Re: [RFC PATCH 3/4] PM / devfreq: rockchip: add devfreq driver for rk3399 dmc

Chanwoo Choi
2016-06-01T11:47:35Z

Hi Lin,

This patch include the two features as following:
- Monitor the ddr load
- Control the ddr's clock with ondemand governor based on load

The "Monitor the ddr load" has the specific the address in SoC.
Namely, it is separate the module.
So, I implemented the devfreq-event framework[1] which was merged.

It is right method to separate two feature from your device driver.
You can refer to patch[2][3]. The patch[2] show how to implement the
"monitor the ddr load"
by using Devfreq-Event framework and the patch[3] include the method
how to implement the rk3399 dmc driver.

[1] Devfreq-Event framework
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=f262f28c147051e7aa6daaf4fb5996833ffadff4

[2] Exynos Noc probe driver by using Devfreq-Event framework
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0179a913875a8b39eaf5b848c876439a3a4650af

[3] Exynos Busfreq driver using the devfreq-evnet framework to get the
monitored data
- https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=0722249ac1f3dcc3af9e9d7ed89792a68f066660

If you have more information and help, please let me know. I'll help you.

Thanks,
Chanwoo Choi

On Wed, Jun 1, 2016 at 6:35 PM, Lin Huang <hl@rock-chips.com> wrote:
> there is dfi controller on rk3399 platform, it can monitor
> ddr load, register this controller to devfreq framework, and
> default to use simple_ondeamnd policy, and do ddr frequency
> scaling base on this result.
>
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> ---
> drivers/devfreq/Kconfig | 2 +-
> drivers/devfreq/Makefile | 1 +
> drivers/devfreq/rockchip/Kconfig | 14 +
> drivers/devfreq/rockchip/Makefile | 2 +
> drivers/devfreq/rockchip/rk3399_dmc.c | 438 ++++++++++++++++++++++++++++++++
> drivers/devfreq/rockchip/rockchip_dmc.c | 132 ++++++++++
> include/soc/rockchip/rockchip_dmc.h | 44 ++++
> 7 files changed, 632 insertions(+), 1 deletion(-)
> create mode 100644 drivers/devfreq/rockchip/Kconfig
> create mode 100644 drivers/devfreq/rockchip/Makefile
> create mode 100644 drivers/devfreq/rockchip/rk3399_dmc.c
> create mode 100644 drivers/devfreq/rockchip/rockchip_dmc.c
> create mode 100644 include/soc/rockchip/rockchip_dmc.h
>
> diff --git a/drivers/devfreq/Kconfig b/drivers/devfreq/Kconfig
> index 78dac0e..a883744 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -101,5 +101,5 @@ config ARM_TEGRA_DEVFREQ
> operating frequencies and voltages with OPP support.
>
> source "drivers/devfreq/event/Kconfig"
> -
> +source "drivers/devfreq/rockchip/Kconfig"
> endif # PM_DEVFREQ
> diff --git a/drivers/devfreq/Makefile b/drivers/devfreq/Makefile
> index 09f11d9..48e2ae6 100644
> --- a/drivers/devfreq/Makefile
> +++ b/drivers/devfreq/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_DEVFREQ_GOV_PASSIVE) += governor_passive.o
> # DEVFREQ Drivers
> obj-$(CONFIG_ARM_EXYNOS_BUS_DEVFREQ) += exynos-bus.o
> obj-$(CONFIG_ARM_TEGRA_DEVFREQ) += tegra-devfreq.o
> +obj-$(CONFIG_ARCH_ROCKCHIP) += rockchip/
>
> # DEVFREQ Event Drivers
> obj-$(CONFIG_PM_DEVFREQ_EVENT) += event/
> diff --git a/drivers/devfreq/rockchip/Kconfig b/drivers/devfreq/rockchip/Kconfig
> new file mode 100644
> index 0000000..617b5fe
> --- /dev/null
