LXR linux/arch/arm/mach-kirkwood/cpuidle.c

   1/*
   2 * arch/arm/mach-kirkwood/cpuidle.c
   3 *
   4 * CPU idle Marvell Kirkwood SoCs
   5 *
   6 * This file is licensed under the terms of the GNU General Public
   7 * License version 2.  This program is licensed "as is" without any
   8 * warranty of any kind, whether express or implied.
   9 *
  10 * The cpu idle uses wait-for-interrupt and DDR self refresh in order
  11 * to implement two idle states -
  12 * #1 wait-for-interrupt
  13 * #2 wait-for-interrupt and DDR self refresh
  14 */
  15
  16#include <linux/kernel.h>
  17#include <linux/init.h>
  18#include <linux/platform_device.h>
  19#include <linux/cpuidle.h>
  20#include <linux/io.h>
  21#include <linux/export.h>
  22#include <asm/proc-fns.h>
  23#include <asm/cpuidle.h>
  24#include <mach/kirkwood.h>
  25
  26#define KIRKWOOD_MAX_STATES     2
  27
  28/* Actual code that puts the SoC in different idle states */
  29static int kirkwood_enter_idle(struct cpuidle_device *dev,
  30                                struct cpuidle_driver *drv,
  31                               int index)
  32{
  33        writel(0x7, DDR_OPERATION_BASE);
  34        cpu_do_idle();
  35
  36        return index;
  37}
  38
  39static struct cpuidle_driver kirkwood_idle_driver = {
  40        .name                   = "kirkwood_idle",
  41        .owner                  = THIS_MODULE,
  42        .en_core_tk_irqen       = 1,
  43        .states[0]              = ARM_CPUIDLE_WFI_STATE,
  44        .states[1]              = {
  45                .enter                  = kirkwood_enter_idle,
  46                .exit_latency           = 10,
  47                .target_residency       = 100000,
  48                .flags                  = CPUIDLE_FLAG_TIME_VALID,
  49                .name                   = "DDR SR",
  50                .desc                   = "WFI and DDR Self Refresh",
  51        },
  52        .state_count = KIRKWOOD_MAX_STATES,
  53};
  54
  55static DEFINE_PER_CPU(struct cpuidle_device, kirkwood_cpuidle_device);
  56
  57/* Initialize CPU idle by registering the idle states */
  58static int kirkwood_init_cpuidle(void)
  59{
  60        struct cpuidle_device *device;
  61
  62        device = &per_cpu(kirkwood_cpuidle_device, smp_processor_id());
  63        device->state_count = KIRKWOOD_MAX_STATES;
  64
  65        cpuidle_register_driver(&kirkwood_idle_driver);
  66        if (cpuidle_register_device(device)) {
  67                printk(KERN_ERR "kirkwood_init_cpuidle: Failed registering\n");
  68                return -EIO;
  69        }
  70        return 0;
  71}
  72
  73device_initcall(kirkwood_init_cpuidle);
  74