Re: [PATCH 1/2] PM / devfreq: exynos-ppmu: Add the support of PPMUv2 for Exynos5433

[Chanwoo Choi <cw00.choi@samsung.com>]

Hi Krzysztof,

On 07/23/2015 04:28 PM, Krzysztof Kozlowski wrote:
> On 23.07.2015 10:57, Chanwoo Choi wrote:
>> This patch adds the support for PPMU (Platform Performance Monitoring Unit)
>> version 2.0 for Exynos5433 SoC. Exynos5433 SoC must need PPMUv2 which is
>> quite different from PPMUv1.1. The exynos-ppmu.c driver supports both PPMUv1.1
>> and PPMUv2.
>>
>> Cc: MyungJoo Ham <myungjoo.ham@samsung.com>
>> Cc: Kyungmin Park <kyungmin.park@samsung.com>
>> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> 
> Hi,
> 
> Few comments at the end.
> 
>> ---
>>  drivers/devfreq/event/exynos-ppmu.c | 168 ++++++++++++++++++++++++++++++++++--
>>  drivers/devfreq/event/exynos-ppmu.h |  70 +++++++++++++++
>>  2 files changed, 231 insertions(+), 7 deletions(-)
>>
>> diff --git a/drivers/devfreq/event/exynos-ppmu.c b/drivers/devfreq/event/exynos-ppmu.c
>> index 7d99d13bacd8..6066dc18fc73 100644
>> --- a/drivers/devfreq/event/exynos-ppmu.c
>> +++ b/drivers/devfreq/event/exynos-ppmu.c
>> @@ -1,7 +1,7 @@
>>  /*
>>   * exynos_ppmu.c - EXYNOS PPMU (Platform Performance Monitoring Unit) support
>>   *
>> - * Copyright (c) 2014 Samsung Electronics Co., Ltd.
>> + * Copyright (c) 2014-2015 Samsung Electronics Co., Ltd.
>>   * Author : Chanwoo Choi <cw00.choi@samsung.com>
>>   *
>>   * This program is free software; you can redistribute it and/or modify
>> @@ -82,6 +82,15 @@ struct __exynos_ppmu_events {
>>  	PPMU_EVENT(mscl),
>>  	PPMU_EVENT(fimd0x),
>>  	PPMU_EVENT(fimd1x),

(snip)

>> +static int exynos_ppmu_v2_get_event(struct devfreq_event_dev *edev,
>> +				    struct devfreq_event_data *edata)
>> +{
>> +	struct exynos_ppmu *info = devfreq_event_get_drvdata(edev);
>> +	int id = exynos_ppmu_find_ppmu_id(edev);
>> +	u32 pmnc, cntenc;
>> +	u32 pmcnt_high, pmcnt_low;
>> +	u64 load_count = 0;
>> +
>> +	/* Disable PPMU */
>> +	pmnc = __raw_readl(info->ppmu.base + PPMUv2_PMNC);
>> +	pmnc &= ~PPMU_PMNC_ENABLE_MASK;
>> +	__raw_writel(pmnc, info->ppmu.base + PPMUv2_PMNC);
>> +
>> +	/* Read cycle count and performance count */
>> +	edata->total_count = __raw_readl(info->ppmu.base + PPMUv2_CCNT);
>> +
>> +	switch (id) {
>> +	case PPMU_PMNCNT0:
>> +	case PPMU_PMNCNT1:
>> +	case PPMU_PMNCNT2:
>> +		load_count = __raw_readl(info->ppmu.base + PPMUv2_PMNCT(id));
>> +		break;
>> +	case PPMU_PMNCNT3:
>> +		pmcnt_high = __raw_readl(info->ppmu.base + PPMUv2_PMCNT3_HIGH);
>> +		pmcnt_low = __raw_readl(info->ppmu.base + PPMUv2_PMCNT3_LOW);
>> +		load_count = (u64)((pmcnt_high & 0xff) << 32) + (u64)pmcnt_low;
>> +		break;
>> +	}
>> +	edata->load_count = load_count;
>> +
>> +	/* Disable all counters */
>> +	cntenc = __raw_readl(info->ppmu.base + PPMUv2_CNTENC);
>> +	cntenc |= (PPMU_CCNT_MASK | (PPMU_ENABLE << id));
>> +	__raw_writel(cntenc, info->ppmu.base + PPMUv2_CNTENC);
>> +
>> +	dev_dbg(&edev->dev, "%25s (load: %ld / %ld)\n", edev->desc->name,
>> +					edata->load_count, edata->total_count);
>> +	return 0;
>> +}
>> +
>> +static struct devfreq_event_ops exynos_ppmu_v2_ops = {
> 
> This can be const.

