linux-stable.git/drivers/clk, branch v5.4.282

clk: davinci: da8xx-cfgchip: Initialize clk_init_data before use

2024-08-19T03:33:37+00:00

commit a83b22754e351f13fb46596c85f667dc33da71ec upstream.

The flag attribute of the struct clk_init_data isn't initialized before
the devm_clk_hw_register() call. This can lead to unexpected behavior
during registration.

Initialize the entire clk_init_data to zero at declaration.

Cc: stable@vger.kernel.org
Fixes: 58e1e2d2cd89 ("clk: davinci: cfgchip: Add TI DA8XX USB PHY clocks")
Signed-off-by: Bastien Curutchet 
Reviewed-by: David Lechner 
Link: https://lore.kernel.org/r/20240718115534.41513-1-bastien.curutchet@bootlin.com
Signed-off-by: Stephen Boyd 
Signed-off-by: Greg Kroah-Hartman

clk: Don't hold prepare_lock when calling kref_put()

2024-05-17T09:43:53+00:00

[ Upstream commit 6f63af7511e7058f3fa4ad5b8102210741c9f947 ]

We don't need to hold the prepare_lock when dropping a ref on a struct
clk_core. The release function is only freeing memory and any code with
a pointer reference has already unlinked anything pointing to the
clk_core. This reduces the holding area of the prepare_lock a bit.

Note that we also don't call free_clk() with the prepare_lock held.
There isn't any reason to do that.

Reviewed-by: Douglas Anderson 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20240325184204.745706-3-sboyd@kernel.org
Signed-off-by: Sasha Levin

clk: sunxi-ng: h6: Reparent CPUX during PLL CPUX rate change

2024-05-17T09:43:50+00:00

[ Upstream commit 7e91ed763dc07437777bd012af7a2bd4493731ff ]

While PLL CPUX clock rate change when CPU is running from it works in
vast majority of cases, now and then it causes instability. This leads
to system crashes and other undefined behaviour. After a lot of testing
(30+ hours) while also doing a lot of frequency switches, we can't
observe any instability issues anymore when doing reparenting to stable
clock like 24 MHz oscillator.

Fixes: 524353ea480b ("clk: sunxi-ng: add support for the Allwinner H6 CCU")
Reported-by: Chad Wagner 
Link: https://forum.libreelec.tv/thread/27295-orange-pi-3-lts-freezes/
Tested-by: Chad Wagner 
Reviewed-by: Chen-Yu Tsai 
Link: https://lore.kernel.org/r/20231013181712.2128037-1-jernej.skrabec@gmail.com
Signed-off-by: Jernej Skrabec 
Signed-off-by: Sasha Levin

clk: Get runtime PM before walking tree during disable_unused

2024-05-02T14:18:31+00:00

[ Upstream commit e581cf5d216289ef292d1a4036d53ce90e122469 ]

Doug reported [1] the following hung task:

