linux-kernel - Re: [PATCH v3 02/23] gcc-sdm845: Add rates to the GP clocks

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CABTCjFBxOEdpbdYnbvPyf2MRE5m-3gfvHtaPbDF5PmkQZ2kV1w@mail.gmail.com>
Date: Fri, 19 Jul 2024 12:01:48 +0300
From: Dzmitry Sankouski <dsankouski@...il.com>
To: Konrad Dybcio <konrad.dybcio@...aro.org>
Cc: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, Sebastian Reichel <sre@...nel.org>, 
	Bjorn Andersson <andersson@...nel.org>, Michael Turquette <mturquette@...libre.com>, 
	Stephen Boyd <sboyd@...nel.org>, Neil Armstrong <neil.armstrong@...aro.org>, 
	Jessica Zhang <quic_jesszhan@...cinc.com>, Sam Ravnborg <sam@...nborg.org>, 
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>, Maxime Ripard <mripard@...nel.org>, 
	Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>, 
	Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Lee Jones <lee@...nel.org>, Dmitry Torokhov <dmitry.torokhov@...il.com>, Pavel Machek <pavel@....cz>, 
	Liam Girdwood <lgirdwood@...il.com>, Mark Brown <broonie@...nel.org>, 
	Uwe Kleine-König <ukleinek@...nel.org>, 
	Krzysztof Kozlowski <krzk@...nel.org>, Chanwoo Choi <cw00.choi@...sung.com>, phone-devel@...r.kernel.org, 
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org, 
	linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org, 
	dri-devel@...ts.freedesktop.org, devicetree@...r.kernel.org, 
	linux-input@...r.kernel.org, linux-leds@...r.kernel.org, 
	linux-pwm@...r.kernel.org, linux-samsung-soc@...r.kernel.org
Subject: Re: [PATCH v3 02/23] gcc-sdm845: Add rates to the GP clocks

Why cannot max values be defined as ((2 ^ mnd_width) - 1) and ((2 ^
hid_width) - 1)?

вт, 18 июн. 2024 г. в 22:12, Konrad Dybcio <konrad.dybcio@...aro.org>:
>
>
>
> On 6/18/24 20:55, Dmitry Baryshkov wrote:
> > On Tue, Jun 18, 2024 at 08:50:52PM GMT, Konrad Dybcio wrote:
> >>
> >>
> >> On 6/18/24 19:50, Dmitry Baryshkov wrote:
> >>> On Tue, Jun 18, 2024 at 04:59:36PM GMT, Dzmitry Sankouski wrote:
> >>>> sdm845 has "General Purpose" clocks that can be muxed to
> >>>> SoC pins.
> >>>>
> >>>> Those clocks may be used as e.g. PWM sources for external peripherals.
> >>>> Add more frequencies to the table for those clocks so it's possible
> >>>> for arbitrary peripherals to make use of them.
> >>>>
> >>>> See also: bf8bb8eaccf(clk: qcom: gcc-msm8916: Add rates to the GP clocks)
> >>>
> >>> Each time I look at the table attached to the GP CLK, I feel that it's
> >>> plain wrong. In the end the GPCLK can in theory have arbitrary value
> >>> depending on the usecase.
> >>>
> >>> Bjorn, Konrad, maybe we should add special clk_ops for GP CLK which
> >>> allow more flexibility than a default clk_rcg2_ops?
> >>
> >> If we can somehow get max m/n/d values for all possible parents, sure
> >
> > Calculate them at runtime?
>
> We'd be calculating the mnd values for a frequency that's either equal or
> reasonably close to the one requested. My worry is that we somehow need
> to get the maximum values they can take (unless they're well-known)
>
> Konrad