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Commit cdb56cbf authored by Markus Mayer's avatar Markus Mayer Committed by Rafael J. Wysocki
Browse files

cpufreq: bmips-cpufreq: CPUfreq driver for Broadcom's BMIPS SoCs 



Add the MIPS CPUfreq driver. This driver currently supports CPUfreq on
BMIPS5xxx-based SoCs.

Signed-off-by: default avatarMarkus Mayer <mmayer@broadcom.com>
Acked-by: default avatarFlorian Fainelli <f.fainelli@gmail.com>
Acked-by: default avatarViresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent a8d709b0

drivers/cpufreq/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -263,6 +263,16 @@ config IA64_ACPI_CPUFREQ 
endif



if MIPS

config BMIPS_CPUFREQ

	tristate "BMIPS CPUfreq Driver"

	help

	  This option adds a CPUfreq driver for BMIPS processors with

	  support for configurable CPU frequency.



	  For now, BMIPS5 chips are supported (such as the Broadcom 7425).



	  If in doubt, say N.



config LOONGSON2_CPUFREQ

	tristate "Loongson2 CPUFreq Driver"

	help

drivers/cpufreq/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -98,6 +98,7 @@ obj-$(CONFIG_POWERNV_CPUFREQ) += powernv-cpufreq.o 
# Other platform drivers

obj-$(CONFIG_AVR32_AT32AP_CPUFREQ)	+= at32ap-cpufreq.o

obj-$(CONFIG_BFIN_CPU_FREQ)		+= blackfin-cpufreq.o

obj-$(CONFIG_BMIPS_CPUFREQ)		+= bmips-cpufreq.o

obj-$(CONFIG_CRIS_MACH_ARTPEC3)		+= cris-artpec3-cpufreq.o

obj-$(CONFIG_ETRAXFS)			+= cris-etraxfs-cpufreq.o

obj-$(CONFIG_IA64_ACPI_CPUFREQ)		+= ia64-acpi-cpufreq.o

drivers/cpufreq/bmips-cpufreq.c

0 → 100644
+188 −0
Original line number Diff line number Diff line 
/*

 * CPU frequency scaling for Broadcom BMIPS SoCs

 *

 * Copyright (c) 2017 Broadcom

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation version 2.

 *

 * This program is distributed "as is" WITHOUT ANY WARRANTY of any

 * kind, whether express or implied; without even the implied warranty

 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/cpufreq.h>

#include <linux/module.h>

#include <linux/of_address.h>

#include <linux/slab.h>



/* for mips_hpt_frequency */

#include <asm/time.h>



#define BMIPS_CPUFREQ_PREFIX	"bmips"

#define BMIPS_CPUFREQ_NAME	BMIPS_CPUFREQ_PREFIX "-cpufreq"



#define TRANSITION_LATENCY	(25 * 1000)	/* 25 us */



#define BMIPS5_CLK_DIV_SET_SHIFT	0x7

#define BMIPS5_CLK_DIV_SHIFT		0x4

#define BMIPS5_CLK_DIV_MASK		0xf



enum bmips_type {

	BMIPS5000,

	BMIPS5200,

};



struct cpufreq_compat {

	const char *compatible;

	unsigned int bmips_type;

	unsigned int clk_mult;

	unsigned int max_freqs;

};



#define BMIPS(c, t, m, f) { \

	.compatible = c, \

	.bmips_type = (t), \

	.clk_mult = (m), \

	.max_freqs = (f), \

}



static struct cpufreq_compat bmips_cpufreq_compat[] = {

	BMIPS("brcm,bmips5000", BMIPS5000, 8, 4),

	BMIPS("brcm,bmips5200", BMIPS5200, 8, 4),

	{ }

};



static struct cpufreq_compat *priv;



static int htp_freq_to_cpu_freq(unsigned int clk_mult)

{

	return mips_hpt_frequency * clk_mult / 1000;

}



static struct cpufreq_frequency_table *

bmips_cpufreq_get_freq_table(const struct cpufreq_policy *policy)

