linux-kernel - Re: [PATCH v5 3/8] hisi_ptt: Register PMU device for PTT trace

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Message-ID: <20220308102157.00003725@Huawei.com>
Date:   Tue, 8 Mar 2022 10:21:57 +0000
From:   Jonathan Cameron <Jonathan.Cameron@...wei.com>
To:     Yicong Yang <yangyicong@...ilicon.com>
CC:     <gregkh@...uxfoundation.org>, <helgaas@...nel.org>,
        <alexander.shishkin@...ux.intel.com>, <lorenzo.pieralisi@....com>,
        <will@...nel.org>, <mark.rutland@....com>,
        <mathieu.poirier@...aro.org>, <suzuki.poulose@....com>,
        <mike.leach@...aro.org>, <leo.yan@...aro.org>,
        <daniel.thompson@...aro.org>, <joro@...tes.org>,
        <john.garry@...wei.com>, <shameerali.kolothum.thodi@...wei.com>,
        <robin.murphy@....com>, <peterz@...radead.org>, <mingo@...hat.com>,
        <acme@...nel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <coresight@...ts.linaro.org>, <linux-pci@...r.kernel.org>,
        <linux-perf-users@...r.kernel.org>,
        <iommu@...ts.linux-foundation.org>, <prime.zeng@...wei.com>,
        <liuqi115@...wei.com>, <zhangshaokun@...ilicon.com>,
        <linuxarm@...wei.com>, <song.bao.hua@...ilicon.com>
Subject: Re: [PATCH v5 3/8] hisi_ptt: Register PMU device for PTT trace

On Tue, 8 Mar 2022 16:49:25 +0800
Yicong Yang <yangyicong@...ilicon.com> wrote:

> Register PMU device of PTT trace, then users can use trace through perf
> command. The driver makes use of perf AUX trace and support following
> events to configure the trace:
> 
> - filter: select Root port or Endpoint to trace
> - type: select the type of traced TLP headers
> - direction: select the direction of traced TLP headers
> - format: select the data format of the traced TLP headers
> 
> This patch adds the PMU driver part of PTT trace. The perf command support
> of PTT trace is added in the following patch.
> 
> Signed-off-by: Yicong Yang <yangyicong@...ilicon.com>

It seems to me that you ended up doing both suggestions for
how to clean up the remove order when it was meant to be
a question of picking one or the other.

Otherwise this looks good to me - so with that tidied up

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>

> ---

> +
> +static int hisi_ptt_register_pmu(struct hisi_ptt *hisi_ptt)
> +{
> +	u16 core_id, sicl_id;
> +	char *pmu_name;
> +	u32 reg;
> +
> +	hisi_ptt->hisi_ptt_pmu = (struct pmu) {
> +		.module		= THIS_MODULE,
> +		.capabilities	= PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
> +		.task_ctx_nr	= perf_sw_context,
> +		.attr_groups	= hisi_ptt_pmu_groups,
> +		.event_init	= hisi_ptt_pmu_event_init,
> +		.setup_aux	= hisi_ptt_pmu_setup_aux,
> +		.free_aux	= hisi_ptt_pmu_free_aux,
> +		.start		= hisi_ptt_pmu_start,
> +		.stop		= hisi_ptt_pmu_stop,
> +		.add		= hisi_ptt_pmu_add,
> +		.del		= hisi_ptt_pmu_del,
> +	};
> +
> +	reg = readl(hisi_ptt->iobase + HISI_PTT_LOCATION);
> +	core_id = FIELD_GET(HISI_PTT_CORE_ID, reg);
> +	sicl_id = FIELD_GET(HISI_PTT_SICL_ID, reg);
> +
> +	pmu_name = devm_kasprintf(&hisi_ptt->pdev->dev, GFP_KERNEL, "hisi_ptt%u_%u",
> +				  sicl_id, core_id);
> +	if (!pmu_name)
> +		return -ENOMEM;
> +
> +	return perf_pmu_register(&hisi_ptt->hisi_ptt_pmu, pmu_name, -1);

As below, you can put back the devm cleanup that you had in v4 now you
have modified how the filter cleanup is done to also be devm managed.

> +}
> +
>  /*
>   * The DMA of PTT trace can only use direct mapping, due to some
>   * hardware restriction. Check whether there is an IOMMU or the
> @@ -303,15 +825,32 @@ static int hisi_ptt_probe(struct pci_dev *pdev,
>  
>  	pci_set_master(pdev);
>  
> +	ret = hisi_ptt_register_irq(hisi_ptt);
> +	if (ret)
> +		return ret;
> +
>  	ret = hisi_ptt_init_ctrls(hisi_ptt);
>  	if (ret) {
>  		pci_err(pdev, "failed to init controls, ret = %d.\n", ret);
>  		return ret;
>  	}
>  
> +	ret = hisi_ptt_register_pmu(hisi_ptt);
> +	if (ret) {
> +		pci_err(pdev, "failed to register pmu device, ret = %d", ret);
> +		return ret;
> +	}
> +
>  	return 0;
>  }
>  
> +void hisi_ptt_remove(struct pci_dev *pdev)
> +{
> +	struct hisi_ptt *hisi_ptt = pci_get_drvdata(pdev);
> +
> +	perf_pmu_unregister(&hisi_ptt->hisi_ptt_pmu);

Now you have the filter cleanup occurring using a devm_add_action_or_reset()
there is no need to have a manual cleanup of this - you can
use the approach of a devm_add_action_or_reset like you had in v4.

As it is the last call in the probe() order it will be the first one
called in the device managed cleanup.

> +}
> +