arch/arm/mach-kirkwood/pm.c

   1 /*
   2  * Power Management driver for Marvell Kirkwood SoCs
   3  *
   4  * Copyright (C) 2013 Ezequiel Garcia <ezequiel@free-electrons.com>
   5  * Copyright (C) 2010 Simon Guinot <sguinot@lacie.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License,
   9  * version 2 of the License.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/suspend.h>
  19 #include <linux/io.h>
  20 #include <mach/bridge-regs.h>
  21
  22 static void __iomem *ddr_operation_base;
  23
  24 static void kirkwood_low_power(void)
  25 {
  26         u32 mem_pm_ctrl;
  27
  28         mem_pm_ctrl = readl(MEMORY_PM_CTRL);
  29
  30         /* Set peripherals to low-power mode */
  31         writel_relaxed(~0, MEMORY_PM_CTRL);
  32
  33         /* Set DDR in self-refresh */
  34         writel_relaxed(0x7, ddr_operation_base);
  35
  36         /*
  37          * Set CPU in wait-for-interrupt state.
  38          * This disables the CPU core clocks,
  39          * the array clocks, and also the L2 controller.
  40          */
  41         cpu_do_idle();
  42
  43         writel_relaxed(mem_pm_ctrl, MEMORY_PM_CTRL);
  44 }
  45
  46 static int kirkwood_suspend_enter(suspend_state_t state)
  47 {
  48         switch (state) {
  49         case PM_SUSPEND_STANDBY:
  50                 kirkwood_low_power();
  51                 break;
  52         default:
  53                 return -EINVAL;
  54         }
  55         return 0;
  56 }
  57
  58 static int kirkwood_pm_valid_standby(suspend_state_t state)
  59 {
  60         return state == PM_SUSPEND_STANDBY;
  61 }
  62
  63 static const struct platform_suspend_ops kirkwood_suspend_ops = {
  64         .enter = kirkwood_suspend_enter,
  65         .valid = kirkwood_pm_valid_standby,
  66 };
  67
  68 int __init kirkwood_pm_init(void)
  69 {
  70         ddr_operation_base = ioremap(DDR_OPERATION_BASE, 4);
  71         suspend_set_ops(&kirkwood_suspend_ops);
  72         return 0;
  73 }