arch/arm/mach-mvebu/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 "kirkwood.h"
  21
  22 static void __iomem *ddr_operation_base;
  23 static void __iomem *memory_pm_ctrl;
  24
  25 static void kirkwood_low_power(void)
  26 {
  27         u32 mem_pm_ctrl;
  28
  29         mem_pm_ctrl = readl(memory_pm_ctrl);
  30
  31         /* Set peripherals to low-power mode */
  32         writel_relaxed(~0, memory_pm_ctrl);
  33
  34         /* Set DDR in self-refresh */
  35         writel_relaxed(0x7, ddr_operation_base);
  36
  37         /*
  38          * Set CPU in wait-for-interrupt state.
  39          * This disables the CPU core clocks,
  40          * the array clocks, and also the L2 controller.
  41          */
  42         cpu_do_idle();
  43
  44         writel_relaxed(mem_pm_ctrl, memory_pm_ctrl);
  45 }
  46
  47 static int kirkwood_suspend_enter(suspend_state_t state)
  48 {
  49         switch (state) {
  50         case PM_SUSPEND_STANDBY:
  51                 kirkwood_low_power();
  52                 break;
  53         default:
  54                 return -EINVAL;
  55         }
  56         return 0;
  57 }
  58
  59 static int kirkwood_pm_valid_standby(suspend_state_t state)
  60 {
  61         return state == PM_SUSPEND_STANDBY;
  62 }
  63
  64 static const struct platform_suspend_ops kirkwood_suspend_ops = {
  65         .enter = kirkwood_suspend_enter,
  66         .valid = kirkwood_pm_valid_standby,
  67 };
  68
  69 int __init kirkwood_pm_init(void)
  70 {
  71         ddr_operation_base = ioremap(DDR_OPERATION_BASE, 4);
  72         memory_pm_ctrl = ioremap(MEMORY_PM_CTRL_PHYS, 4);
  73
  74         suspend_set_ops(&kirkwood_suspend_ops);
  75         return 0;
  76 }