[PATCH v4 4/7] cpufreq: add clk-reg cpufreq driver
Richard Zhao
richard.zhao at linaro.org
Sat Dec 24 08:24:53 EST 2011
On Sat, Dec 24, 2011 at 01:10:40PM +0000, Jamie Iles wrote:
> Hi Richard,
>
> This is looking really nice. A couple of really minor nits inline,
> otherwise:
>
> Reviewed-by: Jamie Iles <jamie at jamieiles.com>
Thanks.
>
> On Thu, Dec 22, 2011 at 03:09:10PM +0800, Richard Zhao wrote:
> > The driver get cpu operation point table from device tree cpu0 node,
> > and adjusts operating points using clk and regulator APIs.
> >
> > It support single core and multi-core ARM SoCs. But currently it assume
> > all cores share the same frequency and voltage.
> >
> > Signed-off-by: Richard Zhao <richard.zhao at linaro.org>
> > ---
> > .../devicetree/bindings/cpufreq/clk-reg-cpufreq | 7 +
> > drivers/cpufreq/Kconfig | 10 +
> > drivers/cpufreq/Makefile | 2 +
> > drivers/cpufreq/clk-reg-cpufreq.c | 289 ++++++++++++++++++++
> > 4 files changed, 308 insertions(+), 0 deletions(-)
> > create mode 100644 Documentation/devicetree/bindings/cpufreq/clk-reg-cpufreq
> > create mode 100644 drivers/cpufreq/clk-reg-cpufreq.c
> >
> > diff --git a/Documentation/devicetree/bindings/cpufreq/clk-reg-cpufreq b/Documentation/devicetree/bindings/cpufreq/clk-reg-cpufreq
> > new file mode 100644
> > index 0000000..bf07c1b
> > --- /dev/null
> > +++ b/Documentation/devicetree/bindings/cpufreq/clk-reg-cpufreq
> > @@ -0,0 +1,7 @@
> > +Generic cpufreq driver based on clk and regulator APIs
> > +
> > +Required properties in /cpus/cpu at 0:
> > +- cpu-freqs : cpu frequency points it support, in unit of Hz.
> > +- cpu-volts : cpu voltages required by the frequency point at the same index,
> > + in unit of uV.
>
> Perhaps clarify here that these are arrays of u32's?
I'm not sure we can use u32 here, because dts always use xxx-cells to describe the
length.
> It may be worth
> giving an example node just to be clear?
I'll give an example.
>
> > +- trans-latency : transition_latency, in unit of ns.
> > diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> > index e24a2a1..95470f1 100644
> > --- a/drivers/cpufreq/Kconfig
> > +++ b/drivers/cpufreq/Kconfig
> > @@ -179,6 +179,16 @@ config CPU_FREQ_GOV_CONSERVATIVE
> >
> > If in doubt, say N.
> >
> > +config CLK_REG_CPUFREQ_DRIVER
> > + tristate "Generic cpufreq driver using clk and regulator APIs"
> > + depends on HAVE_CLK && OF && REGULATOR
> > + select CPU_FREQ_TABLE
> > + help
> > + This adds generic CPUFreq driver based on clk and regulator APIs.
> > + It assumes all cores of the CPU share the same clock and voltage.
> > +
> > + If in doubt, say N.
> > +
> > menu "x86 CPU frequency scaling drivers"
> > depends on X86
> > source "drivers/cpufreq/Kconfig.x86"
> > diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile
> > index ce75fcb..2c4eb33 100644
> > --- a/drivers/cpufreq/Makefile
> > +++ b/drivers/cpufreq/Makefile
> > @@ -13,6 +13,8 @@ obj-$(CONFIG_CPU_FREQ_GOV_CONSERVATIVE) += cpufreq_conservative.o
> > # CPUfreq cross-arch helpers
> > obj-$(CONFIG_CPU_FREQ_TABLE) += freq_table.o
> >
> > +obj-$(CONFIG_CLK_REG_CPUFREQ_DRIVER) += clk-reg-cpufreq.o
> > +
> > ##################################################################################
> > # x86 drivers.
