Sekhar Nori <[email protected]> writes: > Adds a basic CPUFreq driver for DaVinci devices registering with the > kernel CPUFreq infrastructure. > > Signed-off-by: Sekhar Nori <[email protected]>
Looks mostly OK, some minor comments below, mainly based on stuff copied from OMAP... > --- > arch/arm/Kconfig | 2 +- > arch/arm/mach-davinci/Makefile | 3 + > arch/arm/mach-davinci/cpu-davinci.c | 179 > +++++++++++++++++++++++++++ I know this is copied from cpu-omap.c, but I've never liked that name. How about cpufreq.c. > arch/arm/mach-davinci/include/mach/common.h | 3 + > 4 files changed, 186 insertions(+), 1 deletions(-) > create mode 100644 arch/arm/mach-davinci/cpu-davinci.c > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index aef63c8..37ad68a 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -1241,7 +1241,7 @@ endmenu > > menu "CPU Power Management" > > -if (ARCH_SA1100 || ARCH_INTEGRATOR || ARCH_OMAP || ARCH_PXA || ARCH_S3C64XX) > +if (ARCH_SA1100 || ARCH_INTEGRATOR || ARCH_OMAP || ARCH_PXA || ARCH_S3C64XX > || ARCH_DAVINCI) > Can we make this dependent on CONFIG_ARCH_DAVINCI_DA8XX? unless there are plans to make CPUfreq work on DMxxxx. > source "drivers/cpufreq/Kconfig" > > diff --git a/arch/arm/mach-davinci/Makefile b/arch/arm/mach-davinci/Makefile > index 2e11e84..14b9527 100644 > --- a/arch/arm/mach-davinci/Makefile > +++ b/arch/arm/mach-davinci/Makefile > @@ -29,3 +29,6 @@ obj-$(CONFIG_MACH_DAVINCI_DM6467_EVM) += > board-dm646x-evm.o > obj-$(CONFIG_MACH_DAVINCI_DM365_EVM) += board-dm365-evm.o > obj-$(CONFIG_MACH_DAVINCI_DA830_EVM) += board-da830-evm.o > obj-$(CONFIG_MACH_DAVINCI_DA850_EVM) += board-da850-evm.o > + > +# Power Management > +obj-$(CONFIG_CPU_FREQ) += cpu-davinci.o > diff --git a/arch/arm/mach-davinci/cpu-davinci.c > b/arch/arm/mach-davinci/cpu-davinci.c > new file mode 100644 > index 0000000..52527f1 > --- /dev/null > +++ b/arch/arm/mach-davinci/cpu-davinci.c > @@ -0,0 +1,179 @@ > +/* > + * CPU frequency scaling for DaVinci > + * > + * Copyright (C) 2009 Texas Instruments Incorporated - http://www.ti.com/ > + * > + * Based on linux/arch/arm/plat-omap/cpu-omap.c. Original Copyright follows: > + * > + * Copyright (C) 2005 Nokia Corporation > + * Written by Tony Lindgren <[email protected]> > + * > + * Based on cpu-sa1110.c, Copyright (C) 2001 Russell King > + * > + * Copyright (C) 2007-2008 Texas Instruments, Inc. > + * Updated to support OMAP3 > + * Rajendra Nayak <[email protected]> > + * > + * 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/types.h> > +#include <linux/kernel.h> > +#include <linux/sched.h> > +#include <linux/cpufreq.h> > +#include <linux/delay.h> > +#include <linux/init.h> > +#include <linux/err.h> > +#include <linux/clk.h> > +#include <linux/io.h> > + > +#include <mach/hardware.h> > +#include <asm/system.h> > +#include <mach/clock.h> > +#include <mach/common.h> > + > +#include "clock.h" > + > +#define VERY_HI_RATE 900000000 > + > +static struct cpufreq_frequency_table *freq_table; > +static struct clk *armclk; > + > +static int davinci_verify_speed(struct cpufreq_policy *policy) > +{ > + if (freq_table) > + return cpufreq_frequency_table_verify(policy, freq_table); > + > + if (policy->cpu) > + return -EINVAL; > + > + cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, > + policy->cpuinfo.max_freq); > + > + policy->min = clk_round_rate(armclk, policy->min * 1000) / 1000; > + policy->max = clk_round_rate(armclk, policy->max * 1000) / 1000; > + cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq, > + policy->cpuinfo.max_freq); > + return 0; > +} > + > +static unsigned int davinci_getspeed(unsigned int cpu) > +{ > + unsigned long rate; > + > + if (cpu) > + return 0; > + > + rate = clk_get_rate(armclk) / 1000; > + > + return rate; > +} > + > +static int davinci_target(struct cpufreq_policy *policy, > + unsigned int target_freq, > + unsigned int relation) > +{ > + struct cpufreq_freqs freqs; > + int ret = 0; > + > + /* Ensure desired rate is within allowed range. Some govenors > + * (ondemand) will just pass target_freq=0 to get the minimum. */ > + if (target_freq < policy->cpuinfo.min_freq) > + target_freq = policy->cpuinfo.min_freq; > + if (target_freq > policy->cpuinfo.max_freq) > + target_freq = policy->cpuinfo.max_freq; > + > + freqs.old = davinci_getspeed(0); > + freqs.new = clk_round_rate(armclk, target_freq * 1000) / 1000; > + freqs.cpu = 0; > + > + if (freqs.old == freqs.new) > + return ret; > + cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE); > +#ifdef CONFIG_CPU_FREQ_DEBUG > + printk(KERN_DEBUG "cpufreq-davinci: transition: %u --> %u\n", > + freqs.old, freqs.new); > +#endif > + ret = clk_set_rate(armclk, freqs.new * 1000); > + cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE); > + > + return ret; > +} > + > +static int __init davinci_cpu_init(struct cpufreq_policy *policy) > +{ > + int result = 0; > + > + armclk = clk_get(NULL, "arm"); > + if (IS_ERR(armclk)) { > + printk(KERN_ERR "cpufreq-davinci: Unable to get ARM clock\n"); > + return PTR_ERR(armclk); > + } > + > + if (policy->cpu != 0) { > + clk_put(armclk); > + return -EINVAL; > + } > + > + policy->cur = policy->min = policy->max = davinci_getspeed(0); > + > + davinci_soc_info.init_cpufreq_table(&freq_table); > + if (freq_table) { > + result = cpufreq_frequency_table_cpuinfo(policy, freq_table); > + if (!result) > + cpufreq_frequency_table_get_attr(freq_table, > + policy->cpu); > + } else { > + policy->cpuinfo.min_freq = clk_round_rate(armclk, 0) / 1000; > + policy->cpuinfo.max_freq = clk_round_rate(armclk, > + VERY_HI_RATE) / 1000; > + } Rather than use the zero to VERY_HI_RATE range, I'd rather just set the min/max to the current rate and thus not allow any scaling. > + clk_set_rate(armclk, policy->cpuinfo.max_freq * 1000); > + > + policy->min = policy->cpuinfo.min_freq; > + policy->max = policy->cpuinfo.max_freq; > + policy->cur = davinci_getspeed(0); > + > + /* FIXME: what's the actual transition time? */ Can you make a crude guess here from the datasheet? This has an effect on the automatic governors like ondemand. > + policy->cpuinfo.transition_latency = 1 * 1000 * 1000; > + return 0; > +} > + > +static int davinci_cpu_exit(struct cpufreq_policy *policy) > +{ > + clk_put(armclk); > + return 0; > +} > + > +static struct freq_attr *davinci_cpufreq_attr[] = { > + &cpufreq_freq_attr_scaling_available_freqs, > + NULL, > +}; > + > +static struct cpufreq_driver davinci_driver = { > + .flags = CPUFREQ_STICKY, > + .verify = davinci_verify_speed, > + .target = davinci_target, > + .get = davinci_getspeed, > + .init = davinci_cpu_init, > + .exit = davinci_cpu_exit, > + .name = "davinci", > + .attr = davinci_cpufreq_attr, > +}; > + > +static int __init davinci_cpufreq_init(void) > +{> + return cpufreq_register_driver(&davinci_driver); > +} > + > +late_initcall(davinci_cpufreq_init); > + > +/* > + * if ever we want to remove this, upon cleanup call: > + * > + * cpufreq_unregister_driver() > + * cpufreq_frequency_table_put_attr() > + */ > + > diff --git a/arch/arm/mach-davinci/include/mach/common.h > b/arch/arm/mach-davinci/include/mach/common.h > index 1fd3917..1487a57 100644 > --- a/arch/arm/mach-davinci/include/mach/common.h > +++ b/arch/arm/mach-davinci/include/mach/common.h > @@ -12,6 +12,8 @@ > #ifndef __ARCH_ARM_MACH_DAVINCI_COMMON_H > #define __ARCH_ARM_MACH_DAVINCI_COMMON_H > > +#include <linux/cpufreq.h> > + > struct sys_timer; > > extern struct sys_timer davinci_timer; > @@ -68,6 +70,7 @@ struct davinci_soc_info { > struct emac_platform_data *emac_pdata; > dma_addr_t sram_dma; > unsigned sram_len; > + void (*init_cpufreq_table) (struct cpufreq_frequency_table **); > }; > > extern struct davinci_soc_info davinci_soc_info; > -- > 1.6.2.4 > > _______________________________________________ > Davinci-linux-open-source mailing list > [email protected] > http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
