Patchwork [2/2,v2] cpufreq: Add cpufreq driver for Freescale e500mc SoCs

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Submitter tang yuantian
Date March 28, 2013, 9:55 a.m.
Message ID <1364464508-25393-1-git-send-email-Yuantian.Tang@freescale.com>
Download mbox | patch
Permalink /patch/231969/
State Superseded
Delegated to: Kumar Gala
Headers show

Comments

tang yuantian - March 28, 2013, 9:55 a.m.
From: Tang Yuantian <yuantian.tang@freescale.com>

Add cpufreq driver for Freescale e500mc, e5500 and e6500 SoCs
which are capable of changing the frequency of CPU dynamically

Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
Signed-off-by: Li Yang <leoli@freescale.com>
---
v2:
	- change the per_cpu variable to point type
	- fixed other issues

 drivers/cpufreq/Kconfig.powerpc       |  10 ++
 drivers/cpufreq/Makefile              |   1 +
 drivers/cpufreq/ppc-corenet-cpufreq.c | 255 ++++++++++++++++++++++++++++++++++
 3 files changed, 266 insertions(+)
 create mode 100644 drivers/cpufreq/ppc-corenet-cpufreq.c
viresh kumar - March 28, 2013, 2:54 p.m.
On 28 March 2013 15:25,  <Yuantian.Tang@freescale.com> wrote:
> From: Tang Yuantian <yuantian.tang@freescale.com>
>
> Add cpufreq driver for Freescale e500mc, e5500 and e6500 SoCs
> which are capable of changing the frequency of CPU dynamically
>
> Signed-off-by: Tang Yuantian <Yuantian.Tang@freescale.com>
> Signed-off-by: Li Yang <leoli@freescale.com>
> ---
> v2:
>         - change the per_cpu variable to point type
>         - fixed other issues

This changelog is pretty important and useful. People forget what comments
they gave on earlier version.

> diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c

> +/**
> + * struct cpufreq_data - cpufreq driver data
> + * @cpus_per_cluster: CPU numbers per cluster
> + * @cpufreq_lock: the mutex lock

rather add what's its purpose and what it protects.

> + */
> +struct cpufreq_data {
> +       int     cpus_per_cluster;
> +       struct mutex cpufreq_lock;
> +};

You actually need a struct for this? Simply create globals ?

> +/**
> + * struct cpu_data - per CPU data struct
> + * @clk: the clk data of CPU

remove "data"

> + * @parent: the parent node of clock of cpu

s/clock of cpu/cpu clock

> + * @table: frequency table point

point? you mean pointer? Just remove it.

> +struct cpu_data {
> +       struct clk *clk;
> +       struct device_node *parent;
> +       struct cpufreq_frequency_table *table;
> +};
> +
> +static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
> +static struct cpufreq_data freq_data;
> +
> +static unsigned int corenet_cpufreq_get_speed(unsigned int cpu)
> +{
> +       struct cpu_data *data = per_cpu(cpu_data, cpu);
> +
> +       return clk_get_rate(data->clk) / 1000;
> +}
> +
> +/* reduce the duplicated frequency in frequency table */
> +static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
> +               int count)
> +{
> +       int i, j;
> +
> +       for (i = 1; i < count; i++) {
> +               for (j = 0; j < i; j++) {
> +                       if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
> +                                       freq_table[j].frequency !=
> +                                       freq_table[i].frequency)
> +                               continue;
> +
> +                       freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
> +                       break;
> +               }
> +       }
> +}

Looks better now :)

> +static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
> +{
> +       unsigned int cpu = policy->cpu;
> +       struct device_node *np;
> +       int i, count;
> +       struct clk *clk;
> +       struct cpufreq_frequency_table *table;
> +       struct cpu_data *data;
> +
> +       np = of_get_cpu_node(cpu, NULL);
> +       if (!np)
> +               return -ENODEV;
> +
> +       data = kzalloc(sizeof(struct cpu_data), GFP_KERNEL);

I told you, you missed my comment earlier.

