Re: [PATCH v3 6/7] PM / devfreq: rockchip: add devfreq driver for rk3399 dmc

Chanwoo Choi
2016-07-25T06:02:04Z

Hi Lin,

I'm glad to support the for dmc ddr clock scaling with devfreq/devfreq-event.

But, I think that you have to use the standard interface.
As I already mentioned[1] on previous mail, devfreq fwk support
the standard DEVFREQ_TRANSITION_NOTIFIER notifier which has the two notifications.
- DEVFREQ_PRECHANGE
- DEVFREQ_POSTCHANGE
[1] https://patchwork.kernel.org/patch/9194305/

You can use the DEVFREQ_PRECHANGE instead of DMCFREQ_ADJUST
and use the DEVFREQ_POSTCHANGE instead of DMCFREQ_FINISH.

On 2016년 07월 22일 18:07, Lin Huang wrote:
> base on dfi result, we do ddr frequency scaling, register
> dmc driver to devfreq framework, and use simple-ondemand
> policy.
>
> Signed-off-by: Lin Huang <hl@rock-chips.com>
> ---
> Changes in v3:
> - operate dram setting through sip call
> - imporve set rate flow
>
> Changes in v2:
> - None
>
> Changes in v1:
> - move dfi controller to event
> - fix set voltage sequence when set rate fail
> - change Kconfig type from tristate to bool
> - move unuse EXPORT_SYMBOL_GPL()
>
> drivers/devfreq/Kconfig | 1 +
> drivers/devfreq/Makefile | 1 +
> drivers/devfreq/rockchip/Kconfig | 15 +
> drivers/devfreq/rockchip/Makefile | 2 +
> drivers/devfreq/rockchip/rk3399_dmc.c | 482 ++++++++++++++++++++++++++++++++
> drivers/devfreq/rockchip/rockchip_dmc.c | 143 ++++++++++
> include/soc/rockchip/rockchip_dmc.h | 45 +++
> 7 files changed, 689 insertions(+)
> 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 a5be56e..cb67246 100644
> --- a/drivers/devfreq/Kconfig
> +++ b/drivers/devfreq/Kconfig
> @@ -101,5 +101,6 @@ 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-$(CONFIG_PM_DEVFREQ_EVENT) += event/
> diff --git a/drivers/devfreq/rockchip/Kconfig b/drivers/devfreq/rockchip/Kconfig
> new file mode 100644
> index 0000000..7fb1cff
> --- /dev/null
> +++ b/drivers/devfreq/rockchip/Kconfig
> @@ -0,0 +1,15 @@
> +config ARM_ROCKCHIP_DMC_DEVFREQ
> + bool "ARM ROCKCHIP DMC DEVFREQ Driver"
> + depends on ARCH_ROCKCHIP
> + help
> + This adds the DEVFREQ driver framework for the rockchip dmc.
> +
> +config ARM_RK3399_DMC_DEVFREQ
> + bool "ARM RK3399 DMC DEVFREQ Driver"
> + depends on ARM_ROCKCHIP_DMC_DEVFREQ
> + select PM_OPP
> + select DEVFREQ_GOV_SIMPLE_ONDEMAND
> + help
> + This adds the DEVFREQ driver for the RK3399 dmc. It sets the frequency
> + for the memory controller and reads the usage counts from hardware.
> +
> diff --git a/drivers/devfreq/rockchip/Makefile b/drivers/devfreq/rockchip/Makefile
> new file mode 100644
> index 0000000..caca525
> --- /dev/null
> +++ b/drivers/devfreq/rockchip/Makefile
> @@ -0,0 +1,2 @@
> +obj-$(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..f1d6120
> --- /dev/null
> +++ b/drivers/devfreq/rockchip/rk3399_dmc.c
> @@ -0,0 +1,482 @@
> +/*
> + * 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/devfreq-event.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/pm_opp.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>
> +#include "../../firmware/rockchip_sip.h"
> +
> +struct dram_timing {
> + unsigned int ddr3_speed_bin;
> + unsigned int pd_idle;
> + unsigned int sr_idle;
> + unsigned int sr_mc_gate_idle;
> + unsigned int srpd_lite_idle;
> + unsigned int standby_idle;
> + unsigned int dram_dll_dis_freq;
> + unsigned int phy_dll_dis_freq;
> + unsigned int ddr3_odt_dis_freq;
> + unsigned int ddr3_drv;
> + unsigned int ddr3_odt;
> + unsigned int phy_ddr3_ca_drv;
> + unsigned int phy_ddr3_dq_drv;
> + unsigned int phy_ddr3_odt;
> + unsigned int lpddr3_odt_dis_freq;
> + unsigned int lpddr3_drv;
> + unsigned int lpddr3_odt;
> + unsigned int phy_lpddr3_ca_drv;
> + unsigned int phy_lpddr3_dq_drv;
> + unsigned int phy_lpddr3_odt;
> + unsigned int lpddr4_odt_dis_freq;
> + unsigned int lpddr4_drv;
> + unsigned int lpddr4_dq_odt;
> + unsigned int lpddr4_ca_odt;
> + unsigned int phy_lpddr4_ca_drv;
> + unsigned int phy_lpddr4_ck_cs_drv;
> + unsigned int phy_lpddr4_dq_drv;
> + unsigned int phy_lpddr4_odt;
> +};
> +
> +struct rk3399_dmcfreq {
> + struct device *dev;
> + struct devfreq *devfreq;
> + struct devfreq_simple_ondemand_data ondemand_data;
> + struct clk *dmc_clk;
> + struct devfreq_event_dev *edev;
> + struct mutex lock;
> + struct notifier_block dmc_nb;
> + struct dram_timing *timing;
> + wait_queue_head_t wait_dcf_queue;
> + int irq;
> + int wait_dcf_flag;
> + 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);

