linux-toradex.git/drivers/power/ab8500_fg.c, branch v4.1.12

power_supply: Change ownership from driver to core

2015-03-13T22:15:51+00:00

Change the ownership of power_supply structure from each driver
implementing the class to the power supply core.

The patch changes power_supply_register() function thus all drivers
implementing power supply class are adjusted.

Each driver provides the implementation of power supply. However it
should not be the owner of power supply class instance because it is
exposed by core to other subsystems with power_supply_get_by_name().
These other subsystems have no knowledge when the driver will unregister
the power supply. This leads to several issues when driver is unbound -
mostly because user of power supply accesses freed memory.

Instead let the core own the instance of struct 'power_supply'.  Other
users of this power supply will still access valid memory because it
will be freed when device reference count reaches 0. Currently this
means "it will leak" but power_supply_put() call in next patches will
solve it.

This solves invalid memory references in following race condition
scenario:

Thread 1: charger manager
Thread 2: power supply driver, used by charger manager

THREAD 1 (charger manager)         THREAD 2 (power supply driver)
==========================         ==============================
psy = power_supply_get_by_name()
                                   Driver unbind, .remove
                                     power_supply_unregister()
                                     Device fully removed
psy->get_property()

The 'get_property' call is executed in invalid context because the driver was
unbound and struct 'power_supply' memory was freed.

This could be observed easily with charger manager driver (here compiled
with max17040 fuel gauge):

$ cat /sys/devices/virtual/power_supply/cm-battery/capacity &
$ echo "1-0036" > /sys/bus/i2c/drivers/max17040/unbind
[   55.725123] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[   55.732584] pgd = d98d4000
[   55.734060] [00000000] *pgd=5afa2831, *pte=00000000, *ppte=00000000
[   55.740318] Internal error: Oops: 80000007 [#1] PREEMPT SMP ARM
[   55.746210] Modules linked in:
[   55.749259] CPU: 1 PID: 2936 Comm: cat Tainted: G        W       3.19.0-rc1-next-20141226-00048-gf79f475f3c44-dirty #1496
[   55.760190] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[   55.766270] task: d9b76f00 ti: daf54000 task.ti: daf54000
[   55.771647] PC is at 0x0
[   55.774182] LR is at charger_get_property+0x2f4/0x36c
[   55.779201] pc : [<00000000>]    lr : []    psr: 60000013
[   55.779201] sp : daf55e90  ip : 00000003  fp : 00000000
[   55.790657] r10: 00000000  r9 : c06e2878  r8 : d9b26c68
[   55.795865] r7 : dad81610  r6 : daec7410  r5 : daf55ebc  r4 : 00000000
[   55.802367] r3 : 00000000  r2 : daf55ebc  r1 : 0000002a  r0 : d9b26c68
[   55.808879] Flags: nZCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment user
[   55.815994] Control: 10c5387d  Table: 598d406a  DAC: 00000015
[   55.821723] Process cat (pid: 2936, stack limit = 0xdaf54210)
[   55.827451] Stack: (0xdaf55e90 to 0xdaf56000)
[   55.831795] 5e80:                                     60000013 c01459c4 0000002a c06f8ef8
[   55.839956] 5ea0: db651000 c06f8ef8 daebac00 c04cb668 daebac08 c0346864 00000000 c01459c4
[   55.848115] 5ec0: d99eaa80 c06f8ef8 00000fff 00001000 db651000 c027f25c c027f240 d99eaa80
[   55.856274] 5ee0: d9a06c00 c0146218 daf55f18 00001000 d99eaa80 db4c18c0 00000001 00000001
[   55.864468] 5f00: daf55f80 c0144c78 c0144c54 c0107f90 00015000 d99eaab0 00000000 00000000
[   55.872603] 5f20: 000051c7 00000000 db4c18c0 c04a9370 00015000 00001000 daf55f80 00001000
[   55.880763] 5f40: daf54000 00015000 00000000 c00e53dc db4c18c0 c00e548c 0000000d 00008124
[   55.888937] 5f60: 00000001 00000000 00000000 db4c18c0 db4c18c0 00001000 00015000 c00e5550
[   55.897099] 5f80: 00000000 00000000 00001000 00001000 00015000 00000003 00000003 c000f364
[   55.905239] 5fa0: 00000000 c000f1a0 00001000 00015000 00000003 00015000 00001000 0001333c
[   55.913399] 5fc0: 00001000 00015000 00000003 00000003 00000002 00000000 00000000 00000000
[   55.921560] 5fe0: 7fffe000 be999850 0000a225 b6f3c19c 60000010 00000003 00000000 00000000
[   55.929744] [] (charger_get_property) from [] (power_supply_show_property+0x48/0x20c)
[   55.939286] [] (power_supply_show_property) from [] (dev_attr_show+0x1c/0x48)
[   55.948130] [] (dev_attr_show) from [] (sysfs_kf_seq_show+0x84/0x104)
[   55.956298] [] (sysfs_kf_seq_show) from [] (kernfs_seq_show+0x24/0x28)
[   55.964536] [] (kernfs_seq_show) from [] (seq_read+0x1b0/0x484)
[   55.972172] [] (seq_read) from [] (__vfs_read+0x18/0x4c)
[   55.979188] [] (__vfs_read) from [] (vfs_read+0x7c/0x100)
[   55.986304] [] (vfs_read) from [] (SyS_read+0x40/0x8c)
[   55.993164] [] (SyS_read) from [] (ret_fast_syscall+0x0/0x48)
[   56.000626] Code: bad PC value
[   56.011652] ---[ end trace 7b64343fbdae8ef1 ]---

