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

From: [email-masked] (hl)
Date: Thu, 2 Jun 2016 11:26:17 +0800

Hi Chanwoo Choi,

     I just check the devfreq-event framework code, it is good,
i will do more dig to see whether it can fit for rk3399 dmc, thank you.

On 2016?06?01? 19:47, Chanwoo Choi wrote:
> 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 <[email-masked]> 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 <[email-masked]>
>> ---
>>   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 <[email-masked]>
>> + *
>> + * 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 <[email-masked]>
>> + * 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
>>
>
>

-- 
Lin Huang