{

	struct cpufreq_frequency_table *table;

	unsigned long cpu_freq;

	int i;



	cpu_freq = htp_freq_to_cpu_freq(priv->clk_mult);



	table = kmalloc((priv->max_freqs + 1) * sizeof(*table), GFP_KERNEL);

	if (!table)

		return ERR_PTR(-ENOMEM);



	for (i = 0; i < priv->max_freqs; i++) {

		table[i].frequency = cpu_freq / (1 << i);

		table[i].driver_data = i;

	}

	table[i].frequency = CPUFREQ_TABLE_END;



	return table;

}



static unsigned int bmips_cpufreq_get(unsigned int cpu)

{

	unsigned int div;

	uint32_t mode;



	switch (priv->bmips_type) {

	case BMIPS5200:

	case BMIPS5000:

		mode = read_c0_brcm_mode();

		div = ((mode >> BMIPS5_CLK_DIV_SHIFT) & BMIPS5_CLK_DIV_MASK);

		break;

	default:

		div = 0;

	}



	return htp_freq_to_cpu_freq(priv->clk_mult) / (1 << div);

}



static int bmips_cpufreq_target_index(struct cpufreq_policy *policy,

				      unsigned int index)

{

	unsigned int div = policy->freq_table[index].driver_data;



	switch (priv->bmips_type) {

	case BMIPS5200:

	case BMIPS5000:

		change_c0_brcm_mode(BMIPS5_CLK_DIV_MASK << BMIPS5_CLK_DIV_SHIFT,

				    (1 << BMIPS5_CLK_DIV_SET_SHIFT) |

				    (div << BMIPS5_CLK_DIV_SHIFT));

		break;

	default:

		return -ENOTSUPP;

	}



	return 0;

}



static int bmips_cpufreq_exit(struct cpufreq_policy *policy)

{

	kfree(policy->freq_table);



	return 0;

}



static int bmips_cpufreq_init(struct cpufreq_policy *policy)

{

	struct cpufreq_frequency_table *freq_table;

	int ret;



	freq_table = bmips_cpufreq_get_freq_table(policy);

	if (IS_ERR(freq_table)) {

		ret = PTR_ERR(freq_table);

		pr_err("%s: couldn't determine frequency table (%d).\n",

			BMIPS_CPUFREQ_NAME, ret);

		return ret;

	}



	ret = cpufreq_generic_init(policy, freq_table, TRANSITION_LATENCY);

	if (ret)

		bmips_cpufreq_exit(policy);

	else

		pr_info("%s: registered\n", BMIPS_CPUFREQ_NAME);



	return ret;

}



static struct cpufreq_driver bmips_cpufreq_driver = {

	.flags		= CPUFREQ_NEED_INITIAL_FREQ_CHECK,

	.verify		= cpufreq_generic_frequency_table_verify,

	.target_index	= bmips_cpufreq_target_index,

	.get		= bmips_cpufreq_get,

	.init		= bmips_cpufreq_init,

	.exit		= bmips_cpufreq_exit,

	.attr		= cpufreq_generic_attr,

	.name		= BMIPS_CPUFREQ_PREFIX,

};



static int __init bmips_cpufreq_probe(void)

{

	struct cpufreq_compat *cc;

	struct device_node *np;



	for (cc = bmips_cpufreq_compat; cc->compatible; cc++) {

		np = of_find_compatible_node(NULL, "cpu", cc->compatible);

		if (np) {

			of_node_put(np);

			priv = cc;

			break;

		}

	}



	/* We hit the guard element of the array. No compatible CPU found. */

	if (!cc->compatible)

		return -ENODEV;



	return cpufreq_register_driver(&bmips_cpufreq_driver);

}

device_initcall(bmips_cpufreq_probe);



MODULE_AUTHOR("Markus Mayer <mmayer@broadcom.com>");

MODULE_DESCRIPTION("CPUfreq driver for Broadcom BMIPS SoCs");

MODULE_LICENSE("GPL");