linux-kernel - Re: [PATCH v4 1/4] clk: qcom: branch: Add clk_branch2_mdio

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: <23b1ff70-21c0-f4e2-c377-55317f69357c@quicinc.com>
Date:   Fri, 18 Aug 2023 16:20:33 +0800
From:   Jie Luo <quic_luoj@...cinc.com>
To:     Bjorn Andersson <andersson@...nel.org>
CC:     <agross@...nel.org>, <konrad.dybcio@...aro.org>,
        <mturquette@...libre.com>, <sboyd@...nel.org>,
        <robh+dt@...nel.org>, <krzysztof.kozlowski+dt@...aro.org>,
        <conor+dt@...nel.org>, <catalin.marinas@....com>,
        <will@...nel.org>, <p.zabel@...gutronix.de>,
        <linux-arm-msm@...r.kernel.org>, <linux-clk@...r.kernel.org>,
        <devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <quic_srichara@...cinc.com>
Subject: Re: [PATCH v4 1/4] clk: qcom: branch: Add clk_branch2_mdio_ops



On 8/18/2023 11:29 AM, Bjorn Andersson wrote:
> On Tue, Aug 15, 2023 at 04:52:02PM +0800, Luo Jie wrote:
>> Add the clk_branch2_mdio_ops for supporting clock controller
>> where the hardware register is accessed by MDIO bus, and the
>> spin clock can't be used because of sleep during the MDIO
> 
> spin clock?
> 
> I believe you're trying to say that the underlying access to the MDIO
> bus can not be done in non-sleepable context and we can therefor not use
> enable/disable to operate it?

Hi Bjorn,
Thanks for the review comments.
yes, the MDIO operation can't be done in non-sleepable context, and 
enable/disable clock is using spin lock, so i enable the clock in 
.prepare ops.

will fix this typo"spin clock" to "spin lock"

> 
>> operation.
>>
>> The clock is enabled by the .prepare instead of .enable when
>> the clk_branch2_mdio_ops is used.
>>
>> Signed-off-by: Luo Jie <quic_luoj@...cinc.com>
>> ---
>>   drivers/clk/qcom/clk-branch.c | 7 +++++++
>>   drivers/clk/qcom/clk-branch.h | 1 +
>>   2 files changed, 8 insertions(+)
>>
>> diff --git a/drivers/clk/qcom/clk-branch.c b/drivers/clk/qcom/clk-branch.c
>> index fc4735f74f0f..5e08c026ca4a 100644
>> --- a/drivers/clk/qcom/clk-branch.c
>> +++ b/drivers/clk/qcom/clk-branch.c
>> @@ -153,3 +153,10 @@ const struct clk_ops clk_branch_simple_ops = {
>>   	.is_enabled = clk_is_enabled_regmap,
>>   };
>>   EXPORT_SYMBOL_GPL(clk_branch_simple_ops);
>> +
>> +const struct clk_ops clk_branch2_mdio_ops = {
>> +	.prepare = clk_branch2_enable,
>> +	.unprepare = clk_branch2_disable,
> 
> I see none of the clocks specify halt_check, which would imply that
> these two calls just turns into clk_enable_regmap() and
> clk_disable_regmap().
> 
> So, isn't this then equivalent to clk_branch_simple_ops?
> 
> Regards,
> Bjorn
> 

Thanks Bjorn for pointing this, i will add the the halt_check in the 
next patch set, halt_check is applicable.

>> +	.is_prepared = clk_is_enabled_regmap,
>> +};
>> +EXPORT_SYMBOL_GPL(clk_branch2_mdio_ops);
>> diff --git a/drivers/clk/qcom/clk-branch.h b/drivers/clk/qcom/clk-branch.h
>> index 0cf800b9d08d..4b006e8eec5e 100644
>> --- a/drivers/clk/qcom/clk-branch.h
>> +++ b/drivers/clk/qcom/clk-branch.h
>> @@ -85,6 +85,7 @@ extern const struct clk_ops clk_branch_ops;
>>   extern const struct clk_ops clk_branch2_ops;
>>   extern const struct clk_ops clk_branch_simple_ops;
>>   extern const struct clk_ops clk_branch2_aon_ops;
>> +extern const struct clk_ops clk_branch2_mdio_ops;
>>   
>>   #define to_clk_branch(_hw) \
>>   	container_of(to_clk_regmap(_hw), struct clk_branch, clkr)
>> -- 
>> 2.17.1
>>