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 #include "common.h"
  22
  23 static void __iomem *ddr_operation_base;
  24 static void __iomem *memory_pm_ctrl;
  25
  26 static void kirkwood_low_power(void)
  27 {
  28         u32 mem_pm_ctrl;
  29
  30         mem_pm_ctrl = readl(memory_pm_ctrl);
  31
  32         /* Set peripherals to low-power mode */
  33         writel_relaxed(~0, memory_pm_ctrl);
  34
  35         /* Set DDR in self-refresh */
  36         writel_relaxed(0x7, ddr_operation_base);
  37
  38         /*
  39          * Set CPU in wait-for-interrupt state.
  40          * This disables the CPU core clocks,
  41          * the array clocks, and also the L2 controller.
  42          */
  43         cpu_do_idle();
  44
  45         writel_relaxed(mem_pm_ctrl, memory_pm_ctrl);
  46 }
  47
  48 static int kirkwood_suspend_enter(suspend_state_t state)
  49 {
  50         switch (state) {
  51         case PM_SUSPEND_STANDBY:
  52                 kirkwood_low_power();
  53                 break;
  54         default:
  55                 return -EINVAL;
  56         }
  57         return 0;
  58 }
  59
  60 static int kirkwood_pm_valid_standby(suspend_state_t state)
  61 {
  62         return state == PM_SUSPEND_STANDBY;
  63 }
  64
  65 static const struct platform_suspend_ops kirkwood_suspend_ops = {
  66         .enter = kirkwood_suspend_enter,
  67         .valid = kirkwood_pm_valid_standby,
  68 };
  69
  70 void __init kirkwood_pm_init(void)
  71 {
  72         ddr_operation_base = ioremap(DDR_OPERATION_BASE, 4);
  73         memory_pm_ctrl = ioremap(MEMORY_PM_CTRL_PHYS, 4);
  74
  75         suspend_set_ops(&kirkwood_suspend_ops);
  76 }