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yaml
---
r: 62149
b: refs/heads/master
c: cb5ec75
h: refs/heads/master
i:
  62147: b41b43b
v: v3
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Paul Mundt committed Jul 20, 2007
1 parent 43731c9 commit 3edb4a8
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Showing 3 changed files with 82 additions and 136 deletions.
2 changes: 1 addition & 1 deletion [refs]
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@@ -1,2 +1,2 @@
---
refs/heads/master: fe04d7798f611bca333df27d44484bdd62eef53f
refs/heads/master: cb5ec75b8b0410bba4ae612d13a2f26e938bc49c
2 changes: 1 addition & 1 deletion trunk/arch/sh/Kconfig
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Expand Up @@ -475,7 +475,7 @@ source "drivers/cpufreq/Kconfig"

config SH_CPU_FREQ
tristate "SuperH CPU Frequency driver"
depends on CPU_FREQ && CPU_SH4 && BROKEN
depends on CPU_FREQ
select CPU_FREQ_TABLE
help
This adds the cpufreq driver for SuperH. At present, only
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214 changes: 80 additions & 134 deletions trunk/arch/sh/kernel/cpufreq.c
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Expand Up @@ -3,89 +3,51 @@
*
* cpufreq driver for the SuperH processors.
*
* Copyright (C) 2002, 2003, 2004, 2005 Paul Mundt
* Copyright (C) 2002 - 2007 Paul Mundt
* Copyright (C) 2002 M. R. Brown
*
* 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; either version 2 of the License, or (at your
* option) any later version.
* Clock framework bits from arch/avr32/mach-at32ap/cpufreq.c
*
* Copyright (C) 2004-2007 Atmel Corporation
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/types.h>
#include <linux/cpufreq.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/cpumask.h>
#include <linux/smp.h>
#include <linux/sched.h> /* set_cpus_allowed() */

#include <linux/io.h>
#include <linux/clk.h>
#include <asm/processor.h>
#include <asm/watchdog.h>
#include <asm/freq.h>
#include <asm/io.h>

/*
* For SuperH, each policy change requires that we change the IFC, BFC, and
* PFC at the same time. Here we define sane values that won't trash the
* system.
*
* Note the max set is computed at runtime, we use the divisors that we booted
* with to setup our maximum operating frequencies.
*/
struct clock_set {
unsigned int ifc;
unsigned int bfc;
unsigned int pfc;
} clock_sets[] = {
#if defined(CONFIG_CPU_SH3) || defined(CONFIG_CPU_SH2)
{ 0, 0, 0 }, /* not implemented yet */
#elif defined(CONFIG_CPU_SH4)
{ 4, 8, 8 }, /* min - IFC: 1/4, BFC: 1/8, PFC: 1/8 */
{ 1, 2, 2 }, /* max - IFC: 1, BFC: 1/2, PFC: 1/2 */
#endif
};

#define MIN_CLOCK_SET 0
#define MAX_CLOCK_SET (ARRAY_SIZE(clock_sets) - 1)

/*
* For the time being, we only support two frequencies, which in turn are
* aimed at the POWERSAVE and PERFORMANCE policies, which in turn are derived
* directly from the respective min/max clock sets. Technically we could
* support a wider range of frequencies, but these vary far too much for each
* CPU subtype (and we'd have to construct a frequency table for each subtype).
*
* Maybe something to implement in the future..
*/
#define SH_FREQ_MAX 0
#define SH_FREQ_MIN 1
#include <asm/clock.h>

static struct cpufreq_frequency_table sh_freqs[] = {
{ SH_FREQ_MAX, 0 },
{ SH_FREQ_MIN, 0 },
{ 0, CPUFREQ_TABLE_END },
};
static struct clk *cpuclk;

static void sh_cpufreq_update_clocks(unsigned int set)
static unsigned int sh_cpufreq_get(unsigned int cpu)
{
current_cpu_data.cpu_clock = current_cpu_data.master_clock / clock_sets[set].ifc;
current_cpu_data.bus_clock = current_cpu_data.master_clock / clock_sets[set].bfc;
current_cpu_data.module_clock = current_cpu_data.master_clock / clock_sets[set].pfc;
current_cpu_data.loops_per_jiffy = loops_per_jiffy;
return (clk_get_rate(cpuclk) + 500) / 1000;
}

/* XXX: This needs to be split out per CPU and CPU subtype. */
/*
* Here we notify other drivers of the proposed change and the final change.
*/
static int sh_cpufreq_setstate(unsigned int cpu, unsigned int set)
static int sh_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned short frqcr = ctrl_inw(FRQCR);
unsigned int cpu = policy->cpu;
cpumask_t cpus_allowed;
struct cpufreq_freqs freqs;
long freq;

if (!cpu_online(cpu))
return -ENODEV;
Expand All @@ -95,125 +57,109 @@ static int sh_cpufreq_setstate(unsigned int cpu, unsigned int set)

BUG_ON(smp_processor_id() != cpu);

freqs.cpu = cpu;
freqs.old = current_cpu_data.cpu_clock / 1000;
freqs.new = (current_cpu_data.master_clock / clock_sets[set].ifc) / 1000;
/* Convert target_freq from kHz to Hz */
freq = clk_round_rate(cpuclk, target_freq * 1000);

cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
#if defined(CONFIG_CPU_SH3)
frqcr |= (newstate & 0x4000) << 14;
frqcr |= (newstate & 0x000c) << 2;
#elif defined(CONFIG_CPU_SH4)
/*
* FRQCR.PLL2EN is 1, we need to allow the PLL to stabilize by
* initializing the WDT.
*/
if (frqcr & (1 << 9)) {
__u8 csr;

