linux-kernel - Re: [PATCH 08/13] thermal/drivers/hisi: Fix configuration register setting

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: <e5775d5d-bd5d-5472-31e6-a0751a9aa0ce@linaro.org>
Date:   Sat, 2 Sep 2017 10:34:34 +0200
From:   Daniel Lezcano <daniel.lezcano@...aro.org>
To:     Leo Yan <leo.yan@...aro.org>
Cc:     rui.zhang@...el.com, edubezval@...il.com, linux-pm@...r.kernel.org,
        kevin.wangtao@...aro.org, open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 08/13] thermal/drivers/hisi: Fix configuration register
 setting

On 02/09/2017 04:54, Leo Yan wrote:
> On Wed, Aug 30, 2017 at 10:47:32AM +0200, Daniel Lezcano wrote:
>> The TEMP0_CFG configuration register contains different field to set up the
>> temperature controller. However in the code, nothing prevents a setup to
>> overwrite the previous one: eg. writing the hdak value overwrites the sensor
>> selection, the sensor selection overwrites the hdak value.
>>
>> In order to prevent such thing, use a regmap-like mechanism by reading the
>> value before, set the corresponding bits and write the result.
>>
>> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
>> ---
>>  drivers/thermal/hisi_thermal.c | 30 +++++++++++++++++++++++++-----
>>  1 file changed, 25 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c
>> index d77a938..3e03908 100644
>> --- a/drivers/thermal/hisi_thermal.c
>> +++ b/drivers/thermal/hisi_thermal.c
>> @@ -132,19 +132,39 @@ static inline void hisi_thermal_enable(void __iomem *addr, int value)
>>  	writel(value, addr + TEMP0_EN);
>>  }
>>  
>> -static inline void hisi_thermal_sensor_select(void __iomem *addr, int sensor)
>> +static inline int hisi_thermal_get_temperature(void __iomem *addr)
>>  {
>> -	writel((sensor << 12), addr + TEMP0_CFG);
>> +	return hisi_thermal_step_to_temp(readl(addr + TEMP0_VALUE));
>>  }
>>  
>> -static inline int hisi_thermal_get_temperature(void __iomem *addr)
>> +/*
>> + * Temperature configuration register - Sensor selection
>> + *
>> + * Bits [19:12]
>> + *
>> + * 0x0: local sensor (default)
>> + * 0x1: remote sensor 1 (ACPU cluster 1)
>> + * 0x2: remote sensor 2 (ACPU cluster 0)
>> + * 0x3: remote sensor 3 (G3D)
>> + */
>> +static inline void hisi_thermal_sensor_select(void __iomem *addr, int sensor)
>>  {
>> -	return hisi_thermal_step_to_temp(readl(addr + TEMP0_VALUE));
>> +	writel(readl(addr + TEMP0_CFG) | (sensor << 12), addr + TEMP0_CFG);
> 
> nitpick: maybe it's better to firstly clear related bits and then set
> value?

Sorry, I don't get the comment. Can you elaborate ?


-- 
 <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs

Follow Linaro:  <http://www.facebook.com/pages/Linaro> Facebook |
<http://twitter.com/#!/linaroorg> Twitter |
<http://www.linaro.org/linaro-blog/> Blog