> +++ b/drivers/devfreq/rockchip/Kconfig
> @@ -0,0 +1,14 @@
> +config ARM_ROCKCHIP_DMC_DEVFREQ
> + tristate "ARM ROCKCHIP DMC DEVFREQ Driver"
> + depends on ARCH_ROCKCHIP
> + help
> + This adds the DEVFREQ driver framework for the rockchip dmc.
> +
> +config ARM_RK3399_DMC_DEVFREQ
> + tristate "ARM RK3399 DMC DEVFREQ Driver"
> + depends on ARM_ROCKCHIP_DMC_DEVFREQ
> + select PM_OPP
> + select DEVFREQ_GOV_SIMPLE_ONDEMAND
> + help
> + This adds the DEVFREQ driver for the RK3399 dmc. It sets the frequency
> + for the memory controller and reads the usage counts from hardware.
> diff --git a/drivers/devfreq/rockchip/Makefile b/drivers/devfreq/rockchip/Makefile
> new file mode 100644
> index 0000000..caca525
> --- /dev/null
> +++ b/drivers/devfreq/rockchip/Makefile
> @@ -0,0 +1,2 @@
> +obj-$(CONFIG_ARM_ROCKCHIP_DMC_DEVFREQ) += rockchip_dmc.o
> +obj-$(CONFIG_ARM_RK3399_DMC_DEVFREQ) += rk3399_dmc.o
> diff --git a/drivers/devfreq/rockchip/rk3399_dmc.c b/drivers/devfreq/rockchip/rk3399_dmc.c
> new file mode 100644
> index 0000000..4907d38
> --- /dev/null
> +++ b/drivers/devfreq/rockchip/rk3399_dmc.c
> @@ -0,0 +1,438 @@
> +/*
> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
> + * Author: Lin Huang <hl@rock-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/completion.h>
> +#include <linux/delay.h>
> +#include <linux/devfreq.h>
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_opp.h>
> +#include <linux/regmap.h>
> +#include <linux/regulator/consumer.h>
> +#include <linux/rwsem.h>
> +#include <linux/suspend.h>
> +#include <linux/syscore_ops.h>
> +
> +#include <soc/rockchip/rockchip_dmc.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 rk3399_dmcfreq {
> + struct device *dev;
> + struct devfreq *devfreq;
> + struct devfreq_simple_ondemand_data ondemand_data;
> + struct clk *dmc_clk;
> + struct completion dcf_hold_completion;
> + struct dmc_usage ch_usage[RK3399_DMC_NUM_CH];
> + struct mutex lock;
> + struct notifier_block dmc_nb;
> + int irq;
> + void __iomem *regs;
> + struct regmap *regmap_pmu;
> + struct regulator *vdd_center;
> + unsigned long rate, target_rate;
> + unsigned long volt, target_volt;
> +};
> +
> +static int rk3399_dmcfreq_target(struct device *dev, unsigned long *freq,
> + u32 flags)
> +{
> + struct platform_device *pdev = container_of(dev, struct platform_device,
> + dev);
> + struct rk3399_dmcfreq *dmcfreq = platform_get_drvdata(pdev);
> + struct dev_pm_opp *opp;
> + unsigned long old_clk_rate = dmcfreq->rate;
> + unsigned long target_volt, target_rate;
> + int err;
> +
> + rcu_read_lock();
> + opp = devfreq_recommended_opp(dev, freq, flags);
> + if (IS_ERR(opp)) {
> + rcu_read_unlock();
> + return PTR_ERR(opp);
> + }
> + target_rate = dev_pm_opp_get_freq(opp);
> + target_volt = dev_pm_opp_get_voltage(opp);
> +
> + opp = devfreq_recommended_opp(dev, &dmcfreq->rate, flags);
> + if (IS_ERR(opp)) {
> + rcu_read_unlock();
> + return PTR_ERR(opp);
> + }
> + dmcfreq->volt = dev_pm_opp_get_voltage(opp);
> + rcu_read_unlock();
> +
> + if (dmcfreq->rate == target_rate)
> + return 0;
> +
> + mutex_lock(&dmcfreq->lock);
> +
> + /*
> + * if frequency scaling from low to high, adjust voltage first;
> + * if frequency scaling from high to low, adjuset frequency first;
> + */
> + if (old_clk_rate < target_rate) {
