arch/arm/mach-mvebu/pm.c

   1 /*
   2  * Suspend/resume support. Currently supporting Armada XP only.
   3  *
   4  * Copyright (C) 2014 Marvell
   5  *
   6  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   7  *
   8  * This file is licensed under the terms of the GNU General Public
   9  * License version 2.  This program is licensed "as is" without any
  10  * warranty of any kind, whether express or implied.
  11  */
  12
  13 #include <linux/cpu_pm.h>
  14 #include <linux/delay.h>
  15 #include <linux/gpio.h>
  16 #include <linux/io.h>
  17 #include <linux/kernel.h>
  18 #include <linux/mbus.h>
  19 #include <linux/of_address.h>
  20 #include <linux/suspend.h>
  21 #include <asm/cacheflush.h>
  22 #include <asm/outercache.h>
  23 #include <asm/suspend.h>
  24
  25 #include "coherency.h"
  26 #include "pmsu.h"
  27
  28 #define SDRAM_CONFIG_OFFS                  0x0
  29 #define  SDRAM_CONFIG_SR_MODE_BIT          BIT(24)
  30 #define SDRAM_OPERATION_OFFS               0x18
  31 #define  SDRAM_OPERATION_SELF_REFRESH      0x7
  32 #define SDRAM_DLB_EVICTION_OFFS            0x30c
  33 #define  SDRAM_DLB_EVICTION_THRESHOLD_MASK 0xff
  34
  35 static void (*mvebu_board_pm_enter)(void __iomem *sdram_reg, u32 srcmd);
  36 static void __iomem *sdram_ctrl;
  37
  38 static int mvebu_pm_powerdown(unsigned long data)
  39 {
  40         u32 reg, srcmd;
  41
  42         flush_cache_all();
  43         outer_flush_all();
  44
  45         /*
  46          * Issue a Data Synchronization Barrier instruction to ensure
  47          * that all state saving has been completed.
  48          */
  49         dsb();
  50
  51         /* Flush the DLB and wait ~7 usec */
  52         reg = readl(sdram_ctrl + SDRAM_DLB_EVICTION_OFFS);
  53         reg &= ~SDRAM_DLB_EVICTION_THRESHOLD_MASK;
  54         writel(reg, sdram_ctrl + SDRAM_DLB_EVICTION_OFFS);
  55
  56         udelay(7);
  57
  58         /* Set DRAM in battery backup mode */
  59         reg = readl(sdram_ctrl + SDRAM_CONFIG_OFFS);
  60         reg &= ~SDRAM_CONFIG_SR_MODE_BIT;
  61         writel(reg, sdram_ctrl + SDRAM_CONFIG_OFFS);
  62
  63         /* Prepare to go to self-refresh */
  64
  65         srcmd = readl(sdram_ctrl + SDRAM_OPERATION_OFFS);
  66         srcmd &= ~0x1F;
  67         srcmd |= SDRAM_OPERATION_SELF_REFRESH;
  68
  69         mvebu_board_pm_enter(sdram_ctrl + SDRAM_OPERATION_OFFS, srcmd);
  70
  71         return 0;
  72 }
  73
  74 #define BOOT_INFO_ADDR      0x3000
  75 #define BOOT_MAGIC_WORD     0xdeadb002
  76 #define BOOT_MAGIC_LIST_END 0xffffffff
  77
  78 /*
  79  * Those registers are accessed before switching the internal register
  80  * base, which is why we hardcode the 0xd0000000 base address, the one
  81  * used by the SoC out of reset.
  82  */
  83 #define MBUS_WINDOW_12_CTRL       0xd00200b0
  84 #define MBUS_INTERNAL_REG_ADDRESS 0xd0020080
  85
  86 #define SDRAM_WIN_BASE_REG(x)   (0x20180 + (0x8*x))
  87 #define SDRAM_WIN_CTRL_REG(x)   (0x20184 + (0x8*x))
  88
  89 static phys_addr_t mvebu_internal_reg_base(void)
  90 {
  91         struct device_node *np;
  92         __be32 in_addr[2];
  93
  94         np = of_find_node_by_name(NULL, "internal-regs");
  95         BUG_ON(!np);
  96
  97         /*
  98          * Ask the DT what is the internal register address on this
  99          * platform. In the mvebu-mbus DT binding, 0xf0010000
 100          * corresponds to the internal register window.
