From: Sylwester Nawrocki <s.nawrocki@samsung.com>
To: Chanwoo Choi <cw00.choi@samsung.com>, tomasz.figa@gmail.com
Cc: linux-clk@vger.kernel.org, sboyd@kernel.org,
mturquette@baylibre.com, linux-samsung-soc@vger.kernel.org,
linux-kernel@vger.kernel.org, b.zolnierkie@samsung.com,
m.szyprowski@samsung.com
Subject: Re: [PATCH v3] clk: samsung: Prevent potential endless loop in the PLL set_rate ops
Date: Tue, 15 Sep 2020 13:34:24 +0200 [thread overview]
Message-ID: <c3c40d62-f5bb-6b13-0af9-ce774718eaa6@samsung.com> (raw)
In-Reply-To: <28cd3eeb-816d-b369-11a9-16cd2c1af87c@samsung.com>
On 14.08.2020 02:46, Chanwoo Choi wrote:
> On 8/13/20 6:55 PM, Sylwester Nawrocki wrote:
>> In the .set_rate callback for some PLLs there is a loop polling state
>> of the PLL lock bit and it may become an endless loop when something
>> goes wrong with the PLL. For some PLLs there is already code for polling
>> with a timeout but it uses the ktime API, which doesn't work in some
>> conditions when the set_rate op is called, in particular during
>> initialization of the clk provider before the clocksource initialization
>> has completed. Hence the ktime API cannot be used to reliably detect
>> the PLL locking timeout.
>>
>> This patch adds a common helper function for busy waiting on the PLL lock
>> bit with timeout detection.
>> Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
>> ---
>> Changes for v3:
>> - use busy-loop with udelay() instead of ktime API
>> Changes for v2:
>> - use common readl_relaxed_poll_timeout_atomic() macro
>> ---
>> drivers/clk/samsung/clk-pll.c | 94 ++++++++++++++++---------------------------
>> 1 file changed, 34 insertions(+), 60 deletions(-)
> Thanks.
>
> Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
Patch applied, thank you for your comments.
next prev parent reply other threads:[~2020-09-15 11:49 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20200813095520eucas1p209432599420d62e0e54a5545334c329c@eucas1p2.samsung.com>
2020-08-13 9:55 ` [PATCH v3] clk: samsung: Prevent potential endless loop in the PLL set_rate ops Sylwester Nawrocki
2020-08-14 0:46 ` Chanwoo Choi
2020-09-15 11:34 ` Sylwester Nawrocki [this message]
2020-09-17 10:20 ` Sylwester Nawrocki
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