Signed-off-by: Krzysztof Kozlowski 
Reviewed-by: Bartlomiej Zolnierkiewicz 

[for the nvec part]
Reviewed-by: Marc Dietrich 

[for compal-laptop.c]
Acked-by: Darren Hart 

[for the mfd part]
Acked-by: Lee Jones 

[for the hid part]
Acked-by: Jiri Kosina 

[for the acpi part]
Acked-by: Rafael J. Wysocki 

Signed-off-by: Sebastian Reichel

power_supply: ab8500: Use power_supply_*() API for accessing function attrs

2015-03-13T22:15:49+00:00

Replace direct calls to power supply function attributes with wrappers.
Wrappers provide safe access in case of unregistering the power
supply (e.g. by removing the driver). Replace:
 - get_property -> power_supply_get_property

Signed-off-by: Krzysztof Kozlowski 
Acked-by: Jonghwa Lee 
Acked-by: Pavel Machek 
Acked-by: Linus Walleij 
Reviewed-by: Bartlomiej Zolnierkiewicz 
Reviewed-by: Sebastian Reichel 
Signed-off-by: Sebastian Reichel

power_supply: Move run-time configuration to separate structure

2015-03-13T22:15:12+00:00

Add new structure 'power_supply_config' for holding run-time
initialization data like of_node, supplies and private driver data.

The power_supply_register() function is changed so all power supply
drivers need updating.

When registering the power supply this new 'power_supply_config' should be
used instead of directly initializing 'struct power_supply'. This allows
changing the ownership of power_supply structure from driver to the
power supply core in next patches.

When a driver does not use of_node or supplies then it should use NULL
as config. If driver uses of_node or supplies then it should allocate
config on stack and initialize it with proper values.

Signed-off-by: Krzysztof Kozlowski 
Reviewed-by: Bartlomiej Zolnierkiewicz 
Acked-by: Pavel Machek 

[for the nvec part]
Reviewed-by: Marc Dietrich 

[for drivers/platform/x86/compal-laptop.c]
Reviewed-by: Darren Hart 

[for drivers/hid/*]
Reviewed-by: Jiri Kosina 

Signed-off-by: Sebastian Reichel

ab8500_fg.c: only request threaded IRQs when necessary

2015-03-07T19:32:22+00:00

All 5 IRQ handlers of the driver are requested as threaded interrupt
handlers.  However, only 1 handler can block.  The remaining 4 handlers
defer the actual handling to a workqueue.  Hence, 4 of 5 IRQ handlers
have a considerable overhead, since they are executed in a kernel thread
to schedule another kernel thread (workqueue).

