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Sudeep Holla 09bebb1adb power: vexpress: fix corruption in notifier registration
Vexpress platforms provide two different restart handlers: SYS_REBOOT
that restart the entire system, while DB_RESET only restarts the
daughter board containing the CPU. DB_RESET is overridden by SYS_REBOOT
if it exists.

notifier_chain_register used in register_restart_handler by design
relies on notifiers to be registered once only, however vexpress restart
notifier can get registered twice. When this happen it corrupts list
of notifiers, as result some notifiers can be not called on proper
event, traverse on list can be cycled forever, and second unregister
can access already freed memory.

So far, since this was the only restart handler in the system, no issue
was observed even if the same notifier was registered twice. However
commit 6c5c0d48b6 ("watchdog: sp805: add restart handler") added
support for SP805 restart handlers and since the system under test
contains two vexpress restart and two SP805 watchdog instances, it was
observed that during the boot traversing the restart handler list looped
forever as there's a cycle in that list resulting in boot hang.

This patch fixes the issues by ensuring that the notifier is installed
only once.

Cc: Sebastian Reichel <sre@kernel.org>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Fixes: 46c99ac662 ("power/reset: vexpress: Register with kernel restart handler")
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.co.uk>
2018-07-06 16:23:45 +02:00
Ben Dooks 0a14d280e1 power: vexpress: make dev_attr_active static
The dev_attr_active is not exported or defined to be used
outside the driver, so make it static to avoid the following
warning:

drivers/power/reset/vexpress-poweroff.c:77:1: warning: symbol 'dev_attr_active' was not declared. Should it be static?

Cc: Liviu Dudau <liviu.dudau@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
2016-06-13 09:55:51 +01:00
Fabian Frederick 8fb0885504 power: constify of_device_id array
of_device_id is always used as const.
(See driver.of_match_table and open firmware functions)

Signed-off-by: Fabian Frederick <fabf@skynet.be>

[for vexpress]
Acked-by: Sudeep Holla <sudeep.holla@arm.com>

Signed-off-by: Sebastian Reichel <sre@kernel.org>
2015-03-20 13:23:06 +01:00
Pawel Moll 8f961c0a53 power/reset: vexpress: Remove non-DT code
Now, as all VE platforms have to be booted with DT,
the code handling non-DT case can be removed.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Sebastian Reichel <sre@kernel.org>
2015-01-21 03:19:54 +01:00
Guenter Roeck 46c99ac662 power/reset: vexpress: Register with kernel restart handler
Use the kernel restart handler instead of setting arm_pm_restart directly.
This allows for more than one restart handler in the system.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2014-11-17 03:07:08 +01:00
Pawel Moll 3b9334ac83 mfd: vexpress: Convert custom func API to regmap
Components of the Versatile Express platform (configuration
microcontrollers on motherboard and daughterboards in particular)
talk to each other over a custom configuration bus. They
provide miscellaneous functions (from clock generator control
to energy sensors) which are represented as platform devices
(and Device Tree nodes). The transactions on the bus can
be generated by different "bridges" in the system, some
of which are universal for the whole platform (for the price
of high transfer latencies), others restricted to a subsystem
(but much faster).

Until now drivers for such functions were using custom "func"
API, which is being replaced in this patch by regmap calls.
This required:

* a rework (and move to drivers/bus directory, as suggested
  by Samuel and Arnd) of the config bus core, which is much
  simpler now and uses device model infrastructure (class)
  to keep track of the bridges; non-DT case (soon to be
  retired anyway) is simply covered by a special device
  registration function

* the new config-bus driver also takes over device population,
  so there is no need for special matching table for
  of_platform_populate nor "simple-bus" hack in the arm64
  model dtsi file (relevant bindings documentation has
  been updated); this allows all the vexpress devices
  fit into normal device model, making it possible
  to remove plenty of early inits and other hacks in
  the near future

* adaptation of the syscfg bridge implementation in the
  sysreg driver, again making it much simpler; there is
  a special case of the "energy" function spanning two
  registers, where they should be both defined in the tree
  now, but backward compatibility is maintained in the code

* modification of the relevant drivers:

  * hwmon - just a straight-forward API change
  * power/reset driver - API change
  * regulator - API change plus error handling
    simplification
  * osc clock driver - this one required larger rework
    in order to turn in into a standard platform driver

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Mark Brown <broonie@linaro.org>
Acked-by: Lee Jones <lee.jones@linaro.org>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Mike Turquette <mturquette@linaro.org>
2014-05-15 17:02:18 +01:00
Pawel Moll d08b80373c power/reset: vexpress: Fix restart/power off operation
The restart/power off implementation in the vexpress driver
used to obtain the config function when necessary. This was
wrong in two respects:

1. It required memory allocation with disabled interrupts
(it worked, but lockdep - when enabled - reported warnings).

2. Used jiffies-based timeout, while jiffies are not running
at this stage of system shutdown (therefore a config
transaction error - if happened - would have never be reported).

Fixed by pre-allocating the config function per device
and using mdelay for timeout.

Signed-off-by: Pawel Moll <pawel.moll@arm.com>
2014-04-24 17:20:50 +01:00
Robin Holt 7b6d864b48 reboot: arm: change reboot_mode to use enum reboot_mode
Preparing to move the parsing of reboot= to generic kernel code forces
the change in reboot_mode handling to use the enum.

[akpm@linux-foundation.org: fix arch/arm/mach-socfpga/socfpga.c]
Signed-off-by: Robin Holt <holt@sgi.com>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Russ Anderson <rja@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-07-09 10:33:29 -07:00
Catalin Marinas 65deb78285 arm: vexpress: Decouple vexpress-poweroff implementation from machine_desc
This patch adds the pm_power_off and arm_pm_restart variable settings to
the vexpress-poweroff.c driver to decouple it from the machine_desc
definition.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Pawel Moll <pawel.moll@arm.com>
2013-03-21 15:17:40 +00:00
Catalin Marinas 2655f51d0a arm: vexpress: Move the poweroff/restart code to drivers/power/reset
This patch moves the arch/arm/mach-vexpress/reset.c functionality to
drivers/platform/reset/ and adds the necessary Kconfig wiring.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Pawel Moll <pawel.moll@arm.com>
2013-03-21 15:17:39 +00:00