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lineage_android_kernel_xiaomi_sdm845
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Trent Piepho 1228a3336d rtc: snvs: Add timeouts to avoid kernel lockups 
[ 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 <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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
 		2018-12-21 14:11:40 +01:00
..
Kconfig rtc: sun6i: Disable the build as a module 2017-03-12 06:41:52 +01:00
Makefile rtc: isl12057: remove driver 2016-08-31 18:21:34 +02:00
class.c rtc: make class.c explicitly non-modular 2016-03-14 17:08:18 +01:00
hctosys.c rtc: hctosys: Add missing range error reporting 2018-11-21 09:26:03 +01:00
interface.c rtc: ensure rtc_set_alarm fails when alarms are not supported 2018-08-03 07:55:13 +02:00
rtc-88pm80x.c
…
rtc-88pm860x.c
…
rtc-ab-b5ze-s3.c
…
rtc-ab3100.c
…
rtc-ab8500.c
…
rtc-abx80x.c rtc: abx80x: use devm_add_action_or_reset() 2016-07-19 17:27:42 +02:00
rtc-ac100.c rtc: ac100: Add NULL checking for devm_kzalloc call 2016-09-22 00:14:41 +02:00
rtc-armada38x.c
…
rtc-as3722.c rtc: as3722: Drop IRQF_EARLY_RESUME flag 2016-03-14 17:08:25 +01:00
rtc-asm9260.c rtc: asm9260: fix module autoload 2016-10-19 08:45:48 +02:00
rtc-at32ap700x.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-at91rm9200.c
…
rtc-at91rm9200.h
…
rtc-at91sam9.c rtc: at91sam9: Fix missing spin_lock_init() 2016-07-26 00:09:18 +02:00
rtc-au1xxx.c
…
rtc-bfin.c
…
rtc-bq32k.c rtc: bq32k: Fix handling of oscillator failure flag 2016-08-31 18:21:35 +02:00
rtc-bq4802.c rtc: bq4802: add error handling for devm_ioremap 2018-09-26 08:36:39 +02:00
rtc-cmos.c rtc: cmos: Do not assume irq 8 for rtc when there are no legacy irqs 2018-03-24 11:00:09 +01:00
rtc-coh901331.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-core.h
…
rtc-da9052.c rtc: explicitly set tm_sec = 0 for drivers with minute accurancy 2016-07-19 18:15:21 +02:00
rtc-da9055.c rtc: explicitly set tm_sec = 0 for drivers with minute accurancy 2016-07-19 18:15:21 +02:00
rtc-da9063.c rtc: da9063: avoid writing undefined data to rtc 2016-01-11 20:19:57 +01:00
rtc-davinci.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-dev.c
…
rtc-digicolor.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-dm355evm.c
…
rtc-ds1216.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-ds1286.c rtc: ds1286: move header to linux/rtc 2016-07-08 16:23:11 +02:00
rtc-ds1302.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-ds1305.c rtc: simplify implementations of read_alarm 2016-07-09 10:24:45 +02:00
rtc-ds1307.c rtc: ds1307: add Intersil ISL12057 support 2016-08-31 18:21:34 +02:00
rtc-ds1343.c rtc: simplify implementations of read_alarm 2016-07-09 10:24:45 +02:00
rtc-ds1347.c rtc: ds1347: changed raw spi calls to register map calls 2016-09-22 00:14:40 +02:00
rtc-ds1374.c rtc: ds1374: wdt: Fix stop/start ioctl always returning -EINVAL 2018-03-24 11:00:22 +01:00
rtc-ds1390.c
…
rtc-ds1511.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-ds1553.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-ds1672.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-ds1685.c rtc: simplify implementations of read_alarm 2016-07-09 10:24:45 +02:00
