• Stephen Boyd's avatar
    clkdev: Always allocate a struct clk and call __clk_get() w/ CCF · 73e0e496
    Stephen Boyd authored
    of_clk_get_by_clkspec() returns a struct clk pointer but it
    doesn't create a new handle for the consumers when we're using
    the common clock framework. Instead it just returns whatever the
    clk provider hands out. When the consumers go to call clk_put()
    we get an Oops.
    
    Unable to handle kernel paging request at virtual address 00200200
    pgd = c0004000
    [00200200] *pgd=00000000
    Internal error: Oops: 805 [#1] PREEMPT SMP ARM
    Modules linked in:
    CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.19.0-rc1-00104-ga251361a-dirty #992
    Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
    task: ee00b000 ti: ee088000 task.ti: ee088000
    PC is at __clk_put+0x24/0xd0
    LR is at clk_prepare_lock+0xc/0xec
    pc : [<c03eef38>]    lr : [<c03ec1f4>]    psr: 20000153
    sp : ee089de8  ip : 00000000  fp : 00000000
    r10: ee02f480  r9 : 00000001  r8 : 00000000
    r7 : ee031cc0  r6 : ee089e08  r5 : 00000000  r4 : ee02f480
    r3 : 00100100  r2 : 00200200  r1 : 0000091e  r0 : 00000001
    Flags: nzCv  IRQs on  FIQs off  Mode SVC_32  ISA ARM  Segment kernel
    Control: 10c5387d  Table: 4000404a  DAC: 00000015
    Process swapper/0 (pid: 1, stack limit = 0xee088238)
    Stack: (0xee089de8 to 0xee08a000)
    9de0:                   ee7c8f14 c03f0ec8 ee089e08 00000000 c0718dc8 00000001
    9e00: 00000000 c04ee0f0 ee7e0844 00000001 00000181 c04edb58 ee2bd320 00000000
    9e20: 00000000 c011dc5c ee16a1e0 00000000 00000000 c0718dc8 ee16a1e0 ee2bd1e0
    9e40: c0641740 ee16a1e0 00000000 ee2bd320 c0718dc8 ee1d3e10 ee1d3e10 00000000
    9e60: c0769a88 00000000 c0718dc8 00000000 00000000 c02c3124 c02c310c ee1d3e10
    9e80: c07b4eec 00000000 c0769a88 c02c1d0c ee1d3e10 c0769a88 ee1d3e44 00000000
    9ea0: c07091dc c02c1eb8 00000000 c0769a88 c02c1e2c c02c0544 ee005478 ee1676c0
    9ec0: c0769a88 ee3a4e80 c0760ce8 c02c150c c0669b90 c0769a88 c0746cd8 c0769a88
    9ee0: c0746cd8 ee2bc4c0 c0778c00 c02c24e0 00000000 c0746cd8 c0746cd8 c07091f0
    9f00: 00000000 c0008944 c04f405c 00000025 ee00b000 60000153 c074ab00 00000000
    9f20: 00000000 c074ab90 60000153 00000000 ef7fca5d c050860c 000000b6 c0036b88
    9f40: c065ecc4 c06bc728 00000006 00000006 c074ab30 ef7fca40 c0739bdc 00000006
    9f60: c0718dbc c0778c00 000000b6 c0718dc8 c06ed598 c06edd64 00000006 00000006
    9f80: c06ed598 c003b438 00000000 c04e64f4 00000000 00000000 00000000 00000000
    9fa0: 00000000 c04e64fc 00000000 c000e838 00000000 00000000 00000000 00000000
    9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 c0c0c0c0 c0c0c0c0
    [<c03eef38>] (__clk_put) from [<c03f0ec8>] (of_clk_set_defaults+0xe0/0x2c0)
    [<c03f0ec8>] (of_clk_set_defaults) from [<c02c3124>] (platform_drv_probe+0x18/0xa4)
    [<c02c3124>] (platform_drv_probe) from [<c02c1d0c>] (driver_probe_device+0x10c/0x22c)
    [<c02c1d0c>] (driver_probe_device) from [<c02c1eb8>] (__driver_attach+0x8c/0x90)
    [<c02c1eb8>] (__driver_attach) from [<c02c0544>] (bus_for_each_dev+0x54/0x88)
    [<c02c0544>] (bus_for_each_dev) from [<c02c150c>] (bus_add_driver+0xd4/0x1d0)
    [<c02c150c>] (bus_add_driver) from [<c02c24e0>] (driver_register+0x78/0xf4)
    [<c02c24e0>] (driver_register) from [<c07091f0>] (fimc_md_init+0x14/0x30)
    [<c07091f0>] (fimc_md_init) from [<c0008944>] (do_one_initcall+0x80/0x1d0)
    [<c0008944>] (do_one_initcall) from [<c06edd64>] (kernel_init_freeable+0x108/0x1d4)
    [<c06edd64>] (kernel_init_freeable) from [<c04e64fc>] (kernel_init+0x8/0xec)
    [<c04e64fc>] (kernel_init) from [<c000e838>] (ret_from_fork+0x14/0x3c)
    Code: ebfff4ae e5943014 e5942018 e3530000 (e5823000)
    
    Let's create a per-user handle here so that clk_put() can
    properly unlink it and free the handle. Now that we allocate a
    clk structure here we need to free it if __clk_get() fails so
    bury the __clk_get() call in __of_clk_get_from_provider(). We
    need to handle the same problem in clk_get_sys() so export
    __clk_free_clk() to clkdev.c and do the same thing, except let's
    use a union to make this code #ifdef free.
    
    This fixes the above crash, properly calls __clk_get() when
    of_clk_get_from_provider() is called, and cleans up the clk
    structure on the error path of clk_get_sys().
    
    Fixes: 035a61c3 "clk: Make clk API return per-user struct clk instances"
    Reported-by: default avatarSylwester Nawrocki <s.nawrocki@samsung.com>
    Reported-by: default avatarAlban Browaeys <alban.browaeys@gmail.com>
    Tested-by: default avatarSylwester Nawrocki <s.nawrocki@samsung.com>
    Tested-by: default avatarAlban Browaeys <prahal@yahoo.com>
    Reviewed-by: default avatarTomeu Vizoso <tomeu.vizoso@collabora.com>
    Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
    Signed-off-by: default avatarMichael Turquette <mturquette@linaro.org>
    73e0e496
clk.h 1.12 KB