OK.

> 
>> +	.disable = exynos_ppmu_v2_disable,
>> +	.set_event = exynos_ppmu_v2_set_event,
>> +	.get_event = exynos_ppmu_v2_get_event,
>> +};
>> +
>> +static struct of_device_id exynos_ppmu_id_match[] = {
> 
> In the previous patch this was not present but now it can be made 'const'.

OK for adding the 'const'. 
The original 'exynos_ppmu_id_match' is located on below of this patch.

> 
>> +	{
>> +		.compatible = "samsung,exynos-ppmu",
>> +		.data = (void *)&exynos_ppmu_ops,
>> +	}, {
>> +		.compatible = "samsung,exynos-ppmu-v2",
>> +		.data = (void *)&exynos_ppmu_v2_ops,
>> +	},
>> +	{ /* sentinel */ },
>> +};
>> +
>> +static struct devfreq_event_ops *exynos_bus_get_ops(struct device_node *np)
>> +{
>> +	const struct of_device_id *match;
>> +
>> +	match = of_match_node(exynos_ppmu_id_match, np);
>> +	return (struct devfreq_event_ops *)match->data;
>> +}
>> +
>>  static int of_get_devfreq_events(struct device_node *np,
>>  				 struct exynos_ppmu *info)
>>  {
>> @@ -238,7 +397,7 @@ static int of_get_devfreq_events(struct device_node *np,
>>  			continue;
>>  		}
>>  
>> -		desc[j].ops = &exynos_ppmu_ops;
>> +		desc[j].ops = exynos_bus_get_ops(np);
> 
> So for each ops callback (get/set/disable) you will have another layer
> of indirection where you will be matching the device each time?
> 
> That seems like a waste of CPU time. Just match it once here and use
> either old ops or new ops_v2.

OK. I'll rework to reduce the unneeded operation.

> 
> 
>>  		desc[j].driver_data = info;
>>  
>>  		of_property_read_string(node, "event-name", &desc[j].name);
>> @@ -354,11 +513,6 @@ static int exynos_ppmu_remove(struct platform_device *pdev)
>>  	return 0;
>>  }
>>  
>> -static struct of_device_id exynos_ppmu_id_match[] = {
>> -	{ .compatible = "samsung,exynos-ppmu", },
>> -	{ /* sentinel */ },
>> -};
>> -
>>  static struct platform_driver exynos_ppmu_driver = {
>>  	.probe	= exynos_ppmu_probe,
>>  	.remove	= exynos_ppmu_remove,
>> diff --git a/drivers/devfreq/event/exynos-ppmu.h b/drivers/devfreq/event/exynos-ppmu.h
>> index 4e831d48c138..9a7cf6394f37 100644
>> --- a/drivers/devfreq/event/exynos-ppmu.h
>> +++ b/drivers/devfreq/event/exynos-ppmu.h
>> @@ -26,6 +26,9 @@ enum ppmu_counter {
>>  	PPMU_PMNCNT_MAX,
>>  };
>>  
>> +/***
>> + * PPMUv1.1 Definitions
>> + */
>>  enum ppmu_event_type {
>>  	PPMU_RO_BUSY_CYCLE_CNT	= 0x0,
>>  	PPMU_WO_BUSY_CYCLE_CNT	= 0x1,
>> @@ -90,4 +93,71 @@ enum ppmu_reg {
>>  #define PPMU_PMNCT(x)			(PPMU_PMCNT0 + (0x10 * x))
>>  #define PPMU_BEVTxSEL(x)		(PPMU_BEVT0SEL + (0x100 * x))
>>  
>> +/***
>> + * PPMUv2.0 definitions
>> + */
>> +enum ppmuv2_mode {
>> +	PPMUv2_MODE_MANUAL = 0,
>> +	PPMUv2_MODE_AUTO = 1,
>> +	PPMUv2_MODE_CIG = 2,	/* CIG (Conditional Interrupt Generation) */
> 
> Mixing lower-upper case looks odd to me. How about:
> PPMU2_MODE_MANUAL = 0,
> or
> PPMU_V2_MODE_MANUAL = 0,
> ?
> 
> (here and everywhere below)

As you know, after deciding the compatible name about using '-v2',
we can decide the correct register name.

Best Regards,
Chanwoo Choi