[v2,0/6] Exynos5: cleanup clocks handling in power domains

Hello,

This patchset performs cleanup of the clock handling during Exynos power
domain power on/off sequences. This has been achieved by moving all clock
related operations from Exynos power domain driver to respective Exynos
clock controller drivers. Such change is possible after introducinng
runtime power-management in common clock framework.

Another nice result of this cleanup is removal of deplock warning reported
in the following thread (the 'second issue'):
https://www.spinics.net/lists/linux-samsung-soc/msg61766.html

[    5.932966] ======================================================
[    5.937199] usb 5-1: new high-speed USB device number 2 using xhci-hcd
[    5.939073] WARNING: possible circular locking dependency detected
[    5.939110] 4.15.0-rc8-next-20180116 #1121 Tainted: G        W       
[    5.958143] ------------------------------------------------------
[    5.964299] kworker/0:1/59 is trying to acquire lock:
[    5.969304]  (&genpd->mlock){+.+.}, at: [<6abc3872>] genpd_runtime_resume+0x104/0x260
[    5.977155] 
[    5.977155] but task is already holding lock:
[    5.982926]  (prepare_lock){+.+.}, at: [<74cef905>] clk_prepare_lock+0x10/0xf8
[    5.990143] 
[    5.990143] which lock already depends on the new lock.
[    5.990143] 
[    5.998309] 
[    5.998309] the existing dependency chain (in reverse order) is:
[    6.005739] 
[    6.005739] -> #1 (prepare_lock){+.+.}:
[    6.011042]        mutex_lock_nested+0x1c/0x24
[    6.015419]        clk_prepare_lock+0x50/0xf8
[    6.019755]        clk_unprepare+0x1c/0x2c
[    6.023841]        exynos_pd_power+0x1a8/0x1e4
[    6.028246]        genpd_power_off+0x160/0x274
[    6.032664]        genpd_power_off_work_fn+0x2c/0x40
[    6.037630]        process_one_work+0x2d4/0x8f0
[    6.042104]        worker_thread+0x38/0x584
[    6.046268]        kthread+0x138/0x168
[    6.049981]        ret_from_fork+0x14/0x20
[    6.054044]          (null)
[    6.056794] 
[    6.056794] -> #0 (&genpd->mlock){+.+.}:
[    6.062238]        __mutex_lock+0x7c/0xa68
[    6.066278]        mutex_lock_nested+0x1c/0x24
[    6.070703]        genpd_runtime_resume+0x104/0x260
[    6.075557]        __rpm_callback+0xc0/0x21c
[    6.079792]        rpm_callback+0x20/0x80
[    6.083774]        rpm_resume+0x558/0x7dc
[    6.087762]        __pm_runtime_resume+0x60/0x98
[    6.092367]        clk_core_prepare+0x44/0x490
[    6.096783]        clk_prepare+0x20/0x30
[    6.100674]        amba_get_enable_pclk+0x2c/0x60
[    6.105363]        amba_device_try_add+0x8c/0x20c
[    6.110041]        amba_deferred_retry_func+0x40/0xbc
[    6.115080]        process_one_work+0x2d4/0x8f0
[    6.119569]        worker_thread+0x38/0x584
[    6.123727]        kthread+0x138/0x168
[    6.127444]        ret_from_fork+0x14/0x20
[    6.131510]          (null)
[    6.134263] 
[    6.134263] other info that might help us debug this:
[    6.134263] 
[    6.142328]  Possible unsafe locking scenario:
[    6.142328] 
[    6.148178]        CPU0                    CPU1
[    6.152656]        ----                    ----
[    6.157160]   lock(prepare_lock);
[    6.160439]                                lock(&genpd->mlock);
[    6.166365]                                lock(prepare_lock);
[    6.172168]   lock(&genpd->mlock);
[    6.175517] 
[    6.175517]  *** DEADLOCK ***
[    6.175517] 
[    6.181475] 4 locks held by kworker/0:1/59:
[    6.185580]  #0:  ((wq_completion)"events"){+.+.}, at: [<f71c19aa>] process_one_work+0x210/0x8f0
[    6.194407]  #1:  ((deferred_retry_work).work){+.+.}, at: [<f71c19aa>] process_one_work+0x210/0x8f0
[    6.203422]  #2:  (deferred_devices_lock){+.+.}, at: [<3e940c1f>] amba_deferred_retry_func+0x1c/0xbc
[    6.212522]  #3:  (prepare_lock){+.+.}, at: [<74cef905>] clk_prepare_lock+0x10/0xf8
[    6.220128] 
[    6.220128] stack backtrace:
[    6.224438] CPU: 0 PID: 59 Comm: kworker/0:1 Tainted: G        W        4.15.0-rc8-next-20180116 #1121
[    6.233757] Hardware name: SAMSUNG EXYNOS (Flattened Device Tree)
[    6.239791] Workqueue: events amba_deferred_retry_func
[    6.244929] [<c0111f90>] (unwind_backtrace) from [<c010e360>] (show_stack+0x10/0x14)
[    6.252670] [<c010e360>] (show_stack) from [<c0a19860>] (dump_stack+0x98/0xc4)
[    6.259877] [<c0a19860>] (dump_stack) from [<c0181478>] (print_circular_bug.constprop.17+0x210/0x32c)
[    6.269077] [<c0181478>] (print_circular_bug.constprop.17) from [<c01848f8>] (__lock_acquire+0x155c/0x1ac8)
[    6.278786] [<c01848f8>] (__lock_acquire) from [<c0185884>] (lock_acquire+0xe0/0x2bc)
[    6.286558] [<c0185884>] (lock_acquire) from [<c0a31788>] (__mutex_lock+0x7c/0xa68)
[    6.294181] [<c0a31788>] (__mutex_lock) from [<c0a32190>] (mutex_lock_nested+0x1c/0x24)
[    6.302161] [<c0a32190>] (mutex_lock_nested) from [<c05885dc>] (genpd_runtime_resume+0x104/0x260)
[    6.311008] [<c05885dc>] (genpd_runtime_resume) from [<c057c6c4>] (__rpm_callback+0xc0/0x21c)
[    6.319484] [<c057c6c4>] (__rpm_callback) from [<c057c840>] (rpm_callback+0x20/0x80)
[    6.327185] [<c057c840>] (rpm_callback) from [<c057c2a8>] (rpm_resume+0x558/0x7dc)
[    6.334721] [<c057c2a8>] (rpm_resume) from [<c057c58c>] (__pm_runtime_resume+0x60/0x98)
[    6.342706] [<c057c58c>] (__pm_runtime_resume) from [<c04b7f6c>] (clk_core_prepare+0x44/0x490)
[    6.351297] [<c04b7f6c>] (clk_core_prepare) from [<c04ba304>] (clk_prepare+0x20/0x30)
[    6.359081] [<c04ba304>] (clk_prepare) from [<c04b52f4>] (amba_get_enable_pclk+0x2c/0x60)
[    6.367229] [<c04b52f4>] (amba_get_enable_pclk) from [<c04b5510>] (amba_device_try_add+0x8c/0x20c)
[    6.376164] [<c04b5510>] (amba_device_try_add) from [<c04b56f8>] (amba_deferred_retry_func+0x40/0xbc)
[    6.385361] [<c04b56f8>] (amba_deferred_retry_func) from [<c01465b4>] (process_one_work+0x2d4/0x8f0)
[    6.394457] [<c01465b4>] (process_one_work) from [<c0147860>] (worker_thread+0x38/0x584)
[    6.402497] [<c0147860>] (worker_thread) from [<c014d794>] (kthread+0x138/0x168)
[    6.409852] [<c014d794>] (kthread) from [<c01010b4>] (ret_from_fork+0x14/0x20)

