watchdog: dw_wdt: Simplify clk management

Use devm_clk_get_enabled() instead of hand-writing it.
This saves some LoC.

Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/f6094c55cacf9637d835cd49290d9e888faeb0f7.1682491863.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: Fix the error handling path of dw_wdt_drv_probe()

The commit in Fixes has only updated the remove function and missed the
error handling path of the probe.

Add the missing reset_control_assert() call.

Fixes: 65a3b6935d92 ("watchdog: dw_wdt: get reset lines from dt")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/fbb650650bbb33a8fa2fd028c23157bedeed50e1.1682491863.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is (mostly) ignored
and this typically results in resource leaks. To improve here there is a
quest to make the remove callback return void. In the first step of this
quest all drivers are converted to .remove_new() which already returns
void.

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20230303213716.2123717-12-u.kleine-koenig@pengutronix.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: stop on reboot

HW running watchdogs are just watchdogs that are enabled before the
Linux driver is probed, usually by the bootloader (eg. U-Boot).

When the system is shutting down, the mechanism for keeping a HW running
watchdog pinged is also stopped, but the watchdog itself is not stopped,
causing a reset, and preventing the system from being shut down.

Opt into stopping watchdogs on reboot.

Signed-off-by: Cosmin Tanislav <cosmin.tanislav@analog.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221118150809.102505-1-cosmin.tanislav@analog.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: Fix comment typo

The double `have' is duplicated in the comment, remove one.

Signed-off-by: Jason Wang <wangborong@cdjrlc.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220716041951.34714-1-wangborong@cdjrlc.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: Remove #ifdef guards for PM related functions

Use the new DEFINE_SIMPLE_DEV_PM_OPS() and pm_sleep_ptr() macros to
handle the .suspend/.resume callbacks.

These macros allow the suspend and resume functions to be automatically
dropped by the compiler when CONFIG_SUSPEND is disabled, without having
to use #ifdef guards. Not using #ifdef guards means that the code is
always compiled independently of any Kconfig option, and thanks to that
bugs and regressions are easier to catch.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220628193449.160585-3-paul@crapouillou.net
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: Fix duplicate included linux/kernel.h

Clean up the following includecheck warning:

./drivers/watchdog/dw_wdt.c: linux/kernel.h is included more than once.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/1620904182-74107-1-git-send-email-jiapeng.chong@linux.alibaba.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: Replace HTTP links with HTTPS ones

Rationale:
Reduces attack surface on kernel devs opening the links for MITM
as HTTPS traffic is much harder to manipulate.

Deterministic algorithm:
For each file:
If not .svg:
For each line:
If doesn't contain `\bxmlns\b`:
For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`:
If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`:
If both the HTTP and HTTPS versions
return 200 OK and serve the same content:
Replace HTTP with HTTPS.

Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20200713205821.38223-1-grandmaster@al2klimov.de
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: Add DebugFS files

For the sake of the easier device-driver debug procedure, we added a
DebugFS file with the controller registers state. It's available only if
kernel is configured with DebugFS support.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org
Link: https://lore.kernel.org/r/20200530073557.22661-8-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: Add pre-timeouts support

DW Watchdog can rise an interrupt in case if IRQ request mode is enabled
and timer reaches the zero value. In this case the IRQ lane is left
pending until either the next watchdog kick event (watchdog restart) or
until the WDT_EOI register is read or the device/system reset. This
interface can be used to implement the pre-timeout functionality
optionally provided by the Linux kernel watchdog devices.

IRQ mode provides a two stages timeout interface. It means the IRQ is
raised when the counter reaches zero, while the system reset occurs only
after subsequent timeout if the timer restart is not performed. Due to
this peculiarity the pre-timeout value is actually set to the achieved
hardware timeout, while the real watchdog timeout is considered to be
twice as much of it. This applies a significant limitation on the
pre-timeout values, so current implementation supports either zero value,
which disables the pre-timeout events, or non-zero values, which imply
the pre-timeout to be at least half of the current watchdog timeout.

