Hi Richard, On Mon, Dec 19, 2011 at 11:21:40AM +0800, Richard Zhao wrote: > 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.z...@linaro.org> > --- > .../devicetree/bindings/cpufreq/generic-cpufreq | 7 + > drivers/cpufreq/Kconfig | 8 + > drivers/cpufreq/Makefile | 2 + > drivers/cpufreq/generic-cpufreq.c | 251 > ++++++++++++++++++++ > 4 files changed, 268 insertions(+), 0 deletions(-) > create mode 100644 Documentation/devicetree/bindings/cpufreq/generic-cpufreq > create mode 100644 drivers/cpufreq/generic-cpufreq.c > > diff --git a/Documentation/devicetree/bindings/cpufreq/generic-cpufreq > b/Documentation/devicetree/bindings/cpufreq/generic-cpufreq > new file mode 100644 > index 0000000..15dd780 > --- /dev/null > +++ b/Documentation/devicetree/bindings/cpufreq/generic-cpufreq > @@ -0,0 +1,7 @@ > +Generic cpufreq driver > + > +Required properties in /cpus/cpu@0: > +- compatible : "generic-cpufreq"
I'm not convinced this is the best way to do this. By requiring a generic-cpufreq compatible string we're encoding Linux driver information into the hardware description. The only way I can see to avoid this is to provide a generic_clk_cpufreq_init() function that platforms can call in their machine init code to use the driver. > +- cpu-freqs : cpu frequency points it support > +- cpu-volts : cpu voltages required by the frequency point at the same index > +- trans-latency : transition_latency > diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig > index e24a2a1..216eecd 100644 > --- a/drivers/cpufreq/Kconfig > +++ b/drivers/cpufreq/Kconfig > @@ -179,6 +179,14 @@ config CPU_FREQ_GOV_CONSERVATIVE > > If in doubt, say N. > > +config GENERIC_CPUFREQ_DRIVER > + bool "Generic cpufreq driver using clock/regulator/devicetree" > + help > + This adds generic CPUFreq driver. It assumes all > + cores of the CPU share the same clock and voltage. > + > + If in doubt, say N. I think this needs dependencies on HAVE_CLK, OF and REGULATOR. > + > 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..2dbdab1 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_GENERIC_CPUFREQ_DRIVER) += generic-cpufreq.o > + > > ################################################################################## > # x86 drivers. > # Link order matters. K8 is preferred to ACPI because of firmware bugs in > early > diff --git a/drivers/cpufreq/generic-cpufreq.c > b/drivers/cpufreq/generic-cpufreq.c > new file mode 100644 > index 0000000..781bb9b > --- /dev/null > +++ b/drivers/cpufreq/generic-cpufreq.c > @@ -0,0 +1,251 @@ > +/* > + * 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> > + > +static u32 *cpu_freqs; /* HZ */ > +static u32 *cpu_volts; /* uV */ > +static u32 trans_latency; /* ns */ > +static int cpu_op_nr; > + > +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) > + regulator_set_voltage(cpu_reg, > + cpu_volts[index], cpu_volts[index]); > + > + ret = clk_set_rate(cpu_clk, freq); > + if (ret != 0) { > + pr_err("generic-cpufreq: 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 generic_verify_speed(struct cpufreq_policy *policy) > +{ > + return cpufreq_frequency_table_verify(policy, freq_table); > +} > + > +static unsigned int generic_get_speed(unsigned int cpu) > +{ > + return clk_get_rate(cpu_clk) / 1000; > +} > + > +static int generic_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 this fails then we'll still be notifying the transition at the requested rate even though it didn't work. I guess we should really get the rate of the clk and put that into freqs for the POSTCHANGE notification. > + > + for_each_possible_cpu(cpu) { > + freqs.cpu = cpu; > + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); > + } > + > + return ret; > +} > + > +static int generic_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, freq_table); > + > + if (ret < 0) { > + pr_err("%s: invalid frequency table for cpu %d\n", > + __func__, policy->cpu); > + return ret; > + } > + > + cpufreq_frequency_table_get_attr(freq_table, policy->cpu); > + return 0; > +} > + > +static int generic_cpufreq_exit(struct cpufreq_policy *policy) > +{ > + cpufreq_frequency_table_put_attr(policy->cpu); > + return 0; > +} > + > +static struct cpufreq_driver generic_cpufreq_driver = { > + .flags = CPUFREQ_STICKY, > + .verify = generic_verify_speed, > + .target = generic_set_target, > + .get = generic_get_speed, > + .init = generic_cpufreq_init, > + .exit = generic_cpufreq_exit, > + .name = "generic", This may be a little too generic? "generic-reg-clk"? > +}; > + > +static int __devinit generic_cpufreq_driver_init(void) > +{ > + struct device_node *cpu0; > + const struct property *pp; > + int i, ret; > + > + pr_info("Generic CPU frequency driver\n"); > + > + cpu0 = of_find_node_by_path("/cpus/cpu@0"); > + if (!cpu0) > + return -ENODEV; > + > + if (!of_device_is_compatible(cpu0, "generic-cpufreq")) > + return -ENODEV; As above, I'd personally rather not use compatible strings, but if you do, then I think return 0 here rather than -ENODEV else I believe you'll get a potentially confusing message on the console for platforms that don't use this. > + > + 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 > + pr_warn("%s: invalid cpu_volts!\n", __func__); > + } > + > + if (of_property_read_u32(cpu0, "trans-latency", &trans_latency)) > + trans_latency = CPUFREQ_ETERNAL; > + > + freq_table = kmalloc(sizeof(struct cpufreq_frequency_table) > + * (cpu_op_nr + 1), GFP_KERNEL); > + if (!freq_table) > + goto free_cpu_volts; > + > + for (i = 0; i < cpu_op_nr; i++) { > + freq_table[i].index = i; > + freq_table[i].frequency = cpu_freqs[i] / 1000; > + } > + > + freq_table[i].index = i; > + freq_table[i].frequency = CPUFREQ_TABLE_END; > + > + cpu_clk = clk_get(NULL, "cpu"); > + if (IS_ERR(cpu_clk)) { > + pr_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)) { > + pr_warn("%s: regulator cpu get failed.\n", __func__); > + cpu_reg = NULL; > + } > + } > + > + ret = cpufreq_register_driver(&generic_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(freq_table); > +free_cpu_volts: > + kfree(cpu_volts); > +free_cpu_freqs: > + kfree(cpu_freqs); > +put_node: > + of_node_put(cpu0); > + > + return ret; > +} > + > +static void generic_cpufreq_driver_exit(void) > +{ > + cpufreq_unregister_driver(&generic_cpufreq_driver); > + kfree(cpu_freqs); > + kfree(cpu_volts); > + kfree(freq_table); > + clk_put(cpu_clk); Should this do something with the regulator too? Jamie _______________________________________________ linaro-dev mailing list linaro-dev@lists.linaro.org http://lists.linaro.org/mailman/listinfo/linaro-dev
