If you've got code that does this in a tight loop
1. Open watchdog
2. Send 'expect close'
3. Close watchdog
...you'll eventually trigger a watchdog reset. You can reproduce this
by using daisydog (1) and running:
while true; do daisydog -c > /dev/null; done
The problem is that each time you write to the watchdog for 'expect
close' it moves the timer .5 seconds out. The timer thus never fires
and never pats the watchdog for you.
1: http://git.chromium.org/gitweb/?p=chromiumos/third_party/daisydog.git
Signed-off-by: Doug Anderson <dianders@chromium.org>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Right now the dw_wdt uses a spinlock to protect dw_wdt_open(). The
problem is that while holding the spinlock we call:
-> dw_wdt_set_top()
-> dw_wdt_top_in_seconds()
-> clk_get_rate()
-> clk_prepare_lock()
-> mutex_lock()
Locking a mutex while holding a spinlock is not allowed and leads to
warnings like "BUG: spinlock wrong CPU on CPU#1", among other
problems.
There's no reason to use a spinlock. Only dw_wdt_open() was protected
and the test_and_set_bit() at the start of that function protects us
anyway.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Tested-by: Jisheng Zhang <jszhang@marvell.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The dw_wdt_set_top() function takes in a value in seconds. In
dw_wdt_open() we were calling it with a value that's supposed to
represent the maximum value programmed into the "top" register with a
comment saying that we were trying to set the watchdog to its maximum
value. Instead we ended up setting the watchdog to ~15 seconds.
Let's fix this. However, setting things to the "max" gives me an 86
second watchdog in the system I'm looking at. 86 seconds feels a
little too long. We'll explicitly choose 30 seconds as a more
reasonable value.
NOTE: Ideally this driver should be transitioned to be a real watchdog
driver. Then we could use "watchdog_init_timeout" and let the timeout
be specified in a number of ways (device tree, module parameter, etc).
This patch should be considered a bit of a stopgap solution.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
On some dw_wdt implementations the "top" register may be initted to 0
at bootup. In such a case, each "pat" of the watchdog will reset the
timer to 0xffff. That's pretty short.
The input clock of the wdt can be any of a wide range of values. On
an rk3288 system, I've seen the wdt clock be 24.75 MHz. That means
each tick is ~40ns and we'll count to 0xffff in ~2.6ms.
Because of the above two facts, it's a really good idea to pat the
watchdog after initting the "top" register properly and before
enabling the watchdog. If you don't then there's no way we'll get the
next heartbeat in time.
Jisheng Zhang fixed this problem on some dw_wdt versions by using the
TOP_INIT feature. However, the dw_wdt on rk3288 doesn't have TOP_INIT
so it's a good idea to also pat the watchdog manually.
Signed-off-by: Doug Anderson <dianders@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The kernel core now provides an API to trigger a system restart.
Register with it to support restarting the system via. watchdog.
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The TOP_INIT, ie bit 4-7 of the WDOG_TIMEOUT_RANGE_REG_OFFSET register
may be zero, so the timeout period may be very short after initialization
is done, thus the system may be reset soon after enabling. We fix this
problem by also initialising the TOP_INIT when setting TOP in function
dw_wdt_set_top().
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
devm_ioremap_resource() checks for valid resource.
Remove the un-necessary check after platform_get_resource().
Signed-off-by: George Cherian <george.cherian@ti.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
There is nothing ARM specific in this driver, and we intend to use it on the
Xtensa architecture. Also, clk.h now includes stubs for !CONFIG_HAVE_CLK, so
the driver should build anyway.
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
I just can't find any value in MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR)
and MODULE_ALIAS_MISCDEV(TEMP_MINOR) statements.
Either the device is enumerated and the driver already has a module
alias (e.g. PCI, USB etc.) that will get the right driver loaded
automatically.
Or the device is not enumerated and loading its driver will lead to
more or less intrusive hardware poking. Such hardware poking should be
limited to a bare minimum, so the user should really decide which
drivers should be tried and in what order. Trying them all in
arbitrary order can't do any good.
On top of that, loading that many drivers at once bloats the kernel
log. Also many drivers will stay loaded afterward, bloating the output
of "lsmod" and wasting memory. Some modules (cs5535_mfgpt which gets
loaded as a dependency) can't even be unloaded!
If defining char-major-10-130 is needed then it should happen in
user-space.
Signed-off-by: Jean Delvare <jdelvare@suse.de>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Mike Frysinger <vapier.adi@gmail.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Cc: Zwane Mwaikambo <zwane@arm.linux.org.uk>
Cc: Jim Cromie <jim.cromie@gmail.com>
This is necessary to make the driver work with platforms using the
common clock framework.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The dw_wdt only provides PM_SLEEP operations, so convert the driver
to use SIMPLE_DEV_PM_OPS instead of populating the struct manually.
This has the added effect of simplifying the CONFIG_PM ifdefs.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
'dw_wdt_write' is used only in this file. Make it static.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Use devm_clk_get() to make cleanup paths more simple.
Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
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>
Cc: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devexit is no
longer needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devinit is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CONFIG_HOTPLUG is going away as an option so __devexit_p is no longer
needed.
Signed-off-by: Bill Pemberton <wfp5p@virginia.edu>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Kukjin Kim <kgene.kim@samsung.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Use the current logging styles.
Make sure all output has a prefix.
Add missing newlines.
Remove now unnecessary PFX, NAME, and miscellaneous other #defines.
Coalesce formats.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Reimplement a call to devm_request_mem_region followed by a call to ioremap
or ioremap_nocache by a call to devm_request_and_ioremap.
The semantic patch that makes this transformation is as follows:
(http://coccinelle.lip6.fr/)
// <smpl>
@nm@
expression myname;
identifier i;
@@
struct platform_driver i = { .driver = { .name = myname } };
@@
expression dev,res,size;
expression nm.myname;
@@
-if (!devm_request_mem_region(dev, res->start, size,
- \(res->name\|dev_name(dev)\|myname\))) {
- ...
- return ...;
-}
... when != res->start
(
-devm_ioremap(dev,res->start,size)
+devm_request_and_ioremap(dev,res)
|
-devm_ioremap_nocache(dev,res->start,size)
+devm_request_and_ioremap(dev,res)
)
... when any
when != res->start
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
This patch converts the drivers in drivers/watchdog/* to use the
module_platform_driver() macro which makes the code smaller and a bit
simpler.
Signed-off-by: Axel Lin <axel.lin@gmail.com>
Cc: Nicolas Thill <nico@openwrt.org>
Cc: Florian Fainelli <florian@openwrt.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Paul Cercueil <paul@crapouillou.net>
Cc: Marc Zyngier <maz@misterjones.org>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Alejandro Cabrera <aldaya@gmail.com>
Cc: "George G. Davis" <gdavis@mvista.com>
Cc: Sylver Bruneau <sylver.bruneau@googlemail.com>
Cc: Vitaly Wool <vital@embeddedalley.com>
Cc: Mika Westerberg <mika.westerberg@iki.fi>
Cc: Timo Kokkonen <timo.t.kokkonen@nokia.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
The Synopsys DesignWare watchdog is found in several ARM based systems
and provides a choice of 16 timeout periods depending on the clock
input. The watchdog cannot be disabled once started.
Signed-off-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Viresh Kumar <viresh.kumar@st.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Doug Anderson