You need to write: sizeof(*data) :(

> +       if (!data)
> +               return -ENOMEM;
> +
> +       data->clk = of_clk_get(np, 0);
> +       data->parent = of_parse_phandle(np, "clocks", 0);
> +       if (!data->parent) {
> +               pr_err("%s: could not get clock information\n", __func__);
> +               goto err_nomem2;
> +       }
> +
> +       count = of_property_count_strings(data->parent, "clock-names");
> +
> +       table = kcalloc(count + 1,
> +                       sizeof(struct cpufreq_frequency_table), GFP_KERNEL);

sizeof(*table)

> +       if (!table) {
> +               pr_err("%s: no memory\n", __func__);
> +               goto err_nomem2;
> +       }
> +
> +       for (i = cpu; i < freq_data.cpus_per_cluster + cpu; i++)
> +               cpumask_set_cpu(i, policy->cpus);

I can see some regression here. Suppose you have two clusters of 4
cpus each: (0123) and (4567).. Now at boot time above code will work
perfectly fine. Now you hot unplug 0,1,2,3 and then hotplug 3 in.

Here, init would be called for cpu 3 and so you will end up saving 3456
in your policy->cpus

:)

> +       for (i = 0; i < count; i++) {
> +               table[i].index = i;
> +               clk = of_clk_get(data->parent, i);
> +               table[i].frequency = clk_get_rate(clk) / 1000;
> +       }
> +       freq_table_redup(table, count);
> +       table[i].frequency = CPUFREQ_TABLE_END;
> +
> +       data->table = table;
> +       per_cpu(cpu_data, cpu) = data;
> +
> +       policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
> +       policy->cur = corenet_cpufreq_get_speed(policy->cpu);
> +
> +       /* set the min and max frequency properly */
> +       i = cpufreq_frequency_table_cpuinfo(policy, table);

i doesn't suit here, use variable like ret or err..
And move this just after the line where you set freq as TABLE_END.
So that you don't execute unnecessary code for error case.

> +static int corenet_cpufreq_verify(struct cpufreq_policy *policy)
> +{
> +       struct cpufreq_frequency_table *table;
> +
> +       table = per_cpu(cpu_data, policy->cpu)->table;

merge above two lines.

> +       return cpufreq_frequency_table_verify(policy, table);
> +}
> +
> +static int corenet_cpufreq_target(struct cpufreq_policy *policy,
> +               unsigned int target_freq, unsigned int relation)
> +{
> +       struct cpufreq_freqs freqs;
> +       unsigned int new;
> +       struct clk *parent;
> +       int ret;
> +       struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
> +
> +       cpufreq_frequency_table_target(policy, data->table,
> +                       target_freq, relation, &new);
> +
> +       if (policy->cur == data->table[new].frequency)
> +               return 0;
> +
> +       freqs.old = policy->cur;
> +       freqs.new = data->table[new].frequency;
> +       freqs.cpu = policy->cpu;
> +
> +       mutex_lock(&freq_data.cpufreq_lock);
> +       cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);

You need to notify freq change for all cpus in this group :)

BUT you don't need to worry about it due to this:

http://patches.linaro.org/15569/

> +       parent = of_clk_get(data->parent, new);
> +       ret = clk_set_parent(data->clk, parent);
> +       if (ret) {
> +               mutex_unlock(&freq_data.cpufreq_lock);

Probably for error case too you need to notify others about completion
of freq change, but with old freq.

> +               return ret;
> +       }
> +
> +       cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> +       mutex_unlock(&freq_data.cpufreq_lock);
> +
> +       return 0;
> +}
> +
> +static struct freq_attr *corenet_cpu_clks_attr[] = {

name it better, maybe corenet_cpufreq_attr ?

> +       &cpufreq_freq_attr_scaling_available_freqs,
> +       NULL,
> +};
> +
> +static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
> +       .name           = "ppc_cpufreq",
> +       .owner          = THIS_MODULE,
> +       .flags          = CPUFREQ_CONST_LOOPS,
> +       .init           = corenet_cpufreq_cpu_init,
> +       .exit           = __exit_p(corenet_cpufreq_cpu_exit),
> +       .verify         = corenet_cpufreq_verify,
> +       .target         = corenet_cpufreq_target,
> +       .get            = corenet_cpufreq_get_speed,
> +       .attr           = corenet_cpu_clks_attr,
> +};
> +
> +static const struct of_device_id node_matches[] __initconst = {
> +       { .compatible = "fsl,qoriq-clockgen-1.0", .data = (void *)1, },
> +       { .compatible = "fsl,qoriq-clockgen-2", .data = (void *)8, },
> +       {}
> +};
> +
> +static int __init ppc_corenet_cpufreq_init(void)
> +{
> +       int ret = 0;
> +       struct device_node  *np;
> +       const struct of_device_id *match;
> +
> +       np = of_find_matching_node(NULL, node_matches);
> +       if (!np)
> +               return -ENODEV;
> +
> +       match = of_match_node(node_matches, np);
> +       freq_data.cpus_per_cluster = (unsigned long)match->data;
> +       mutex_init(&freq_data.cpufreq_lock);
> +       of_node_put(np);
> +
> +       ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
> +       if (ret)
> +               return ret;
> +
> +       pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");

