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authorPavel Kubelun <be.dissent@gmail.com>2016-11-02 22:37:28 +0300
committerJohn Crispin <john@phrozen.org>2016-11-03 08:28:16 +0100
commit681f28990d7b44e218335968ebb4cfaca1349a77 (patch)
treeb2e9d93775ceb215c0294eef17d5bdfe1b5a295a /target/linux/ipq806x
parenta154a3d8bec45339c5f4f20b9dc6987652c63e41 (diff)
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ipq806x: switch to generic cpufreq driver cpufreq-dt
This fixes ondemand frequency scaling and moves ipq806x onto upstream driver Also switching to ondemand frequency scaling as it is fixed now Signed-off-by: Pavel Kubelun <be.dissent@gmail.com>
Diffstat (limited to 'target/linux/ipq806x')
-rw-r--r--target/linux/ipq806x/config-4.410
-rw-r--r--target/linux/ipq806x/patches-4.4/145-cpufreq-Add-a-cpufreq-krait-based-on-cpufre.patch461
-rw-r--r--target/linux/ipq806x/patches-4.4/172-cpufreq-dt-Handle-OPP-voltage-adjust-events.patch184
-rw-r--r--target/linux/ipq806x/patches-4.4/173-cpufreq-dt-Add-L2-frequency-scaling-support.patch161
-rw-r--r--target/linux/ipq806x/patches-4.4/174-cpufreq-dt-Add-missing-rcu_read_lock-for-find_device_opp.patch33
5 files changed, 383 insertions, 466 deletions
diff --git a/target/linux/ipq806x/config-4.4 b/target/linux/ipq806x/config-4.4
index 1972e36..7f0c7a9 100644
--- a/target/linux/ipq806x/config-4.4
+++ b/target/linux/ipq806x/config-4.4
@@ -77,7 +77,7 @@ CONFIG_COMMON_CLK=y
CONFIG_COMMON_CLK_QCOM=y
CONFIG_COMPACTION=y
CONFIG_COREDUMP=y
-# CONFIG_CPUFREQ_DT is not set
+CONFIG_CPUFREQ_DT=y
CONFIG_CPU_32v6K=y
CONFIG_CPU_32v7=y
CONFIG_CPU_ABRT_EV7=y
@@ -89,7 +89,8 @@ CONFIG_CPU_COPY_V6=y
CONFIG_CPU_CP15=y
CONFIG_CPU_CP15_MMU=y
CONFIG_CPU_FREQ=y
-CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y
+# CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE is not set
+CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y
CONFIG_CPU_FREQ_GOV_COMMON=y
# CONFIG_CPU_FREQ_GOV_CONSERVATIVE is not set
CONFIG_CPU_FREQ_GOV_ONDEMAND=y
@@ -105,7 +106,7 @@ CONFIG_CPU_IDLE_GOV_MENU=y
CONFIG_CPU_PABRT_V7=y
CONFIG_CPU_PM=y
CONFIG_CPU_RMAP=y
-# CONFIG_CPU_THERMAL is not set
+CONFIG_CPU_THERMAL=y
CONFIG_CPU_TLB_V7=y
CONFIG_CPU_V7=y
CONFIG_CRC16=y
@@ -146,7 +147,6 @@ CONFIG_GENERIC_ALLOCATOR=y
CONFIG_GENERIC_BUG=y
CONFIG_GENERIC_CLOCKEVENTS=y
CONFIG_GENERIC_CLOCKEVENTS_BROADCAST=y
-CONFIG_GENERIC_CPUFREQ_KRAIT=y
CONFIG_GENERIC_IDLE_POLL_SETUP=y
CONFIG_GENERIC_IO=y
CONFIG_GENERIC_IRQ_SHOW=y
@@ -378,7 +378,7 @@ CONFIG_QCOM_BAM_DMA=y
CONFIG_QCOM_GDSC=y
CONFIG_QCOM_GSBI=y
CONFIG_QCOM_HFPLL=y
-# CONFIG_QCOM_PM is not set
+CONFIG_QCOM_PM=y
CONFIG_QCOM_QFPROM=y
CONFIG_QCOM_SCM=y
CONFIG_QCOM_SCM_32=y
diff --git a/target/linux/ipq806x/patches-4.4/145-cpufreq-Add-a-cpufreq-krait-based-on-cpufre.patch b/target/linux/ipq806x/patches-4.4/145-cpufreq-Add-a-cpufreq-krait-based-on-cpufre.patch
deleted file mode 100644
index 67770e8..0000000
--- a/target/linux/ipq806x/patches-4.4/145-cpufreq-Add-a-cpufreq-krait-based-on-cpufre.patch
+++ /dev/null
@@ -1,461 +0,0 @@
-From dd77db4143290689d3a5e1ec61627233d0711b66 Mon Sep 17 00:00:00 2001
-From: Stephen Boyd <sboyd@codeaurora.org>
-Date: Fri, 30 May 2014 16:36:11 -0700
-Subject: [PATCH] FROMLIST: cpufreq: Add a cpufreq-krait based on cpufreq-cpu0
-
-Krait processors have individual clocks for each CPU that can
-scale independently from one another. cpufreq-cpu0 is fairly
-close to this, but assumes that there is only one clock for all
-CPUs. Add a driver to support the Krait configuration.