/*
* Set the overflow period to the highest available,
* in this case a 1/4096 division ratio yields a 5.25ms
* overflow period. See asm-sh/watchdog.h for more
* information and a range of other divisors.
*/
csr = sh_wdt_read_csr();
csr |= WTCSR_CKS_4096;
sh_wdt_write_csr(csr);

sh_wdt_write_cnt(0);
}
frqcr &= 0x0e00; /* Clear ifc, bfc, pfc */
frqcr |= get_ifc_value(clock_sets[set].ifc) << 6;
frqcr |= get_bfc_value(clock_sets[set].bfc) << 3;
frqcr |= get_pfc_value(clock_sets[set].pfc);
#endif
ctrl_outw(frqcr, FRQCR);
sh_cpufreq_update_clocks(set);
if (freq < (policy->min * 1000) || freq > (policy->max * 1000))
return -EINVAL;

pr_debug("cpufreq: requested frequency %u Hz\n", target_freq * 1000);

freqs.cpu = cpu;
freqs.old = sh_cpufreq_get(cpu);
freqs.new = (freq + 500) / 1000;
freqs.flags = 0;

cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
set_cpus_allowed(current, cpus_allowed);
clk_set_rate(cpuclk, freq);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

pr_debug("cpufreq: set frequency %lu Hz\n", freq);

return 0;
}

static int sh_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
unsigned int min_freq, max_freq;
unsigned int ifc, bfc, pfc;
printk(KERN_INFO "cpufreq: SuperH CPU frequency driver.\n");

if (!cpu_online(policy->cpu))
return -ENODEV;

/* Update our maximum clock set */
get_current_frequency_divisors(&ifc, &bfc, &pfc);
clock_sets[MAX_CLOCK_SET].ifc = ifc;
clock_sets[MAX_CLOCK_SET].bfc = bfc;
clock_sets[MAX_CLOCK_SET].pfc = pfc;

/* Convert from Hz to kHz */
max_freq = current_cpu_data.cpu_clock / 1000;
min_freq = (current_cpu_data.master_clock / clock_sets[MIN_CLOCK_SET].ifc) / 1000;

sh_freqs[SH_FREQ_MAX].frequency = max_freq;
sh_freqs[SH_FREQ_MIN].frequency = min_freq;
cpuclk = clk_get(NULL, "cpu_clk");
if (IS_ERR(cpuclk)) {
printk(KERN_ERR "cpufreq: couldn't get CPU clk\n");
return PTR_ERR(cpuclk);
}

/* cpuinfo and default policy values */
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
policy->cpuinfo.min_freq = (clk_round_rate(cpuclk, 1) + 500) / 1000;
policy->cpuinfo.max_freq = (clk_round_rate(cpuclk, ~0UL) + 500) / 1000;
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
policy->cur = max_freq;

return cpufreq_frequency_table_cpuinfo(policy, &sh_freqs[0]);
}
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
policy->cur = sh_cpufreq_get(policy->cpu);
policy->min = policy->cpuinfo.min_freq;
policy->max = policy->cpuinfo.max_freq;

static int sh_cpufreq_verify(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, &sh_freqs[0]);
}

static int sh_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
unsigned int set, idx = 0;
/*
* Catch the cases where the clock framework hasn't been wired up
* properly to support scaling.
*/
if (unlikely(policy->min == policy->max)) {
printk(KERN_ERR "cpufreq: clock framework rate rounding "
"not supported on this CPU.\n");

if (cpufreq_frequency_table_target(policy, &sh_freqs[0], target_freq, relation, &idx))
clk_put(cpuclk);
return -EINVAL;
}

set = (idx == SH_FREQ_MIN) ? MIN_CLOCK_SET : MAX_CLOCK_SET;
printk(KERN_INFO "cpufreq: Frequencies - Minimum %u.%03u MHz, "
"Maximum %u.%03u MHz.\n",
policy->min / 1000, policy->min % 1000,
policy->max / 1000, policy->max % 1000);

sh_cpufreq_setstate(policy->cpu, set);
return 0;
}

static int sh_cpufreq_verify(struct cpufreq_policy *policy)
{
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
policy->cpuinfo.max_freq);
return 0;
}

static int sh_cpufreq_exit(struct cpufreq_policy *policy)
{
clk_put(cpuclk);
return 0;
}

static struct cpufreq_driver sh_cpufreq_driver = {
.owner = THIS_MODULE,
.name = "SH cpufreq",
.name = "sh",
.init = sh_cpufreq_cpu_init,
.verify = sh_cpufreq_verify,
.target = sh_cpufreq_target,
.get = sh_cpufreq_get,
.exit = sh_cpufreq_exit,
};

static int __init sh_cpufreq_init(void)
static int __init sh_cpufreq_module_init(void)
{
if (!current_cpu_data.cpu_clock)
return -EINVAL;
if (cpufreq_register_driver(&sh_cpufreq_driver))
return -EINVAL;

return 0;
return cpufreq_register_driver(&sh_cpufreq_driver);
}

static void __exit sh_cpufreq_exit(void)
static void __exit sh_cpufreq_module_exit(void)
{
cpufreq_unregister_driver(&sh_cpufreq_driver);
}

module_init(sh_cpufreq_init);
module_exit(sh_cpufreq_exit);
module_init(sh_cpufreq_module_init);
module_exit(sh_cpufreq_module_exit);

MODULE_AUTHOR("Paul Mundt <lethal@linux-sh.org>");
MODULE_DESCRIPTION("cpufreq driver for SuperH");
MODULE_LICENSE("GPL");

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