This patchset affects Exynos5250 and Exynos5420/5422/5800 SoCs.

Changes has been tested on Snow Chromebook (Exynos5250), Peach-Pit
Chromebook2 (Exynos5420) and Odroid XU3/XU4 (Exynos5422) boards with
latest linux-next kernel.

If possible I would like to get patches 1-4 merged to current clk-next
tree and patches 5-6 queued to next merge cycle.

Best regards
Marek Szyprowski
Samsung R&D Institute Poland


Changelog:

v2:
- fixed minor style issues pointed by Krzysztof Kozlowski


Patch summary:

Marek Szyprowski (6):
  soc: samsung: pm_domains: Add blacklisting clock handling
  clk: samsung: Add Exynos5 sub-CMU clock driver
  clk: samsung: exynos5420: Move PD-dependent clocks to Exynos5 sub-CMU
    driver
  clk: samsung: exynos5250: Move PD-dependent clocks to Exynos5 sub-CMU
    driver
  soc: samsung: pm_domains: Deprecate support for clocks
  ARM: dts: exynos: Remove obsolete clock properties from power domains

 .../devicetree/bindings/power/pd-samsung.txt       |  20 +--
 arch/arm/boot/dts/exynos5250.dtsi                  |   4 -
 arch/arm/boot/dts/exynos5420.dtsi                  |  14 --
 drivers/clk/samsung/Makefile                       |   2 +
 drivers/clk/samsung/clk-exynos5-subcmu.c           | 188 +++++++++++++++++++++
 drivers/clk/samsung/clk-exynos5-subcmu.h           |  26 +++
 drivers/clk/samsung/clk-exynos5250.c               |  51 ++++--
 drivers/clk/samsung/clk-exynos5420.c               | 121 ++++++++++---
 drivers/soc/samsung/pm_domains.c                   |  79 +--------
 9 files changed, 351 insertions(+), 154 deletions(-)
 create mode 100644 drivers/clk/samsung/clk-exynos5-subcmu.c
 create mode 100644 drivers/clk/samsung/clk-exynos5-subcmu.h

-- 
2.15.0

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