-
-TODO: Merge into cpufreq-cpu0? Or make generic?
-
-Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
-
----
- drivers/cpufreq/Kconfig | 13 +++
- drivers/cpufreq/Makefile | 1 +
- drivers/cpufreq/cpufreq-krait.c | 190 ++++++++++++++++++++++++++++++++++++++++
- 3 files changed, 204 insertions(+)
- create mode 100644 drivers/cpufreq/cpufreq-krait.c
-
---- a/drivers/cpufreq/Kconfig
-+++ b/drivers/cpufreq/Kconfig
-@@ -198,6 +198,19 @@ config CPUFREQ_DT
-
- If in doubt, say N.
-
-+config GENERIC_CPUFREQ_KRAIT
-+ tristate "Krait cpufreq driver"
-+ depends on HAVE_CLK && OF
-+ # if CPU_THERMAL is on and THERMAL=m, CPU0 cannot be =y:
-+ depends on !CPU_THERMAL || THERMAL
-+ select PM_OPP
-+ help
-+ This adds a generic cpufreq driver for CPU0 frequency management.
-+ It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
-+ systems which share clock and voltage across all CPUs.
-+
-+ If in doubt, say N.
-+
- if X86
- source "drivers/cpufreq/Kconfig.x86"
- endif
---- a/drivers/cpufreq/Makefile
-+++ b/drivers/cpufreq/Makefile
-@@ -13,6 +13,7 @@ obj-$(CONFIG_CPU_FREQ_GOV_CONSERVATIVE)
- obj-$(CONFIG_CPU_FREQ_GOV_COMMON) += cpufreq_governor.o
-
- obj-$(CONFIG_CPUFREQ_DT) += cpufreq-dt.o
-+obj-$(CONFIG_GENERIC_CPUFREQ_KRAIT) += cpufreq-krait.o
-
- ##################################################################################
- # x86 drivers.
---- /dev/null
-+++ b/drivers/cpufreq/cpufreq-krait.c
-@@ -0,0 +1,390 @@
-+/*
-+ * Copyright (C) 2012 Freescale Semiconductor, Inc.
-+ * Copyright (c) 2014, The Linux Foundation. All rights reserved.
-+ *
-+ * The OPP code in function krait_set_target() is reused from
-+ * drivers/cpufreq/omap-cpufreq.c
-+ *
-+ * This program is free software; you can redistribute it and/or modify
-+ * it under the terms of the GNU General Public License version 2 as
-+ * published by the Free Software Foundation.
-+ */
-+
-+#include <linux/clk.h>
-+#include <linux/cpu.h>
-+#include <linux/cpu_cooling.h>
-+#include <linux/cpufreq.h>
-+#include <linux/cpumask.h>
-+#include <linux/err.h>
-+#include <linux/module.h>
-+#include <linux/of.h>
-+#include <linux/pm_opp.h>
-+#include <linux/platform_device.h>
-+#include <linux/regulator/consumer.h>
-+#include <linux/slab.h>
-+#include <linux/thermal.h>
-+
-+static unsigned int transition_latency;
-+static unsigned int voltage_tolerance; /* in percentage */
-+
-+static struct device *cpu_dev;
-+static DEFINE_PER_CPU(struct clk *, krait_cpu_clks);
-+static DEFINE_PER_CPU(struct regulator *, krait_supply_core);
-+static struct cpufreq_frequency_table *freq_table;
-+static struct thermal_cooling_device *cdev;
-+
-+struct cache_points {
-+ unsigned long cache_freq;
-+ unsigned int cache_volt;
-+ unsigned long cpu_freq;
-+};
-+
-+static struct regulator *krait_l2_reg;
-+static struct clk *krait_l2_clk;
-+static struct cache_points *krait_l2_points;
-+static int nr_krait_l2_points;
-+
-+static int krait_parse_cache_points(struct device *dev,
-+ struct device_node *of_node)
-+{
-+ const struct property *prop;
-+ const __be32 *val;
-+ int nr, i;
-+
-+ prop = of_find_property(of_node, "cache-points-kHz", NULL);
-+ if (!prop)
-+ return -ENODEV;
-+ if (!prop->value)
-+ return -ENODATA;
-+
-+ /*
-+ * Each OPP is a set of tuples consisting of frequency and
-+ * cpu-frequency like <freq-kHz volt-uV freq-kHz>.