You don't need to send the notification in target function.
When you use the DEVFREQ_TRANSITION_NOTIFIER notifier,
devfreq send the notification before calling the target() and after calling the target().

> + dmcfreq->wait_dcf_flag = 1;
> +
> + 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);

ditto.

> + goto out;
> + }
> +
> + /*
> + * wait until bcf irq happen, it means freq scaling finish in bl31,
> + * use 100ms as timeout time
> + */
> + wait_event_timeout(dmcfreq->wait_dcf_queue,
> + !dmcfreq->wait_dcf_flag, HZ / 10);
> +
> + dmc_event(DMCFREQ_FINISH);

ditto.

> +
> + /*
> + * check the dpll rate
> + * there only two result we will get,
> + * 1. ddr frequency scaling fail, we still get the old rate
> + * 2, ddr frequency scaling sucessful, we get the rate we set
> + */
> + dmcfreq->rate = clk_get_rate(dmcfreq->dmc_clk);
> +
> + /* if get the incorrect rate, set voltage to old value */
> + 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);
> + } else 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);
> +
> +out:
> + mutex_unlock(&dmcfreq->lock);
> + return err;
> +}
> +
> +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);
> + struct devfreq_event_data edata;
> +
> + devfreq_event_get_event(dmcfreq->edev, &edata);
> +
> + stat->current_frequency = dmcfreq->rate;
> + stat->busy_time = edata.load_count;
> + stat->total_time = edata.total_count;
> +
> + 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_event_enable_edev(dmcfreq->edev);
> + devfreq_resume_device(dmcfreq->devfreq);
> + return NOTIFY_OK;
> + } else if (event == DMC_DISABLE) {
> + devfreq_event_disable_edev(dmcfreq->edev);
> + devfreq_suspend_device(dmcfreq->devfreq);
> +
> + /* 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;
> +
> + dmcfreq->wait_dcf_flag = 0;
> + wake_up(&dmcfreq->wait_dcf_queue);
> +
> + /* clr dcf irq */
> + sip_smc_clr_ddr_irq();
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int of_do_get_timing(struct device_node *np,
> + struct dram_timing *timing)
> +{
> + int ret;
> +
> + ret = of_property_read_u32(np, "ddr3_speed_bin",
> + &timing->ddr3_speed_bin);
> + ret |= of_property_read_u32(np, "pd_idle", &timing->pd_idle);
> + ret |= of_property_read_u32(np, "sr_idle", &timing->sr_idle);
> + ret |= of_property_read_u32(np, "sr_mc_gate_idle",
> + &timing->sr_mc_gate_idle);
> + ret |= of_property_read_u32(np, "srpd_lite_idle",
> + &timing->srpd_lite_idle);
> + ret |= of_property_read_u32(np, "standby_idle", &timing->standby_idle);
> + ret |= of_property_read_u32(np, "dram_dll_dis_freq",
> + &timing->dram_dll_dis_freq);
> + ret |= of_property_read_u32(np, "phy_dll_dis_freq",
> + &timing->phy_dll_dis_freq);
> + ret |= of_property_read_u32(np, "ddr3_odt_dis_freq",
> + &timing->ddr3_odt_dis_freq);
> + ret |= of_property_read_u32(np, "ddr3_drv", &timing->ddr3_drv);
> + ret |= of_property_read_u32(np, "ddr3_odt", &timing->ddr3_odt);