Note that we ask the interrupt controller to detect the rising-edge
pre-timeout interrupts to prevent the high-level-IRQs flood, since
if the pre-timeout happens, the IRQ lane will be left pending until
it's cleared by the timer restart.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org
Link: https://lore.kernel.org/r/20200530073557.22661-7-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: Support devices with asynch clocks

DW Watchdog IP core can be synthesised with asynchronous timer/APB
clocks support (WDT_ASYNC_CLK_MODE_ENABLE == 1). In this case
separate clock signals are supposed to be used to feed watchdog timer
and APB interface of the device. Currently the driver supports
the synchronous mode only. Since there is no way to determine which
mode was actually activated for device from its registers, we have to
rely on the platform device configuration data. If optional "pclk"
clock source is supplied, we consider the device working in asynchronous
mode, otherwise the driver falls back to the synchronous configuration.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org
Link: https://lore.kernel.org/r/20200530073557.22661-6-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: Support devices with non-fixed TOP values

In case if the DW Watchdog IP core is synthesised with
WDT_USE_FIX_TOP == false, the TOP interval indexes make the device
to load a custom periods to the counter. These periods are hardwired
at the IP synthesis stage and can be within [2^8, 2^(WDT_CNT_WIDTH - 1)].
Alas their values can't be detected at runtime and must be somehow
supplied to the driver so one could properly determine the watchdog
timeout intervals. For this purpose we suggest to have a vendor-
specific dts property "snps,watchdog-tops" utilized, which would
provide an array of sixteen counter values. At device probe stage they
will be used to initialize the watchdog device timeouts determined
from the array values and current clocks source rate.

In order to have custom TOP values supported the driver must be
altered in the following way. First of all the fixed-top values
ready-to-use array must be determined for compatibility with currently
supported devices, which were synthesised with WDT_USE_FIX_TOP == true.
It will be used if either fixed TOP feature is detected being enabled or
no custom TOPs are fetched from the device dt node. Secondly at the probe
stage we must initialize an array of the watchdog timeouts corresponding
to the detected TOPs list and the reference clock rate. For generality the
procedure of initialization is designed in a way to support the TOPs array
with no limitations on the items order or value. Finally the watchdog
period search methods should be altered to support the new timeouts data
structure.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Cc: Alexey Malahov <Alexey.Malahov@baikalelectronics.ru>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: linux-mips@vger.kernel.org
Cc: devicetree@vger.kernel.org
Link: https://lore.kernel.org/r/20200530073557.22661-5-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw_wdt: ping watchdog to reset countdown before start

Currently on an rk3288 SoC when trying to use the watchdog the SoC will
instantly reset. This is due to the watchdog countdown counter being set
to its initial value of 0x0. Reset the watchdog counter before start in
order to correctly start the countdown timer from the right position.

Signed-off-by: Jack Mitchell <ml@embed.me.uk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200107155155.278521-1-ml@embed.me.uk
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: make DesignWare watchdog allow users to set bigger timeout value

watchdog_dev.c provides means to allow users to set bigger timeout value
than HW can support, make DesignWare watchdog align with this.

Signed-off-by: Peng Wang <peng.1.wang@nokia-sbell.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/8fa54e92c6cd4544a7a3eb60a373ac43@nokia-sbell.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

watchdog: Convert to use devm_platform_ioremap_resource

Use devm_platform_ioremap_resource to reduce source code size,
improve readability, and reduce the likelyhood of bugs.

The conversion was done automatically with coccinelle using the
following semantic patch.