> + err = regulator_set_voltage(dmcfreq->vdd_center, target_volt,
> + target_volt);
> + if (err) {
> + dev_err(dev, "Unable to set vol %lu\n", target_volt);
> + goto out;
> + }
> + }
> +
> + dmc_event(DMCFREQ_ADJUST);
> + err = clk_set_rate(dmcfreq->dmc_clk, target_rate);
> + if (err) {
> + dev_err(dev,
> + "Unable to set freq %lu. Current freq %lu. Error %d\n",
> + target_rate, old_clk_rate, err);
> + regulator_set_voltage(dmcfreq->vdd_center, dmcfreq->volt,
> + dmcfreq->volt);
> + dmc_event(DMCFREQ_FINISH);
> + goto out;
> + }
> +
> + /* wait until bcf irq happen, it means ddr scaling finish in bl31 */
> + reinit_completion(&dmcfreq->dcf_hold_completion);
> + wait_for_completion(&dmcfreq->dcf_hold_completion);
> + dmc_event(DMCFREQ_FINISH);
> +
> + if (old_clk_rate > target_rate)
> + err = regulator_set_voltage(dmcfreq->vdd_center, target_volt,
> + target_volt);
> + if (err)
> + dev_err(dev, "Unable to set vol %lu\n", target_volt);
> +
> + /* check the rate we get whether correct */
> + dmcfreq->rate = clk_get_rate(dmcfreq->dmc_clk);
> + if (dmcfreq->rate != target_rate) {
> + dev_err(dev, "get wrong ddr frequency, Request freq %lu,\
> + Current freq %lu\n", target_rate, dmcfreq->rate);
> + regulator_set_voltage(dmcfreq->vdd_center, dmcfreq->volt,
> + dmcfreq->volt);
> + }
> +out:
> + mutex_unlock(&dmcfreq->lock);
> + return err;
> +}
> +
> +static void rk3399_dmc_start_hardware_counter(struct device *dev)
> +{
> + struct platform_device *pdev = container_of(dev, struct platform_device,
> + dev);
> + struct rk3399_dmcfreq *dmcfreq = platform_get_drvdata(pdev);
> + void __iomem *dfi_regs = dmcfreq->regs;
> + u32 val;
> + u32 ddr_type;
> +
> + /* get ddr type */
> + regmap_read(dmcfreq->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 rk3399_dmc_stop_hardware_counter(struct device *dev)
> +{
> + struct platform_device *pdev = container_of(dev, struct platform_device,
> + dev);
> + struct rk3399_dmcfreq *dmcfreq = platform_get_drvdata(pdev);
> + void __iomem *dfi_regs = dmcfreq->regs;
> + u32 val;
> +
> + val = readl_relaxed(dfi_regs + DDRMON_CTRL);
> + val &= ~SOFTWARE_EN;
> + writel_relaxed(val, dfi_regs + DDRMON_CTRL);
> +}
> +
> +static int rk3399_dmc_get_busier_ch(struct device *dev)
> +{
> + struct platform_device *pdev = container_of(dev, struct platform_device,
> + dev);
> + struct rk3399_dmcfreq *dmcfreq = platform_get_drvdata(pdev);
> + u32 tmp, max = 0;
> + u32 i, busier_ch = 0;
> + void __iomem *dfi_regs = dmcfreq->regs;
> +
> + rk3399_dmc_stop_hardware_counter(dev);
> +
> + /* Find out which channel is busier */
> + for (i = 0; i < RK3399_DMC_NUM_CH; i++) {
> + dmcfreq->ch_usage[i].access = readl_relaxed(dfi_regs +
> + DDRMON_CH0_DFI_ACCESS_NUM + i * 20);
> + dmcfreq->ch_usage[i].total = readl_relaxed(dfi_regs +
> + DDRMON_CH0_COUNT_NUM + i * 20);
> + tmp = dmcfreq->ch_usage[i].access;
> + if (tmp > max) {
> + busier_ch = i;
> + max = tmp;
> + }
> + }
> + rk3399_dmc_start_hardware_counter(dev);
> +
> + return busier_ch;
> +}
> +
> +static int rk3399_dmcfreq_get_dev_status(struct device *dev,
> + struct devfreq_dev_status *stat)
> +{
> + struct platform_device *pdev = container_of(dev, struct platform_device,
> + dev);
> + struct rk3399_dmcfreq *dmcfreq = platform_get_drvdata(pdev);
