linux-kernel - Re: [PATCH v2] clk: keystone: sci-clk: Adding support for non contiguous 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]

Date: Tue, 6 Feb 2024 19:56:30 +0530
From: CHANDRU DHAVAMANI <chandru@...com>
To: "Kumar, Udit" <u-kumar1@...com>, Kamlesh Gurudasani <kamlesh@...com>,
        Nishanth Menon <nm@...com>
CC: <kristo@...nel.org>, <ssantosh@...nel.org>, <rishabh@...com>,
        <vigneshr@...com>, <mturquette@...libre.com>, <sboyd@...nel.org>,
        <linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
        <linux-clk@...r.kernel.org>
Subject: Re: [PATCH v2] clk: keystone: sci-clk: Adding support for non
 contiguous clocks


On 06/02/24 19:45, Kumar, Udit wrote:
>
> On 2/6/2024 7:24 PM, Kamlesh Gurudasani wrote:
>> Nishanth Menon <nm@...com> writes:
>>
>>> On 16:13-20240206, Udit Kumar wrote:
>>>> Most of clocks and their parents are defined in contiguous range,
>>>> But in few cases, there is gap in clock numbers[0].
>>>> Driver assumes clocks to be in contiguous range, and add their clock
>>>> ids incrementally.
>>>>
>>>> New firmware started returning error while calling get_freq and is_on
>>>> API for non-available clock ids.
>>>>
>>>> In this fix, driver checks and adds only valid clock ids.
>>>>
>>>> Fixes: 3c13933c6033 ("clk: keystone: sci-clk: add support for 
>>>> dynamically probing clocks")
>>>>
>>>> [0] 
>>>> https://software-dl.ti.com/tisci/esd/latest/5_soc_doc/j7200/clocks.html 
>>>>
>>>> Section Clocks for NAVSS0_CPTS_0 Device,
>>>> clock id 12-15 not present.
>>>>
>>>> Signed-off-by: Udit Kumar <u-kumar1@...com>
>>>>                   while (num_parents--) {
>>>> +                    /* Check if this clock id is valid */
>>>> +                    ret = provider->ops->get_freq(provider->sci,
>>>> +                        sci_clk->dev_id, clk_id, &freq);
>>> get_freq is a bit expensive as it has to walk the clock tree to find
>>> the clock frequency (at least the first time?). just wondering if
>>> there is lighter alternative here?
>>>
>> How about get_clock? Doesn't read the registers at least.
>
> Said API needs, some flags to be passed,
>
> Can those flag be set to zero, Chandru ?


get_clock doesn't require any flags to be passed.


>
>
>> Regards,
>> Kamlesh