-+ */
-+ nr = prop->length / sizeof(u32);
-+ if (nr % 3) {
-+ dev_err(dev, "%s: Invalid cache points\n", __func__);
-+ return -EINVAL;
-+ }
-+ nr /= 3;
-+
-+ krait_l2_points = devm_kcalloc(dev, nr, sizeof(*krait_l2_points),
-+ GFP_KERNEL);
-+ if (!krait_l2_points)
-+ return -ENOMEM;
-+ nr_krait_l2_points = nr;
-+
-+ for (i = 0, val = prop->value; i < nr; i++) {
-+ unsigned long cache_freq = be32_to_cpup(val++) * 1000;
-+ unsigned int cache_volt = be32_to_cpup(val++);
-+ unsigned long cpu_freq = be32_to_cpup(val++) * 1000;
-+
-+ krait_l2_points[i].cache_freq = cache_freq;
-+ krait_l2_points[i].cache_volt = cache_volt;
-+ krait_l2_points[i].cpu_freq = cpu_freq;
-+ }
-+
-+ return 0;
-+}
-+
-+static int krait_set_target(struct cpufreq_policy *policy, unsigned int index)
-+{
-+ struct dev_pm_opp *opp;
-+ unsigned long volt = 0, volt_old = 0, tol = 0;
-+ unsigned long freq, max_cpu_freq = 0;
-+ unsigned int old_freq, new_freq;
-+ long freq_Hz, freq_exact;
-+ int ret, i;
-+ struct clk *cpu_clk;
-+ struct regulator *core;
-+ unsigned int cpu;
-+
-+ cpu_clk = per_cpu(krait_cpu_clks, policy->cpu);
-+
-+ freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
-+ if (freq_Hz <= 0)
-+ freq_Hz = freq_table[index].frequency * 1000;
-+
-+ freq_exact = freq_Hz;
-+ new_freq = freq_Hz / 1000;
-+ old_freq = clk_get_rate(cpu_clk) / 1000;
-+
-+ core = per_cpu(krait_supply_core, policy->cpu);
-+
-+ rcu_read_lock();
-+ opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
-+ if (IS_ERR(opp)) {
-+ rcu_read_unlock();
-+ pr_err("failed to find OPP for %ld\n", freq_Hz);
-+ return PTR_ERR(opp);
-+ }
-+ volt = dev_pm_opp_get_voltage(opp);
-+ rcu_read_unlock();
-+ tol = volt * voltage_tolerance / 100;
-+ volt_old = regulator_get_voltage(core);
-+
-+ pr_debug("%u MHz, %ld mV --> %u MHz, %ld mV\n",
-+ old_freq / 1000, volt_old ? volt_old / 1000 : -1,
-+ new_freq / 1000, volt ? volt / 1000 : -1);
-+
-+ /* scaling up? scale voltage before frequency */
-+ if (new_freq > old_freq) {
-+ ret = regulator_set_voltage_tol(core, volt, tol);
-+ if (ret) {
-+ pr_err("failed to scale voltage up: %d\n", ret);
-+ return ret;
-+ }
-+ }
-+
-+ ret = clk_set_rate(cpu_clk, freq_exact);
-+ if (ret) {
-+ pr_err("failed to set clock rate: %d\n", ret);
-+ return ret;
-+ }
-+
-+ /* scaling down? scale voltage after frequency */
-+ if (new_freq < old_freq) {
-+ ret = regulator_set_voltage_tol(core, volt, tol);
-+ if (ret) {
-+ pr_err("failed to scale voltage down: %d\n", ret);
-+ clk_set_rate(cpu_clk, old_freq * 1000);
-+ }
-+ }
-+
-+ for_each_possible_cpu(cpu) {
-+ freq = clk_get_rate(per_cpu(krait_cpu_clks, cpu));
-+ max_cpu_freq = max(max_cpu_freq, freq);
-+ }
-+
-+ for (i = 0; i < nr_krait_l2_points; i++) {
-+ if (max_cpu_freq >= krait_l2_points[i].cpu_freq) {
-+ if (krait_l2_reg) {
-+ ret = regulator_set_voltage_tol(krait_l2_reg,
-+ krait_l2_points[i].cache_volt,
-+ tol);
-+ if (ret) {
-+ pr_err("failed to scale l2 voltage: %d\n",
-+ ret);
-+ }
-+ }
-+ ret = clk_set_rate(krait_l2_clk,
-+ krait_l2_points[i].cache_freq);
-+ if (ret)
-+ pr_err("failed to scale l2 clk: %d\n", ret);
-+ break;
-+ }
-+
-+ }
-+
-+ return ret;
-+}
-+
-+static int krait_cpufreq_init(struct cpufreq_policy *policy)
-+{
-+ int ret;
-+
-+ policy->clk = per_cpu(krait_cpu_clks, policy->cpu);
-+
-+ ret = cpufreq_table_validate_and_show(policy, freq_table);
-+ if (ret) {
-+ pr_err("%s: invalid frequency table: %d\n", __func__, ret);
-+ return ret;
-+ }
-+
-+ policy->cpuinfo.transition_latency = transition_latency;
-+
-+ return 0;
-+}
-+
-+static struct cpufreq_driver krait_cpufreq_driver = {
-+ .flags = CPUFREQ_STICKY,
-+ .verify = cpufreq_generic_frequency_table_verify,
-+ .target_index = krait_set_target,
-+ .get = cpufreq_generic_get,
-+ .init = krait_cpufreq_init,
-+ .name = "generic_krait",
-+ .attr = cpufreq_generic_attr,
-+};
-+
-+static int krait_cpufreq_probe(struct platform_device *pdev)
-+{
-+ struct device_node *np, *cache;
-+ int ret, i;
-+ unsigned int cpu;
-+ struct device *dev;
-+ struct clk *clk;
-+ struct regulator *core;
-+ unsigned long freq_Hz, freq, max_cpu_freq = 0;
-+ struct dev_pm_opp *opp;
-+ unsigned long volt, tol;
-+
-+ cpu_dev = get_cpu_device(0);
-+ if (!cpu_dev) {
-+ pr_err("failed to get krait device\n");
-+ return -ENODEV;
-+ }
-+
-+ np = of_node_get(cpu_dev->of_node);
-+ if (!np) {
-+ pr_err("failed to find krait node\n");
-+ return -ENOENT;
-+ }
-+
-+ ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
-+ if (ret) {
-+ pr_err("failed to init cpufreq table: %d\n", ret);
-+ goto out_put_node;
-+ }
-+
-+ of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);
-+
-+ if (of_property_read_u32(np, "clock-latency", &transition_latency))
-+ transition_latency = CPUFREQ_ETERNAL;
-+
-+ cache = of_find_next_cache_node(np);
-+ if (cache) {
-+ struct device_node *vdd;
-+
-+ vdd = of_parse_phandle(cache, "vdd_dig-supply", 0);
-+ if (vdd) {
-+ krait_l2_reg = regulator_get(NULL, vdd->name);
-+ if (IS_ERR(krait_l2_reg)) {
-+ pr_warn("failed to get l2 vdd_dig supply\n");
-+ krait_l2_reg = NULL;
-+ }
-+ of_node_put(vdd);
-+ }
-+
-+ krait_l2_clk = of_clk_get(cache, 0);
-+ if (!IS_ERR(krait_l2_clk)) {
-+ ret = krait_parse_cache_points(&pdev->dev, cache);
-+ if (ret)
-+ clk_put(krait_l2_clk);
-+ }
-+ if (IS_ERR(krait_l2_clk) || ret)
-+ krait_l2_clk = NULL;
-+ }
-+
-+ for_each_possible_cpu(cpu) {
-+ dev = get_cpu_device(cpu);
-+ if (!dev) {
-+ pr_err("failed to get krait device\n");
-+ ret = -ENOENT;
-+ goto out_free_table;
-+ }
-+ per_cpu(krait_cpu_clks, cpu) = clk = devm_clk_get(dev, NULL);
-+ if (IS_ERR(clk)) {
-+ ret = PTR_ERR(clk);
-+ goto out_free_table;
-+ }
-+ core = devm_regulator_get(dev, "core");
-+ if (IS_ERR(core)) {
-+ pr_debug("failed to get core regulator\n");
-+ ret = PTR_ERR(core);
-+ goto out_free_table;
-+ }
-+ per_cpu(krait_supply_core, cpu) = core;
-+
-+ freq = freq_Hz = clk_get_rate(clk);
-+
-+ rcu_read_lock();
-+ opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
-+ if (IS_ERR(opp)) {
-+ rcu_read_unlock();
-+ pr_err("failed to find OPP for %ld\n", freq_Hz);
-+ ret = PTR_ERR(opp);
-+ goto out_free_table;
-+ }
-+ volt = dev_pm_opp_get_voltage(opp);
-+ rcu_read_unlock();
-+
-+ tol = volt * voltage_tolerance / 100;
-+ ret = regulator_set_voltage_tol(core, volt, tol);
-+ if (ret) {
-+ pr_err("failed to scale voltage up: %d\n", ret);
-+ goto out_free_table;
-+ }
-+ ret = regulator_enable(core);
-+ if (ret) {
-+ pr_err("failed to enable regulator: %d\n", ret);
-+ goto out_free_table;
-+ }
-+ max_cpu_freq = max(max_cpu_freq, freq);
-+ }
-+
-+ for (i = 0; i < nr_krait_l2_points; i++) {
-+ if (max_cpu_freq >= krait_l2_points[i].cpu_freq) {
-+ if (krait_l2_reg) {
-+ ret = regulator_set_voltage_tol(krait_l2_reg,
-+ krait_l2_points[i].cache_volt,
-+ tol);
-+ if (ret)
-+ pr_err("failed to scale l2 voltage: %d\n",
-+ ret);
-+ ret = regulator_enable(krait_l2_reg);
-+ if (ret)
-+ pr_err("failed to enable l2 voltage: %d\n",
-+ ret);
-+ }
-+ break;
-+ }
-+
-+ }
-+
-+ ret = cpufreq_register_driver(&krait_cpufreq_driver);
-+ if (ret) {
-+ pr_err("failed register driver: %d\n", ret);
-+ goto out_free_table;
-+ }
-+ of_node_put(np);
-+
-+ /*
-+ * For now, just loading the cooling device;
-+ * thermal DT code takes care of matching them.
-+ */
-+ for_each_possible_cpu(cpu) {
-+ dev = get_cpu_device(cpu);
-+ np = of_node_get(dev->of_node);
-+ if (of_find_property(np, "#cooling-cells", NULL)) {
-+ cdev = of_cpufreq_cooling_register(np, cpumask_of(cpu));
-+ if (IS_ERR(cdev))
-+ pr_err("running cpufreq without cooling device: %ld\n",
-+ PTR_ERR(cdev));
-+ }
-+ of_node_put(np);
-+ }
-+
-+ return 0;
-+
-+out_free_table:
-+ regulator_put(krait_l2_reg);
-+ clk_put(krait_l2_clk);
-+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
-+out_put_node:
-+ of_node_put(np);
-+ return ret;
-+}
-+
-+static int krait_cpufreq_remove(struct platform_device *pdev)
-+{
-+ cpufreq_cooling_unregister(cdev);
-+ cpufreq_unregister_driver(&krait_cpufreq_driver);
-+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
-+ clk_put(krait_l2_clk);
-+ regulator_put(krait_l2_reg);
-+
-+ return 0;
-+}
-+
-+static struct platform_driver krait_cpufreq_platdrv = {
-+ .driver = {
-+ .name = "cpufreq-krait",
-+ .owner = THIS_MODULE,
-+ },
-+ .probe = krait_cpufreq_probe,
-+ .remove = krait_cpufreq_remove,
-+};
-+module_platform_driver(krait_cpufreq_platdrv);
-+
-+MODULE_DESCRIPTION("Krait CPUfreq driver");
-+MODULE_LICENSE("GPL v2");
---- a/drivers/cpufreq/qcom-cpufreq.c
-+++ b/drivers/cpufreq/qcom-cpufreq.c
-@@ -168,11 +168,8 @@ static int __init qcom_cpufreq_populate_
-
- static int __init qcom_cpufreq_driver_init(void)
- {
-- struct cpufreq_dt_platform_data pdata = { .independent_clocks = true };
- struct platform_device_info devinfo = {
-- .name = "cpufreq-dt",
-- .data = &pdata,
-- .size_data = sizeof(pdata),
-+ .name = "cpufreq-krait",
- };
- struct device *cpu_dev;
- struct device_node *np;
diff --git a/target/linux/ipq806x/patches-4.4/172-cpufreq-dt-Handle-OPP-voltage-adjust-events.patch b/target/linux/ipq806x/patches-4.4/172-cpufreq-dt-Handle-OPP-voltage-adjust-events.patch
new file mode 100644
index 0000000..60ebe13
--- /dev/null
+++ b/target/linux/ipq806x/patches-4.4/172-cpufreq-dt-Handle-OPP-voltage-adjust-events.patch
@@ -0,0 +1,184 @@
+From 175329015c8a0b480240da222822d2f8316f074d Mon Sep 17 00:00:00 2001
+From: Stephen Boyd <sboyd@codeaurora.org>
+Date: Mon, 1 Jun 2015 18:47:58 -0700
+Subject: cpufreq-dt: Handle OPP voltage adjust events
+
+On some SoCs the Adaptive Voltage Scaling (AVS) technique is
+employed to optimize the operating voltage of a device. At a
+given frequency, the hardware monitors dynamic factors and either
+makes a suggestion for how much to adjust a voltage for the
+current frequency, or it automatically adjusts the voltage
+without software intervention.
+
+In the former case, an AVS driver will call
+dev_pm_opp_modify_voltage() and update the voltage for the
+particular OPP the CPUs are using. Add an OPP notifier to
+cpufreq-dt so that we can adjust the voltage of the CPU when AVS
+updates the OPP.