@r@
identifier res, pdev;
expression a;
expression index;
expression e;
@@

<+...
- res = platform_get_resource(pdev, IORESOURCE_MEM, index);
- a = devm_ioremap_resource(e, res);
+ a = devm_platform_ioremap_resource(pdev, index);
...+>

@depends on r@
identifier r.res;
@@
- struct resource *res;
... when != res

@@
identifier res, pdev;
expression index;
expression a;
@@
- struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, index);
- a = devm_ioremap_resource(&pdev->dev, res);
+ a = devm_platform_ioremap_resource(pdev, index);

Cc: Joel Stanley <joel@jms.id.au>
Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Linus Walleij <linus.walleij@linaro.org>
Cc: Baruch Siach <baruch@tkos.co.il>
Cc: Keguang Zhang <keguang.zhang@gmail.com>
Cc: Vladimir Zapolskiy <vz@mleia.com>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Avi Fishman <avifishman70@gmail.com>
Cc: Nancy Yuen <yuenn@google.com>
Cc: Brendan Higgins <brendanhiggins@google.com>
Cc: Wan ZongShun <mcuos.com@gmail.com>
Cc: Michal Simek <michal.simek@xilinx.com>
Cc: Sylvain Lemieux <slemieux.tyco@gmail.com>
Cc: Kukjin Kim <kgene@kernel.org>
Cc: Barry Song <baohua@kernel.org>
Cc: Orson Zhai <orsonzhai@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Maxime Ripard <maxime.ripard@bootlin.com>
Cc: Chen-Yu Tsai <wens@csie.org>
Cc: Marc Gonzalez <marc.w.gonzalez@free.fr>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Shawn Guo <shawnguo@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Tested-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Acked-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Maxime Ripard <maxime.ripard@bootlin.com>
Acked-by: Michal Simek <michal.simek@xilinx.com> (cadence/xilinx wdts)
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Patrice Chotard <patrice.chotard@st.com>
Acked-by: Vladimir Zapolskiy <vz@mleia.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

watchdog: dw: remove useless pr_fmt

When switch to watchdog infrastructure, pr_* usage is removed, so
there's no any users of the pr_fmt, remove it.

Signed-off-by: Jisheng Zhang <Jisheng.Zhang@synaptics.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@linux-watchdog.org>

watchdog: dw: save/restore control and timeout across suspend/resume

Some platforms lose this state in suspend. It should be safe to do this
unconditionally.

Signed-off-by: Brian Norris <briannorris@chromium.org>
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>

watchdog: dw: RMW the control register

RK3399 has rst_pulse_length in CONTROL_REG[4:2], determining the length
of pulse to issue for system reset. We shouldn't clobber this value,
because that might make the system reset ineffective. On RK3399, we're
seeing that a value of 000b (meaning 2 cycles) yields an unreliable
(partial?) reset, and so we only fully reset after the watchdog fires a
second time. If we retain the system default (010b, or 8 clock cycles),
then the watchdog reset is much more reliable.

Read-modify-write retains the system value and improves reset
reliability.

It seems we were intentionally clobbering the response mode previously,
to ensure we performed a system reset (we don't support an interrupt
notification), so retain that explicitly.

Signed-off-by: Brian Norris <briannorris@chromium.org>
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>

watchdog: dw_wdt: add stop watchdog operation

The only way of stopping the watchdog is by resetting it.
Add the watchdog op for stopping the device and reset if
a reset line is provided.

At same time WDOG_HW_RUNNING should be remove from dw_wdt_start.
As commented by Guenter Roeck:
dw_wdt sets WDOG_HW_RUNNING in its open function. Result is
that the kref_get() in watchdog_open() won't be executed. But then
kref_put() in close will be called since the watchdog now does stop.
This causes the imbalance.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog@vger.kernel.org
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>

watchdog: dw_wdt: get reset lines from dt

The dw_wdt has an external reset line, that can keep the device in reset
and therefore rendering it useless and also is the only way of stopping
the watchdog once it was started.

