cris-etraxfs-cpufreq.c
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#include <linux/init.h>
#include <linux/module.h>
#include <linux/cpufreq.h>
#include <hwregs/reg_map.h>
#include <arch/hwregs/reg_rdwr.h>
#include <arch/hwregs/config_defs.h>
#include <arch/hwregs/bif_core_defs.h>
static int
cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
void *data);
static struct notifier_block cris_sdram_freq_notifier_block = {
.notifier_call = cris_sdram_freq_notifier
};
static struct cpufreq_frequency_table cris_freq_table[] = {
{0, 0x01, 6000},
{0, 0x02, 200000},
{0, 0, CPUFREQ_TABLE_END},
};
static unsigned int cris_freq_get_cpu_frequency(unsigned int cpu)
{
reg_config_rw_clk_ctrl clk_ctrl;
clk_ctrl = REG_RD(config, regi_config, rw_clk_ctrl);
return clk_ctrl.pll ? 200000 : 6000;
}
static int cris_freq_target(struct cpufreq_policy *policy, unsigned int state)
{
reg_config_rw_clk_ctrl clk_ctrl;
clk_ctrl = REG_RD(config, regi_config, rw_clk_ctrl);
local_irq_disable();
/* Even though we may be SMP they will share the same clock
* so all settings are made on CPU0. */
if (cris_freq_table[state].frequency == 200000)
clk_ctrl.pll = 1;
else
clk_ctrl.pll = 0;
REG_WR(config, regi_config, rw_clk_ctrl, clk_ctrl);
local_irq_enable();
return 0;
}
static int cris_freq_cpu_init(struct cpufreq_policy *policy)
{
return cpufreq_generic_init(policy, cris_freq_table, 1000000);
}
static struct cpufreq_driver cris_freq_driver = {
.get = cris_freq_get_cpu_frequency,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = cris_freq_target,
.init = cris_freq_cpu_init,
.name = "cris_freq",
.attr = cpufreq_generic_attr,
};
static int __init cris_freq_init(void)
{
int ret;
ret = cpufreq_register_driver(&cris_freq_driver);
cpufreq_register_notifier(&cris_sdram_freq_notifier_block,
CPUFREQ_TRANSITION_NOTIFIER);
return ret;
}
static int
cris_sdram_freq_notifier(struct notifier_block *nb, unsigned long val,
void *data)
{
int i;
struct cpufreq_freqs *freqs = data;
if (val == CPUFREQ_PRECHANGE) {
reg_bif_core_rw_sdram_timing timing =
REG_RD(bif_core, regi_bif_core, rw_sdram_timing);
timing.cpd = (freqs->new == 200000 ? 0 : 1);
if (freqs->new == 200000)
for (i = 0; i < 50000; i++) ;
REG_WR(bif_core, regi_bif_core, rw_sdram_timing, timing);
}
return 0;
}
module_init(cris_freq_init);