> + int busier_ch;
> +
> + busier_ch = rk3399_dmc_get_busier_ch(dev);
> + stat->current_frequency = dmcfreq->rate;
> + stat->busy_time = dmcfreq->ch_usage[busier_ch].access;
> + stat->total_time = dmcfreq->ch_usage[busier_ch].total;
> +
> + return 0;
> +}
> +
> +static int rk3399_dmcfreq_get_cur_freq(struct device *dev, unsigned long *freq)
> +{
> + struct platform_device *pdev = container_of(dev, struct platform_device,
> + dev);
> + struct rk3399_dmcfreq *dmcfreq = platform_get_drvdata(pdev);
> +
> + *freq = dmcfreq->rate;
> +
> + return 0;
> +}
> +
> +static void rk3399_dmcfreq_exit(struct device *dev)
> +{
> + struct platform_device *pdev = container_of(dev, struct platform_device,
> + dev);
> + struct rk3399_dmcfreq *dmcfreq = platform_get_drvdata(pdev);
> +
> + devfreq_unregister_opp_notifier(dev, dmcfreq->devfreq);
> +}
> +
> +static struct devfreq_dev_profile rk3399_devfreq_dmc_profile = {
> + .polling_ms = 200,
> + .target = rk3399_dmcfreq_target,
> + .get_dev_status = rk3399_dmcfreq_get_dev_status,
> + .get_cur_freq = rk3399_dmcfreq_get_cur_freq,
> + .exit = rk3399_dmcfreq_exit,
> +};
> +
> +static __maybe_unused int rk3399_dmcfreq_suspend(struct device *dev)
> +{
> + rockchip_dmc_disable();
> + return 0;
> +}
> +
> +static __maybe_unused int rk3399_dmcfreq_resume(struct device *dev)
> +{
> + rockchip_dmc_enable();
> + return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(rk3399_dmcfreq_pm, rk3399_dmcfreq_suspend,
> + rk3399_dmcfreq_resume);
> +
> +static int rk3399_dmc_enable_notify(struct notifier_block *nb,
> + unsigned long event, void *data)
> +{
> + struct rk3399_dmcfreq *dmcfreq =
> + container_of(nb, struct rk3399_dmcfreq, dmc_nb);
> + unsigned long freq = ULONG_MAX;
> +
> + if (event == DMC_ENABLE) {
> + devfreq_resume_device(dmcfreq->devfreq);
> + rk3399_dmc_start_hardware_counter(dmcfreq->dev);
> + return NOTIFY_OK;
> + } else if (event == DMC_DISABLE) {
> + devfreq_suspend_device(dmcfreq->devfreq);
> + rk3399_dmc_stop_hardware_counter(dmcfreq->dev);
> +
> + /* when disable dmc, set sdram to max frequency */
> + rk3399_dmcfreq_target(dmcfreq->dev, &freq, 0);
> + return NOTIFY_OK;
> + }
> +
> + return NOTIFY_DONE;
> +}
> +
> +static irqreturn_t rk3399_dmc_irq(int irq, void *dev_id)
> +{
> + struct rk3399_dmcfreq *dmcfreq = dev_id;
> +
> + complete(&dmcfreq->dcf_hold_completion);
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int rk3399_dmcfreq_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct rk3399_dmcfreq *data;
> + struct resource *res;
> + int ret, irq;
> + struct device_node *np = pdev->dev.of_node, *node;
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0) {
> + dev_err(&pdev->dev, "no dmc irq resource\n");
> + return -EINVAL;
> + }
> +
> + data = devm_kzalloc(dev, sizeof(struct rk3399_dmcfreq), GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
> +
> + mutex_init(&data->lock);
> + 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->vdd_center = devm_regulator_get(dev, "center");
> + if (IS_ERR(data->vdd_center)) {
> + dev_err(dev, "Cannot get the regulator \"center\"\n");
> + return PTR_ERR(data->vdd_center);
> + }
> +
> + data->dmc_clk = devm_clk_get(dev, "dmc_clk");
> + if (IS_ERR(data->dmc_clk)) {
> + dev_err(dev, "Cannot get the clk dmc_clk\n");
> + return PTR_ERR(data->dmc_clk);