Or write it as:

ret = cpufreq_register_driver();
if (!ret)
    pr_info();

return ret;

> +
> +       return ret;
> +}
> +module_init(ppc_corenet_cpufreq_init);
> +
> +static void __exit ppc_corenet_cpufreq_exit(void)
> +{
> +       cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
> +}
> +module_exit(ppc_corenet_cpufreq_exit);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
> +MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");
tang yuantian - March 29, 2013, 2:51 a.m.
> > +static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy) {
> > +       unsigned int cpu = policy->cpu;
> > +       struct device_node *np;
> > +       int i, count;
> > +       struct clk *clk;
> > +       struct cpufreq_frequency_table *table;
> > +       struct cpu_data *data;
> > +
> > +       np = of_get_cpu_node(cpu, NULL);
> > +       if (!np)
> > +               return -ENODEV;
> > +
> > +       data = kzalloc(sizeof(struct cpu_data), GFP_KERNEL);
> 
> I told you, you missed my comment earlier.
> 
> You need to write: sizeof(*data) :(
> 
This is new added statement, what you told last time is about the next kcalloc()...

Are there some reasons that we can't use sizeof(struct cpu_data)
instead of sizeof(*data)?

> > +       if (!data)
> > +               return -ENOMEM;
> > +
> > +       data->clk = of_clk_get(np, 0);
> > +       data->parent = of_parse_phandle(np, "clocks", 0);
> > +       if (!data->parent) {
> > +               pr_err("%s: could not get clock information\n",
> __func__);
> > +               goto err_nomem2;
> > +       }
> > +
> > +       count = of_property_count_strings(data->parent,
> > + "clock-names");
> > +
> > +       table = kcalloc(count + 1,
> > +                       sizeof(struct cpufreq_frequency_table),
> > + GFP_KERNEL);
> 
> sizeof(*table)
> 
Ditto.

> > +       if (!table) {
> > +               pr_err("%s: no memory\n", __func__);
> > +               goto err_nomem2;
> > +       }
> > +
> > +       for (i = cpu; i < freq_data.cpus_per_cluster + cpu; i++)
> > +               cpumask_set_cpu(i, policy->cpus);
> 
> I can see some regression here. Suppose you have two clusters of 4 cpus
> each: (0123) and (4567).. Now at boot time above code will work perfectly
> fine. Now you hot unplug 0,1,2,3 and then hotplug 3 in.
> 
> Here, init would be called for cpu 3 and so you will end up saving 3456
> in your policy->cpus
> 
> :)
Good catch.. will fix.

Regards,
Yuantian
viresh kumar - March 29, 2013, 3:16 a.m.
On 29 March 2013 08:21, Tang Yuantian-B29983 <B29983@freescale.com> wrote:
>> > +static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy) {
>> > +       unsigned int cpu = policy->cpu;
>> > +       struct device_node *np;
>> > +       int i, count;
>> > +       struct clk *clk;
>> > +       struct cpufreq_frequency_table *table;
>> > +       struct cpu_data *data;
>> > +
>> > +       np = of_get_cpu_node(cpu, NULL);
>> > +       if (!np)
>> > +               return -ENODEV;
>> > +
>> > +       data = kzalloc(sizeof(struct cpu_data), GFP_KERNEL);
>>
>> I told you, you missed my comment earlier.
>>
>> You need to write: sizeof(*data) :(
>>
> This is new added statement, what you told last time is about the next kcalloc()...

I said about using sizeof() in generic, I copied below from my first
mail on this topic

> +       table = kcalloc(count + 1,

kzalloc??

> +                       sizeof(struct cpufreq_frequency_table), GFP_KERNEL);

sizeof(*table)

And you missed this one as you never replied to it. :)

> Are there some reasons that we can't use sizeof(struct cpu_data)
> instead of sizeof(*data)?

