Re: [PATCH v3 09/20] soc: mediatek: mtk-svs: Move t-calibration-data retrieval to svs_probe()

[Eugen Hristev <eugen.hristev@collabora.com>]

On 11/22/23 14:41, AngeloGioacchino Del Regno wrote:
> Il 22/11/23 12:23, Eugen Hristev ha scritto:
>> On 11/21/23 14:50, AngeloGioacchino Del Regno wrote:
>>> The t-calibration-data (SVS-Thermal calibration data) shall exist for
>>> all SoCs or SVS won't work anyway: move it to the common svs_probe()
>>> function and remove it from all of the per-SoC efuse_parsing() probe
>>> callbacks.
>>>
>>> Signed-off-by: AngeloGioacchino Del Regno 
>>> <angelogioacchino.delregno@collabora.com>
>>> ---
>>>   drivers/soc/mediatek/mtk-svs.c | 32 ++++++--------------------------
>>>   1 file changed, 6 insertions(+), 26 deletions(-)
>>>
>>> diff --git a/drivers/soc/mediatek/mtk-svs.c 
>>> b/drivers/soc/mediatek/mtk-svs.c
>>> index ab564d48092b..1042af2aee3f 100644
>>> --- a/drivers/soc/mediatek/mtk-svs.c
>>> +++ b/drivers/soc/mediatek/mtk-svs.c
>>> @@ -1884,11 +1884,6 @@ static bool svs_mt8195_efuse_parsing(struct 
>>> svs_platform *svsp)
>>>           svsb->vmax += svsb->dvt_fixed;
>>>       }
>>> -    ret = svs_get_efuse_data(svsp, "t-calibration-data",
>>> -                 &svsp->tefuse, &svsp->tefuse_max);
>>> -    if (ret)
>>> -        return false;
>>> -
>>
>> Hello Angelo,
>>
>> if you removed the code using `ret` in this patch, it makes sense to 
>> also remove the variable here instead of doing it in patch 18.
>> It will avoid unused variable warnings for this patch.
>>
>>
> 
> Yes, though the comment is not for this function, but rather for 8183. 
> Anyway, that
> makes sense, but if it's the only change of this v3, it's something that 
> I can fix
> while applying instead of sending another 20 patches round. Thanks.
> 
>>>       for (i = 0; i < svsp->tefuse_max; i++)
>>>           if (svsp->tefuse[i] != 0)
>>>               break;
>>> @@ -1949,11 +1944,6 @@ static bool svs_mt8192_efuse_parsing(struct 
>>> svs_platform *svsp)
>>>           svsb->vmax += svsb->dvt_fixed;
>>>       }
>>> -    ret = svs_get_efuse_data(svsp, "t-calibration-data",
>>> -                 &svsp->tefuse, &svsp->tefuse_max);
>>> -    if (ret)
>>> -        return false;
>>> -
>>>       for (i = 0; i < svsp->tefuse_max; i++)
>>>           if (svsp->tefuse[i] != 0)
>>>               break;
>>> @@ -2009,11 +1999,6 @@ static bool svs_mt8188_efuse_parsing(struct 
>>> svs_platform *svsp)
>>>           svsb->vmax += svsb->dvt_fixed;
>>>       }
>>> -    ret = svs_get_efuse_data(svsp, "t-calibration-data",
>>> -                 &svsp->tefuse, &svsp->tefuse_max);
>>> -    if (ret)
>>> -        return false;
>>> -
>>>       for (i = 0; i < svsp->tefuse_max; i++)
>>>           if (svsp->tefuse[i] != 0)
>>>               break;
>>> @@ -2097,11 +2082,6 @@ static bool svs_mt8186_efuse_parsing(struct 
>>> svs_platform *svsp)
>>>           svsb->vmax += svsb->dvt_fixed;
>>>       }
>>> -    ret = svs_get_efuse_data(svsp, "t-calibration-data",
>>> -                 &svsp->tefuse, &svsp->tefuse_max);
>>> -    if (ret)
>>> -        return false;
>>> -
>>>       golden_temp = (svsp->tefuse[0] >> 24) & GENMASK(7, 0);
>>>       if (!golden_temp)
>>>           golden_temp = 50;
>>> @@ -2198,11 +2178,6 @@ static bool svs_mt8183_efuse_parsing(struct 
>>> svs_platform *svsp)
>>>           }
>>>       }
>>> -    ret = svs_get_efuse_data(svsp, "t-calibration-data",
>>> -                 &svsp->tefuse, &svsp->tefuse_max);
>>> -    if (ret)
>>> -        return false;
>>> -
>>>       /* Thermal efuse parsing */
>>>       adc_ge_t = (svsp->tefuse[1] >> 22) & GENMASK(9, 0);
>>>       adc_oe_t = (svsp->tefuse[1] >> 12) & GENMASK(9, 0);
>>> @@ -3040,8 +3015,13 @@ static int svs_probe(struct platform_device 
>>> *pdev)
>>>       ret = svs_get_efuse_data(svsp, "svs-calibration-data",
>>>                    &svsp->efuse, &svsp->efuse_max);
>>> +    if (ret)
>>> +        return dev_err_probe(&pdev->dev, ret, "Cannot read SVS 
>>> calibration\n");
>>
>> With the previous code, if svs-calibration-data could not be read, the 
>> code would go to svs_probe_free_efuse. In your case, it returns directly.
>> I believe that svs_get_efuse_data using nvmem_cell_read does not 
>> allocate the buffer for the efuse , hence no more need to free it ? 
>> The exit code is checking if it's ERR or NULL, but still, if the 
>> buffer was not allocated, it doesn't make sense to jump there indeed.
>> In that case, you are also changing the behavior here , and your 
>> commit appears to do more than a simple move.
>>
> 
> I'm not changing the behavior: the previous behavior was to fail and 
> free the efuse
> variable if previously allocated, the current behavior is to fail and 
> free the
> efuse variable if previously allocated, and the tefuse variable if 
> previously
> allocated, which is a result of the actual move of the retrieval of the 
> thermal
> fuse calibration data.
> 
> I really don't see anything implicit here.
> 

Previous behavior was


ret = svs_get_efuse_data (efuse)

if (ret) goto svs_probe_free_efuse


Now, you have it as

ret = svs_get_efuse_data (efuse)

if (ret) return dev_err_probe...


>>> +
>>> +    ret = svs_get_efuse_data(svsp, "t-calibration-data",
>>> +                 &svsp->tefuse, &svsp->tefuse_max);
>>>       if (ret) {
>>> -        ret = -EPERM;
>>> +        dev_err_probe(&pdev->dev, ret, "Cannot read SVS-Thermal 
>>> calibration\n");
>>>           goto svs_probe_free_efuse;
>>
>> again in this case the tefuse has not been allocated I assume.
>>
>> So previous code was a bit excessive in trying to free the efuse/tefuse ?
> 
> The previous code was performing an useless error check on something 
> that was not
> supposed to be allocated *yet*. Yes, it was wrong before.
> 
> Cheers,
> Angelo
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