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path: root/drivers/rtc/rtc-snvs.c
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2018-07-11rtc: snvs: Add timeouts to avoid kernel lockupsTrent Piepho
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 <alexandre.belloni@free-electrons.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Fabio Estevam <fabio.estevam@nxp.com> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie> Signed-off-by: Trent Piepho <tpiepho@impinj.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2018-05-22rtc: snvs: Switch to SPDX identifierFabio Estevam
Adopt the SPDX license identifier headers to ease license compliance management. Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2018-04-03rtc: snvs: Fix usage of snvs_rtc_enableBryan O'Donoghue
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] [<c010d630>] (__irq_svc) from [<c0c2e9ec>] (_raw_spin_unlock_irqrestore+0x34/0x44) [ 36.102122] [<c0c2e9ec>] (_raw_spin_unlock_irqrestore) from [<c072e32c>] (regmap_read+0x4c/0x5c) [ 36.110938] [<c072e32c>] (regmap_read) from [<c085d0f4>] (rtc_write_sync_lp+0x6c/0x98) [ 36.118881] [<c085d0f4>] (rtc_write_sync_lp) from [<c085d160>] (snvs_rtc_alarm_irq_enable+0x40/0x4c) [ 36.128041] [<c085d160>] (snvs_rtc_alarm_irq_enable) from [<c08567b4>] (rtc_timer_do_work+0xd8/0x1a8) [ 36.137291] [<c08567b4>] (rtc_timer_do_work) from [<c01441b8>] (process_one_work+0x28c/0x76c) [ 36.145840] [<c01441b8>] (process_one_work) from [<c01446cc>] (worker_thread+0x34/0x58c) [ 36.153961] [<c01446cc>] (worker_thread) from [<c014aee4>] (kthread+0x138/0x150) [ 36.161388] [<c014aee4>] (kthread) from [<c0107e14>] (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] [<c0c288b0>] (__schedule) from [<c0c29134>] (schedule+0x3c/0xa0) [ 36.192739] [<c0c29134>] (schedule) from [<c0c2db80>] (schedule_timeout+0x78/0x4e0) [ 36.200422] [<c0c2db80>] (schedule_timeout) from [<c01a7ab0>] (rcu_gp_kthread+0x648/0x1864) [ 36.208800] [<c01a7ab0>] (rcu_gp_kthread) from [<c014aee4>] (kthread+0x138/0x150) [ 36.216309] [<c014aee4>] (kthread) from [<c0107e14>] (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 <pure.logic@nexus-software.ie> Acked-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
2017-05-05rtc: snvs: fix an incorrect check of return valuePan Bian
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 <bianpan2016@163.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2017-02-01rtc: snvs: add a missing write syncGuy Shapiro
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 <guy.shapiro@mobi-wize.com> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2016-05-20rtc: snvs: return error in case enable_irq_wake failsStefan Agner
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 <stefan@agner.ch> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2015-07-15rtc: snvs: use syscon to access registerFrank Li
snvs included rtc, on/off key, power-off module change to syscon to access register Signed-off-by: Frank Li <Frank.Li@freescale.com> Acked-by: Alexandre Belloni <alexandre.belloni@free-electrons.com> Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
2015-06-25rtc: snvs: fix wakealarm by call enable_irq_wake earlierStefan Agner
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: <stable@vger.kernel.org> # 3.19 Signed-off-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
2014-12-14Merge tag 'driver-core-3.19-rc1' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core 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_<level>_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 ...