+
+Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
+---
+ drivers/cpufreq/cpufreq-dt.c | 72 ++++++++++++++++++++++++++++++++++++++++----
+ 1 file changed, 66 insertions(+), 6 deletions(-)
+
+--- a/drivers/cpufreq/cpufreq-dt.c
++++ b/drivers/cpufreq/cpufreq-dt.c
+@@ -34,6 +34,9 @@ struct private_data {
+ struct regulator *cpu_reg;
+ struct thermal_cooling_device *cdev;
+ unsigned int voltage_tolerance; /* in percentage */
++ struct notifier_block opp_nb;
++ struct mutex lock;
++ unsigned long opp_freq;
+ };
+
+ static struct freq_attr *cpufreq_dt_attr[] = {
+@@ -42,6 +45,42 @@ static struct freq_attr *cpufreq_dt_attr
+ NULL,
+ };
+
++static int opp_notifier(struct notifier_block *nb, unsigned long event,
++ void *data)
++{
++ struct dev_pm_opp *opp = data;
++ struct private_data *priv = container_of(nb, struct private_data,
++ opp_nb);
++ struct device *cpu_dev = priv->cpu_dev;
++ struct regulator *cpu_reg = priv->cpu_reg;
++ unsigned long volt, tol, freq;
++ int ret = 0;
++
++ switch (event) {
++ case OPP_EVENT_ADJUST_VOLTAGE:
++ volt = dev_pm_opp_get_voltage(opp);
++ freq = dev_pm_opp_get_freq(opp);
++ tol = volt * priv->voltage_tolerance / 100;
++
++ mutex_lock(&priv->lock);
++ if (freq == priv->opp_freq)
++ ret = regulator_set_voltage_tol(cpu_reg, volt,
++ tol);
++ mutex_unlock(&priv->lock);
++ if (ret) {
++ dev_err(cpu_dev,
++ "failed to scale voltage up: %d\n",
++ ret);
++ return ret;
++ }
++ break;
++ default:
++ break;
++ }
++
++ return 0;
++}
++
+ static int set_target(struct cpufreq_policy *policy, unsigned int index)
+ {
+ struct dev_pm_opp *opp;
+@@ -53,6 +92,7 @@ static int set_target(struct cpufreq_pol
+ unsigned long volt = 0, volt_old = 0, tol = 0;
+ unsigned int old_freq, new_freq;
+ long freq_Hz, freq_exact;
++ unsigned long opp_freq = 0;
+ int ret;
+
+ freq_Hz = clk_round_rate(cpu_clk, freq_table[index].frequency * 1000);
+@@ -63,8 +103,8 @@ static int set_target(struct cpufreq_pol
+ new_freq = freq_Hz / 1000;
+ old_freq = clk_get_rate(cpu_clk) / 1000;
+
++ mutex_lock(&priv->lock);
+ if (!IS_ERR(cpu_reg)) {
+- unsigned long opp_freq;
+
+ rcu_read_lock();
+ opp = dev_pm_opp_find_freq_ceil(cpu_dev, &freq_Hz);
+@@ -72,7 +112,8 @@ static int set_target(struct cpufreq_pol
+ rcu_read_unlock();
+ dev_err(cpu_dev, "failed to find OPP for %ld\n",
+ freq_Hz);
+- return PTR_ERR(opp);
++ ret = PTR_ERR(opp);
++ goto out;
+ }
+ volt = dev_pm_opp_get_voltage(opp);
+ opp_freq = dev_pm_opp_get_freq(opp);
+@@ -93,7 +134,7 @@ static int set_target(struct cpufreq_pol
+ if (ret) {
+ dev_err(cpu_dev, "failed to scale voltage up: %d\n",
+ ret);
+- return ret;
++ goto out;
+ }
+ }
+
+@@ -102,7 +143,7 @@ static int set_target(struct cpufreq_pol
+ dev_err(cpu_dev, "failed to set clock rate: %d\n", ret);
+ if (!IS_ERR(cpu_reg) && volt_old > 0)
+ regulator_set_voltage_tol(cpu_reg, volt_old, tol);
+- return ret;
++ goto out;
+ }
+
+ /* scaling down? scale voltage after frequency */
+@@ -112,9 +153,12 @@ static int set_target(struct cpufreq_pol
+ dev_err(cpu_dev, "failed to scale voltage down: %d\n",
+ ret);
+ clk_set_rate(cpu_clk, old_freq * 1000);
++ goto out;
+ }
+ }
+-
++ priv->opp_freq = opp_freq;
++out:
++ mutex_unlock(&priv->lock);
+ return ret;
+ }
+
+@@ -201,6 +245,7 @@ static int cpufreq_init(struct cpufreq_p
+ unsigned int transition_latency;
+ bool need_update = false;
+ int ret;
++ struct srcu_notifier_head *opp_srcu_head;
+
+ ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
+ if (ret) {
+@@ -277,6 +322,19 @@ static int cpufreq_init(struct cpufreq_p
+ goto out_free_opp;
+ }
+
++ mutex_init(&priv->lock);
++
++ opp_srcu_head = dev_pm_opp_get_notifier(cpu_dev);
++ if (IS_ERR(opp_srcu_head)) {
++ ret = PTR_ERR(opp_srcu_head);
++ goto out_free_priv;
