drivers/watchdog/simatic-ipc-wdt.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Siemens SIMATIC IPC driver for Watchdogs
   4  *
   5  * Copyright (c) Siemens AG, 2020-2021
   6  *
   7  * Authors:
   8  *  Gerd Haeussler <gerd.haeussler.ext@siemens.com>
   9  */
  10
  11 #include <linux/device.h>
  12 #include <linux/errno.h>
  13 #include <linux/init.h>
  14 #include <linux/io.h>
  15 #include <linux/ioport.h>
  16 #include <linux/kernel.h>
  17 #include <linux/module.h>
  18 #include <linux/pci.h>
  19 #include <linux/platform_data/x86/p2sb.h>
  20 #include <linux/platform_data/x86/simatic-ipc-base.h>
  21 #include <linux/platform_device.h>
  22 #include <linux/sizes.h>
  23 #include <linux/util_macros.h>
  24 #include <linux/watchdog.h>
  25
  26 #define WD_ENABLE_IOADR                 0x62
  27 #define WD_TRIGGER_IOADR                0x66
  28 #define GPIO_COMMUNITY0_PORT_ID         0xaf
  29 #define PAD_CFG_DW0_GPP_A_23            0x4b8
  30 #define SAFE_EN_N_427E                  0x01
  31 #define SAFE_EN_N_227E                  0x04
  32 #define WD_ENABLED                      0x01
  33 #define WD_TRIGGERED                    0x80
  34 #define WD_MACROMODE                    0x02
  35
  36 #define TIMEOUT_MIN     2
  37 #define TIMEOUT_DEF     64
  38 #define TIMEOUT_MAX     64
  39
  40 #define GP_STATUS_REG_227E      0x404D  /* IO PORT for SAFE_EN_N on 227E */
  41
  42 static bool nowayout = WATCHDOG_NOWAYOUT;
  43 module_param(nowayout, bool, 0000);
  44 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  45                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  46
  47 static struct resource gp_status_reg_227e_res =
  48         DEFINE_RES_IO_NAMED(GP_STATUS_REG_227E, SZ_1, KBUILD_MODNAME);
  49
  50 static struct resource io_resource_enable =
  51         DEFINE_RES_IO_NAMED(WD_ENABLE_IOADR, SZ_1,
  52                             KBUILD_MODNAME " WD_ENABLE_IOADR");
  53
  54 static struct resource io_resource_trigger =
  55         DEFINE_RES_IO_NAMED(WD_TRIGGER_IOADR, SZ_1,
  56                             KBUILD_MODNAME " WD_TRIGGER_IOADR");
  57
  58 /* the actual start will be discovered with p2sb, 0 is a placeholder */
  59 static struct resource mem_resource =
  60         DEFINE_RES_MEM_NAMED(0, 0, "WD_RESET_BASE_ADR");
  61
  62 static u32 wd_timeout_table[] = {2, 4, 6, 8, 16, 32, 48, 64 };
  63 static void __iomem *wd_reset_base_addr;
  64
  65 static int wd_start(struct watchdog_device *wdd)
  66 {
  67         outb(inb(WD_ENABLE_IOADR) | WD_ENABLED, WD_ENABLE_IOADR);
  68         return 0;
  69 }
  70
  71 static int wd_stop(struct watchdog_device *wdd)
  72 {
  73         outb(inb(WD_ENABLE_IOADR) & ~WD_ENABLED, WD_ENABLE_IOADR);
  74         return 0;
  75 }
  76
  77 static int wd_ping(struct watchdog_device *wdd)
  78 {
  79         inb(WD_TRIGGER_IOADR);
  80         return 0;
  81 }
  82
  83 static int wd_set_timeout(struct watchdog_device *wdd, unsigned int t)
  84 {
  85         int timeout_idx = find_closest(t, wd_timeout_table,
  86                                        ARRAY_SIZE(wd_timeout_table));
  87
  88         outb((inb(WD_ENABLE_IOADR) & 0xc7) | timeout_idx << 3, WD_ENABLE_IOADR);
  89         wdd->timeout = wd_timeout_table[timeout_idx];
  90         return 0;
  91 }
  92
  93 static const struct watchdog_info wdt_ident = {
  94         .options        = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
  95                           WDIOF_SETTIMEOUT,
  96         .identity       = KBUILD_MODNAME,
  97 };
  98
  99 static const struct watchdog_ops wdt_ops = {
 100         .owner          = THIS_MODULE,
 101         .start          = wd_start,
 102         .stop           = wd_stop,
 103         .ping           = wd_ping,
 104         .set_timeout    = wd_set_timeout,
 105 };
 106
 107 static void wd_secondary_enable(u32 wdtmode)
 108 {
 109         u16 resetbit;
 110
 111         /* set safe_en_n so we are not just WDIOF_ALARMONLY */
 112         if (wdtmode == SIMATIC_IPC_DEVICE_227E) {
 113                 /* enable SAFE_EN_N on GP_STATUS_REG_227E */
 114                 resetbit = inb(GP_STATUS_REG_227E);
 115                 outb(resetbit & ~SAFE_EN_N_227E, GP_STATUS_REG_227E);
 116         } else {
 117                 /* enable SAFE_EN_N on PCH D1600 */
