERR(). Signed-off-by: Pan Bian Signed-off-by: Alexandre Belloni

rtc: snvs: add a missing write sync

2017-02-01T11:44:24Z

The clear of the LPTA_EN flag should be synced before writing to the alarm register. Omitting this synchronization creates a race when trying to change existing alarm. Signed-off-by: Guy Shapiro Signed-off-by: Alexandre Belloni

rtc: snvs: return error in case enable_irq_wake fails

2016-05-20T10:33:51Z

If enable_irq_wake fails, we should return that error code so that entering suspend fails. Otherwise we will get a WARNING along with the hint of a unbalanced wake disable: Unbalanced IRQ 37 wake disable Signed-off-by: Stefan Agner Signed-off-by: Alexandre Belloni