This change splits up the 5 interrupt handlers into top halves (_th) and
bottom halves (_bh) and resolves the aforementioned overhead by only
requesting threaded interrupts (i.e., bottom halves) when necessary.

Signed-off-by: Valentin Rothberg 
Signed-off-by: Sebastian Reichel

ab8500_fg: use jiffies_to_msecs for jiffies conversion

2015-02-25T21:47:12+00:00

Converting jiffies to milliseconds by "val * 1000 / HZ" is technically
OK but jiffies_to_msecs(val) is the cleaner solution and handles all
corner cases correctly. This is a minor API consolidation only and
should make things more readable.

Signed-off-by: Nicholas Mc Guire 
Signed-off-by: Sebastian Reichel

ab8500_fg: match return type of wait_for_completion_timeout

2015-02-25T21:47:12+00:00

return type of wait_for_completion_timeout is unsigned long not int. as
timeout is used for wait_for_completion_timeout exclusively here its
type is simply changed to unsigned long.

Signed-off-by: Nicholas Mc Guire 
Signed-off-by: Sebastian Reichel

power_supply: ab8500_fg: Simplify creation and removal of sysfs entries

2015-02-25T21:26:32+00:00

Simplify a little ab8500_fg_sysfs_psy_create_attrs () and
ab8500_fg_sysfs_psy_remove_attrs() functions because they received
pointer to power supply device which was then converted into power
supply instance. Then it was converted into struct ab8500_fg. The path
looked like:
	ab8500_fg->psy.dev -> psy -> ab8500_fg

Instead just pass pointer to struct ab8500_fg directly so all
conversions won't be necessary.

Signed-off-by: Krzysztof Kozlowski 
Signed-off-by: Sebastian Reichel

power: ab8500_fg.c: Remove unused function

2015-01-21T13:06:48+00:00

Remove the function ab8500_fg_reinit() that is not used anywhere.

This was partially found by using a static code analysis program called cppcheck.

Signed-off-by: Rickard Strandqvist 
Acked-by: Arnd Bergmann 
Signed-off-by: Sebastian Reichel

Merge tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core

2014-12-15T00:10:09+00:00

Pull driver core update from Greg KH:
 "Here's the set of driver core patches for 3.19-rc1.

  They are dominated by the removal of the .owner field in platform
  drivers.  They touch a lot of files, but they are "simple" changes,
  just removing a line in a structure.

  Other than that, a few minor driver core and debugfs changes.  There
  are some ath9k patches coming in through this tree that have been
  acked by the wireless maintainers as they relied on the debugfs
  changes.

  Everything has been in linux-next for a while"

* tag 'driver-core-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/driver-core: (324 commits)
  Revert "ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries"
  fs: debugfs: add forward declaration for struct device type
  firmware class: Deletion of an unnecessary check before the function call "vunmap"
  firmware loader: fix hung task warning dump
  devcoredump: provide a one-way disable function
  device: Add dev__once variants
  ath: ath9k: use debugfs_create_devm_seqfile() helper for seq_file entries
  ath: use seq_file api for ath9k debugfs files
  debugfs: add helper function to create device related seq_file
  drivers/base: cacheinfo: remove noisy error boot message
  Revert "core: platform: add warning if driver has no owner"
  drivers: base: support cpu cache information interface to userspace via sysfs
  drivers: base: add cpu_device_create to support per-cpu devices
  topology: replace custom attribute macros with standard DEVICE_ATTR*
  cpumask: factor out show_cpumap into separate helper function
  driver core: Fix unbalanced device reference in drivers_probe
  driver core: fix race with userland in device_add()
  sysfs/kernfs: make read requests on pre-alloc files use the buffer.
  sysfs/kernfs: allow attributes to request write buffer be pre-allocated.
  fs: sysfs: return EGBIG on write if offset is larger than file size
  ...

power: drop owner assignment from platform_drivers

2014-10-20T14:21:27+00:00

A platform_driver does not need to set an owner, it will be populated by the
driver core.

Signed-off-by: Wolfram Sang