user/sven/linux.git/drivers/rtc/rtc-snvs.c, branch v4.14.151

rtc: snvs: fix possible race condition

2019-10-07T16:55:10Z

[ Upstream commit 6fd4fe9b496d9ba3382992ff4fde3871d1b6f63d ] The RTC IRQ is requested before the struct rtc_device is allocated, this may lead to a NULL pointer dereference in IRQ handler. To fix this issue, allocating the rtc_device struct before requesting the RTC IRQ using devm_rtc_allocate_device, and use rtc_register_device to register the RTC device. Signed-off-by: Anson Huang Reviewed-by: Dong Aisheng Link: https://lore.kernel.org/r/20190716071858.36750-1-Anson.Huang@nxp.com Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin

rtc: snvs: Add timeouts to avoid kernel lockups

2018-12-21T13:13:18Z

[ Upstream commit cd7f3a249dbed2858e6c2f30e5be7f1f7a709ee2 ] 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 Signed-off-by: Sasha Levin

rtc: snvs: Fix usage of snvs_rtc_enable

2018-05-25T14:18:00Z

[ Upstream commit 1485991c024603b2fb4ae77beb7a0d741128a48e ] 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 Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

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

rtc: snvs: use syscon to access register

2015-07-15T02:15:10Z

snvs included rtc, on/off key, power-off module change to syscon to access register Signed-off-by: Frank Li Acked-by: Alexandre Belloni Signed-off-by: Shawn Guo

rtc: snvs: fix wakealarm by call enable_irq_wake earlier

2015-06-24T23:13:38Z

When entering suspend while an wakeup alarm is set, enable_set_wake should make sure that the RTC interrupt keep being enabled and the .irq_set_wake for the RTC interrupt get called. However, since the driver uses the suspend_noirq callback, the call to enable_irq_wake has been made after disabling the interrupts. While .irq_set_wake has been called properly, the interrupt remained disabled. Use the suspend callback to call enable_irq_wake early enough to ensure the RTC interrupt remains enabled. Fixes: 7654e9d4fd8f ("drivers/rtc/rtc-snvs: fix suspend/resume") Cc: # 3.19 Signed-off-by: Stefan Agner Signed-off-by: Alexandre Belloni

Merge tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2014-12-15T00:10:09Z

Pull driver core update from Greg KH: "Here's the set of driver core patches for 3.19-rc1. They are dominated by the removal of the .owner field in platform drivers. They touch a lot of files, but they are "simple" changes, just removing a line in a structure. Other than that, a few minor driver core and debugfs changes. There are some ath9k patches coming in through this tree that have been acked by the wireless maintainers as they relied on the debugfs changes. Everything has been in linux-next for a while" * tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits) Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries" fs: debugfs: add forward declaration for struct device type firmware class: Deletion of an unnecessary check before the function call "vunmap" firmware loader: fix hung task warning dump devcoredump: provide a one-way disable function device: Add dev__once variants ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries ath: use seq_file api for ath9k debugfs files debugfs: add helper function to create device related seq_file drivers/base: cacheinfo: remove noisy error boot message Revert "core: platform: add warning if driver has no owner" drivers: base: support cpu cache information interface to userspace via sysfs drivers: base: add cpu_device_create to support per-cpu devices topology: replace custom attribute macros with standard DEVICE_ATTR* cpumask: factor out show_cpumap into separate helper function driver core: Fix unbalanced device reference in drivers_probe driver core: fix race with userland in device_add() sysfs/kernfs: make read requests on pre-alloc files use the buffer. sysfs/kernfs: allow attributes to request write buffer be pre-allocated. fs: sysfs: return EGBIG on write if offset is larger than file size ...

rtc: snvs: fix build with CONFIG_PM_SLEEP disabled

2014-12-13T20:42:45Z

Commit 7654e9d4fd8f ("drivers/rtc/rtc-snvs: fix suspend/resume") replaces SIMPLE_DEV_PM_OPS with direct declaration of snvs_rtc_pm_ops, but does so outside #ifdef CONFIG_PM_SLEEP. This causes the driver build to fail if CONFIG_PM_SLEEP is not configured. Fixes: 7654e9d4fd8f ("drivers/rtc/rtc-snvs: fix suspend/resume") Signed-off-by: Guenter Roeck Cc: Sanchayan Maity Cc: Alessandro Zummo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds