[PATCH v2 RESEND] ARM: NUC900: Add cpufreq driver for nuc900 CPUs

[mcuos.com@gmail.com (Wan ZongShun)]

Dear Li Jie,

Okay, please send your patch to me as a attached file.

Li Jie :
> Hi, Wan:
> 
> This this the cpufreq_driver for NUC900 v2
> Problems which you and Russell mentioned in v1 have been fixed:
> 
> 1. declare nuc900_set_clkval() in cpu.h
> 2. use macros instead of numbers
> 3. rename module, nuc900 -> nuc900-cpufreq
> 4. include linux/io.h, not asm/io.h
> ....and so on
> 
> diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
> index 233a222..600b313 100644
> --- a/arch/arm/Kconfig
> +++ b/arch/arm/Kconfig
> @@ -539,6 +539,7 @@ config ARCH_W90X900
>  	select COMMON_CLKDEV
>  	select GENERIC_TIME
>  	select GENERIC_CLOCKEVENTS
> +	select ARCH_HAS_CPUFREQ
>  	help
>  	  Support for Nuvoton (Winbond logic dept.) ARM9 processor,
>  	  At present, the w90x900 has been renamed nuc900, regarding
> diff --git a/arch/arm/mach-w90x900/Makefile b/arch/arm/mach-w90x900/Makefile
> index 828c032..7f114fb 100644
> --- a/arch/arm/mach-w90x900/Makefile
> +++ b/arch/arm/mach-w90x900/Makefile
> @@ -5,7 +5,7 @@
>  # Object file lists.
> 
>  obj-y				:= irq.o time.o mfp.o gpio.o clock.o
> -obj-y				+= clksel.o dev.o cpu.o
> +obj-y				+= clksel.o dev.o cpu.o cpufreq.o
>  # W90X900 CPU support files
> 
>  obj-$(CONFIG_CPU_W90P910)	+= nuc910.o
> diff --git a/arch/arm/mach-w90x900/cpu.c b/arch/arm/mach-w90x900/cpu.c
> index 921cef9..7b608b8 100644
> --- a/arch/arm/mach-w90x900/cpu.c
> +++ b/arch/arm/mach-w90x900/cpu.c
> @@ -107,7 +107,7 @@ struct platform_device nuc900_serial_device = {
>  };
> 
>  /*Set NUC900 series cpu frequence*/
> -static int __init nuc900_set_clkval(unsigned int cpufreq)
> +int nuc900_set_clkval(unsigned int cpufreq)
>  {
>  	unsigned int pllclk, ahbclk, apbclk, val;
> 
> @@ -156,6 +156,8 @@ static int __init nuc900_set_clkval(unsigned int cpufreq)
> 
>  	return 	0;
>  }
> +EXPORT_SYMBOL(nuc900_set_clkval);
> +
>  static int __init nuc900_set_cpufreq(char *str)
>  {
>  	unsigned long cpufreq, val;
> diff --git a/arch/arm/mach-w90x900/cpu.h b/arch/arm/mach-w90x900/cpu.h
> index 4d58ba1..ca0bce5 100644
> --- a/arch/arm/mach-w90x900/cpu.h
> +++ b/arch/arm/mach-w90x900/cpu.h
> @@ -49,6 +49,7 @@ extern void nuc900_clock_source(struct device *dev,
> unsigned char *src);
>  extern void nuc900_init_clocks(void);
>  extern void nuc900_map_io(struct map_desc *mach_desc, int mach_size);
>  extern void nuc900_board_init(struct platform_device **device, int size);
> +extern int nuc900_set_clkval(unsigned int cpufreq);
> 
>  /* for either public between 910 and 920, or between 920 and 950 */
> 
> diff --git a/arch/arm/mach-w90x900/cpufreq.c b/arch/arm/mach-w90x900/cpufreq.c
> new file mode 100644
> index 0000000..467fc26
> --- /dev/null
> +++ b/arch/arm/mach-w90x900/cpufreq.c
> @@ -0,0 +1,154 @@
> +/* linux/arch/arm/mach-w90x900/cpufreq.c
> + *
> + * NUC900 CPUfreq Support
> + *
> + * Li Jie <eltshanli@gmail.com>
> + *
> + * 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/kernel.h>
> +#include <linux/types.h>
> +#include <linux/init.h>
> +#include <linux/cpufreq.h>
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +#include <linux/platform_device.h>
> +
> +#include <asm/mach/map.h>
> +#include <mach/hardware.h>
> +#include <mach/regs-clock.h>
> +
> +#include "cpu.h"
> +
> +#define	CPUFREQ_66M	66000
> +#define	CPUFREQ_100M	100000
> +#define	CPUFREQ_120M	120000
> +#define	CPUFREQ_166M	166000
> +#define	CPUFREQ_200M	200000
> +
> +static struct cpufreq_frequency_table nuc900_freq_table[] = {
> +	{ 0, CPUFREQ_66M  },
> +	{ 1, CPUFREQ_100M },
> +	{ 2, CPUFREQ_120M },
> +	{ 3, CPUFREQ_166M },
> +	{ 4, CPUFREQ_200M },
> +	{ 5, CPUFREQ_TABLE_END },
> +};
> +
> +static int nuc900_cpufreq_verify_speed(struct cpufreq_policy *policy)
> +{
> +	if (policy->cpu != 0)
> +		return -EINVAL;
> +
> +	return cpufreq_frequency_table_verify(policy, nuc900_freq_table);
> +}
> +
> +static unsigned int nuc900_cpufreq_get_speed(unsigned int cpu)
> +{
> +	int pllclk;
> +
> +	if (cpu != 0)
> +		return 0;
> +
> +	pllclk = __raw_readl(REG_PLLCON0);
> +
> +	switch (pllclk) {
> +	case PLL_66MHZ:
> +		return CPUFREQ_66M;
> +	case PLL_100MHZ:
> +		return CPUFREQ_100M;
> +	case PLL_120MHZ:
> +		return CPUFREQ_120M;
> +	case PLL_166MHZ:
> +		return CPUFREQ_166M;
> +	case PLL_200MHZ:
> +		return CPUFREQ_200M;
> +	}
> +
> +	pr_err("cpufreq: Failed to get frequency: %x\n", pllclk);
> +	return 0;
> +}
> +
> +static int nuc900_cpufreq_set_target(struct cpufreq_policy *policy,
> +				      unsigned int target_freq,
> +				      unsigned int relation)
> +{
> +	int ret;
> +	unsigned int i;
> +	struct cpufreq_freqs freqs;
> +
> +	ret = cpufreq_frequency_table_target(policy, nuc900_freq_table,
> +					     target_freq, relation, &i);
> +	if (ret != 0)
> +		return ret;
> +
> +	freqs.cpu = 0;
> +	freqs.old = nuc900_cpufreq_get_speed(0);
> +	freqs.new = nuc900_freq_table[i].frequency;
> +	freqs.flags = 0;
> +
> +	if (freqs.old == freqs.new)
> +		return 0;
> +
> +	pr_debug("cpufreq: Transition %d-%dkHz\n", freqs.old, freqs.new);
> +
> +	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
> +
> +	nuc900_set_clkval(freqs.new / 1000);
> +	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
> +
> +	return 0;
> +}
> +
> +static int __init nuc900_cpufreq_driver_init(struct cpufreq_policy *policy)
> +{
> +	int ret;
> +
> +	if (policy->cpu != 0)
> +		return -EINVAL;
> +
> +	policy->cur = nuc900_cpufreq_get_speed(0);
> +
> +	policy->cpuinfo.transition_latency = 2 * 1000; /* FIXME, assumed */
> +	policy->cpuinfo.min_freq = 66000;	       /* khz */
> +	policy->cpuinfo.max_freq = 200000;
> +	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
> +
> +	ret = cpufreq_frequency_table_cpuinfo(policy, nuc900_freq_table);
> +	if (ret != 0)
> +		pr_err("cpufreq: Failed to configure frequency table: %d\n",
> +		       ret);
> +
> +	return ret;
> +}
> +
> +static struct cpufreq_driver nuc900_cpufreq_driver = {
> +	.owner		= THIS_MODULE,
> +	.flags          = 0,
> +	.verify		= nuc900_cpufreq_verify_speed,
> +	.target		= nuc900_cpufreq_set_target,
> +	.get		= nuc900_cpufreq_get_speed,
> +	.init		= nuc900_cpufreq_driver_init,
> +	.name		= "nuc900-cpufreq",
> +};
> +
> +static int __init nuc900_cpufreq_init(void)
> +{
> +	return cpufreq_register_driver(&nuc900_cpufreq_driver);
> +}
> +
> +static void __exit nuc900_cpufreq_exit(void)
> +{
> +	cpufreq_unregister_driver(&nuc900_cpufreq_driver);
> +}
> +
> +MODULE_AUTHOR ("Li Jie <eltshanli@gmail.com>");
> +MODULE_DESCRIPTION ("cpufreq driver for NUC900");
> +MODULE_LICENSE ("GPL");
> +
> +module_init(nuc900_cpufreq_init);
> +module_exit(nuc900_cpufreq_exit);
>