rtc-ds1742.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-ds2404.c rtc: ds2404: move rtc-ds2404.h to platform_data 2016-06-27 10:48:28 +02:00
rtc-ds3232.c rtc: simplify implementations of read_alarm 2016-07-09 10:24:45 +02:00
rtc-efi-platform.c
…
rtc-efi.c rtc: efi: Fail probing if RTC reads don't work 2016-06-06 17:07:33 +02:00
rtc-em3027.c
…
rtc-ep93xx.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-fm3130.c
…
rtc-gemini.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-generic.c rtc: generic: remove get_rtc_time/set_rtc_time wrappers 2016-06-04 00:23:35 +02:00
rtc-hid-sensor-time.c
…
rtc-hym8563.c rtc: hym8563: in .read_alarm set .tm_sec to 0 to signal minute accuracy 2016-07-19 18:18:06 +02:00
rtc-imxdi.c rtc: imxdi: fix spelling mistake in warning message 2016-01-11 20:19:58 +01:00
rtc-isl1208.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-isl12022.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-jz4740.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-lib.c
…
rtc-lp8788.c
…
rtc-lpc24xx.c
…
rtc-lpc32xx.c rtc: lpc32xx: remove irq > NR_IRQS check from probe() 2016-01-11 20:19:59 +01:00
rtc-ls1x.c
…
rtc-m41t80.c rtc: m41t80: fix SQW dividers override when setting a date 2018-04-13 19:48:14 +02:00
rtc-m41t93.c
…
rtc-m41t94.c
…
rtc-m48t35.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-m48t59.c
…
rtc-m48t86.c rtc: m48t86: move m48t86.h to platform_data 2016-06-27 18:15:25 +02:00
rtc-max6900.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-max6902.c
…
rtc-max6916.c rtc: add support for Maxim max6916 2016-06-04 16:05:59 +02:00
rtc-max8907.c
…
rtc-max8925.c
…
rtc-max8997.c
…
rtc-max8998.c
…
rtc-max77686.c rtc: max77686: Use REGMAP_IRQ_REG for regmap-rtc-irqs initialisation 2016-03-14 17:08:27 +01:00
rtc-mc13xxx.c rtc: mc13xxx: remove UIE signaling 2016-05-20 12:33:51 +02:00
rtc-mc146818-lib.c rtc: move mc146818 helper functions out-of-line 2016-06-26 01:20:08 +02:00
rtc-mcp795.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-moxart.c
…
rtc-mpc5121.c
…
rtc-mrst.c rtc: simplify implementations of read_alarm 2016-07-09 10:24:45 +02:00
rtc-msm6242.c
…
rtc-mt6397.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-mv.c
…
rtc-mxc.c rtc: mxc: remove UIE signaling 2016-05-20 12:33:51 +02:00
rtc-nuc900.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-omap.c rtc: omap: fix potential crash on power off 2018-09-09 20:01:22 +02:00
rtc-opal.c rtc: opal: Fix OPAL RTC driver OPAL_BUSY loops 2018-05-01 15:13:09 -07:00
rtc-palmas.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-pcap.c
…
rtc-pcf2123.c rtc: pcf2123: Add missing error code assignment before test 2016-08-31 18:21:34 +02:00
rtc-pcf2127.c rtc: pcf2127: fix a kmemleak caused in pcf2127_i2c_gather_write 2018-12-01 09:44:20 +01:00
rtc-pcf8523.c rtc: pcf8523: properly handle oscillator stop bit 2016-03-14 17:08:30 +01:00
rtc-pcf8563.c rtc: pcf8563: fix output clock rate 2017-12-20 10:07:27 +01:00
rtc-pcf8583.c
…
rtc-pcf50633.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-pcf85063.c rtc: pcf85063: Add support for the PCF85063A device 2016-07-19 19:11:54 +02:00