> + };
> +
> + /*
> + * We add a devfreq driver to our parent since it has a device tree node
> + * with operating points.
> + */
> + if (dev_pm_opp_of_add_table(dev)) {
> + dev_err(dev, "Invalid operating-points in device tree.\n");
> + return -EINVAL;
> + }
> +
> + of_property_read_u32(np, "upthreshold",
> + &data->ondemand_data.upthreshold);
> +
> + of_property_read_u32(np, "downdifferential",
> + &data->ondemand_data.downdifferential);
> +
> + data->devfreq = devfreq_add_device(dev,
> + &rk3399_devfreq_dmc_profile,
> + "simple_ondemand",
> + &data->ondemand_data);
> + if (IS_ERR(data->devfreq))
> + return PTR_ERR(data->devfreq);
> +
> + devfreq_register_opp_notifier(dev, data->devfreq);
> +
> + data->dmc_nb.notifier_call = rk3399_dmc_enable_notify;
> + dmc_register_notifier(&data->dmc_nb);
> +
> + data->irq = irq;
> + ret = devm_request_irq(dev, irq, rk3399_dmc_irq, IRQF_ONESHOT,
> + dev_name(dev), data);
> + if (ret) {
> + dev_err(dev, "failed to request dmc irq: %d\n", ret);
> + return ret;
> + }
> +
> + init_completion(&data->dcf_hold_completion);
> +
> + /* 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;
> + platform_set_drvdata(pdev, data);
> +
> + return 0;
> +}
> +
> +static int rk3399_dmcfreq_remove(struct platform_device *pdev)
> +{
> + struct rk3399_dmcfreq *dmcfreq = platform_get_drvdata(pdev);
> +
> + devfreq_remove_device(dmcfreq->devfreq);
> + regulator_put(dmcfreq->vdd_center);
> +
> + return 0;
> +}
> +
> +static const struct of_device_id rk3399dmc_devfreq_of_match[] = {
> + { .compatible = "rockchip,rk3399-dmc" },
> + { },
> +};
> +
> +static struct platform_driver rk3399_dmcfreq_driver = {
> + .probe = rk3399_dmcfreq_probe,
> + .remove = rk3399_dmcfreq_remove,
> + .driver = {
> + .name = "rk3399-dmc-freq",
> + .pm = &rk3399_dmcfreq_pm,
> + .of_match_table = rk3399dmc_devfreq_of_match,
> + },
> +};
> +module_platform_driver(rk3399_dmcfreq_driver);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_DESCRIPTION("RK3399 dmcfreq driver with devfreq framework");
> diff --git a/drivers/devfreq/rockchip/rockchip_dmc.c b/drivers/devfreq/rockchip/rockchip_dmc.c
> new file mode 100644
> index 0000000..ecc6598
> --- /dev/null
> +++ b/drivers/devfreq/rockchip/rockchip_dmc.c
> @@ -0,0 +1,132 @@
> +/*
> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
> + * Author: Lin Huang <hl@rock-chips.com>
> + * Base on: https://chromium-review.googlesource.com/#/c/231477/
> + *
> + * 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/mutex.h>
> +#include <soc/rockchip/rockchip_dmc.h>
> +
> +static int num_wait;
> +static int num_disable;
> +static BLOCKING_NOTIFIER_HEAD(dmc_notifier_list);
> +static DEFINE_MUTEX(dmc_en_lock);
> +static DEFINE_MUTEX(dmc_sync_lock);
> +
> +void dmc_event(int event)
> +{
> + mutex_lock(&dmc_sync_lock);
> + blocking_notifier_call_chain(&dmc_notifier_list, event, NULL);
> + mutex_unlock(&dmc_sync_lock);
> +}
> +EXPORT_SYMBOL_GPL(dmc_event);
> +
> +/**
> + * rockchip_dmc_enabled - Returns true if dmc freq is enabled, false otherwise.
> + */
> +bool rockchip_dmc_enabled(void)
> +{
> + return num_disable <= 0 && num_wait <= 1;
> +}
> +EXPORT_SYMBOL_GPL(rockchip_dmc_enabled);
> +
> +/**
> + * rockchip_dmc_enable - Enable dmc frequency scaling. Will only enable
