Message-id: <57515B4F.5000309@samsung.com>
Date:	Fri, 03 Jun 2016 19:26:23 +0900
From:	Chanwoo Choi <cw00.choi@...sung.com>
To:	Lin Huang <hl@...k-chips.com>, heiko@...ech.de,
	mark.yao@...k-chips.com, myungjoo.ham@...sung.com
Cc:	mturquette@...libre.com, sboyd@...eaurora.org,
	linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-rockchip@...ts.infradead.org, airlied@...ux.ie,
	dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
	kyungmin.park@...sung.com, dianders@...omium.org,
	dbasehore@...omium.org, huangtao@...k-chips.com, typ@...k-chips.com
Subject: Re: [RFC PATCH v1 4/6] PM / devfreq: event: support rockchip dfi
 controller

Hi Lin,

I add the some comment on below. If you modify it,
You can add my acked-by tag. Looks good to me.

Acked-by: Chanwoo Choi <cw00.choi@...sung.com>

Also, I'd like you to add me to mail thread
on next version because I'm supporter of devfreq-event.

On 2016년 06월 03일 18:55, Lin Huang wrote:
> on rk3399 platform, there is dfi conroller can monitor
> ddr load, base on this result, we can do ddr freqency
> scaling.
> 
> Signed-off-by: Lin Huang <hl@...k-chips.com>
> ---
> Changes in v1:
> - NOne
> 
>  drivers/devfreq/event/Kconfig        |   7 +
>  drivers/devfreq/event/Makefile       |   1 +
>  drivers/devfreq/event/rockchip-dfi.c | 265 +++++++++++++++++++++++++++++++++++
>  3 files changed, 273 insertions(+)
>  create mode 100644 drivers/devfreq/event/rockchip-dfi.c
> 
> diff --git a/drivers/devfreq/event/Kconfig b/drivers/devfreq/event/Kconfig
> index 1e8b4f4..6ebdc13 100644
> --- a/drivers/devfreq/event/Kconfig
> +++ b/drivers/devfreq/event/Kconfig
> @@ -30,4 +30,11 @@ config DEVFREQ_EVENT_EXYNOS_PPMU
>  	  (Platform Performance Monitoring Unit) counters to estimate the
>  	  utilization of each module.
>  
> +config DEVFREQ_EVENT_ROCKCHIP_DFI
> +	bool "ROCKCHIP DFI DEVFREQ event Driver"
> +	depends on ARCH_ROCKCHIP
> +	help
> +	  This add the devfreq-event driver for Rockchip SoC. It provides DFI

You better to full name of 'DFI' abbreviation as following:
- DFI (Dxxx Fxxx Ixxx)