2014-12-13rtc: snvs: fix build with CONFIG_PM_SLEEP disabledGuenter Roeck
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 <linux@roeck-us.net> Cc: Sanchayan Maity <maitysanchayan@gmail.com> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10drivers/rtc/rtc-snvs: fix suspend/resumeSanchayan Maity
The alarm interrupt handler also reads registers which are part of SNVS and need clocks enabled. However, the resume function is called after IRQ's have been enabled, hence this leads to a abort: Unhandled fault: external abort on non-linefetch (0x1008) at 0x908c604c Internal error: : 1008 [#1] ARM Modules linked in: CPU: 0 PID: 421 Comm: sh Not tainted 3.18.0-rc5-00135-g0689c67-dirty #1592 task: 8e03e800 ti: 8cad8000 task.ti: 8cad8000 PC is at snvs_rtc_irq_handler+0x14/0x74 LR is at handle_irq_event_percpu+0x3c/0x144 Fix this by using the .{suspend/resume}_noirq callbacks instead of .{suspend/resume} . Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com> Cc: Shawn Guo <shawn.guo@linaro.org> Cc: Stefan Agner <stefan@agner.ch> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-12-10drivers/rtc/rtc-snvs: add clock supportSanchayan Maity
Add clock enable and disable support for the SNVS peripheral, which is required for using the RTC within the SNVS block. The clock is not strictly enforced, as this would break the i.MX devices. The clocking for the i.MX devices seems to be enabled elsewhere and enabling RTC SNVS for Vybrid results in a crash. This patch adds the clock support but also makes it optional so Vybrid platform can use the clock if defined while making sure not to break i.MX. Signed-off-by: Sanchayan Maity <maitysanchayan@gmail.com> Cc: Shawn Guo <shawn.guo@linaro.org> Acked-by: Stefan Agner <stefan@agner.ch> Acked-by: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-10-20rtc: drop owner assignment from platform_driversWolfram Sang
A platform_driver does not need to set an owner, it will be populated by the driver core. Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2013-11-13drivers/rtc/rtc-snvs.c: remove redundant of_match_ptrSachin Kamat
The data structure of_match_ptr() protects is always compiled in. Hence of_match_ptr() is not needed. Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-03drivers/rtc/rtc-snvs.c: remove empty functionSachin Kamat
After the switch to devm_* functions and the removal of rtc_device_unregister(), the 'remove' function does not do anything. Delete it. Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-04-29rtc: rtc-snvs: use devm_rtc_device_register()Jingoo Han
devm_rtc_device_register() is device managed and makes cleanup paths simpler. Signed-off-by: Jingoo Han <jg1.han@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-21Merge branch 'akpm' (incoming from Andrew)Linus Torvalds
Merge misc patches from Andrew Morton: - Florian has vanished so I appear to have become fbdev maintainer again :( - Joel and Mark are distracted to welcome to the new OCFS2 maintainer - The backlight queue - Small core kernel changes - lib/ updates - The rtc queue - Various random bits * akpm: (164 commits) rtc: rtc-davinci: use devm_*() functions rtc: rtc-max8997: use devm_request_threaded_irq() rtc: rtc-max8907: use devm_request_threaded_irq() rtc: rtc-da9052: use devm_request_threaded_irq() rtc: rtc-wm831x: use devm_request_threaded_irq() rtc: rtc-tps80031: use devm_request_threaded_irq() rtc: rtc-lp8788: use devm_request_threaded_irq() rtc: rtc-coh901331: use devm_clk_get() rtc: rtc-vt8500: use devm_*() functions rtc: rtc-tps6586x: use devm_request_threaded_irq() rtc: rtc-imxdi: use devm_clk_get() rtc: rtc-cmos: use dev_warn()/dev_dbg() instead of printk()/pr_debug() rtc: rtc-pcf8583: use dev_warn() instead of printk() rtc: rtc-sun4v: use pr_warn() instead of printk() rtc: rtc-vr41xx: use dev_info() instead of printk() rtc: rtc-rs5c313: use pr_err() instead of printk() rtc: rtc-at91rm9200: use dev_dbg()/dev_err() instead of printk()/pr_debug() rtc: rtc-rs5c372: use dev_dbg()/dev_warn() instead of printk()/pr_debug() rtc: rtc-ds2404: use dev_err() instead of printk() rtc: rtc-efi: use dev_err()/dev_warn()/pr_err() instead of printk() ...
2013-02-21drivers/rtc: use of_match_ptr() macroSachin Kamat
This eliminates having an #ifdef returning NULL for the case when OF is disabled. Maintains consistency in cases where OF is always selected. Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-01-22rtc: Convert to devm_ioremap_resource()Thierry Reding
Convert all uses of devm_request_and_ioremap() to the newly introduced devm_ioremap_resource() which provides more consistent error handling. devm_ioremap_resource() provides its own error messages so all explicit error messages can be removed from the failure code paths. Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-01-03Drivers: rtc: remove __dev* attributes.Greg Kroah-Hartman
CONFIG_HOTPLUG is going away as an option. As a result, the __dev* markings need to be removed. This change removes the use of __devinit, __devexit_p, __devinitdata, __devinitconst, and __devexit from these drivers. Based on patches originally written by Bill Pemberton, but redone by me in order to handle some of the coding style issues better, by hand. Cc: Bill Pemberton <wfp5p@virginia.edu> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Srinidhi Kasagar <srinidhi.kasagar@stericsson.com> Cc: Linus Walleij <linus.walleij@linaro.org> Cc: Mike Frysinger <vapier.adi@gmail.com> Cc: Wan ZongShun <mcuos.com@gmail.com> Cc: Guan Xuetao <gxt@mprc.pku.edu.cn> Cc: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-10-06rtc: snvs: add Freescale rtc-snvs driverShawn Guo
Add an RTC driver for Freescale Secure Non-Volatile Storage (SNVS) Low Power (LP) RTC. Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Reviewed-by: Stephen Boyd <sboyd@codeaurora.org> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Kim Phillips <kim.phillips@freescale.com> Cc: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>