rtc-pic32.c rtc: pic32: Delete owner assignment 2016-08-31 18:21:35 +02:00
rtc-pl030.c
…
rtc-pl031.c rtc: pl031: make interrupt optional 2017-12-25 14:23:43 +01:00
rtc-pm8xxx.c rtc: rtc-pm8xxx: Add support for pm8018 rtc 2016-08-31 09:33:33 +01:00
rtc-proc.c
…
rtc-ps3.c
…
rtc-puv3.c
…
rtc-pxa.c
…
rtc-r9701.c
…
rtc-rc5t583.c rtc: explicitly set tm_sec = 0 for drivers with minute accurancy 2016-07-19 18:15:21 +02:00
rtc-rk808.c
…
rtc-rp5c01.c
…
rtc-rs5c313.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-rs5c348.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-rs5c372.c rtc: simplify implementations of read_alarm 2016-07-09 10:24:45 +02:00
rtc-rv3029c2.c rtc: rv3029: hide unused i2c device table 2016-05-21 17:07:16 +02:00
rtc-rv8803.c rtc: rv8803: set VDETOFF and SWOFF via device tree 2016-10-12 13:24:39 +02:00
rtc-rx4581.c
…
rtc-rx6110.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-rx8010.c rtc: rx8010: change lock mechanism 2017-11-21 09:23:25 +01:00
rtc-rx8025.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-rx8581.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-s3c.c rtc: s3c: Add s3c_rtc_{enable/disable}_clk in s3c_rtc_setfreq() 2016-07-19 17:48:06 +02:00
rtc-s3c.h
…
rtc-s5m.c rtc: s5m: De-inline large functions to save space 2016-03-14 17:08:18 +01:00
rtc-s35390a.c rtc: s35390a: improve two comments in .set_alarm 2016-07-11 23:22:35 +02:00
rtc-sa1100.c
…
rtc-sa1100.h
…
rtc-sh.c rtc: sh: don't validate alarm time provided to .set_alarm 2016-07-11 23:22:33 +02:00
rtc-sirfsoc.c
…
rtc-snvs.c rtc: snvs: Add timeouts to avoid kernel lockups 2018-12-21 14:11:40 +01:00
rtc-spear.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-st-lpc.c
…
rtc-starfire.c
…
rtc-stk17ta8.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-stmp3xxx.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-sun4v.c
…
rtc-sun6i.c rtc: sun6i: Switch to the external oscillator 2017-03-12 06:41:52 +01:00
rtc-sunxi.c rtc: sunxi: use of_device_get_match_data 2016-01-11 20:19:57 +01:00
rtc-sysfs.c rtc: sysfs: fix a cast removing the const attribute 2016-08-31 18:21:35 +02:00
rtc-tegra.c rtc: tegra: Implement clock handling 2017-04-21 09:31:24 +02:00
rtc-test.c
…
rtc-tile.c
…
rtc-tps6586x.c rtc: tps6586x: rename so module can be autoloaded 2016-05-21 17:07:17 +02:00
rtc-tps65910.c rtc: tps65910: Drop IRQF_EARLY_RESUME flag 2016-03-14 17:08:23 +01:00
rtc-tps80031.c rtc: tps80031: Drop IRQF_EARLY_RESUME flag 2016-03-14 17:08:24 +01:00
rtc-twl.c rtc: constify rtc_class_ops structures 2016-09-02 01:24:06 +02:00
rtc-tx4939.c rtc: tx4939: avoid unintended sign extension on a 24 bit shift 2018-05-25 16:13:15 +02:00
rtc-v3020.c rtc: v3020: move rtc-v3020.h to platform_data 2016-07-09 10:24:21 +02:00
rtc-vr41xx.c rtc: vr41xx: Wire up alarm_irq_enable 2016-03-14 17:08:25 +01:00
rtc-vt8500.c
…
rtc-wm831x.c
…
rtc-wm8350.c
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rtc-x1205.c rtc: remove useless DRV_VERSION 2016-05-20 12:33:51 +02:00
rtc-xgene.c
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rtc-zynqmp.c rtc: zynqmp: Update seconds time programming logic 2016-05-20 12:33:51 +02:00
systohc.c
…