> > # Link order matters. K8 is preferred to ACPI because of firmware bugs in early
> > diff --git a/drivers/cpufreq/clk-reg-cpufreq.c b/drivers/cpufreq/clk-reg-cpufreq.c
> > new file mode 100644
> > index 0000000..c30d2c5
> > --- /dev/null
> > +++ b/drivers/cpufreq/clk-reg-cpufreq.c
> > @@ -0,0 +1,289 @@
> > +/*
> > + * Copyright (C) 2011 Freescale Semiconductor, Inc.
> > + */
> > +
> > +/*
> > + * The code contained herein is licensed under the GNU General Public
> > + * License. You may obtain a copy of the GNU General Public License
> > + * Version 2 or later at the following locations:
> > + *
> > + * http://www.opensource.org/licenses/gpl-license.html
> > + * http://www.gnu.org/copyleft/gpl.html
> > + */
> > +
> > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> > +
> > +#include <linux/module.h>
> > +#include <linux/cpufreq.h>
> > +#include <linux/clk.h>
> > +#include <linux/regulator/consumer.h>
> > +#include <linux/err.h>
> > +#include <linux/slab.h>
> > +#include <linux/of.h>
> > +
> > +static u32 *cpu_freqs; /* Hz */
> > +static u32 *cpu_volts; /* uV */
> > +static u32 trans_latency; /* ns */
> > +static int cpu_op_nr;
> > +static unsigned int cur_index;
> > +
> > +static struct clk *cpu_clk;
> > +static struct regulator *cpu_reg;
> > +static struct cpufreq_frequency_table *freq_table;
> > +
> > +static int set_cpu_freq(unsigned long freq, int index, int higher)
> > +{
> > + int ret = 0;
> > +
> > + if (higher && cpu_reg) {
> > + ret = regulator_set_voltage(cpu_reg,
> > + cpu_volts[index * 2], cpu_volts[index * 2 + 1]);
> > + if (ret) {
> > + pr_err("set cpu voltage failed!\n");
> > + return ret;
> > + }
> > + }
> > +
> > + ret = clk_set_rate(cpu_clk, freq);
> > + if (ret) {
> > + if (cpu_reg)
> > + regulator_set_voltage(cpu_reg, cpu_volts[cur_index * 2],
> > + cpu_volts[cur_index * 2 + 1]);
> > + pr_err("cannot set CPU clock rate\n");
> > + return ret;
> > + }
> > +
> > + if (!higher && cpu_reg) {
> > + ret = regulator_set_voltage(cpu_reg,
> > + cpu_volts[index * 2], cpu_volts[index * 2 + 1]);
> > + if (ret)
> > + pr_warn("set cpu voltage failed, might run on"
> > + " higher voltage!\n");
> > + ret = 0;
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static int clk_reg_verify_speed(struct cpufreq_policy *policy)
> > +{
> > + return cpufreq_frequency_table_verify(policy, freq_table);
> > +}
> > +
> > +static unsigned int clk_reg_get_speed(unsigned int cpu)
> > +{
> > + return clk_get_rate(cpu_clk) / 1000;
> > +}
> > +
> > +static int clk_reg_set_target(struct cpufreq_policy *policy,
> > + unsigned int target_freq, unsigned int relation)
> > +{
> > + struct cpufreq_freqs freqs;
> > + unsigned long freq_Hz;
> > + int cpu;
> > + int ret = 0;
> > + unsigned int index;
> > +
> > + cpufreq_frequency_table_target(policy, freq_table,
> > + target_freq, relation, &index);
