arch/arm/mach-mvebu/system-controller.c

   1 /*
   2  * System controller support for Armada 370 and XP platforms.
   3  *
   4  * Copyright (C) 2012 Marvell
   5  *
   6  * Lior Amsalem <alior@marvell.com>
   7  * Gregory CLEMENT <gregory.clement@free-electrons.com>
   8  * Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
   9  *
  10  * This file is licensed under the terms of the GNU General Public
  11  * License version 2.  This program is licensed "as is" without any
  12  * warranty of any kind, whether express or implied.
  13  *
  14  * The Armada 370 and Armada XP SoCs both have a range of
  15  * miscellaneous registers, that do not belong to a particular device,
  16  * but rather provide system-level features. This basic
  17  * system-controller driver provides a device tree binding for those
  18  * registers, and implements utility functions offering various
  19  * features related to those registers.
  20  *
  21  * For now, the feature set is limited to restarting the platform by a
  22  * soft-reset, but it might be extended in the future.
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/init.h>
  27 #include <linux/of_address.h>
  28 #include <linux/io.h>
  29 #include <linux/reboot.h>
  30
  31 static void __iomem *system_controller_base;
  32
  33 struct mvebu_system_controller {
  34         u32 rstoutn_mask_offset;
  35         u32 system_soft_reset_offset;
  36
  37         u32 rstoutn_mask_reset_out_en;
  38         u32 system_soft_reset;
  39 };
  40 static struct mvebu_system_controller *mvebu_sc;
  41
  42 const struct mvebu_system_controller armada_370_xp_system_controller = {
  43         .rstoutn_mask_offset = 0x60,
  44         .system_soft_reset_offset = 0x64,
  45         .rstoutn_mask_reset_out_en = 0x1,
  46         .system_soft_reset = 0x1,
  47 };
  48
  49 const struct mvebu_system_controller orion_system_controller = {
  50         .rstoutn_mask_offset = 0x108,
  51         .system_soft_reset_offset = 0x10c,
  52         .rstoutn_mask_reset_out_en = 0x4,
  53         .system_soft_reset = 0x1,
  54 };
  55
  56 static struct of_device_id of_system_controller_table[] = {
  57         {
  58                 .compatible = "marvell,orion-system-controller",
  59                 .data = (void *) &orion_system_controller,
  60         }, {
  61                 .compatible = "marvell,armada-370-xp-system-controller",
  62                 .data = (void *) &armada_370_xp_system_controller,
  63         },
  64         { /* end of list */ },
  65 };
  66
  67 void mvebu_restart(enum reboot_mode mode, const char *cmd)
  68 {
  69         if (!system_controller_base) {
  70                 pr_err("Cannot restart, system-controller not available: check the device tree\n");
  71         } else {
  72                 /*
  73                  * Enable soft reset to assert RSTOUTn.
  74                  */
  75                 writel(mvebu_sc->rstoutn_mask_reset_out_en,
  76                         system_controller_base +
  77                         mvebu_sc->rstoutn_mask_offset);
  78                 /*
  79                  * Assert soft reset.
  80                  */
  81                 writel(mvebu_sc->system_soft_reset,
  82                         system_controller_base +
  83                         mvebu_sc->system_soft_reset_offset);
  84         }
  85
  86         while (1)
  87                 ;
  88 }
  89
  90 static int __init mvebu_system_controller_init(void)
  91 {
  92         struct device_node *np;
  93
  94         np = of_find_matching_node(NULL, of_system_controller_table);
  95         if (np) {
  96                 const struct of_device_id *match =
  97                     of_match_node(of_system_controller_table, np);
  98                 BUG_ON(!match);
  99                 system_controller_base = of_iomap(np, 0);
 100                 mvebu_sc = (struct mvebu_system_controller *)match->data;
 101                 of_node_put(np);
 102         }
 103
 104         return 0;
 105 }
 106
 107 arch_initcall(mvebu_system_controller_init);