linux-kernel - Re: [PATCH 3/6] media: venus: hfi_venus: Support only updating certain bits with presets

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Message-ID: <fdbdbf61-e372-b81d-3a14-7ed27b1249a3@linaro.org>
Date:   Fri, 4 Aug 2023 21:51:22 +0100
From:   Bryan O'Donoghue <bryan.odonoghue@...aro.org>
To:     Konrad Dybcio <konrad.dybcio@...aro.org>,
        Stanimir Varbanov <stanimir.k.varbanov@...il.com>,
        Vikash Garodia <quic_vgarodia@...cinc.com>,
        Bryan O'Donoghue <bryan.odonoghue@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Mauro Carvalho Chehab <mchehab@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>
Cc:     Marijn Suijten <marijn.suijten@...ainline.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        linux-media@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/6] media: venus: hfi_venus: Support only updating
 certain bits with presets

On 04/08/2023 21:50, Bryan O'Donoghue wrote:
> On 04/08/2023 21:09, Konrad Dybcio wrote:
>> On some platforms (like SM8350) we're expected to only touch certain bits
>> (such as 0 and 4 corresponding to mask 0x11). Add support for doing so.
>>
>> Signed-off-by: Konrad Dybcio <konrad.dybcio@...aro.org>
>> ---
>>   drivers/media/platform/qcom/venus/core.h      |  1 +
>>   drivers/media/platform/qcom/venus/hfi_venus.c | 15 ++++++++++++---
>>   2 files changed, 13 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/media/platform/qcom/venus/core.h 
>> b/drivers/media/platform/qcom/venus/core.h
>> index d996abd339e1..2999c24392f5 100644
>> --- a/drivers/media/platform/qcom/venus/core.h
>> +++ b/drivers/media/platform/qcom/venus/core.h
>> @@ -38,6 +38,7 @@ struct freq_tbl {
>>   struct reg_val {
>>       u32 reg;
>>       u32 value;
>> +    u32 mask;
>>   };
>>   struct bw_tbl {
>> diff --git a/drivers/media/platform/qcom/venus/hfi_venus.c 
>> b/drivers/media/platform/qcom/venus/hfi_venus.c
>> index 19fc6575a489..d4bad66f7293 100644
>> --- a/drivers/media/platform/qcom/venus/hfi_venus.c
>> +++ b/drivers/media/platform/qcom/venus/hfi_venus.c
>> @@ -349,10 +349,19 @@ static void venus_set_registers(struct 
>> venus_hfi_device *hdev)
>>       const struct venus_resources *res = hdev->core->res;
>>       const struct reg_val *tbl = res->reg_tbl;
>>       unsigned int count = res->reg_tbl_size;
>> -    unsigned int i;
>> +    unsigned int i, val;
> 
> u32 val;
> 
>> +
>> +    for (i = 0; i < count; i++) {
>> +        val = tbl[i].value;
> 
> struct reg_val looks like this
> 
> struct reg_val {
>          u32 reg;
>          u32 value;
> };
> 
> val should be declared a u32
> 
>> -    for (i = 0; i < count; i++)
>> -        writel(tbl[i].value, hdev->core->base + tbl[i].reg);
>> +        /* In some cases, we only want to update certain bits */
> 
> I'll trust this is a legitimate and true statement.
> 
>> +        if (tbl[i].mask) {
>> +            val = readl(hdev->core->base + tbl[i].reg);
>> +            val = (val & ~tbl[i].mask) | (tbl[i].value & tbl[i].mask);
> 
> feels like something regmap_update_bits() already does though, I prefer 
> this because there's less code in it.
> 
>> +        }
>> +
>> +        writel(val, hdev->core->base + tbl[i].reg);
>> +    }
> 
> With the val declaration fix
> 
> Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@...aro.org>

Reviewed-by: Bryan O'Donoghue <bryan.odonoghue@...aro.org>