linux-kernel - Re: [PATCH V5 1/3] firmware: qcom_scm: provide a read-modify-write function

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Message-ID: <3ab86e8d-cc00-d0bb-20f8-4c75c90a7db8@quicinc.com>
Date:   Sun, 23 Jul 2023 19:25:03 +0530
From:   Kathiravan T <quic_kathirav@...cinc.com>
To:     Trilok Soni <quic_tsoni@...cinc.com>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konrad.dybcio@...aro.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        "Elliot Berman" <quic_eberman@...cinc.com>,
        Mukesh Ojha <quic_mojha@...cinc.com>,
        Kalle Valo <kvalo@...nel.org>,
        Loic Poulain <loic.poulain@...aro.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-gpio@...r.kernel.org>
CC:     <quic_srichara@...cinc.com>, <quic_sjaganat@...cinc.com>,
        <quic_anusha@...cinc.com>, <quic_saahtoma@...cinc.com>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
Subject: Re: [PATCH V5 1/3] firmware: qcom_scm: provide a read-modify-write
 function


On 7/22/2023 6:47 AM, Trilok Soni wrote:
> On 7/20/2023 12:04 AM, Kathiravan T wrote:
>> From: Mukesh Ojha <quic_mojha@...cinc.com>
>>
>> It was realized by Srinivas K. that there is a need of read-modify-write
>> scm exported function so that it can be used by multiple clients.
>>
>> Let's introduce qcom_scm_io_update_field() which masks out the bits and
>> write the passed value to that bit-offset.
>>
>> Suggested-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
>> Signed-off-by: Mukesh Ojha <quic_mojha@...cinc.com>
>> Signed-off-by: Kathiravan T <quic_kathirav@...cinc.com>
>> ---
>> Changes in V5:
>>     - No changes
>>
>>   drivers/firmware/qcom_scm.c            | 15 +++++++++++++++
>>   include/linux/firmware/qcom/qcom_scm.h |  2 ++
>>   2 files changed, 17 insertions(+)
>>
>> diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
>> index fde33acd46b7..104d86e49b97 100644
>> --- a/drivers/firmware/qcom_scm.c
>> +++ b/drivers/firmware/qcom_scm.c
>> @@ -407,6 +407,21 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
>>   }
>>   EXPORT_SYMBOL(qcom_scm_set_remote_state);
>>   +int qcom_scm_io_update_field(phys_addr_t addr, unsigned int mask, 
>> unsigned int val)
>> +{
>> +    unsigned int old, new;
>> +    int ret;
>> +
>> +    ret = qcom_scm_io_readl(addr, &old);
>> +    if (ret)
>> +        return ret;
>> +
>> +    new = (old & ~mask) | (val & mask);
>> +
>> +    return qcom_scm_io_writel(addr, new);
>> +}
>> +EXPORT_SYMBOL(qcom_scm_io_update_field);
>
> EXPORT_SYMBO_GPL please.


Sure, is it okay if I send the patch to convert the existing 
EXPORT_SYMBOL to EXPORT_SYMBOL_GPL as well?


>
>> +
>>   static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
>>   {
>>       struct qcom_scm_desc desc = {
>> diff --git a/include/linux/firmware/qcom/qcom_scm.h 
>> b/include/linux/firmware/qcom/qcom_scm.h
>> index 250ea4efb7cb..ca41e4eb33ad 100644
>> --- a/include/linux/firmware/qcom/qcom_scm.h
>> +++ b/include/linux/firmware/qcom/qcom_scm.h
>> @@ -84,6 +84,8 @@ extern bool qcom_scm_pas_supported(u32 peripheral);
>>     extern int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val);
>>   extern int qcom_scm_io_writel(phys_addr_t addr, unsigned int val);
>> +extern int qcom_scm_io_update_field(phys_addr_t addr, unsigned int 
>> mask,
>> +                    unsigned int val);
>>     extern bool qcom_scm_restore_sec_cfg_available(void);
>>   extern int qcom_scm_restore_sec_cfg(u32 device_id, u32 spare);