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/*
* Copyright 2012 Calxeda, Inc.
*
* Based on arch/arm/plat-mxc/cpuidle.c:
* Copyright 2012 Freescale Semiconductor, Inc.
* Copyright 2012 Linaro Ltd.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/cpuidle.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/time.h>
#include <linux/delay.h>
#include <linux/suspend.h>
#include <asm/cpuidle.h>
#include <asm/proc-fns.h>
#include <asm/smp_scu.h>
#include <asm/suspend.h>
#include <asm/cacheflush.h>
#include <asm/cp15.h>
extern void highbank_set_cpu_jump(int cpu, void *jump_addr);
extern void *scu_base_addr;
static struct cpuidle_device __percpu *calxeda_idle_cpuidle_devices;
static inline unsigned int get_auxcr(void)
{
unsigned int val;
asm("mrc p15, 0, %0, c1, c0, 1 @ get AUXCR" : "=r" (val) : : "cc");
return val;
}
static inline void set_auxcr(unsigned int val)
{
asm volatile("mcr p15, 0, %0, c1, c0, 1 @ set AUXCR"
: : "r" (val) : "cc");
isb();
}
static noinline void calxeda_idle_restore(void)
{
set_cr(get_cr() | CR_C);
set_auxcr(get_auxcr() | 0x40);
scu_power_mode(scu_base_addr, SCU_PM_NORMAL);
}
static int calxeda_idle_finish(unsigned long val)
{
/* Already flushed cache, but do it again as the outer cache functions
* dirty the cache with spinlocks */
flush_cache_all();
set_auxcr(get_auxcr() & ~0x40);
set_cr(get_cr() & ~CR_C);
scu_power_mode(scu_base_addr, SCU_PM_DORMANT);
cpu_do_idle();
/* Restore things if we didn't enter power-gating */
calxeda_idle_restore();
return 1;
}
static int calxeda_pwrdown_idle(struct cpuidle_device *dev,
struct cpuidle_driver *drv,
int index)
{
highbank_set_cpu_jump(smp_processor_id(), cpu_resume);
cpu_suspend(0, calxeda_idle_finish);
return index;
}
static void calxeda_idle_cpuidle_devices_uninit(void)
{
int i;
struct cpuidle_device *dev;
for_each_possible_cpu(i) {
dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, i);
cpuidle_unregister_device(dev);
}
free_percpu(calxeda_idle_cpuidle_devices);
}
static struct cpuidle_driver calxeda_idle_driver = {
.name = "calxeda_idle",
.states = {
ARM_CPUIDLE_WFI_STATE,
{
.name = "PG",
.desc = "Power Gate",
.flags = CPUIDLE_FLAG_TIME_VALID,
.exit_latency = 30,
.power_usage = 50,
.target_residency = 200,
.enter = calxeda_pwrdown_idle,
},
},
.state_count = 2,
};
static int __init calxeda_cpuidle_init(void)
{
int cpu_id;
int ret;
struct cpuidle_device *dev;
struct cpuidle_driver *drv = &calxeda_idle_driver;
if (!of_machine_is_compatible("calxeda,highbank"))
return -ENODEV;
ret = cpuidle_register_driver(drv);
if (ret)
return ret;
calxeda_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
if (calxeda_idle_cpuidle_devices == NULL) {
ret = -ENOMEM;
goto unregister_drv;
}
/* initialize state data for each cpuidle_device */
for_each_possible_cpu(cpu_id) {
dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, cpu_id);
dev->cpu = cpu_id;
dev->state_count = drv->state_count;
ret = cpuidle_register_device(dev);
if (ret) {
pr_err("Failed to register cpu %u, error: %d\n",
cpu_id, ret);
goto uninit;
}
}
return 0;
uninit:
calxeda_idle_cpuidle_devices_uninit();
unregister_drv:
cpuidle_unregister_driver(drv);
return ret;
}
module_init(calxeda_cpuidle_init);
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