On Tue 04 Jul 2023 at 22:54, Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx> wrote:
> Hello Jerome,
>
> Thank you for the review!
>
> On Tue, Jul 04, 2023 at 09:43:41PM +0200, Jerome Brunet wrote:
>>
>> On Mon 03 Jul 2023 at 23:04, Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx> wrote:
>>
>> > The function meson_clk_pll_enable() can be invoked under the enable_lock
>> > spinlock from the clk core logic
>>
>> ---
>> > (please refer to
>> > drivers/clk/clk.c:clk_core_enable_lock()), which risks a kernel panic
>> > during the usleep_range() call:
>> >
>>
>> This part of the comment is not very useful - please drop it
>>
>
> Do you mean a stack trace or reference to clk_core_enable_lock()?
The comment about clk_core_enable_lock.
The stack trace is useful, it may help people googling the warning
>
>> > BUG: scheduling while atomic: kworker/u4:2/36/0x00000002
>> > Modules linked in: g_ffs usb_f_fs libcomposite
>> > CPU: 1 PID: 36 Comm: kworker/u4:2 Not tainted 6.4.0-rc5 #273
>> > Workqueue: events_unbound async_run_entry_fn
>> > Call trace:
>> > dump_backtrace+0x9c/0x128
>> > show_stack+0x20/0x38
>> > dump_stack_lvl+0x48/0x60
>> > dump_stack+0x18/0x28
>> > __schedule_bug+0x58/0x78
>> > __schedule+0x828/0xa88
>> > schedule+0x64/0xd8
>> > schedule_hrtimeout_range_clock+0xd0/0x208
>> > schedule_hrtimeout_range+0x1c/0x30
>> > usleep_range_state+0x6c/0xa8
>> > meson_clk_pll_enable+0x1f4/0x310
>> > clk_core_enable+0x78/0x200
>> > clk_core_enable+0x58/0x200
>> > clk_core_enable+0x58/0x200
>> > clk_core_enable+0x58/0x200
>> > clk_enable+0x34/0x60
>> >
>> > Considering that this code is expected to be used in an atomic context,
>> > it is required to use the udelay() function instead of usleep_range()
>> > for the atomic context safety.
>>
>> Please use an imperative form, instructing the code to change
>>
>
> Ack
>
>> >
>> > Fixes: b6ec400aa153 ("clk: meson: introduce new pll power-on sequence for A1 SoC family")
>> > Reported-by: Jan Dakinevich <yvdakinevich@xxxxxxxxxxxxxx>
>> > Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxx>
>> > Signed-off-by: Jan Dakinevich <yvdakinevich@xxxxxxxxxxxxxx>
>>
>> The tags are confusing here
>> I suppose a 2 lines change has not be been written with 4 hands ;)
>>
>> If Jan just reported and you made the change then drop his signed-off
>> If he did the job, then drop the reported-by and change the author
>>
>
> No problem :) Sometimes 2 lines change is produced during 4 hands
> debugging :)
>
>> > ---
>> > drivers/clk/meson/clk-pll.c | 4 ++--
>> > 1 file changed, 2 insertions(+), 2 deletions(-)
>> >
>> > diff --git a/drivers/clk/meson/clk-pll.c b/drivers/clk/meson/clk-pll.c
>> > index 56ec2210f1ad..eef6f37c8d8d 100644
>> > --- a/drivers/clk/meson/clk-pll.c
>> > +++ b/drivers/clk/meson/clk-pll.c
>> > @@ -367,9 +367,9 @@ static int meson_clk_pll_enable(struct clk_hw *hw)
>> > * 3. enable the lock detect module
>> > */
>> > if (MESON_PARM_APPLICABLE(&pll->current_en)) {
>> > - usleep_range(10, 20);
>> > + udelay(10);
>> > meson_parm_write(clk->map, &pll->current_en, 1);
>> > - usleep_range(40, 50);
>> > + udelay(40);
>> > };
>> >
>> > if (MESON_PARM_APPLICABLE(&pll->l_detect)) {
>>