> + * frequency scaling if there are 1 or fewer notifiers. Call to undo
> + * rockchip_dmc_disable.
> + */
> +void rockchip_dmc_enable(void)
> +{
> + mutex_lock(&dmc_en_lock);
> + num_disable--;
> + WARN_ON(num_disable < 0);
> + if (rockchip_dmc_enabled())
> + dmc_event(DMC_ENABLE);
> + mutex_unlock(&dmc_en_lock);
> +}
> +EXPORT_SYMBOL_GPL(rockchip_dmc_enable);
> +
> +/**
> + * rockchip_dmc_disable - Disable dmc frequency scaling. Call when something
> + * cannot coincide with dmc frequency scaling.
> + */
> +void rockchip_dmc_disable(void)
> +{
> + mutex_lock(&dmc_en_lock);
> + if (rockchip_dmc_enabled())
> + dmc_event(DMC_DISABLE);
> + num_disable++;
> + mutex_unlock(&dmc_en_lock);
> +}
> +EXPORT_SYMBOL_GPL(rockchip_dmc_disable);
> +
> +int dmc_register_notifier(struct notifier_block *nb)
> +{
> + int ret;
> +
> + if (!nb)
> + return -EINVAL;
> +
> + ret = blocking_notifier_chain_register(&dmc_notifier_list, nb);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(dmc_register_notifier);
> +
> +int dmc_unregister_notifier(struct notifier_block *nb)
> +{
> + int ret;
> +
> + if (!nb)
> + return -EINVAL;
> +
> + ret = blocking_notifier_chain_unregister(&dmc_notifier_list, nb);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL_GPL(dmc_unregister_notifier);
> +
> +int rockchip_dmc_get(struct notifier_block *nb)
> +{
> + if (!nb)
> + return -EINVAL;
> +
> + mutex_lock(&dmc_en_lock);
> +
> + /* if use two vop, need to disable dmc */
> + if (num_wait == 1 && num_disable <= 0)
> + dmc_event(DMC_DISABLE);
> + num_wait++;
> + dmc_register_notifier(nb);
> + mutex_unlock(&dmc_en_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(rockchip_dmc_get);
> +
> +int rockchip_dmc_put(struct notifier_block *nb)
> +{
> + if (!nb)
> + return -EINVAL;
> +
> + mutex_lock(&dmc_en_lock);
> + num_wait--;
> +
> + /* from 2 vop back to 1 vop, need enable dmc */
> + if (num_wait == 1 && num_disable <= 0)
> + dmc_event(DMC_ENABLE);
> + dmc_unregister_notifier(nb);
> + mutex_unlock(&dmc_en_lock);
> +
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(rockchip_dmc_put);
> diff --git a/include/soc/rockchip/rockchip_dmc.h b/include/soc/rockchip/rockchip_dmc.h
> new file mode 100644
> index 0000000..6bb58d6
> --- /dev/null
> +++ b/include/soc/rockchip/rockchip_dmc.h
> @@ -0,0 +1,44 @@
> +/*
> + * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
> + *
> + * 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.
> + */
> +
> +#ifndef __SOC_ROCKCHIP_DMC_H
> +#define __SOC_ROCKCHIP_DMC_H
> +
> +#include <linux/notifier.h>
> +
> +#define DMC_ENABLE 0
> +#define DMC_DISABLE 1
> +#define DMCFREQ_ADJUST 2
> +#define DMCFREQ_FINISH 3
> +
> +#ifdef CONFIG_ARM_ROCKCHIP_DMC_DEVFREQ
> +int rockchip_dmc_get(struct notifier_block *nb);
> +int rockchip_dmc_put(struct notifier_block *nb);
> +#else
> +static inline int rockchip_dmc_get(struct notifier_block *nb)
> +{
> + return 0;
> +}
> +static inline int rockchip_dmc_put(struct notifier_block *nb)
> +{
> + return 0;
> +}
> +#endif
> +
> +void dmc_event(int event);
> +int dmc_register_notifier(struct notifier_block *nb);
> +int dmc_unregister_notifier(struct notifier_block *nb);
> +void rockchip_dmc_enable(void);
> +void rockchip_dmc_disable(void);
> +bool rockchip_dmc_enabled(void);
> +#endif
> --
> 1.9.1
>