Documentation/CodiingStyle: Chapter 14: Allocating memory

>> > +       if (!table) {
>> > +               pr_err("%s: no memory\n", __func__);
>> > +               goto err_nomem2;
>> > +       }
>> > +
>> > +       for (i = cpu; i < freq_data.cpus_per_cluster + cpu; i++)
>> > +               cpumask_set_cpu(i, policy->cpus);
>>
>> I can see some regression here. Suppose you have two clusters of 4 cpus
>> each: (0123) and (4567).. Now at boot time above code will work perfectly
>> fine. Now you hot unplug 0,1,2,3 and then hotplug 3 in.
>>
>> Here, init would be called for cpu 3 and so you will end up saving 3456
>> in your policy->cpus
>>
>> :)
> Good catch.. will fix.

Thanks.
tang yuantian - March 29, 2013, 4:47 a.m.
> -----Original Message-----

> From: Viresh Kumar [mailto:viresh.kumar@linaro.org]

> Sent: 2013年3月29日 11:17

> To: Tang Yuantian-B29983

> Cc: rjw@sisk.pl; cpufreq@vger.kernel.org; linux-pm@vger.kernel.org;

> linuxppc-dev@lists.ozlabs.org; Li Yang-R58472

> Subject: Re: [PATCH 2/2 v2] cpufreq: Add cpufreq driver for Freescale

> e500mc SoCs

> 

> On 29 March 2013 08:21, Tang Yuantian-B29983 <B29983@freescale.com> wrote:

> >> > +static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)

> {

> >> > +       unsigned int cpu = policy->cpu;

> >> > +       struct device_node *np;

> >> > +       int i, count;

> >> > +       struct clk *clk;

> >> > +       struct cpufreq_frequency_table *table;

> >> > +       struct cpu_data *data;

> >> > +

> >> > +       np = of_get_cpu_node(cpu, NULL);

> >> > +       if (!np)

> >> > +               return -ENODEV;

> >> > +

> >> > +       data = kzalloc(sizeof(struct cpu_data), GFP_KERNEL);

> >>

> >> I told you, you missed my comment earlier.

> >>

> >> You need to write: sizeof(*data) :(

> >>

> > This is new added statement, what you told last time is about the next

> kcalloc()...

> 

> I said about using sizeof() in generic, I copied below from my first mail

> on this topic

> 

> > +       table = kcalloc(count + 1,

> 

> kzalloc??

> 

> > +                       sizeof(struct cpufreq_frequency_table),

> > + GFP_KERNEL);

> 

> sizeof(*table)

> 

> And you missed this one as you never replied to it. :)

I thought it was OK here. Apparently, sizeof(*table) is better.
But kcalloc is OK.
 
> 

> > Are there some reasons that we can't use sizeof(struct cpu_data)

> > instead of sizeof(*data)?

> 

> Documentation/CodiingStyle: Chapter 14: Allocating memory

> 

Thanks

Regards,
Yuantian

> >> > +       if (!table) {

> >> > +               pr_err("%s: no memory\n", __func__);

> >> > +               goto err_nomem2;

> >> > +       }

> >> > +

> >> > +       for (i = cpu; i < freq_data.cpus_per_cluster + cpu; i++)

> >> > +               cpumask_set_cpu(i, policy->cpus);

> >>

> >> I can see some regression here. Suppose you have two clusters of 4

> >> cpus

> >> each: (0123) and (4567).. Now at boot time above code will work

> >> perfectly fine. Now you hot unplug 0,1,2,3 and then hotplug 3 in.

> >>

> >> Here, init would be called for cpu 3 and so you will end up saving

> >> 3456 in your policy->cpus

> >>

> >> :)

> > Good catch.. will fix.

> 

> Thanks.
viresh kumar - March 29, 2013, 4:50 a.m.
On 29 March 2013 10:17, Tang Yuantian-B29983 <B29983@freescale.com> wrote:
> I thought it was OK here. Apparently, sizeof(*table) is better.
> But kcalloc is OK.

Yes yes, Kcalloc is okay... I have misread that part earlier when i
suggested kzalloc.
In last mail i was referring to sizeof() only.

