It support single core and multi-core ARM SoCs. But it assume all cores share the same frequency and voltage. Signed-off-by: Richard Zhao <richard.zhao@xxxxxxxxxx> --- drivers/cpufreq/Kconfig.arm | 8 ++ drivers/cpufreq/Makefile | 1 + drivers/cpufreq/arm-cpufreq.c | 269 +++++++++++++++++++++++++++++++++++++++++ 3 files changed, 278 insertions(+), 0 deletions(-) create mode 100644 drivers/cpufreq/arm-cpufreq.c diff --git a/drivers/cpufreq/Kconfig.arm b/drivers/cpufreq/Kconfig.arm index 72a0044..a0f7d35 100644 --- a/drivers/cpufreq/Kconfig.arm +++ b/drivers/cpufreq/Kconfig.arm @@ -2,6 +2,14 @@ # ARM CPU Frequency scaling drivers # +config ARM_GENERIC_CPUFREQ + bool "ARM generic" + help + This adds ARM generic CPUFreq driver. It assumes all + cores of the SoC share the same clock and voltage. + + If in doubt, say N. + config ARM_S3C64XX_CPUFREQ bool "Samsung S3C64XX" depends on CPU_S3C6410 diff --git a/drivers/cpufreq/Makefile b/drivers/cpufreq/Makefile index ce75fcb..6ccf02d 100644 --- a/drivers/cpufreq/Makefile +++ b/drivers/cpufreq/Makefile @@ -39,6 +39,7 @@ obj-$(CONFIG_X86_CPUFREQ_NFORCE2) += cpufreq-nforce2.o ################################################################################## # ARM SoC drivers +obj-$(CONFIG_ARM_GENERIC_CPUFREQ) += arm-cpufreq.o obj-$(CONFIG_UX500_SOC_DB8500) += db8500-cpufreq.o obj-$(CONFIG_ARM_S3C64XX_CPUFREQ) += s3c64xx-cpufreq.o obj-$(CONFIG_ARM_S5PV210_CPUFREQ) += s5pv210-cpufreq.o diff --git a/drivers/cpufreq/arm-cpufreq.c b/drivers/cpufreq/arm-cpufreq.c new file mode 100644 index 0000000..e4d20da --- /dev/null +++ b/drivers/cpufreq/arm-cpufreq.c @@ -0,0 +1,269 @@ +/* + * 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 + */ + +#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> +#include <asm/cpu.h> + +static u32 *cpu_freqs; /* HZ */ +static u32 *cpu_volts; /* uV */ +static u32 trans_latency; /* ns */ +static int cpu_op_nr; + +static DEFINE_PER_CPU(unsigned long, l_p_j_ref); +static unsigned long l_p_j_ref_freq; + +static struct clk *cpu_clk; +static struct regulator *cpu_reg; +static struct cpufreq_frequency_table *arm_freq_table; + +static int set_cpu_freq(unsigned long freq, int index, int higher) +{ + int ret = 0; + + if (higher && cpu_reg) + regulator_set_voltage(cpu_reg, + cpu_volts[index], cpu_volts[index]); + + ret = clk_set_rate(cpu_clk, freq); + if (ret != 0) { + printk(KERN_DEBUG "cannot set CPU clock rate\n"); + return ret; + } + + if (!higher && cpu_reg) + regulator_set_voltage(cpu_reg, + cpu_volts[index], cpu_volts[index]); + + return ret; +} + +static int arm_verify_speed(struct cpufreq_policy *policy) +{ + return cpufreq_frequency_table_verify(policy, arm_freq_table); +} + +static unsigned int arm_get_speed(unsigned int cpu) +{ + return clk_get_rate(cpu_clk) / 1000; +} + +static int arm_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, arm_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 = clk_round_rate(cpu_clk, cpu_freqs[index]); + 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)); + +#ifdef CONFIG_SMP + /* loops_per_jiffy is not updated by the cpufreq core for SMP systems. + * So update it for all CPUs. + */ + for_each_possible_cpu(cpu) + per_cpu(cpu_data, cpu).loops_per_jiffy = + cpufreq_scale(per_cpu(l_p_j_ref, cpu), l_p_j_ref_freq, + freqs.new); +#endif + + for_each_possible_cpu(cpu) { + freqs.cpu = cpu; + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); + } + + return ret; +} + +static int arm_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); + /* Manual states, that PLL stabilizes in two CLK32 periods */ + policy->cpuinfo.transition_latency = trans_latency; + + ret = cpufreq_frequency_table_cpuinfo(policy, arm_freq_table); + + if (ret < 0) { + printk(KERN_ERR "%s: invalid frequency table for cpu %d\n", + __func__, policy->cpu); + return ret; + } + + cpufreq_frequency_table_get_attr(arm_freq_table, policy->cpu); + return 0; +} + +static int arm_cpufreq_exit(struct cpufreq_policy *policy) +{ + cpufreq_frequency_table_put_attr(policy->cpu); + return 0; +} + +static struct cpufreq_driver arm_cpufreq_driver = { + .flags = CPUFREQ_STICKY, + .verify = arm_verify_speed, + .target = arm_set_target, + .get = arm_get_speed, + .init = arm_cpufreq_init, + .exit = arm_cpufreq_exit, + .name = "arm", +}; + +static int __devinit arm_cpufreq_driver_init(void) +{ + struct device_node *cpu0; + const struct property *pp; + int cpu, i, ret; + + printk(KERN_INFO "ARM SoC generic CPU frequency driver\n"); + + cpu0 = of_find_node_by_path("/cpus/cpu@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 == pp->length / sizeof(u32)) { + cpu_volts = kzalloc(sizeof(*cpu_freqs) * cpu_op_nr, + GFP_KERNEL); + if (!cpu_volts) + goto free_cpu_freqs; + of_property_read_u32_array(cpu0, "cpu-volts", + cpu_volts, cpu_op_nr); + } else + printk(KERN_WARNING "cpufreq: invalid cpu_volts!\n"); + } + + if (of_property_read_u32(cpu0, "trans-latency", &trans_latency)) + trans_latency = CPUFREQ_ETERNAL; + + arm_freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) + * (cpu_op_nr + 1), GFP_KERNEL); + if (!arm_freq_table) + goto free_cpu_volts; + + for (i = 0; i < cpu_op_nr; i++) { + arm_freq_table[i].index = i; + arm_freq_table[i].frequency = cpu_freqs[i] / 1000; + } + + arm_freq_table[i].index = i; + arm_freq_table[i].frequency = CPUFREQ_TABLE_END; + + cpu_clk = clk_get(NULL, "cpu"); + if (IS_ERR(cpu_clk)) { + printk(KERN_ERR "%s: failed to get cpu clock\n", __func__); + ret = PTR_ERR(cpu_clk); + goto free_freq_table; + } + + if (cpu_volts) { + cpu_reg = regulator_get(NULL, "cpu"); + if (IS_ERR(cpu_reg)) { + printk(KERN_WARNING + "cpufreq: regulator cpu get failed.\n"); + cpu_reg = NULL; + } + } + + l_p_j_ref_freq = clk_get_rate(cpu_clk); + for_each_possible_cpu(cpu) + per_cpu(l_p_j_ref, cpu) = + per_cpu(cpu_data, cpu).loops_per_jiffy; + + ret = cpufreq_register_driver(&arm_cpufreq_driver); + if (ret) + goto reg_put; + + of_node_put(cpu0); + + return 0; + +reg_put: + if (cpu_reg) + regulator_put(cpu_reg); + clk_put(cpu_clk); +free_freq_table: + kfree(arm_freq_table); +free_cpu_volts: + kfree(cpu_volts); +free_cpu_freqs: + kfree(cpu_freqs); +put_node: + of_node_put(cpu0); + + return ret; +} + +static void arm_cpufreq_driver_exit(void) +{ + cpufreq_unregister_driver(&arm_cpufreq_driver); + kfree(cpu_freqs); + kfree(cpu_volts); + kfree(arm_freq_table); + clk_put(cpu_clk); +} + +module_init(arm_cpufreq_driver_init); +module_exit(arm_cpufreq_driver_exit); + +MODULE_AUTHOR("Freescale Semiconductor Inc. Richard Zhao <richard.zhao@xxxxxxxxxxxxx>"); +MODULE_DESCRIPTION("ARM SoC generic CPUFreq driver"); +MODULE_LICENSE("GPL"); -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe cpufreq" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
