Eric Lee / smarc-fsl-linux-kernel

27 Jul, 2015

1 commit

14 Mar, 2015

2 commits

  • 297d716f6   power_supply: Change ownership from driver to core ... Browse Code »

    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 : [] 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

    Krzysztof Kozlowski
     
  • 2dc9215d7   power_supply: Move run-time configuration to separate structure ... Browse Code »

    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

    Krzysztof Kozlowski
     

29 Nov, 2012

3 commits

23 Aug, 2012

2 commits

  • deacc4fe5   ds2781_battery: Replace call to kzalloc with devm_kzalloc ... Browse Code »

    With devm_kzalloc there is no need of freeing at the errorpath and also
    at unregister it.

    Signed-off-by: Devendra Naga
    Signed-off-by: Anton Vorontsov

    Devendra Naga
     
  • bc6e51d88   ds2781_battery: Convert to module_platform_driver ... Browse Code »

    module_platform_driver can be used to replace the platform_driver
    register and unregister functions, with the calls to module_init
    and module_exit,

    i.e. all the code that is doing like the below

    static int __init mymod_init(void)
    {
    return platform_driver_register(&drv_operations);
    }

    static void __exit mymod_exit(void)
    {
    platform_driver_unregister(&drv_operations);
    }

    module_init(mymod_init);
    module_exit(mymod_exit);

    can be replaced with
    module_platform_driver(drv_operations)...

    Signed-off-by: Devendra Naga
    Signed-off-by: Anton Vorontsov

    Devendra Naga
     

01 Aug, 2012

1 commit

  • 4b24ff711   Merge tag 'for-v3.6' of git://git.infradead.org/battery-2.6 ... Browse Code »

    Pull battery updates from Anton Vorontsov:
    "The tag contains just a few battery-related changes for v3.6. It's is
    all pretty straightforward, except one thing.

    One of our patches added thermal support for power supply class, but
    thermal/ subsystem changed under our feet. We (well, Stephen, that
    is) caught the issue and it was decided[1] that I'd just delay the
    battery pull request, and then will fix it up by merging upstream back
    into battery tree at the specific commit.

    That's not all though: another[2] small fixup for thermal subsystem
    was needed to get rid of a warning in power supply subsystem (the
    warning was not drivers/power's "fault", the thermal registration
    function just needed a proper const annotation, which is also done by
    a small commit on top of the merge.

    So, to sum this up:
    - The 'master' branch of the battery tree was in the -next tree for
    weeks, was never rebased, altered etc. It should be all OK;
    - Although, for-v3.6 tag contains the 'master' branch + merge + the
    warning fix.

    [1] http://lkml.org/lkml/2012/6/19/23
    [2] http://lkml.org/lkml/2012/6/18/28"

    * tag 'for-v3.6' of git://git.infradead.org/battery-2.6: (23 commits)
    thermal: Constify 'type' argument for the registration routine
    olpc-battery: update CHARGE_FULL_DESIGN property for BYD LiFe batteries
    olpc-battery: Add VOLTAGE_MAX_DESIGN property
    charger-manager: Fix build break related to EXTCON
    lp8727_charger: Move header file into platform_data directory
    power_supply: Add min/max alert properties for CAPACITY, TEMP, TEMP_AMBIENT
    bq27x00_battery: Add support for BQ27425 chip
    charger-manager: Set current limit of regulator for over current protection
    charger-manager: Use EXTCON Subsystem to detect charger cables for charging
    test_power: Add VOLTAGE_NOW and BATTERY_TEMP properties
    test_power: Add support for USB AC source
    gpio-charger: Use cansleep version of gpio_set_value
    bq27x00_battery: Add support for power average and health properties
    sbs-battery: Don't trigger false supply_changed event
    twl4030_charger: Allow charger to control the regulator that feeds it
    twl4030_charger: Add backup-battery charging
    twl4030_charger: Fix some typos
    max17042_battery: Support CHARGE_COUNTER power supply attribute
    smb347-charger: Add constant charge and current properties
    power_supply: Add constant charge_current and charge_voltage properties
    ...

    Linus Torvalds
     

18 Jun, 2012

1 commit

14 Jun, 2012

1 commit

  • b02f8bede   W1: split master mutex to avoid deadlocks. ... Browse Code »

    The 'mutex' in struct w1_master is use for two very different
    purposes.

    Firstly it protects various data structures such as the list of all
    slaves.

    Secondly it protects the w1 buss against concurrent accesses.

    This can lead to deadlocks when the ->probe code called while adding a
    slave needs to talk on the bus, as is the case for power_supply
    devices.
    ds2780 and ds2781 drivers contain a work around to track which
    process hold the lock simply to avoid this deadlock. bq27000 doesn't
    have that work around and so deadlocks.

    There are other possible deadlocks involving sysfs.
    When removing a device the sysfs s_active lock is held, so the lock
    that protects the slave list must take precedence over s_active.
    However when access power_supply attributes via sysfs, the s_active
    lock must take precedence over the lock that protects accesses to
    the bus.

    So to avoid deadlocks between w1 slaves and sysfs, these must be
    two separate locks. Making them separate means that the work around
    in ds2780 and ds2781 can be removed.

    So this patch:
    - adds a new mutex: "bus_mutex" which serialises access to the bus.
    - takes in mutex in w1_search and ds1wm_search while they access
    the bus for searching. The mutex is dropped before calling the
    callback which adds the slave.
    - changes all slaves to use bus_mutex instead of mutex to
    protect access to the bus
    - removes w1_ds2790_io_nolock and w1_ds2781_io_nolock, and the
    related code from drivers/power/ds278[01]_battery.c which
    calls them.

    Signed-off-by: NeilBrown
    Acked-by: Evgeniy Polyakov
    Signed-off-by: Greg Kroah-Hartman

    NeilBrown
     

06 May, 2012

1 commit

09 Mar, 2012

1 commit