Patch

diff --git a/drivers/cpufreq/Kconfig.powerpc b/drivers/cpufreq/Kconfig.powerpc
index e76992f..3a0d8d0 100644
--- a/drivers/cpufreq/Kconfig.powerpc
+++ b/drivers/cpufreq/Kconfig.powerpc
@@ -5,3 +5,13 @@  config CPU_FREQ_MAPLE
 	help
 	  This adds support for frequency switching on Maple 970FX
 	  Evaluation Board and compatible boards (IBM JS2x blades).
+
+config PPC_CORENET_CPUFREQ
+	tristate "CPU frequency scaling driver for Freescale E500MC SoCs"
+	depends on PPC_E500MC && OF && COMMON_CLK
+	select CPU_FREQ_TABLE
+	select CLK_PPC_CORENET
+	help
+	  This adds the CPUFreq driver support for Freescale e500mc,
+	  e5500 and e6500 series SoCs which are capable of changing
+	  the CPU's frequency dynamically.
diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
index 863fd18..2416559 100644
--- a/drivers/cpufreq/Makefile
+++ b/drivers/cpufreq/Makefile
@@ -61,3 +61,4 @@  obj-$(CONFIG_ARM_IMX6Q_CPUFREQ)		+= imx6q-cpufreq.o
 ##################################################################################
 # PowerPC platform drivers
 obj-$(CONFIG_CPU_FREQ_MAPLE)		+= maple-cpufreq.o
+obj-$(CONFIG_PPC_CORENET_CPUFREQ)   += ppc-corenet-cpufreq.o
diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c
new file mode 100644
index 0000000..a50ab5a
--- /dev/null
+++ b/drivers/cpufreq/ppc-corenet-cpufreq.c
@@ -0,0 +1,255 @@ 
+/*
+ * Copyright 2013 Freescale Semiconductor, Inc.
+ *
+ * CPU Frequency Scaling driver for Freescale PowerPC corenet SoCs.
+ *
+ * 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/cpufreq.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+/**
+ * struct cpufreq_data - cpufreq driver data
+ * @cpus_per_cluster: CPU numbers per cluster
+ * @cpufreq_lock: the mutex lock
+ */
+struct cpufreq_data {
+	int	cpus_per_cluster;
+	struct mutex cpufreq_lock;
+};
+
+/**
+ * struct cpu_data - per CPU data struct
+ * @clk: the clk data of CPU
+ * @parent: the parent node of clock of cpu
+ * @table: frequency table point
+ */
+struct cpu_data {
+	struct clk *clk;
+	struct device_node *parent;
+	struct cpufreq_frequency_table *table;
+};
+
+static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
+static struct cpufreq_data freq_data;
+
+static unsigned int corenet_cpufreq_get_speed(unsigned int cpu)
+{
+	struct cpu_data *data = per_cpu(cpu_data, cpu);
+
+	return clk_get_rate(data->clk) / 1000;
+}
+
+/* reduce the duplicated frequency in frequency table */
+static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
+		int count)
+{
+	int i, j;
+
+	for (i = 1; i < count; i++) {
+		for (j = 0; j < i; j++) {
+			if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
+					freq_table[j].frequency !=
+					freq_table[i].frequency)
+				continue;
+
+			freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
+			break;
+		}
+	}
+}
+
+static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
+{
+	unsigned int cpu = policy->cpu;
+	struct device_node *np;
+	int i, count;
+	struct clk *clk;
+	struct cpufreq_frequency_table *table;
+	struct cpu_data *data;
+
+	np = of_get_cpu_node(cpu, NULL);
+	if (!np)
+		return -ENODEV;
+
+	data = kzalloc(sizeof(struct cpu_data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->clk = of_clk_get(np, 0);
+	data->parent = of_parse_phandle(np, "clocks", 0);
+	if (!data->parent) {
+		pr_err("%s: could not get clock information\n", __func__);
+		goto err_nomem2;
+	}
+
+	count = of_property_count_strings(data->parent, "clock-names");
+
+	table = kcalloc(count + 1,
+			sizeof(struct cpufreq_frequency_table), GFP_KERNEL);
+	if (!table) {
+		pr_err("%s: no memory\n", __func__);
+		goto err_nomem2;
+	}
+
+	for (i = cpu; i < freq_data.cpus_per_cluster + cpu; i++)