 INFO: task swapper/0:1 blocked for more than 122 seconds.
       Not tainted 5.15.149-21875-gf795ebc40eb8 #1
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 task:swapper/0       state:D stack:    0 pid:    1 ppid:     0 flags:0x00000008
 Call trace:
  __switch_to+0xf4/0x1f4
  __schedule+0x418/0xb80
  schedule+0x5c/0x10c
  rpm_resume+0xe0/0x52c
  rpm_resume+0x178/0x52c
  __pm_runtime_resume+0x58/0x98
  clk_pm_runtime_get+0x30/0xb0
  clk_disable_unused_subtree+0x58/0x208
  clk_disable_unused_subtree+0x38/0x208
  clk_disable_unused_subtree+0x38/0x208
  clk_disable_unused_subtree+0x38/0x208
  clk_disable_unused_subtree+0x38/0x208
  clk_disable_unused+0x4c/0xe4
  do_one_initcall+0xcc/0x2d8
  do_initcall_level+0xa4/0x148
  do_initcalls+0x5c/0x9c
  do_basic_setup+0x24/0x30
  kernel_init_freeable+0xec/0x164
  kernel_init+0x28/0x120
  ret_from_fork+0x10/0x20
 INFO: task kworker/u16:0:9 blocked for more than 122 seconds.
       Not tainted 5.15.149-21875-gf795ebc40eb8 #1
 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
 task:kworker/u16:0   state:D stack:    0 pid:    9 ppid:     2 flags:0x00000008
 Workqueue: events_unbound deferred_probe_work_func
 Call trace:
  __switch_to+0xf4/0x1f4
  __schedule+0x418/0xb80
  schedule+0x5c/0x10c
  schedule_preempt_disabled+0x2c/0x48
  __mutex_lock+0x238/0x488
  __mutex_lock_slowpath+0x1c/0x28
  mutex_lock+0x50/0x74
  clk_prepare_lock+0x7c/0x9c
  clk_core_prepare_lock+0x20/0x44
  clk_prepare+0x24/0x30
  clk_bulk_prepare+0x40/0xb0
  mdss_runtime_resume+0x54/0x1c8
  pm_generic_runtime_resume+0x30/0x44
  __genpd_runtime_resume+0x68/0x7c
  genpd_runtime_resume+0x108/0x1f4
  __rpm_callback+0x84/0x144
  rpm_callback+0x30/0x88
  rpm_resume+0x1f4/0x52c
  rpm_resume+0x178/0x52c
  __pm_runtime_resume+0x58/0x98
  __device_attach+0xe0/0x170
  device_initial_probe+0x1c/0x28
  bus_probe_device+0x3c/0x9c
  device_add+0x644/0x814
  mipi_dsi_device_register_full+0xe4/0x170
  devm_mipi_dsi_device_register_full+0x28/0x70
  ti_sn_bridge_probe+0x1dc/0x2c0
  auxiliary_bus_probe+0x4c/0x94
  really_probe+0xcc/0x2c8
  __driver_probe_device+0xa8/0x130
  driver_probe_device+0x48/0x110
  __device_attach_driver+0xa4/0xcc
  bus_for_each_drv+0x8c/0xd8
  __device_attach+0xf8/0x170
  device_initial_probe+0x1c/0x28
  bus_probe_device+0x3c/0x9c
  deferred_probe_work_func+0x9c/0xd8
  process_one_work+0x148/0x518
  worker_thread+0x138/0x350
  kthread+0x138/0x1e0
  ret_from_fork+0x10/0x20

The first thread is walking the clk tree and calling
clk_pm_runtime_get() to power on devices required to read the clk
hardware via struct clk_ops::is_enabled(). This thread holds the clk
prepare_lock, and is trying to runtime PM resume a device, when it finds
that the device is in the process of resuming so the thread schedule()s
away waiting for the device to finish resuming before continuing. The
second thread is runtime PM resuming the same device, but the runtime
resume callback is calling clk_prepare(), trying to grab the
prepare_lock waiting on the first thread.

This is a classic ABBA deadlock. To properly fix the deadlock, we must
never runtime PM resume or suspend a device with the clk prepare_lock
held. Actually doing that is near impossible today because the global
prepare_lock would have to be dropped in the middle of the tree, the
device runtime PM resumed/suspended, and then the prepare_lock grabbed
again to ensure consistency of the clk tree topology. If anything
changes with the clk tree in the meantime, we've lost and will need to
start the operation all over again.

Luckily, most of the time we're simply incrementing or decrementing the
runtime PM count on an active device, so we don't have the chance to
schedule away with the prepare_lock held. Let's fix this immediate
problem that can be triggered more easily by simply booting on Qualcomm
sc7180.

Introduce a list of clk_core structures that have been registered, or
are in the process of being registered, that require runtime PM to
operate. Iterate this list and call clk_pm_runtime_get() on each of them
without holding the prepare_lock during clk_disable_unused(). This way
we can be certain that the runtime PM state of the devices will be
active and resumed so we can't schedule away while walking the clk tree
with the prepare_lock held. Similarly, call clk_pm_runtime_put() without
the prepare_lock held to properly drop the runtime PM reference. We
remove the calls to clk_pm_runtime_{get,put}() in this path because
they're superfluous now that we know the devices are runtime resumed.

Reported-by: Douglas Anderson 
Closes: https://lore.kernel.org/all/20220922084322.RFC.2.I375b6b9e0a0a5348962f004beb3dafee6a12dfbb@changeid/ [1]
Closes: https://issuetracker.google.com/328070191
Cc: Marek Szyprowski 
Cc: Ulf Hansson 
Cc: Krzysztof Kozlowski 
Fixes: 9a34b45397e5 ("clk: Add support for runtime PM")
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20240325184204.745706-5-sboyd@kernel.org
Reviewed-by: Douglas Anderson 
Signed-off-by: Sasha Levin

clk: Initialize struct clk_core kref earlier

2024-05-02T14:18:31+00:00

[ Upstream commit 9d05ae531c2cff20d5d527f04e28d28e04379929 ]

Initialize this kref once we allocate memory for the struct clk_core so
that we can reuse the release function to free any memory associated
with the structure. This mostly consolidates code, but also clarifies
that the kref lifetime exists once the container structure (struct
clk_core) is allocated instead of leaving it in a half-baked state for
most of __clk_core_init().