> + ret |= of_property_read_u32(np, "phy_ddr3_ca_drv",
> + &timing->phy_ddr3_ca_drv);
> + ret |= of_property_read_u32(np, "phy_ddr3_dq_drv",
> + &timing->phy_ddr3_dq_drv);
> + ret |= of_property_read_u32(np, "phy_ddr3_odt", &timing->phy_ddr3_odt);
> + ret |= of_property_read_u32(np, "lpddr3_odt_dis_freq",
> + &timing->lpddr3_odt_dis_freq);
> + ret |= of_property_read_u32(np, "lpddr3_drv", &timing->lpddr3_drv);
> + ret |= of_property_read_u32(np, "lpddr3_odt", &timing->lpddr3_odt);
> + ret |= of_property_read_u32(np, "phy_lpddr3_ca_drv",
> + &timing->phy_lpddr3_ca_drv);
> + ret |= of_property_read_u32(np, "phy_lpddr3_dq_drv",
> + &timing->phy_lpddr3_dq_drv);
> + ret |= of_property_read_u32(np, "phy_lpddr3_odt",
> + &timing->phy_lpddr3_odt);
> + ret |= of_property_read_u32(np, "lpddr4_odt_dis_freq",
> + &timing->lpddr4_odt_dis_freq);
> + ret |= of_property_read_u32(np, "lpddr4_drv",
> + &timing->lpddr4_drv);
> + ret |= of_property_read_u32(np, "lpddr4_dq_odt",
> + &timing->lpddr4_dq_odt);
> + ret |= of_property_read_u32(np, "lpddr4_ca_odt",
> + &timing->lpddr4_ca_odt);
> + ret |= of_property_read_u32(np, "phy_lpddr4_ca_drv",
> + &timing->phy_lpddr4_ca_drv);
> + ret |= of_property_read_u32(np, "phy_lpddr4_ck_cs_drv",
> + &timing->phy_lpddr4_ck_cs_drv);
> + ret |= of_property_read_u32(np, "phy_lpddr4_dq_drv",
> + &timing->phy_lpddr4_dq_drv);
> + ret |= of_property_read_u32(np, "phy_lpddr4_odt",
> + &timing->phy_lpddr4_odt);
> +
> + return ret;
> +}
> +
> +static struct dram_timing *of_get_ddr_timings(struct device *dev,
> + struct device_node *np)
> +{
> + struct dram_timing *timing = NULL;
> + struct device_node *np_tim;
> +
> + np_tim = of_parse_phandle(np, "ddr_timing", 0);
> + if (np_tim) {
> + timing = devm_kzalloc(dev, sizeof(*timing), GFP_KERNEL);
> + if (!timing)
> + goto err;
> + if (of_do_get_timing(np_tim, timing)) {
> + devm_kfree(dev, timing);
> + goto err;
> + }
> + return timing;
> + }
> +
> +err:
> + if (timing) {
> + devm_kfree(dev, timing);
> + timing = NULL;
> + }
> +
> + return timing;
> +}
> +
> +static int rk3399_dmcfreq_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct rk3399_dmcfreq *data;
> + int ret, irq, index;
> + uint64_t param = 0;
> + uint32_t *timing;
> + struct device_node *np = pdev->dev.of_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);
> +
> + 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);
> + };
> +
> + data->edev = devfreq_event_get_edev_by_phandle(dev, 0);
> + if (IS_ERR(data->edev))
> + return -EPROBE_DEFER;
> +
> + ret = devfreq_event_enable_edev(data->edev);
> + if (ret < 0) {
> + dev_err(dev, "failed to enable devfreq-event devices\n");
> + return ret;
> + }
> +
> + /*
> + * 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->rate = clk_get_rate(data->dmc_clk);
> + rk3399_devfreq_dmc_profile.initial_freq = data->rate;
> + 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, 0,
> + dev_name(dev), data);
> + if (ret) {