+		cpumask_set_cpu(i, policy->cpus);
+
+	for (i = 0; i < count; i++) {
+		table[i].index = i;
+		clk = of_clk_get(data->parent, i);
+		table[i].frequency = clk_get_rate(clk) / 1000;
+	}
+	freq_table_redup(table, count);
+	table[i].frequency = CPUFREQ_TABLE_END;
+
+	data->table = table;
+	per_cpu(cpu_data, cpu) = data;
+
+	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
+	policy->cur = corenet_cpufreq_get_speed(policy->cpu);
+
+	/* set the min and max frequency properly */
+	i = cpufreq_frequency_table_cpuinfo(policy, table);
+	if (i) {
+		pr_err("invalid frequency table: %d\n", i);
+		goto err_nomem1;
+	}
+	cpufreq_frequency_table_get_attr(table, cpu);
+
+	return 0;
+
+err_nomem1:
+	kfree(table);
+err_nomem2:
+	per_cpu(cpu_data, cpu) = NULL;
+	kfree(data);
+
+	return -ENODEV;
+}
+
+static int __exit corenet_cpufreq_cpu_exit(struct cpufreq_policy *policy)
+{
+	struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
+
+	cpufreq_frequency_table_put_attr(policy->cpu);
+	kfree(data->table);
+	kfree(data);
+
+	return 0;
+}
+
+static int corenet_cpufreq_verify(struct cpufreq_policy *policy)
+{
+	struct cpufreq_frequency_table *table;
+
+	table = per_cpu(cpu_data, policy->cpu)->table;
+
+	return cpufreq_frequency_table_verify(policy, table);
+}
+
+static int corenet_cpufreq_target(struct cpufreq_policy *policy,
+		unsigned int target_freq, unsigned int relation)
+{
+	struct cpufreq_freqs freqs;
+	unsigned int new;
+	struct clk *parent;
+	int ret;
+	struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
+
+	cpufreq_frequency_table_target(policy, data->table,
+			target_freq, relation, &new);
+
+	if (policy->cur == data->table[new].frequency)
+		return 0;
+
+	freqs.old = policy->cur;
+	freqs.new = data->table[new].frequency;
+	freqs.cpu = policy->cpu;
+
+	mutex_lock(&freq_data.cpufreq_lock);
+	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
+
+	parent = of_clk_get(data->parent, new);
+	ret = clk_set_parent(data->clk, parent);
+	if (ret) {
+		mutex_unlock(&freq_data.cpufreq_lock);
+		return ret;
+	}
+
+	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
+	mutex_unlock(&freq_data.cpufreq_lock);
+
+	return 0;
+}
+
+static struct freq_attr *corenet_cpu_clks_attr[] = {
+	&cpufreq_freq_attr_scaling_available_freqs,
+	NULL,
+};
+
+static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
+	.name		= "ppc_cpufreq",
+	.owner		= THIS_MODULE,
+	.flags		= CPUFREQ_CONST_LOOPS,
+	.init		= corenet_cpufreq_cpu_init,
+	.exit		= __exit_p(corenet_cpufreq_cpu_exit),
+	.verify		= corenet_cpufreq_verify,
+	.target		= corenet_cpufreq_target,
+	.get		= corenet_cpufreq_get_speed,
+	.attr		= corenet_cpu_clks_attr,
+};
+
+static const struct of_device_id node_matches[] __initconst = {
+	{ .compatible = "fsl,qoriq-clockgen-1.0", .data = (void *)1, },
+	{ .compatible = "fsl,qoriq-clockgen-2", .data = (void *)8, },
+	{}
+};
+
+static int __init ppc_corenet_cpufreq_init(void)
+{
+	int ret = 0;
+	struct device_node  *np;
+	const struct of_device_id *match;
+
+	np = of_find_matching_node(NULL, node_matches);
+	if (!np)
+		return -ENODEV;
+
+	match = of_match_node(node_matches, np);
+	freq_data.cpus_per_cluster = (unsigned long)match->data;
+	mutex_init(&freq_data.cpufreq_lock);
+	of_node_put(np);
+
+	ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
+	if (ret)
+		return ret;
+
+	pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
+
+	return ret;
+}
+module_init(ppc_corenet_cpufreq_init);
+
+static void __exit ppc_corenet_cpufreq_exit(void)
+{
+	cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
+}
+module_exit(ppc_corenet_cpufreq_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
+MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");