The WDOG clocks are sourced from lpo_clk, and lpo_clk is the fixed
32KHz. TOVAL contains the 16-bit value used to set the timeout period of
the watchdog. When the timeout period exceeds 2 seconds, the value
written to the TOVAL register is larger than 16-bit can represent.
Enabling watchdog prescaler can solve this problem.
Two points need to be aware of:
1. watchdog prescaler enables a fixed 256 pre-scaling of watchdog
counter reference clock
2. reconfiguration takes about 55ms on imx93
Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220825083256.14565-8-alice.guo@oss.nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Current driver may meet reconfigure failure caused by below reasons:
1. The wdog on iMX7ULP has different behavior after RCS valid. It needs
to wait more than 2.5 wdog clock for clock sync before next
reconfiguration, while imx8ulp wdog does not need such delay.
2. After unlock, there is 128 bus clock window opened for reconfiguration,
but on iMX8ULP, the HW can't guarantee the latency. So it is possible
the window is closed before the writing arrives to wdog.
3. If the PRES is enabled, the RCS valid time becomes x256 to the time
of PRES disabled. It is about 1715ms on iMX8ULP. So We have to increase
the RCS timeout and can't wait it in IRQ disabled.
The patch updates the driver to handle failures
1. Using different wait for unlock and RCS. Unlock valid time is very short
and only related to bus clock. It must be in IRQ disabled to avoid
being interrupted in 128 clock window. But for RCS time, it is longer
and ok for IRQ enabled.
2. Add retry for any reconfigure failure with default 5 times.
3. Add "fsl,imx8ulp-wdt" compatile string for iMX8ULP and afterwards
platform which don't need more 2.5 wdog clock after RCS valid.
For imx7ulp, add post delay of 2.5 clock after RCS valid.
Signed-off-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Reviewed-by: Jacky Bai <ping.bai@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220825083256.14565-6-alice.guo@oss.nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
When reconfiguring the WDOG Timer of i.MX7ULP, there is a certain
probability causes it to reset. The reason is that the CMD32EN of the
WDOG Timer of i.MX7ULP is disabled in bootloader. The unlock sequence
are two 16-bit writes to the CNT register within 16 bus clocks. Adding
mb() is to guarantee that two 16-bit writes are finished within 16 bus
clocks. Memory barriers cannot be added between these two 16-bit writes
so that writel_relaxed is used.
Suggested-by: Ye Li <ye.li@nxp.com>
Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Signed-off-by: Alice Guo <alice.guo@nxp.com>
Reviewed-by: Ye Li <ye.li@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220825083256.14565-3-alice.guo@oss.nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
According to reference manual, the i.MX7ULP WDOG's operations except
refresh should follow below sequence:
1. disable global interrupts;
2. unlock the wdog and wait unlock bit set;
3. reconfigure the wdog and wait for reconfiguration bit set;
4. enabel global interrupts.
Strictly follow the recommended sequence can make it more robust.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1596150213-31638-1-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Since commit 747d88a1a8 ("watchdog: imx7ulp: Pass the wdog instance in
imx7ulp_wdt_enable()") imx7ulp_wdt_enable() accepts a watchdog_device
structure, so fix one instance that missed such conversion.
This also fixes the following sparse warning:
drivers/watchdog/imx7ulp_wdt.c:115:31: warning: incorrect type in argument 1 (different address spaces)
drivers/watchdog/imx7ulp_wdt.c:115:31: expected struct watchdog_device *wdog
drivers/watchdog/imx7ulp_wdt.c:115:31: got void [noderef] <asn:2>*base
Fixes: 747d88a1a8 ("watchdog: imx7ulp: Pass the wdog instance inimx7ulp_wdt_enable()")
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191120140916.25001-1-festevam@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
The following hang is observed when a 'reboot' command is issued:
# reboot
# Stopping network: OK
Stopping klogd: OK
Stopping syslogd: OK
umount: devtmpfs busy - remounted read-only
[ 8.612079] EXT4-fs (mmcblk0p2): re-mounted. Opts: (null)
The system is going down NOW!
Sent SIGTERM to all processes
Sent SIGKILL to all processes
Requesting system reboot
[ 10.694753] reboot: Restarting system
[ 11.699008] Reboot failed -- System halted
Fix this problem by adding a .restart ops member.
Fixes: 41b630f41b ("watchdog: Add i.MX7ULP watchdog support")
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191029174037.25381-1-festevam@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
The i.MX7ULP Watchdog Timer (WDOG) module is an independent timer
that is available for system use.
It provides a safety feature to ensure that software is executing
as planned and that the CPU is not stuck in an infinite loop or
executing unintended code. If the WDOG module is not serviced
(refreshed) within a certain period, it resets the MCU.
Add driver support for i.MX7ULP watchdog.
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1566999303-18795-2-git-send-email-Anson.Huang@nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