++ }
++
++ priv->opp_nb.notifier_call = opp_notifier;
++ ret = srcu_notifier_chain_register(opp_srcu_head, &priv->opp_nb);
++ if (ret)
++ goto out_free_priv;
++
+ of_property_read_u32(np, "voltage-tolerance", &priv->voltage_tolerance);
+
+ if (!transition_latency)
+@@ -326,7 +384,7 @@ static int cpufreq_init(struct cpufreq_p
+ ret = dev_pm_opp_init_cpufreq_table(cpu_dev, &freq_table);
+ if (ret) {
+ pr_err("failed to init cpufreq table: %d\n", ret);
+- goto out_free_priv;
++ goto out_unregister_nb;
+ }
+
+ priv->cpu_dev = cpu_dev;
+@@ -365,6 +423,8 @@ static int cpufreq_init(struct cpufreq_p
+
+ out_free_cpufreq_table:
+ dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);
++out_unregister_nb:
++ srcu_notifier_chain_unregister(opp_srcu_head, &priv->opp_nb);
+ out_free_priv:
+ kfree(priv);
+ out_free_opp:
diff --git a/target/linux/ipq806x/patches-4.4/173-cpufreq-dt-Add-L2-frequency-scaling-support.patch b/target/linux/ipq806x/patches-4.4/173-cpufreq-dt-Add-L2-frequency-scaling-support.patch
new file mode 100644
index 0000000..5693052
--- /dev/null
+++ b/target/linux/ipq806x/patches-4.4/173-cpufreq-dt-Add-L2-frequency-scaling-support.patch
@@ -0,0 +1,161 @@
+From b4629f9e30e865402c643de6d4668be790fc0539 Mon Sep 17 00:00:00 2001
+From: Georgi Djakov <georgi.djakov@linaro.org>
+Date: Tue, 8 Sep 2015 11:24:41 +0300
+Subject: cpufreq-dt: Add L2 frequency scaling support
+
+Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
+
+Conflicts:
+ drivers/cpufreq/cpufreq-dt.c
+---
+ drivers/cpufreq/cpufreq-dt.c | 54 ++++++++++++++++++++++++++++++++++++++------
+ include/linux/cpufreq.h | 2 ++
+ 2 files changed, 49 insertions(+), 7 deletions(-)
+
+--- a/drivers/cpufreq/cpufreq-dt.c
++++ b/drivers/cpufreq/cpufreq-dt.c
+@@ -86,11 +86,13 @@ static int set_target(struct cpufreq_pol
+ struct dev_pm_opp *opp;
+ struct cpufreq_frequency_table *freq_table = policy->freq_table;
+ struct clk *cpu_clk = policy->clk;
++ struct clk *l2_clk = policy->l2_clk;
+ struct private_data *priv = policy->driver_data;
+ struct device *cpu_dev = priv->cpu_dev;
+ struct regulator *cpu_reg = priv->cpu_reg;
+ unsigned long volt = 0, volt_old = 0, tol = 0;
+- unsigned int old_freq, new_freq;
++ unsigned int old_freq, new_freq, l2_freq;
++ unsigned long new_l2_freq = 0;
+ long freq_Hz, freq_exact;
+ unsigned long opp_freq = 0;
+ int ret;
+@@ -146,6 +148,30 @@ static int set_target(struct cpufreq_pol
+ goto out;
+ }
+
++ if (!IS_ERR(l2_clk) && policy->l2_rate[0] && policy->l2_rate[1] &&
++ policy->l2_rate[2]) {
++ static unsigned long krait_l2[CONFIG_NR_CPUS] = { };
++ int cpu, ret = 0;
++
++ if (freq_exact >= policy->l2_rate[2])
++ new_l2_freq = policy->l2_rate[2];
++ else if (freq_exact >= policy->l2_rate[1])
++ new_l2_freq = policy->l2_rate[1];
++ else
++ new_l2_freq = policy->l2_rate[0];
++
++ krait_l2[policy->cpu] = new_l2_freq;
++ for_each_present_cpu(cpu)
++ new_l2_freq = max(new_l2_freq, krait_l2[cpu]);
++
++ l2_freq = clk_get_rate(l2_clk);
++
++ if (l2_freq != new_l2_freq) {
++ /* scale l2 with the core */
++ ret = clk_set_rate(l2_clk, new_l2_freq);
++ }
++ }
++
+ /* scaling down? scale voltage after frequency */
+ if (!IS_ERR(cpu_reg) && new_freq < old_freq) {
+ ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
+@@ -156,18 +182,21 @@ static int set_target(struct cpufreq_pol
+ goto out;
+ }
+ }
++
+ priv->opp_freq = opp_freq;
++
+ out:
+ mutex_unlock(&priv->lock);
+ return ret;
+ }
+
+ static int allocate_resources(int cpu, struct device **cdev,
+- struct regulator **creg, struct clk **cclk)
++ struct regulator **creg, struct clk **cclk,
++ struct clk **l2)
+ {
+ struct device *cpu_dev;
+ struct regulator *cpu_reg;
+- struct clk *cpu_clk;
++ struct clk *cpu_clk, *l2_clk = NULL;
