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Message-ID: <017265ae-c9d5-4ea0-94eb-9090945cbc91@linaro.org>
Date:   Tue, 10 Oct 2023 21:26:40 +0200
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Subject: Re: [PATCH v5 3/4] cpufreq: qcom-nvmem: add support for IPQ8064
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To:     Christian Marangi <ansuelsmth@gmail.com>
Cc:     Robert Marko <robimarko@gmail.com>, ilia.lin@kernel.org,
        vireshk@kernel.org, nm@ti.com, sboyd@kernel.org,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        conor+dt@kernel.org, agross@kernel.org, andersson@kernel.org,
        rafael@kernel.org, linux-pm@vger.kernel.org,
        devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-arm-msm@vger.kernel.org
References: <20230930102218.229613-1-robimarko@gmail.com>
 <20230930102218.229613-3-robimarko@gmail.com>
 <5b57e0e0-490e-464d-bdc8-5823ad8da2d8@linaro.org>
 <65255add.df0a0220.ff2f9.021d@mx.google.com>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <65255add.df0a0220.ff2f9.021d@mx.google.com>
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On 10/10/23 16:08, Christian Marangi wrote:
> On Tue, Oct 10, 2023 at 03:39:54PM +0200, Konrad Dybcio wrote:
>>
>>
>> On 9/30/23 12:21, Robert Marko wrote:
>>> From: Christian Marangi <ansuelsmth@gmail.com>
>>>
>>> IPQ8064 comes in 3 families:
>>> * IPQ8062 up to 1.0GHz
>>> * IPQ8064/IPQ8066/IPQ8068 up to 1.4GHz
>>> * IPQ8065/IPQ8069 up to 1.7Ghz
>>>
>>> So, in order to be able to support one OPP table, add support for
>>> IPQ8064 family based of SMEM SoC ID-s and correctly set the version so
>>> opp-supported-hw can be correctly used.
>>>
>>> Bit are set with the following logic:
>>> * IPQ8062 BIT 0
>>> * IPQ8064/IPQ8066/IPQ8068 BIT 1
>>> * IPQ8065/IPQ8069 BIT 2
>>>
>>> speed is never fused, only pvs values are fused.
>>>
>>> IPQ806x SoC doesn't have pvs_version so we drop and we use the new
>>> pattern:
>>> opp-microvolt-speed0-pvs<PSV_VALUE>
>>>
>>> Example:
>>> - for ipq8062 psv2
>>>     opp-microvolt-speed0-pvs2 = < 925000 878750 971250>
>>>
>>> Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
>>> Signed-off-by: Robert Marko <robimarko@gmail.com>
>>> ---
>> [...]
>>
>>> +{
>>> +	int speed = 0, pvs = 0, pvs_ver = 0;
>>> +	int msm_id, ret = 0;
>>> +	u8 *speedbin;
>>> +	size_t len;
>>> +
>>> +	speedbin = nvmem_cell_read(speedbin_nvmem, &len);
>>> +
>>> +	if (IS_ERR(speedbin))
>> The stray newline above this line triggers my OCD :D
>>
>>> +		return PTR_ERR(speedbin);
>>> +
>>> +	if (len != 4) {
>>> +		dev_err(cpu_dev, "Unable to read nvmem data. Defaulting to 0!\n");
>>> +		kfree(speedbin);
>>> +		return -ENODEV;
>>> +	}
>>> +
>>> +	get_krait_bin_format_a(cpu_dev, &speed, &pvs, &pvs_ver, speedbin);
>>> +
>>> +	ret = qcom_smem_get_soc_id(&msm_id);
>>> +	if (ret)
>>> +		return ret;
>> speedbin leaks here
>>
>> you can free it right after the get_krait.. call
>>> +
>>> +	switch (msm_id) {
>>> +	case QCOM_ID_IPQ8062:
>>> +		drv->versions = BIT(IPQ8062_VERSION);
>>> +		break;
>>> +	case QCOM_ID_IPQ8064:
>>> +	case QCOM_ID_IPQ8066:
>>> +	case QCOM_ID_IPQ8068:
>>> +		drv->versions = BIT(IPQ8064_VERSION);
>>> +		break;
>>> +	case QCOM_ID_IPQ8065:
>>> +	case QCOM_ID_IPQ8069:
>>> +		drv->versions = BIT(IPQ8065_VERSION);
>>> +		break;
>>> +	default:
>>> +		dev_err(cpu_dev,
>>> +			"SoC ID %u is not part of IPQ8064 family, limiting to 1.0GHz!\n",
>>> +			msm_id);
>>> +		drv->versions = BIT(IPQ8062_VERSION);
>>> +		break;
>>> +	}
>>> +
>>> +	/* IPQ8064 speed is never fused. Only pvs values are fused. */
>>> +	snprintf(*pvs_name, sizeof("speedXX-pvsXX"), "speed%d-pvs%d",
>>> +		 speed, pvs);
>> Then drop the format for `speed` and just throw in a zero!
>>
>> [...]
>>
>>> -	{ .compatible = "qcom,ipq8064", .data = &match_data_krait },
>>> +	{ .compatible = "qcom,ipq8064", .data = &match_data_ipq8064 },
>> This change demands a Fixes tag, because you're essentially saying "the
>> support for this SoC was supposedly there, but it could have never worked
>> and was broken all along".
>>
> 
> Mhhh actually no. We are just changing the opp binding and introducing
> hardcoded versions. But the thing worked and actually it's what was used
> before this change in openwrt. Also current ipq806x dtsi doesn't have
> any opp definition so no regression there. (and also 99% downstream either
> use openwrt or use qcom sdk where this implementation is not used at
> all)
> 
> Given these thing should we still add a fixes tag referencing the commit
> that introduced the compatible for qcom,ipq8064? It's quite problematic
> as this depends on qcom_smem_get_soc_id().
Fixes only hints auto backports, you shouldn't be worried about putting 
fixes on commits that fix bugs.

I see this as a "didnt work" -> "works" commit, which in my eyes 
qualifies as a fix.

Konrad