 101          */
 102         in_addr[0] = cpu_to_be32(0xf0010000);
 103         in_addr[1] = 0x0;
 104
 105         return of_translate_address(np, in_addr);
 106 }
 107
 108 static void mvebu_pm_store_bootinfo(void)
 109 {
 110         u32 *store_addr;
 111         phys_addr_t resume_pc;
 112
 113         store_addr = phys_to_virt(BOOT_INFO_ADDR);
 114         resume_pc = virt_to_phys(armada_370_xp_cpu_resume);
 115
 116         /*
 117          * The bootloader expects the first two words to be a magic
 118          * value (BOOT_MAGIC_WORD), followed by the address of the
 119          * resume code to jump to. Then, it expects a sequence of
 120          * (address, value) pairs, which can be used to restore the
 121          * value of certain registers. This sequence must end with the
 122          * BOOT_MAGIC_LIST_END magic value.
 123          */
 124
 125         writel(BOOT_MAGIC_WORD, store_addr++);
 126         writel(resume_pc, store_addr++);
 127
 128         /*
 129          * Some platforms remap their internal register base address
 130          * to 0xf1000000. However, out of reset, window 12 starts at
 131          * 0xf0000000 and ends at 0xf7ffffff, which would overlap with
 132          * the internal registers. Therefore, disable window 12.
 133          */
 134         writel(MBUS_WINDOW_12_CTRL, store_addr++);
 135         writel(0x0, store_addr++);
 136
 137         /*
 138          * Set the internal register base address to the value
 139          * expected by Linux, as read from the Device Tree.
 140          */
 141         writel(MBUS_INTERNAL_REG_ADDRESS, store_addr++);
 142         writel(mvebu_internal_reg_base(), store_addr++);
 143
 144         /*
 145          * Ask the mvebu-mbus driver to store the SDRAM window
 146          * configuration, which has to be restored by the bootloader
 147          * before re-entering the kernel on resume.
 148          */
 149         store_addr += mvebu_mbus_save_cpu_target(store_addr);
 150
 151         writel(BOOT_MAGIC_LIST_END, store_addr);
 152 }
 153
 154 static int mvebu_pm_enter(suspend_state_t state)
 155 {
 156         if (state != PM_SUSPEND_MEM)
 157                 return -EINVAL;
 158
 159         cpu_pm_enter();
 160
 161         mvebu_pm_store_bootinfo();
 162         cpu_suspend(0, mvebu_pm_powerdown);
 163
 164         outer_resume();
 165
 166         mvebu_v7_pmsu_idle_exit();
 167
 168         set_cpu_coherent();
 169
 170         cpu_pm_exit();
 171
 172         return 0;
 173 }
 174
 175 static const struct platform_suspend_ops mvebu_pm_ops = {
 176         .enter = mvebu_pm_enter,
 177         .valid = suspend_valid_only_mem,
 178 };
 179
 180 int mvebu_pm_init(void (*board_pm_enter)(void __iomem *sdram_reg, u32 srcmd))
 181 {
 182         struct device_node *np;
 183         struct resource res;
 184
 185         if (!of_machine_is_compatible("marvell,armadaxp"))
 186                 return -ENODEV;
 187
 188         np = of_find_compatible_node(NULL, NULL,
 189                                      "marvell,armada-xp-sdram-controller");
 190         if (!np)
 191                 return -ENODEV;
 192
 193         if (of_address_to_resource(np, 0, &res)) {
 194                 of_node_put(np);
 195                 return -ENODEV;
 196         }
 197
 198         if (!request_mem_region(res.start, resource_size(&res),
 199                                 np->full_name)) {
 200                 of_node_put(np);
 201                 return -EBUSY;
 202         }
 203
 204         sdram_ctrl = ioremap(res.start, resource_size(&res));
 205         if (!sdram_ctrl) {
 206                 release_mem_region(res.start, resource_size(&res));
 207                 of_node_put(np);
 208                 return -ENOMEM;
 209         }
 210
 211         of_node_put(np);
 212
 213         mvebu_board_pm_enter = board_pm_enter;
 214
 215         suspend_set_ops(&mvebu_pm_ops);
 216
 217         return 0;
 218 }