> > + freq_Hz = clk_round_rate(cpu_clk, cpu_freqs[index]);
> > + freq_Hz = freq_Hz ? freq_Hz : cpu_freqs[index];
> > + freqs.old = clk_get_rate(cpu_clk) / 1000;
> > + freqs.new = freq_Hz / 1000;
> > + freqs.flags = 0;
> > +
> > + if (freqs.old == freqs.new)
> > + return 0;
> > +
> > + for_each_possible_cpu(cpu) {
> > + freqs.cpu = cpu;
> > + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
> > + }
> > +
> > + ret = set_cpu_freq(freq_Hz, index, (freqs.new > freqs.old));
> > + if (ret)
> > + freqs.new = clk_get_rate(cpu_clk) / 1000;
> > + else
> > + cur_index = index;
> > +
> > + for_each_possible_cpu(cpu) {
> > + freqs.cpu = cpu;
> > + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> > + }
> > +
> > + return ret;
> > +}
> > +
> > +static int clk_reg_cpufreq_init(struct cpufreq_policy *policy)
> > +{
> > + int ret;
> > +
> > + if (policy->cpu >= num_possible_cpus())
> > + return -EINVAL;
> > +
> > + policy->cur = clk_get_rate(cpu_clk) / 1000;
> > + policy->shared_type = CPUFREQ_SHARED_TYPE_ANY;
> > + cpumask_setall(policy->cpus);
> > + policy->cpuinfo.transition_latency = trans_latency;
> > +
> > + ret = cpufreq_frequency_table_cpuinfo(policy, freq_table);
> > +
> > + if (ret < 0) {
> > + pr_err("invalid frequency table for cpu %d\n",
> > + policy->cpu);
> > + return ret;
> > + }
> > +
> > + cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
> > + cpufreq_frequency_table_target(policy, freq_table, policy->cur,
> > + CPUFREQ_RELATION_H, &cur_index);
> > + return 0;
> > +}
> > +
> > +static int clk_reg_cpufreq_exit(struct cpufreq_policy *policy)
> > +{
> > + cpufreq_frequency_table_put_attr(policy->cpu);
> > + return 0;
> > +}
> > +
> > +static struct cpufreq_driver clk_reg_cpufreq_driver = {
> > + .flags = CPUFREQ_STICKY,
> > + .verify = clk_reg_verify_speed,
> > + .target = clk_reg_set_target,
> > + .get = clk_reg_get_speed,
> > + .init = clk_reg_cpufreq_init,
> > + .exit = clk_reg_cpufreq_exit,
> > + .name = "clk-reg",
> > +};
> > +
> > +
>
> Drop the extra newline?
Thanks.
Richard
>
> > +static u32 max_freq = UINT_MAX / 1000; /* kHz */
> > +module_param(max_freq, uint, 0);
> > +MODULE_PARM_DESC(max_freq, "max cpu frequency in unit of kHz");
> > +
> > +static int __devinit clk_reg_cpufreq_driver_init(void)
> > +{
> > + struct device_node *cpu0;
> > + const struct property *pp;
> > + int i, ret;
> > +
> > + cpu0 = of_find_node_by_path("/cpus/cpu at 0");
> > + if (!cpu0)
> > + return -ENODEV;
> > +
> > + pp = of_find_property(cpu0, "cpu-freqs", NULL);
> > + if (!pp) {
> > + ret = -ENODEV;
> > + goto put_node;
> > + }
> > + cpu_op_nr = pp->length / sizeof(u32);
> > + if (!cpu_op_nr) {
> > + ret = -ENODEV;
> > + goto put_node;
> > + }
> > + ret = -ENOMEM;
> > + cpu_freqs = kzalloc(sizeof(*cpu_freqs) * cpu_op_nr, GFP_KERNEL);
> > + if (!cpu_freqs)
> > + goto put_node;