+ int ret = 0;
+ char *reg_cpu0 = "cpu0", *reg_cpu = "cpu", *reg;
+
+@@ -227,6 +256,10 @@ try_again:
+ *cdev = cpu_dev;
+ *creg = cpu_reg;
+ *cclk = cpu_clk;
++
++ l2_clk = clk_get(cpu_dev, "l2");
++ if (!IS_ERR(l2_clk))
++ *l2 = l2_clk;
+ }
+
+ return ret;
+@@ -236,18 +269,20 @@ static int cpufreq_init(struct cpufreq_p
+ {
+ struct cpufreq_frequency_table *freq_table;
+ struct device_node *np;
++ struct device_node *l2_np;
+ struct private_data *priv;
+ struct device *cpu_dev;
+ struct regulator *cpu_reg;
+- struct clk *cpu_clk;
+ struct dev_pm_opp *suspend_opp;
++ struct clk *cpu_clk, *l2_clk;
+ unsigned long min_uV = ~0, max_uV = 0;
+ unsigned int transition_latency;
+ bool need_update = false;
+ int ret;
+ struct srcu_notifier_head *opp_srcu_head;
+
+- ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk);
++ ret = allocate_resources(policy->cpu, &cpu_dev, &cpu_reg, &cpu_clk,
++ &l2_clk);
+ if (ret) {
+ pr_err("%s: Failed to allocate resources: %d\n", __func__, ret);
+ return ret;
+@@ -398,6 +433,11 @@ static int cpufreq_init(struct cpufreq_p
+ if (suspend_opp)
+ policy->suspend_freq = dev_pm_opp_get_freq(suspend_opp) / 1000;
+ rcu_read_unlock();
++ policy->l2_clk = l2_clk;
++
++ l2_np = of_find_node_by_name(NULL, "qcom,l2");
++ if (l2_np)
++ of_property_read_u32_array(l2_np, "qcom,l2-rates", policy->l2_rate, 3);
+
+ ret = cpufreq_table_validate_and_show(policy, freq_table);
+ if (ret) {
+@@ -498,7 +538,7 @@ static int dt_cpufreq_probe(struct platf
+ {
+ struct device *cpu_dev;
+ struct regulator *cpu_reg;
+- struct clk *cpu_clk;
++ struct clk *cpu_clk, *l2_clk;
+ int ret;
+
+ /*
+@@ -508,7 +548,7 @@ static int dt_cpufreq_probe(struct platf
+ *
+ * FIXME: Is checking this only for CPU0 sufficient ?
+ */
+- ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk);
++ ret = allocate_resources(0, &cpu_dev, &cpu_reg, &cpu_clk, &l2_clk);
+ if (ret)
+ return ret;
+
+--- a/include/linux/cpufreq.h
++++ b/include/linux/cpufreq.h
+@@ -67,6 +67,8 @@ struct cpufreq_policy {
+ unsigned int cpu; /* cpu managing this policy, must be online */
+
+ struct clk *clk;
++ struct clk *l2_clk; /* L2 clock */
++ unsigned int l2_rate[3]; /* L2 bus clock rate thresholds */
+ struct cpufreq_cpuinfo cpuinfo;/* see above */
+
+ unsigned int min; /* in kHz */
diff --git a/target/linux/ipq806x/patches-4.4/174-cpufreq-dt-Add-missing-rcu_read_lock-for-find_device_opp.patch b/target/linux/ipq806x/patches-4.4/174-cpufreq-dt-Add-missing-rcu_read_lock-for-find_device_opp.patch
new file mode 100644
index 0000000..1242721
--- /dev/null
+++ b/target/linux/ipq806x/patches-4.4/174-cpufreq-dt-Add-missing-rcu_read_lock-for-find_device_opp.patch
@@ -0,0 +1,33 @@
+From dafae9c5b39e2871bfd8db0b4bad6e850e42ef49 Mon Sep 17 00:00:00 2001
+From: Georgi Djakov <georgi.djakov@linaro.org>
+Date: Wed, 13 Jan 2016 15:10:25 +0200
+Subject: cpufreq-dt: Add missing rcu_read_lock() for find_device_opp()
+
+The function dev_pm_opp_get_notifier() must be called with held
+rcu_read_lock. In order to keep the pointer valid, add rcu_read_lock().
+
+Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
+---
+ drivers/cpufreq/cpufreq-dt.c | 3 +++
+ 1 file changed, 3 insertions(+)
+
+--- a/drivers/cpufreq/cpufreq-dt.c
++++ b/drivers/cpufreq/cpufreq-dt.c
+@@ -359,14 +359,17 @@ static int cpufreq_init(struct cpufreq_p
+
+ mutex_init(&priv->lock);
+
++ rcu_read_lock();
+ opp_srcu_head = dev_pm_opp_get_notifier(cpu_dev);
+ if (IS_ERR(opp_srcu_head)) {
+ ret = PTR_ERR(opp_srcu_head);
++ rcu_read_unlock();
+ goto out_free_priv;
+ }
+
+ priv->opp_nb.notifier_call = opp_notifier;
+ ret = srcu_notifier_chain_register(opp_srcu_head, &priv->opp_nb);
++ rcu_read_unlock();
+ if (ret)
+ goto out_free_priv;
+