linux-kernel - Re: [PATCH v2 7/9] drivers/perf: hisi: Add support for L3C PMU v3

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Message-ID: <9465540b-44da-4f53-a8e9-97a648a0c023@huawei.com>
Date: Wed, 27 Aug 2025 14:21:37 +0800
From: wangyushan <wangyushan12@...wei.com>
To: Jonathan Cameron <Jonathan.Cameron@...wei.com>
CC: <will@...nel.org>, <mark.rutland@....com>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>,
	<robin.murphy@....com>, <yangyicong@...wei.com>, <liuyonglong@...wei.com>,
	<wanghuiqiang@...wei.com>, <prime.zeng@...ilicon.com>,
	<hejunhao3@...artners.com>
Subject: Re: [PATCH v2 7/9] drivers/perf: hisi: Add support for L3C PMU v3



On 8/26/2025 9:12 PM, Jonathan Cameron wrote:
> On Thu, 21 Aug 2025 21:50:47 +0800
> Yushan Wang <wangyushan12@...wei.com> wrote:
>
>> From: Yicong Yang <yangyicong@...ilicon.com>
>>
>> This patch adds support for L3C PMU v3. The v3 L3C PMU supports
>> an extended events space which can be controlled in up to 2 extra
>> address spaces with separate overflow interrupts. The layout
>> of the control/event registers are kept the same. The extended events
>> with original ones together cover the monitoring job of all transactions
>> on L3C.
>>
>> The extended events is specified with `ext=[1|2]` option for the
>> driver to distinguish, like below:
>>
>> perf stat -e hisi_sccl0_l3c0_0/event=<event_id>,ext=1/
>>
>> Currently only event option using config bit [7, 0]. There's
>> still plenty unused space. Make ext using config [16, 17] and
>> reserve bit [15, 8] for event option for future extension.
>>
>> With the capability of extra counters, number of counters for HiSilicon
>> uncore PMU could reach up to 24, the usedmap is extended accordingly.
>>
>> The hw_perf_event::event_base is initialized to the base MMIO
>> address of the event and will be used for later control,
>> overflow handling and counts readout.
>>
>> We still make use of the Uncore PMU framework for handling the
>> events and interrupt migration on CPU hotplug. The framework's
>> cpuhp callback will handle the event migration and interrupt
>> migration of orginial event, if PMU supports extended events
>> then the interrupt of extended events is migrated to the same
>> CPU choosed by the framework.
>>
>> A new HID of HISI0215 is used for this version of L3C PMU.
>>
>> Signed-off-by: Yicong Yang <yangyicong@...ilicon.com>
>> Co-developed-by: Yushan Wang <wangyushan12@...wei.com>
>> Signed-off-by: Yushan Wang <wangyushan12@...wei.com>
> One minor formatting thing I missed in internal reviews. With that
> tidied up (check other patches for this as well)
>
> Acked-by: Jonathan Cameron <jonathan.cameron@...wei.com>
>
>>   
>>   static void hisi_l3c_pmu_stop_counters(struct hisi_pmu *l3c_pmu)
>>   {
>> +	struct hisi_l3c_pmu *hisi_l3c_pmu = to_hisi_l3c_pmu(l3c_pmu);
>> +	unsigned long *used_mask = l3c_pmu->pmu_events.used_mask;
>> +	unsigned long bit = find_first_bit(used_mask, l3c_pmu->num_counters);
>>   	u32 val;
>> +	int i;
>>   
>>   	/*
>> -	 * Clear perf_enable bit in L3C_PERF_CTRL register to stop counting
>> -	 * for all enabled counters.
>> +	 * Check if any counter belongs to the normal range (instead of ext
>> +	 * range). If so, stop it.
>>   	 */
>> -	val = readl(l3c_pmu->base + L3C_PERF_CTRL);
>> -	val &= ~(L3C_PERF_CTRL_EN);
>> -	writel(val, l3c_pmu->base + L3C_PERF_CTRL);
>> +	if (bit < L3C_NR_COUNTERS) {
>> +		val = readl(l3c_pmu->base + L3C_PERF_CTRL);
>> +		val &= ~(L3C_PERF_CTRL_EN);
> Brackets not adding anything here and inconsistently applied.
> Please clean these up.

Sure, sorry for the noises.

Will fix that and look for other similar issues in the patches.

Thanks!

>> +		writel(val, l3c_pmu->base + L3C_PERF_CTRL);
>> +	}
>> +
>> +	/* If not, do stop it on ext ranges. */
>> +	for (i = 0; i < hisi_l3c_pmu->ext_num; i++) {
>> +		bit = find_next_bit(used_mask, L3C_NR_COUNTERS * (i + 2),
>> +				    L3C_NR_COUNTERS * (i + 1));
>> +		if (L3C_CNTR_EXT(bit) != i + 1)
>> +			continue;
>> +
>> +		val = readl(hisi_l3c_pmu->ext_base[i] + L3C_PERF_CTRL);
>> +		val &= ~L3C_PERF_CTRL_EN;
>> +		writel(val, hisi_l3c_pmu->ext_base[i] + L3C_PERF_CTRL);
>> +	}
>>   }