> +	  driver to count ddr load.
> +
>  endif # PM_DEVFREQ_EVENT
> diff --git a/drivers/devfreq/event/Makefile b/drivers/devfreq/event/Makefile
> index 3d6afd3..dda7090 100644
> --- a/drivers/devfreq/event/Makefile
> +++ b/drivers/devfreq/event/Makefile
> @@ -2,3 +2,4 @@
>  
>  obj-$(CONFIG_DEVFREQ_EVENT_EXYNOS_NOCP) += exynos-nocp.o
>  obj-$(CONFIG_DEVFREQ_EVENT_EXYNOS_PPMU) += exynos-ppmu.o
> +obj-$(CONFIG_DEVFREQ_EVENT_ROCKCHIP_DFI) += rockchip-dfi.o
> diff --git a/drivers/devfreq/event/rockchip-dfi.c b/drivers/devfreq/event/rockchip-dfi.c
> new file mode 100644
> index 0000000..e3b020f9
> --- /dev/null
> +++ b/drivers/devfreq/event/rockchip-dfi.c
> @@ -0,0 +1,265 @@
> +/*
> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
> + * Author: Lin Huang <hl@...k-chips.com>
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms and conditions of the GNU General Public License,
> + * version 2, as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope it will be useful, but WITHOUT
> + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
> + * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
> + * more details.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/devfreq-event.h>
> +#include <linux/kernel.h>
> +#include <linux/err.h>
> +#include <linux/init.h>
> +#include <linux/io.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/list.h>
> +#include <linux/of.h>
> +
> +#define RK3399_DMC_NUM_CH	2
> +
> +/* DDRMON_CTRL */
> +#define DDRMON_CTRL	0x04
> +#define CLR_DDRMON_CTRL	(0x1f0000 << 0)
> +#define LPDDR4_EN	(0x10001 << 4)
> +#define HARDWARE_EN	(0x10001 << 3)
> +#define LPDDR3_EN	(0x10001 << 2)
> +#define SOFTWARE_EN	(0x10001 << 1)
> +#define TIME_CNT_EN	(0x10001 << 0)
> +
> +#define DDRMON_CH0_COUNT_NUM		0x28
> +#define DDRMON_CH0_DFI_ACCESS_NUM	0x2c
> +#define DDRMON_CH1_COUNT_NUM		0x3c
> +#define DDRMON_CH1_DFI_ACCESS_NUM	0x40
> +
> +/* pmu grf */
> +#define PMUGRF_OS_REG2	0x308
> +#define DDRTYPE_SHIFT	13
> +#define DDRTYPE_MASK	7
> +
> +enum {
> +	DDR3 = 3,
> +	LPDDR3 = 6,
> +	LPDDR4 = 7,
> +	UNUSED = 0xFF
> +};
> +
> +struct dmc_usage {
> +	u32 access;
> +	u32 total;
> +};
> +
> +struct rockchip_dfi {
> +	struct devfreq_event_dev *edev;
> +	struct devfreq_event_desc *desc;
> +	struct dmc_usage ch_usage[RK3399_DMC_NUM_CH];
> +	struct device *dev;
> +	void __iomem *regs;
> +	struct regmap *regmap_pmu;
> +	struct clk *clk;
> +};
> +
> +static void rockchip_dfi_start_hardware_counter(struct devfreq_event_dev *edev)
> +{
> +	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
> +	void __iomem *dfi_regs = info->regs;
> +	u32 val;
> +	u32 ddr_type;
> +
> +	/* get ddr type */
> +	regmap_read(info->regmap_pmu, PMUGRF_OS_REG2, &val);
> +	ddr_type = (val >> DDRTYPE_SHIFT) & DDRTYPE_MASK;
> +
> +	/* clear DDRMON_CTRL setting */
> +	writel_relaxed(CLR_DDRMON_CTRL, dfi_regs + DDRMON_CTRL);
> +
> +	/* set ddr type to dfi */
> +	if (ddr_type == LPDDR3)
> +		writel_relaxed(LPDDR3_EN, dfi_regs + DDRMON_CTRL);
> +	else if (ddr_type == LPDDR4)
> +		writel_relaxed(LPDDR4_EN, dfi_regs + DDRMON_CTRL);
> +
> +	/* enable count, use software mode */
> +	writel_relaxed(SOFTWARE_EN, dfi_regs + DDRMON_CTRL);
> +}
> +
> +static void rockchip_dfi_stop_hardware_counter(struct devfreq_event_dev *edev)
> +{
> +	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
> +	void __iomem *dfi_regs = info->regs;
> +	u32 val;
> +
> +	val = readl_relaxed(dfi_regs + DDRMON_CTRL);
> +	val &= ~SOFTWARE_EN;
> +	writel_relaxed(val, dfi_regs + DDRMON_CTRL);
> +}
> +
> +static int rockchip_dfi_get_busier_ch(struct devfreq_event_dev *edev)
> +{
> +	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
> +	u32 tmp, max = 0;
> +	u32 i, busier_ch = 0;
> +	void __iomem *dfi_regs = info->regs;
> +
> +	rockchip_dfi_stop_hardware_counter(edev);
> +
> +	/* Find out which channel is busier */
> +	for (i = 0; i < RK3399_DMC_NUM_CH; i++) {
> +		info->ch_usage[i].access = readl_relaxed(dfi_regs +
> +				DDRMON_CH0_DFI_ACCESS_NUM + i * 20);
> +		info->ch_usage[i].total = readl_relaxed(dfi_regs +
> +				DDRMON_CH0_COUNT_NUM + i * 20);
> +		tmp = info->ch_usage[i].access;
> +		if (tmp > max) {
> +			busier_ch = i;
> +			max = tmp;
> +		}
> +	}
> +	rockchip_dfi_start_hardware_counter(edev);
> +
> +	return busier_ch;
> +}
> +
> +static int rockchip_dfi_disable(struct devfreq_event_dev *edev)
> +{
> +	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
> +
> +	rockchip_dfi_stop_hardware_counter(edev);
> +	clk_disable(info->clk);

I prefer to change the function as following. I add the comment on below in probe()
- clk_disable -> clk_disable_unprepare()


> +
> +	return 0;
> +}
> +
> +static int rockchip_dfi_enable(struct devfreq_event_dev *edev)
> +{
> +	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
> +	int ret;
> +
> +	ret = clk_enable(info->clk);

I prefer to change the function as following. I add the comment on below in probe()
- clk_enable -> clk_prepare_enable()

