Reference counting is now implemented in the watchdog core and no longer
required in watchdog drivers.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Reference counting is now implemented in the watchdog core and no longer
required in watchdog drivers.

Since it was implememented a no-op, and since the local memory is allocated
with devm_kzalloc(), the reference counting code in the driver really did
not really work anyway, and this patch effectively fixes a bug which could
cause a crash on unloading if the watchdog device was still open.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Reference counting is now implemented in the watchdog core and no longer
required in watchdog drivers.

Since it was implememented a no-op, and since the local memory is allocated
with devm_kzalloc(), the reference counting code in the driver really did
not really work anyway, and this patch effectively fixes a bug which could
cause a crash on unloading if the watchdog device was still open.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

All variables required by the watchdog core to manage a watchdog are
currently stored in struct watchdog_device. The lifetime of those
variables is determined by the watchdog driver. However, the lifetime
of variables used by the watchdog core differs from the lifetime of
struct watchdog_device. To remedy this situation, watchdog drivers
can implement ref and unref callbacks, to be used by the watchdog
core to lock struct watchdog_device in memory.

While this solves the immediate problem, it depends on watchdog drivers
to actually implement the ref/unref callbacks. This is error prone,
often not implemented in the first place, or not implemented correctly.

To solve the problem without requiring driver support, split the variables
in struct watchdog_device into two data structures - one for variables
associated with the watchdog driver, one for variables associated with
the watchdog core. With this approach, the watchdog core can keep track
of its variable lifetime and no longer depends on ref/unref callbacks
in the driver. As a side effect, some of the variables originally in
struct watchdog_driver are now private to the watchdog core and no longer
visible in watchdog drivers.

As a side effect of the changes made, an ioctl will now always fail
with -ENODEV after a watchdog device was unregistered with the character
device still open. Previously, it would only fail with -ENODEV in some
situations. Also, ioctl operations are now atomic from driver perspective.
With this change, it is now guaranteed that the driver will not unregister
a watchdog between a timeout change and the subsequent ping.

The 'ref' and 'unref' callbacks in struct watchdog_driver are no longer
used and marked as deprecated.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

A watchdog driver should not use watchdog subsystem internal flags.
Use a driver variable and flag instead to maintain the watchdog state
and to determine if a suspend operation is possible or not.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

The watchdog character device is currently created in watchdog_dev.c,
and the watchdog device in watchdog_core.c. This results in
cross-dependencies, since device creation needs to know the watchdog
character device number as well as the watchdog class, both of which
reside in watchdog_dev.c.

Create the watchdog device in watchdog_dev.c to simplify the code.

Inspired by earlier patch set from Damien Riegel.

Cc: Damien Riegel <damien.riegel@savoirfairelinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

The 'dev' pointer in struct watchdog_device is set by the watchdog core
when registering the watchdog device and not by the driver. It points to
the watchdog device, not its parent.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

The device pointer in struct watchdog_device has a different lifetime
than the driver code and should not be used in drivers. Use the pointer
to the parent device instead.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

The device pointer in struct watchdog_device has a different lifetime
than the driver code and should not be used in drivers. Use the pointer
to the parent device instead.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

The device pointer in struct watchdog_device should not be used by drivers
and may be removed in the near future. Use the platform device pointer for
info messages instead.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Stopping a watchdog is a normal operation and does not warrant a log
message.
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This adds a binding for the watchdog in Sigma Designs SMP8642 and
similar devices.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This adds support for the Sigma Designs SMP86xx/SMP87xx family built-in
watchdog.
Signed-off-by: Mans Rullgard <mans@mansr.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This patchs adds documentation for the binding of the Zodiac RAVE
Switch Watchdog Processor. This is an i2c based watchdog.

Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: Kumar Gala <galak@codeaurora.org>
Cc: devicetree@vger.kernel.org
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This patch adds a driver for the Zodiac Aerospace RAVE Watchdog Procesor.
This device implements a watchdog timer, accessible over I2C.
Signed-off-by: Martyn Welch <martyn.welch@collabora.co.uk>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Add WD support for Alphascale asm9260 SoC. This driver
provide support for different function modes:
- HW mode to trigger SoC reset on timeout
- SW mode do soft reset if needed
- DEBUG mode
Signed-off-by: Oleksij Rempel <linux@rempel-privat.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This watchdog is instantiated in a FPGA that is memory mapped. It is
made of only one register, called the feed register. Writing to this
register will re-arm the watchdog for a given time (and enable it if it
was disable). It can be disabled by writing a special value into it.

It is part of a syscon block, and the watchdog register offset in this
block varies from board to board. This offset is passed in the syscon
property after the phandle to the syscon node.
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This patch adds watchdog driver for CSRatlas7 platform.
On CSRatlas7, the 6th timer can act as a watchdog timer
when the Watchdog mode is enabled.
Signed-off-by: Guo Zeng <Guo.Zeng@csr.com>
Signed-off-by: William Wang <William.Wang@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Add SoC specific data in the watchdog driver for the meson8b SoC.
Signed-off-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

With this patch we refactor the driver code to enable watchdog support
for all platforms based on Amlogic meson SoCs.
The new default timeout is also now chosen considering the maximum
timeout allowed by the SoC.
Signed-off-by: Carlo Caione <carlo@endlessm.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This patch is for the rebranding changes for the corporate split at HP.
There are no functional changes with this patch.
Signed-off-by: Tom Mingarelli <thomas.mingarelli@hpe.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Use to_platform_device() instead of open-coding it.
Signed-off-by: Geliang Tang <geliangtang@163.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

With the early_enable module parameter the watchdog can be started
during driver probe time. If this is requested the bets are good that
the timer is already running, so to narrow the gap where the timer is
disabled only call the disable function when the timer shouldn't be
started.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

omap_wdt_start calls pm_runtime_get_sync so dropping a reference just
before calling omap_wdt_start doesn't make much sense. Moreover there is
no point to use the synchronous variant of pm_runtime_put because the
driver doesn't care if the clock is disabled before or after
omap_wdt_probe returns.
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

On 64bit platforms, "(1 << (16 + top)) / clk_get_rate(dw_wdt.clk)" is
sign-extended to 64bit then converted to unsigned 64bit, finally divide
the clk rate. If the top is the maximum TOP i.e 15, "(1 << (16 +15))"
will be sign-extended to 0xffffffff80000000, then converted to unsigned
0xffffffff80000000, which is a huge number, thus the final result is
wrong.

We fix this issue by giving usigned value(1U in this case) at first.

Let's assume clk rate is 25MHZ,
Before the patch:
dw_wdt_top_in_seconds(15) = -864612050

After the patch:
dw_wdt_top_in_seconds(15) = 85
Signed-off-by: Jisheng Zhang <jszhang@marvell.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

the softdog has static variables which are accessed if its timer is
still running after the driver is unloaded. and lead to crash:

   $modprobe softdog
   $echo 1 >/dev/watchdog
   $modprobe -r softdog

   CPU 20 Unable to handle kernel paging request at virtual address
   Oops[#1]:
   CPU: 20 PID: 0 Comm: swapper/20 Not tainted 4.1.13-WR8.0.0.0_standard
   ...
   Modules linked in: [last unloaded: softdog]
    ....
   Call Trace:
   [<ffffffff801e142c>] cascade+0x34/0xb0
   [<ffffffff801e1964>] run_timer_softirq+0x30c/0x368
   [<ffffffff80181044>] __do_softirq+0x1ec/0x418
   [<ffffffff801815d0>] irq_exit+0x90/0x98
   [<ffffffff8010749c>] plat_irq_dispatch+0xa4/0x140
   [<ffffffff80152740>] ret_from_irq+0x0/0x4
   [<ffffffff801529e0>] __r4k_wait+0x20/0x40
   [<ffffffff801c2278>] cpu_startup_entry+0x2a0/0x368
   [<ffffffff8015fa64>] start_secondary+0x444/0x4d8

add the module ref when timer is running to avoid to unload the softdog
module
Signed-off-by: Li RongQing <roy.qing.li@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This allows the system to actually halt even if userspace forgot to
disable the watchdog first. Old behaviour was that the watchdog forced
the system to boot again.
Signed-off-by: Harald Geyer <harald@ccbib.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

