linux/drivers/cpufreq/db8500-cpufreq.c
Linus Walleij bc71c0961c ARM: ux500: core U9540 support
This adds support for the U9540 variant of the U8500 series. This
is an application processor without internal modem. This is the
most basic part with ASIC ID, CPU-related fixes, IRQ list, register
ranges, timer, UART, and L2 cache setup. This is based on a patch
by Michel Jaouen which was rewritten to fit with the latest 3.3
kernel.

ChangeLog v1->v2: deleted the irqs-db9540.h file since we expect to
  migrate to using Device Tree for getting the IRQs to devices.
ChangeLog v2->v3: introduced a fixed virtual offset for the ROM
  as suggested by Arnd Bergmann.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Sebastien Pasdeloup <sebastien.pasdeloup-nonst@stericsson.com>
Signed-off-by: Michel Jaouen <michel.jaouen@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2012-05-02 00:25:13 +02:00

170 lines
4.1 KiB
C

/*
* Copyright (C) STMicroelectronics 2009
* Copyright (C) ST-Ericsson SA 2010
*
* License Terms: GNU General Public License v2
* Author: Sundar Iyer <sundar.iyer@stericsson.com>
* Author: Martin Persson <martin.persson@stericsson.com>
* Author: Jonas Aaberg <jonas.aberg@stericsson.com>
*
*/
#include <linux/kernel.h>
#include <linux/cpufreq.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/mfd/dbx500-prcmu.h>
#include <mach/id.h>
static struct cpufreq_frequency_table freq_table[] = {
[0] = {
.index = 0,
.frequency = 200000,
},
[1] = {
.index = 1,
.frequency = 400000,
},
[2] = {
.index = 2,
.frequency = 800000,
},
[3] = {
/* Used for MAX_OPP, if available */
.index = 3,
.frequency = CPUFREQ_TABLE_END,
},
[4] = {
.index = 4,
.frequency = CPUFREQ_TABLE_END,
},
};
static enum arm_opp idx2opp[] = {
ARM_EXTCLK,
ARM_50_OPP,
ARM_100_OPP,
ARM_MAX_OPP
};
static struct freq_attr *db8500_cpufreq_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
static int db8500_cpufreq_verify_speed(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, freq_table);
}
static int db8500_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
struct cpufreq_freqs freqs;
unsigned int idx;
/* scale the target frequency to one of the extremes supported */
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;
/* Lookup the next frequency */
if (cpufreq_frequency_table_target
(policy, freq_table, target_freq, relation, &idx)) {
return -EINVAL;
}
freqs.old = policy->cur;
freqs.new = freq_table[idx].frequency;
if (freqs.old == freqs.new)
return 0;
/* pre-change notification */
for_each_cpu(freqs.cpu, policy->cpus)
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
/* request the PRCM unit for opp change */
if (prcmu_set_arm_opp(idx2opp[idx])) {
pr_err("db8500-cpufreq: Failed to set OPP level\n");
return -EINVAL;
}
/* post change notification */
for_each_cpu(freqs.cpu, policy->cpus)
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
return 0;
}
static unsigned int db8500_cpufreq_getspeed(unsigned int cpu)
{
int i;
/* request the prcm to get the current ARM opp */
for (i = 0; prcmu_get_arm_opp() != idx2opp[i]; i++)
;
return freq_table[i].frequency;
}
static int __cpuinit db8500_cpufreq_init(struct cpufreq_policy *policy)
{
int i, res;
BUILD_BUG_ON(ARRAY_SIZE(idx2opp) + 1 != ARRAY_SIZE(freq_table));
if (prcmu_has_arm_maxopp())
freq_table[3].frequency = 1000000;
pr_info("db8500-cpufreq : Available frequencies:\n");
for (i = 0; freq_table[i].frequency != CPUFREQ_TABLE_END; i++)
pr_info(" %d Mhz\n", freq_table[i].frequency/1000);
/* get policy fields based on the table */
res = cpufreq_frequency_table_cpuinfo(policy, freq_table);
if (!res)
cpufreq_frequency_table_get_attr(freq_table, policy->cpu);
else {
pr_err("db8500-cpufreq : Failed to read policy table\n");
return res;
}
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;
policy->cur = db8500_cpufreq_getspeed(policy->cpu);
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
/*
* FIXME : Need to take time measurement across the target()
* function with no/some/all drivers in the notification
* list.
*/
policy->cpuinfo.transition_latency = 20 * 1000; /* in ns */
/* policy sharing between dual CPUs */
cpumask_copy(policy->cpus, cpu_present_mask);
policy->shared_type = CPUFREQ_SHARED_TYPE_ALL;
return 0;
}
static struct cpufreq_driver db8500_cpufreq_driver = {
.flags = CPUFREQ_STICKY,
.verify = db8500_cpufreq_verify_speed,
.target = db8500_cpufreq_target,
.get = db8500_cpufreq_getspeed,
.init = db8500_cpufreq_init,
.name = "DB8500",
.attr = db8500_cpufreq_attr,
};
static int __init db8500_cpufreq_register(void)
{
if (!cpu_is_u8500_family())
return -ENODEV;
pr_info("cpufreq for DB8500 started\n");
return cpufreq_register_driver(&db8500_cpufreq_driver);
}
device_initcall(db8500_cpufreq_register);