linux-kernel - Re: [PATCH 4/5] cpufreq: tegra186/tegra194: Handle errors in BPMP response

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Message-ID: <ea6c43ef-8787-168c-a8bf-5d8d41d627e8@kapsi.fi>
Date:   Mon, 4 Oct 2021 10:02:28 +0300
From:   Mikko Perttunen <cyndis@...si.fi>
To:     Viresh Kumar <viresh.kumar@...aro.org>,
        Mikko Perttunen <mperttunen@...dia.com>
Cc:     rafael@...nel.org, thierry.reding@...il.com, jonathanh@...dia.com,
        krzysztof.kozlowski@...onical.com, lorenzo.pieralisi@....com,
        robh@...nel.org, kw@...ux.com, p.zabel@...gutronix.de,
        rui.zhang@...el.com, daniel.lezcano@...aro.org, amitk@...nel.org,
        linux-pm@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-pci@...r.kernel.org
Subject: Re: [PATCH 4/5] cpufreq: tegra186/tegra194: Handle errors in BPMP
 response

On 10/4/21 10:01 AM, Viresh Kumar wrote:
> On 15-09-21, 11:55, Mikko Perttunen wrote:
>> The return value from tegra_bpmp_transfer indicates the success or
>> failure of the IPC transaction with BPMP. If the transaction
>> succeeded, we also need to check the actual command's result code.
>> Add code to do this.
>>
>> While at it, explicitly handle missing CPU clusters, which can
>> occur on floorswept chips. This worked before as well, but
>> possibly only by accident.
>>
>> Signed-off-by: Mikko Perttunen <mperttunen@...dia.com>
>> ---
>>   drivers/cpufreq/tegra186-cpufreq.c | 4 ++++
>>   drivers/cpufreq/tegra194-cpufreq.c | 8 +++++++-
>>   2 files changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/cpufreq/tegra186-cpufreq.c b/drivers/cpufreq/tegra186-cpufreq.c
>> index 5d1943e787b0..6c88827f4e62 100644
>> --- a/drivers/cpufreq/tegra186-cpufreq.c
>> +++ b/drivers/cpufreq/tegra186-cpufreq.c
>> @@ -159,6 +159,10 @@ static struct cpufreq_frequency_table *init_vhint_table(
>>   		table = ERR_PTR(err);
>>   		goto free;
>>   	}
>> +	if (msg.rx.ret) {
>> +		table = ERR_PTR(-EINVAL);
>> +		goto free;
>> +	}
>>   
>>   	for (i = data->vfloor; i <= data->vceil; i++) {
>>   		u16 ndiv = data->ndiv[i];
>> diff --git a/drivers/cpufreq/tegra194-cpufreq.c b/drivers/cpufreq/tegra194-cpufreq.c
>> index a9620e4489ae..ac381db25dbe 100644
>> --- a/drivers/cpufreq/tegra194-cpufreq.c
>> +++ b/drivers/cpufreq/tegra194-cpufreq.c
>> @@ -242,7 +242,7 @@ static int tegra194_cpufreq_init(struct cpufreq_policy *policy)
>>   
>>   	smp_call_function_single(policy->cpu, get_cpu_cluster, &cl, true);
>>   
>> -	if (cl >= data->num_clusters)
>> +	if (cl >= data->num_clusters || !data->tables[cl])
>>   		return -EINVAL;
>>   
>>   	/* set same policy for all cpus in a cluster */
>> @@ -310,6 +310,12 @@ init_freq_table(struct platform_device *pdev, struct tegra_bpmp *bpmp,
>>   	err = tegra_bpmp_transfer(bpmp, &msg);
>>   	if (err)
>>   		return ERR_PTR(err);
>> +	if (msg.rx.ret == -BPMP_EINVAL) {
>> +		/* Cluster not available */
>> +		return NULL;
>> +	}
>> +	if (msg.rx.ret)
>> +		return ERR_PTR(-EINVAL);
>>   
>>   	/*
>>   	 * Make sure frequency table step is a multiple of mdiv to match
> 
> Applied. Thanks.
> 

Thanks!

Mikko