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 <h...@rock-chips.com>
---

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   | 337 ++++++++++++++++++++++++++++++++
 drivers/devfreq/rockchip/rockchip_dmc.c | 143 ++++++++++++++
 include/soc/rockchip/rockchip_dmc.h     |  45 +++++
 7 files changed, 544 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 78dac0e..e57275e 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..41ff71b
--- /dev/null
+++ b/drivers/devfreq/rockchip/rk3399_dmc.c
@@ -0,0 +1,337 @@
+/*
+ * Copyright (c) 2016, Fuzhou Rockchip Electronics Co., Ltd
+ * Author: Lin Huang <h...@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>
+
+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 devfreq_event_dev *edev;
+       struct mutex lock;
+       struct notifier_block dmc_nb;
+       int irq;
+       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);
+       reinit_completion(&dmcfreq->dcf_hold_completion);
+       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 freq scaling finish in bl31 */
+       wait_for_completion(&dmcfreq->dcf_hold_completion);
+       dmc_event(DMCFREQ_FINISH);
+
+       /*
+        * check the rate we get whether is correct
+        * in bl31 dcf, 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);
+
+       /* do not get the right 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;
+
+       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;
+       int ret, irq;
+       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->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);
+
+       init_completion(&data->dcf_hold_completion);
+
+       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;
+       }
+
+       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 <h...@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
-- 
1.9.1

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