> +	if (ret)
> +		return ret;
> +
> +	rockchip_dfi_start_hardware_counter(edev);
> +	return 0;
> +}
> +
> +static int rockchip_dfi_set_event(struct devfreq_event_dev *edev)
> +{
> +	return 0;
> +}
> +
> +static int rockchip_dfi_get_event(struct devfreq_event_dev *edev,
> +				  struct devfreq_event_data *edata)
> +{
> +	struct rockchip_dfi *info = devfreq_event_get_drvdata(edev);
> +	int busier_ch;
> +
> +	busier_ch = rockchip_dfi_get_busier_ch(edev);
> +
> +	edata->load_count = info->ch_usage[busier_ch].access;
> +	edata->total_count = info->ch_usage[busier_ch].total;
> +
> +	return 0;
> +}
> +
> +static const struct devfreq_event_ops rockchip_dfi_ops = {
> +	.disable = rockchip_dfi_disable,
> +	.enable = rockchip_dfi_enable,
> +	.get_event = rockchip_dfi_get_event,
> +	.set_event = rockchip_dfi_set_event,
> +};
> +
> +static const struct of_device_id rockchip_dfi_id_match[] = {
> +	{ .compatible = "rockchip,rk3399-dfi" },
> +	{ },
> +};
> +
> +static int rockchip_dfi_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct rockchip_dfi *data;
> +	struct resource *res;
> +	struct devfreq_event_desc *desc;
> +	int ret;
> +	struct device_node *np = pdev->dev.of_node, *node;
> +
> +	data = devm_kzalloc(dev, sizeof(struct rockchip_dfi), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	data->regs = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(data->regs))
> +		return PTR_ERR(data->regs);
> +
> +	data->clk = devm_clk_get(dev, "pclk_ddr_mon");
> +	if (IS_ERR(data->clk)) {
> +		dev_err(dev, "Cannot get the clk dmc_clk\n");
> +		return PTR_ERR(data->clk);
> +	};
> +
> +	/* try to find the optional reference to the pmu syscon */
> +	node = of_parse_phandle(np, "rockchip,pmu", 0);
> +	if (node) {
> +		data->regmap_pmu = syscon_node_to_regmap(node);
> +		if (IS_ERR(data->regmap_pmu))
> +			return PTR_ERR(data->regmap_pmu);
> +	}
> +	data->dev = dev;
> +
> +	desc = devm_kzalloc(dev, sizeof(*desc), GFP_KERNEL);
> +	if (!desc)
> +		return -ENOMEM;
> +
> +	desc->ops = &rockchip_dfi_ops;
> +	desc->driver_data = data;
> +	desc->name = np->name;
> +	data->desc = desc;
> +
> +	data->edev = devm_devfreq_event_add_edev(&pdev->dev, desc);
> +	if (IS_ERR(data->edev)) {
> +		ret = PTR_ERR(data->edev);
> +		dev_err(&pdev->dev,
> +			"failed to add devfreq-event device\n");
> +		return ret;

You can simply return the PTR_ERR(data->edev) without 'ret' variable as following:

	return PTR_ERR(data->edev);


> +	}
> +
> +	ret = clk_prepare_enable(data->clk);
> +	if (ret) {
> +		dev_err(&pdev->dev, "failed to enable clk: %d\n", ret);
> +		clk_disable_unprepare(data->clk);
> +		return ret;
> +	}

The following two functions handle the clock. So, rockchip_dfi_probe()
don't need to enable the clock. Just pass the role of clock control to the following functions.
Because of calling the twice of enable function of clock, the usage count of clock
is mismatch when disabling the clock.
- rockchip_dfi_enable(struct devfreq_event_dev *edev) enable the clock.
- rockchip_dfi_disable(struct devfreq_event_dev *edev) disable the clock.


> +
> +	platform_set_drvdata(pdev, data);
> +
> +	return 0;
> +}
> +
> +static int rockchip_dfi_remove(struct platform_device *pdev)
> +{
> +	return 0;
> +}

If the rockchip_dfi_remove() don't do anything, you can remove it

> +
> +static struct platform_driver rockchip_dfi_driver = {
> +	.probe	= rockchip_dfi_probe,
> +	.remove	= rockchip_dfi_remove,

ditto.

> +	.driver = {
> +		.name	= "rockchip-dfi",
> +		.of_match_table = rockchip_dfi_id_match,
> +	},
> +};
> +module_platform_driver(rockchip_dfi_driver);
> +
> +MODULE_LICENSE("GPL v2");

You need to add MODULE_AUTHOR("").

> +MODULE_DESCRIPTION("Rockchip dfi driver");
> 

Remove unneeded blank line

Regards,
Chanwoo Choi

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