> + dev_err(dev, "failed to request dmc irq: %d\n", ret);
> + return ret;
> + }
> +
> + /* get dram timing and pass it to bl31 */
> + data->timing = of_get_ddr_timings(dev, np);
> + if (data->timing) {
> + timing = (uint32_t *)data->timing;
> + for (index = 0; index < (sizeof(struct dram_timing) / 4);
> + index++) {
> + param = index;
> + param = param << 32 | *timing++;
> + sip_smc_set_ddr_param(param);
> + param = 0;
> + }
> + }
> + sip_smc_ddr_init();
> +
> + init_waitqueue_head(&data->wait_dcf_queue);
> + data->wait_dcf_flag = 0;
> +
> + 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..78baee5
> --- /dev/null
> +++ b/drivers/devfreq/rockchip/rockchip_dmc.c
> @@ -0,0 +1,143 @@
> +/*
> + * 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);
> +
> +/**
> + * rockchip_dmc_enabled - Returns true if dmc freq is enabled, false otherwise.
> + */
> +bool rockchip_dmc_enabled(void)
> +{
> + return num_disable <= 0 && num_wait <= 1;
> +}
> +
> +/**
> + * 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);
> +}
> +
> +/**
> + * 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);
> +}
> +
> +void dmc_event(int event)
> +{
> + mutex_lock(&dmc_sync_lock);
> + blocking_notifier_call_chain(&dmc_notifier_list, event, NULL);
> + mutex_unlock(&dmc_sync_lock);
> +}
> +
> +/**
> + * dmc_register_notifier - register a driver to dmc chain
> + * @nb: notifier function to register
> + */
> +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;
> +}
> +
> +/**
> + * dmc_unregister_notifier - unregister a driver from dmc chain
> + * @nb: remove notifier function
> + */
> +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;
> +}
> +
> +/**
> + * rockchip_dmc_get - Register the notifier block for the dmc chain.
> + * @nb The dmc notifier block to register
> + */
> +int rockchip_dmc_get(struct notifier_block *nb)
> +{
> + if (!nb)
> + return -EINVAL;
> +
> + mutex_lock(&dmc_en_lock);
> +
> + /*
> + * if have two notifier(enable two vop etc),
> + * 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;
> +}
> +
> +/**
> + * rockchip_dmc_put - Remove the notifier block from the dmc chain.
> + * @nb The dmc notifier block to unregister
> + */
> +int rockchip_dmc_put(struct notifier_block *nb)
> +{
> + if (!nb)
> + return -EINVAL;
> +
> + mutex_lock(&dmc_en_lock);
> + num_wait--;
> +
> + /* if notifier from 2 back to 1, enable dmc again */
> + if (num_wait == 1 && num_disable <= 0)
> + dmc_event(DMC_ENABLE);
> + dmc_unregister_notifier(nb);
> + mutex_unlock(&dmc_en_lock);
> +
> + return 0;
> +}
> diff --git a/include/soc/rockchip/rockchip_dmc.h b/include/soc/rockchip/rockchip_dmc.h
> new file mode 100644
> index 0000000..3f69cbf
> --- /dev/null
> +++ b/include/soc/rockchip/rockchip_dmc.h
> @@ -0,0 +1,45 @@
> +/*
> + * 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
> +
> +#if IS_ENABLED(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
>

Regards,
Chanwoo Choi