 118                 resetbit = ioread16(wd_reset_base_addr);
 119                 iowrite16(resetbit & ~SAFE_EN_N_427E, wd_reset_base_addr);
 120         }
 121 }
 122
 123 static int wd_setup(u32 wdtmode)
 124 {
 125         unsigned int bootstatus = 0;
 126         int timeout_idx;
 127
 128         timeout_idx = find_closest(TIMEOUT_DEF, wd_timeout_table,
 129                                    ARRAY_SIZE(wd_timeout_table));
 130
 131         if (inb(WD_ENABLE_IOADR) & WD_TRIGGERED)
 132                 bootstatus |= WDIOF_CARDRESET;
 133
 134         /* reset alarm bit, set macro mode, and set timeout */
 135         outb(WD_TRIGGERED | WD_MACROMODE | timeout_idx << 3, WD_ENABLE_IOADR);
 136
 137         wd_secondary_enable(wdtmode);
 138
 139         return bootstatus;
 140 }
 141
 142 static struct watchdog_device wdd_data = {
 143         .info = &wdt_ident,
 144         .ops = &wdt_ops,
 145         .min_timeout = TIMEOUT_MIN,
 146         .max_timeout = TIMEOUT_MAX
 147 };
 148
 149 static int simatic_ipc_wdt_probe(struct platform_device *pdev)
 150 {
 151         struct simatic_ipc_platform *plat = pdev->dev.platform_data;
 152         struct device *dev = &pdev->dev;
 153         struct resource *res;
 154         int ret;
 155
 156         switch (plat->devmode) {
 157         case SIMATIC_IPC_DEVICE_227E:
 158                 if (!devm_request_region(dev, gp_status_reg_227e_res.start,
 159                                          resource_size(&gp_status_reg_227e_res),
 160                                          KBUILD_MODNAME)) {
 161                         dev_err(dev,
 162                                 "Unable to register IO resource at %pR\n",
 163                                 &gp_status_reg_227e_res);
 164                         return -EBUSY;
 165                 }
 166                 fallthrough;
 167         case SIMATIC_IPC_DEVICE_427E:
 168                 wdd_data.parent = dev;
 169                 break;
 170         default:
 171                 return -EINVAL;
 172         }
 173
 174         if (!devm_request_region(dev, io_resource_enable.start,
 175                                  resource_size(&io_resource_enable),
 176                                  io_resource_enable.name)) {
 177                 dev_err(dev,
 178                         "Unable to register IO resource at %#x\n",
 179                         WD_ENABLE_IOADR);
 180                 return -EBUSY;
 181         }
 182
 183         if (!devm_request_region(dev, io_resource_trigger.start,
 184                                  resource_size(&io_resource_trigger),
 185                                  io_resource_trigger.name)) {
 186                 dev_err(dev,
 187                         "Unable to register IO resource at %#x\n",
 188                         WD_TRIGGER_IOADR);
 189                 return -EBUSY;
 190         }
 191
 192         if (plat->devmode == SIMATIC_IPC_DEVICE_427E) {
 193                 res = &mem_resource;
 194
 195                 ret = p2sb_bar(NULL, 0, res);
 196                 if (ret)
 197                         return ret;
 198
 199                 /* do the final address calculation */
 200                 res->start = res->start + (GPIO_COMMUNITY0_PORT_ID << 16) +
 201                              PAD_CFG_DW0_GPP_A_23;
 202                 res->end = res->start + SZ_4 - 1;
 203
 204                 wd_reset_base_addr = devm_ioremap_resource(dev, res);
 205                 if (IS_ERR(wd_reset_base_addr))
 206                         return PTR_ERR(wd_reset_base_addr);
 207         }
 208
 209         wdd_data.bootstatus = wd_setup(plat->devmode);
 210         if (wdd_data.bootstatus)
 211                 dev_warn(dev, "last reboot caused by watchdog reset\n");
 212
 213         watchdog_set_nowayout(&wdd_data, nowayout);
 214         watchdog_stop_on_reboot(&wdd_data);
 215         return devm_watchdog_register_device(dev, &wdd_data);
 216 }
 217
 218 static struct platform_driver simatic_ipc_wdt_driver = {
 219         .probe = simatic_ipc_wdt_probe,
 220         .driver = {
 221                 .name = KBUILD_MODNAME,
 222         },
 223 };
 224
 225 module_platform_driver(simatic_ipc_wdt_driver);
 226
 227 MODULE_LICENSE("GPL v2");
 228 MODULE_ALIAS("platform:" KBUILD_MODNAME);
 229 MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");