Get the reset lines for this core from the devicetree. As these lines are
optional, use devm_reset_control_get_optional_shared. If the reset line
is not specified in the devicetree, the reset framework will just skip
deasserting and continue.
This way all users of the driver will continue to function without
any harm, even if the reset line is not specified in the devicetree.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Cc: linux-watchdog@vger.kernel.org
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>
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>

watchdog: dw_wdt: Use watchdog core to install restart handler

Use the infrastructure provided by the watchdog core to install
the restart handler.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>

watchdog: dw_wdt: Read clock rate only once and validate it

Coverity reports:

divide_by_zero: In expression readl(dw_wdt->regs + 8) /
clk_get_rate(dw_wdt->clk), division by expression clk_get_rate(dw_wdt->clk)
which may be zero has undefined behavior.

The clock used for the watchdog timer won't change its rate, so read it
only once during probe. Also validate it and abort the probe function
with an error if it is 0.

Cc: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: dw_wdt: Convert to use watchdog infrastructure

Convert driver to use watchdog infrastructure. This includes
infrastructure support to handle watchdog keepalive if the watchdog
is running while the watchdog device is closed.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: dw_wdt: fix signedness bug in dw_wdt_top_in_seconds()

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>

watchdog: dw_wdt: keepalive the watchdog at write time

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>

watchdog: dw_wdt: No need for a spinlock

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>

watchdog: dw_wdt: Try to get a 30 second watchdog by default

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>

watchdog: dw_wdt: pat the watchdog before enabling it

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>

watchdog: dw_wdt: add restart handler support

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>

watchdog: dw_wdt: initialise TOP_INIT in dw_wdt_set_top()

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>

watchdog: drop owner assignment from platform_drivers

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>

watchdog: dw_wdt: Remove the un-necessary check after platform_get_resource()

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>

watchdog: dw_wdt: remove build dependencies

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>

watchdog: dw: Enable OF support for DW watchdog timer

Add device tree support to the DW watchdog timer.

Signed-off-by: Dinh Nguyen <dinguyen@altera.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Reviewed-by: Pavel Machek <pavel@denx.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Cc: Viresh Kumar <viresh.linux@gmail.com>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Ian Campbell <ijc+devicetree@hellion.org.uk>
Cc: devicetree@vger.kernel.org
Cc: linux-watchdog@vger.kernel.org

watchdog: Get rid of MODULE_ALIAS_MISCDEV statements

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>

watchdog: dw_wdt: Add __user annotation

Added __user annotation to fix the following sparse warnings.

drivers/watchdog/dw_wdt.c:206:38: warning: incorrect type in argument 1 (different address spaces)
drivers/watchdog/dw_wdt.c:206:38: expected void [noderef] <asn:1>*to
drivers/watchdog/dw_wdt.c:206:38: got struct watchdog_info *<noident>
drivers/watchdog/dw_wdt.c:211:24: warning: incorrect type in initializer (different address spaces)
drivers/watchdog/dw_wdt.c:211:24: expected int const [noderef] <asn:1>*register __p
drivers/watchdog/dw_wdt.c:211:24: got int *<noident>

Signed-off-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Jamie Iles <jamie@jamieiles.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: dw_wdt: use clk_prepare_enable and clk_disable_unprepare

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>

watchdog: dw_wdt: convert to SIMPLE_DEV_PM_OPS

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>

watchdog: dw_wdt: Staticize local symbol

'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>

watchdog: dw_wdt: use devm_clk_get()

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>

watchdog: Convert to devm_ioremap_resource()

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>

watchdog: remove use of __devexit

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>

watchdog: remove use of __devinit

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>

watchdog: remove use of __devexit_p

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>

watchdog: nowayout is bool

nowayout is actually a boolean value.
So make it bool for all watchdog device drivers.

Signed-off-by: Wim Van Sebroeck <wim@iguana.be>

watchdog: Use pr_<fmt> and pr_<level>

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>

watchdog: dw_wdt.c: use devm_request_and_ioremap

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>

watchdog: convert drivers/watchdog/* to use module_platform_driver()

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>

watchdog: add support for the Synopsys DesignWare WDT

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>