Reviewed-by: Douglas Anderson 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20240325184204.745706-4-sboyd@kernel.org
Stable-dep-of: e581cf5d2162 ("clk: Get runtime PM before walking tree during disable_unused")
Signed-off-by: Sasha Levin

clk: Print an info line before disabling unused clocks

2024-05-02T14:18:30+00:00

[ Upstream commit 12ca59b91d04df32e41be5a52f0cabba912c11de ]

Currently, the regulator framework informs us before calling into
their unused cleanup paths, which eases at least some debugging. The
same could be beneficial for clocks, so that random shutdowns shortly
after most initcalls are done can be less of a guess.

Add a pr_info before disabling unused clocks to do so.

Reviewed-by: Marijn Suijten 
Signed-off-by: Konrad Dybcio 
Link: https://lore.kernel.org/r/20230307132928.3887737-1-konrad.dybcio@linaro.org
Signed-off-by: Stephen Boyd 
Stable-dep-of: e581cf5d2162 ("clk: Get runtime PM before walking tree during disable_unused")
Signed-off-by: Sasha Levin

clk: remove extra empty line

2024-05-02T14:18:30+00:00

[ Upstream commit 79806d338829b2bf903480428d8ce5aab8e2d24b ]

Remove extra empty line.

Signed-off-by: Claudiu Beznea 
Link: https://lore.kernel.org/r/20220630151205.3935560-1-claudiu.beznea@microchip.com
Signed-off-by: Stephen Boyd 
Stable-dep-of: e581cf5d2162 ("clk: Get runtime PM before walking tree during disable_unused")
Signed-off-by: Sasha Levin

clk: Mark 'all_lists' as const

2024-05-02T14:18:30+00:00

[ Upstream commit 75061a6ff49ba3482c6319ded0c26e6a526b0967 ]

This list array doesn't change at runtime. Mark it const to move to RO
memory.

Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20220217220554.2711696-2-sboyd@kernel.org
Stable-dep-of: e581cf5d2162 ("clk: Get runtime PM before walking tree during disable_unused")
Signed-off-by: Sasha Levin

clk: Remove prepare_lock hold assertion in __clk_release()

2024-05-02T14:18:30+00:00

[ Upstream commit 8358a76cfb47c9a5af627a0c4e7168aa14fa25f6 ]

Removing this assertion lets us move the kref_put() call outside the
prepare_lock section. We don't need to hold the prepare_lock here to
free memory and destroy the clk_core structure. We've already unlinked
the clk from the clk tree and by the time the release function runs
nothing holds a reference to the clk_core anymore so anything with the
pointer can't access the memory that's being freed anyway. Way back in
commit 496eadf821c2 ("clk: Use lockdep asserts to find missing hold of
prepare_lock") we didn't need to have this assertion either.

Fixes: 496eadf821c2 ("clk: Use lockdep asserts to find missing hold of prepare_lock")
Cc: Krzysztof Kozlowski 
Reviewed-by: Douglas Anderson 
Signed-off-by: Stephen Boyd 
Link: https://lore.kernel.org/r/20240325184204.745706-2-sboyd@kernel.org
Signed-off-by: Sasha Levin

clk: qcom: mmcc-msm8974: fix terminating of frequency table arrays

2024-04-13T10:51:24+00:00

[ Upstream commit e2c02a85bf53ae86d79b5fccf0a75ac0b78e0c96 ]

The frequency table arrays are supposed to be terminated with an
empty element. Add such entry to the end of the arrays where it
is missing in order to avoid possible out-of-bound access when
the table is traversed by functions like qcom_find_freq() or
qcom_find_freq_floor().

Only compile tested.

Fixes: d8b212014e69 ("clk: qcom: Add support for MSM8974's multimedia clock controller (MMCC)")
Signed-off-by: Gabor Juhos 
Reviewed-by: Stephen Boyd 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20240229-freq-table-terminator-v1-7-074334f0905c@gmail.com
Signed-off-by: Bjorn Andersson 
Signed-off-by: Sasha Levin