> > + of_property_read_u32_array(cpu0, "cpu-freqs", cpu_freqs, cpu_op_nr);
> > +
> > + pp = of_find_property(cpu0, "cpu-volts", NULL);
> > + if (pp) {
> > + if (cpu_op_nr * 2 == pp->length / sizeof(u32)) {
> > + cpu_volts = kzalloc(sizeof(*cpu_volts) * cpu_op_nr * 2,
> > + GFP_KERNEL);
> > + if (!cpu_volts)
> > + goto free_cpu_freqs;
> > + of_property_read_u32_array(cpu0, "cpu-volts",
> > + cpu_volts, cpu_op_nr * 2);
> > + } else
> > + pr_warn("invalid cpu_volts!\n");
> > + }
> > +
> > + if (of_property_read_u32(cpu0, "trans-latency", &trans_latency))
> > + trans_latency = CPUFREQ_ETERNAL;
> > +
> > + cpu_clk = clk_get(NULL, "cpu");
> > + if (IS_ERR(cpu_clk)) {
> > + pr_err("failed to get cpu clock\n");
> > + ret = PTR_ERR(cpu_clk);
> > + goto free_cpu_volts;
> > + }
> > +
> > + if (cpu_volts) {
> > + cpu_reg = regulator_get(NULL, "cpu");
> > + if (IS_ERR(cpu_reg)) {
> > + pr_warn("regulator cpu get failed.\n");
> > + cpu_reg = NULL;
> > + }
> > + }
> > +
> > + freq_table = kmalloc(sizeof(struct cpufreq_frequency_table)
> > + * (cpu_op_nr + 1), GFP_KERNEL);
> > + if (!freq_table) {
> > + ret = -ENOMEM;
> > + goto reg_put;
> > + }
> > +
> > + for (i = 0; i < cpu_op_nr; i++) {
> > + freq_table[i].index = i;
> > + if (cpu_freqs[i] > max_freq * 1000) {
> > + freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
> > + continue;
> > + }
> > +
> > + if (cpu_reg) {
> > + ret = regulator_is_supported_voltage(cpu_reg,
> > + cpu_volts[i * 2], cpu_volts[i * 2 + 1]);
> > + if (ret <= 0) {
> > + freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
> > + continue;
> > + }
> > + }
> > + freq_table[i].frequency = cpu_freqs[i] / 1000;
> > + }
> > +
> > + freq_table[i].index = i;
> > + freq_table[i].frequency = CPUFREQ_TABLE_END;
> > +
> > + ret = cpufreq_register_driver(&clk_reg_cpufreq_driver);
> > + if (ret)
> > + goto free_freq_table;
> > +
> > + of_node_put(cpu0);
> > +
> > + return 0;
> > +
> > +free_freq_table:
> > + kfree(freq_table);
> > +reg_put:
> > + if (cpu_reg)
> > + regulator_put(cpu_reg);
> > + clk_put(cpu_clk);
> > +free_cpu_volts:
> > + kfree(cpu_volts);
> > +free_cpu_freqs:
> > + kfree(cpu_freqs);
> > +put_node:
> > + of_node_put(cpu0);
> > +
> > + return ret;
> > +}
> > +
> > +static void clk_reg_cpufreq_driver_exit(void)
> > +{
> > + cpufreq_unregister_driver(&clk_reg_cpufreq_driver);
> > + kfree(cpu_freqs);
> > + kfree(cpu_volts);
> > + clk_put(cpu_clk);
> > + if (cpu_reg)
> > + regulator_put(cpu_reg);
> > + kfree(freq_table);
> > +}
> > +
> > +module_init(clk_reg_cpufreq_driver_init);
> > +module_exit(clk_reg_cpufreq_driver_exit);
> > +
> > +MODULE_AUTHOR("Freescale Semiconductor Inc. Richard Zhao <richard.zhao at freescale.com>");
> > +MODULE_DESCRIPTION("Generic CPUFreq driver based on clk and regulator APIs");
> > +MODULE_LICENSE("GPL");
> > --
> > 1.7.5.4
> >
> >
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