For SB800 and later chipsets, the register definitions are the same
with SB800. And for SB700 and older chipsets, the definitions should
be same with SP5100/SB7x0.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Cc: Denis Turischev <denis.turischev@compulab.co.il>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

sp5100_tco watchdog is also supported on AMD KernCZ chipset of Carrizo
platform.
Signed-off-by: Huang Rui <ray.huang@amd.com>
Cc: Denis Turischev <denis.turischev@compulab.co.il>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

AMD Mullins watchdog is fully compatible to the previous Hudson chipset,
reuse the existent sp5100_tco driver.
Signed-off-by: Denis Turischev <denis.turischev@compulab.co.il>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

This patch adds following attributes to watchdog device's sysfs interface
to read its different status.

* state - reads whether device is active or not
* identity - reads Watchdog device's identity string.
* timeout - reads current timeout.
* timeleft - reads timeleft before watchdog generates a reset
* bootstatus - reads status of the watchdog device at boot
* status - reads watchdog device's  internal status bits
* nowayout - reads whether nowayout feature was set or not

Testing with iTCO_wdt:
 # cd /sys/class/watchdog/watchdog1/
 # ls
bootstatus  dev  device  identity  nowayout  power  state
subsystem  timeleft  timeout  uevent
 # cat identity
iTCO_wdt
 # cat timeout
30
 # cat state
inactive
 # echo > /dev/watchdog1
 # cat timeleft
26
 # cat state
active
 # cat bootstatus
0
 # cat nowayout
0
Signed-off-by: Pratyush Anand <panand@redhat.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

We need few sysfs attributes to know different status of a watchdog device.
To do that, we need to associate .dev_groups with watchdog_class. So
convert it from pointer to static.
Putting this static struct in watchdog_dev.c, so that static device
attributes defined in that file can be attached to it.
Signed-off-by: Pratyush Anand <panand@redhat.com>
Suggested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Get rid of the custom reboot notifier block registration and use the one
provided by the watchdog core.
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirlinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Get rid of the custom reboot notifier block registration and use the one
provided by the watchdog core.
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirlinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Get rid of the custom reboot notifier block registration and use the one
provided by the watchdog core.

Note that this watchdog used to stop unconditionnaly on SYS_HALT and
SYS_POWER_OFF. The core function now calls ops->stop on SYS_HALT and
SYS_DOWN. To prevent the watchdog from being stopped on reboot, the
"always-running" property must be set, otherwise it will now be stopped.
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirlinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Get rid of the custom reboot notifier block registration and use the one
provided by the watchdog core.
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirlinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Get rid of the custom reboot notifier block registration and use the one
provided by the watchdog core.
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirlinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Many watchdog drivers register a reboot notifier in order to stop the
watchdog on system reboot. Thus we can factorize this code in the
watchdog core.

For that purpose, a new notifier block is added in watchdog_device for
internal use only, as well as a new watchdog_stop_on_reboot helper
function.

If this helper is called, watchdog core registers the related notifier
block and will stop the watchdog when SYS_HALT or SYS_DOWN is received.

Since this operation can be critical on some platforms, abort the device
registration if the reboot notifier registration fails.
Suggested-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

Get rid of the custom restart handler by using the one provided by the
watchdog core.
Signed-off-by: Damien Riegel <damien.riegel@savoirfairelinux.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Vivien Didelot <vivien.didelot@savoirfairelinux.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>