mirror of
https://github.com/edk2-porting/linux-next.git
synced 2024-12-23 04:34:11 +08:00
e50b6befae
The patch adds support for Kirkwood cpu idle. Two idle states are defined: 1. Wait-for-interrupt (replacing default kirkwood wfi) 2. Wait-for-interrupt and DDR self refresh Signed-off-by: Rabeeh Khoury <rabeeh@marvell.com> Signed-off-by: Nicolas Pitre <nico@marvell.com>
97 lines
2.8 KiB
C
97 lines
2.8 KiB
C
/*
|
|
* arch/arm/mach-kirkwood/cpuidle.c
|
|
*
|
|
* CPU idle Marvell Kirkwood SoCs
|
|
*
|
|
* This file is licensed under the terms of the GNU General Public
|
|
* License version 2. This program is licensed "as is" without any
|
|
* warranty of any kind, whether express or implied.
|
|
*
|
|
* The cpu idle uses wait-for-interrupt and DDR self refresh in order
|
|
* to implement two idle states -
|
|
* #1 wait-for-interrupt
|
|
* #2 wait-for-interrupt and DDR self refresh
|
|
*/
|
|
|
|
#include <linux/kernel.h>
|
|
#include <linux/init.h>
|
|
#include <linux/platform_device.h>
|
|
#include <linux/cpuidle.h>
|
|
#include <linux/io.h>
|
|
#include <asm/proc-fns.h>
|
|
#include <mach/kirkwood.h>
|
|
|
|
#define KIRKWOOD_MAX_STATES 2
|
|
|
|
static struct cpuidle_driver kirkwood_idle_driver = {
|
|
.name = "kirkwood_idle",
|
|
.owner = THIS_MODULE,
|
|
};
|
|
|
|
static DEFINE_PER_CPU(struct cpuidle_device, kirkwood_cpuidle_device);
|
|
|
|
/* Actual code that puts the SoC in different idle states */
|
|
static int kirkwood_enter_idle(struct cpuidle_device *dev,
|
|
struct cpuidle_state *state)
|
|
{
|
|
struct timeval before, after;
|
|
int idle_time;
|
|
|
|
local_irq_disable();
|
|
do_gettimeofday(&before);
|
|
if (state == &dev->states[0])
|
|
/* Wait for interrupt state */
|
|
cpu_do_idle();
|
|
else if (state == &dev->states[1]) {
|
|
/*
|
|
* Following write will put DDR in self refresh.
|
|
* Note that we have 256 cycles before DDR puts it
|
|
* self in self-refresh, so the wait-for-interrupt
|
|
* call afterwards won't get the DDR from self refresh
|
|
* mode.
|
|
*/
|
|
writel(0x7, DDR_OPERATION_BASE);
|
|
cpu_do_idle();
|
|
}
|
|
do_gettimeofday(&after);
|
|
local_irq_enable();
|
|
idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
|
|
(after.tv_usec - before.tv_usec);
|
|
return idle_time;
|
|
}
|
|
|
|
/* Initialize CPU idle by registering the idle states */
|
|
static int kirkwood_init_cpuidle(void)
|
|
{
|
|
struct cpuidle_device *device;
|
|
|
|
cpuidle_register_driver(&kirkwood_idle_driver);
|
|
|
|
device = &per_cpu(kirkwood_cpuidle_device, smp_processor_id());
|
|
device->state_count = KIRKWOOD_MAX_STATES;
|
|
|
|
/* Wait for interrupt state */
|
|
device->states[0].enter = kirkwood_enter_idle;
|
|
device->states[0].exit_latency = 1;
|
|
device->states[0].target_residency = 10000;
|
|
device->states[0].flags = CPUIDLE_FLAG_TIME_VALID;
|
|
strcpy(device->states[0].name, "WFI");
|
|
strcpy(device->states[0].desc, "Wait for interrupt");
|
|
|
|
/* Wait for interrupt and DDR self refresh state */
|
|
device->states[1].enter = kirkwood_enter_idle;
|
|
device->states[1].exit_latency = 10;
|
|
device->states[1].target_residency = 10000;
|
|
device->states[1].flags = CPUIDLE_FLAG_TIME_VALID;
|
|
strcpy(device->states[1].name, "DDR SR");
|
|
strcpy(device->states[1].desc, "WFI and DDR Self Refresh");
|
|
|
|
if (cpuidle_register_device(device)) {
|
|
printk(KERN_ERR "kirkwood_init_cpuidle: Failed registering\n");
|
|
return -EIO;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
device_initcall(kirkwood_init_cpuidle);
|