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/simatic-ipc-base.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/sizes.h>
  22 #include <linux/util_macros.h>
  23 #include <linux/watchdog.h>
  24
  25 #define WD_ENABLE_IOADR                 0x62
  26 #define WD_TRIGGER_IOADR                0x66
  27 #define GPIO_COMMUNITY0_PORT_ID         0xaf
  28 #define PAD_CFG_DW0_GPP_A_23            0x4b8
  29 #define SAFE_EN_N_427E                  0x01
  30 #define SAFE_EN_N_227E                  0x04
  31 #define WD_ENABLED                      0x01
  32 #define WD_TRIGGERED                    0x80
  33 #define WD_MACROMODE                    0x02
  34
  35 #define TIMEOUT_MIN     2
  36 #define TIMEOUT_DEF     64
  37 #define TIMEOUT_MAX     64
  38
  39 #define GP_STATUS_REG_227E      0x404D  /* IO PORT for SAFE_EN_N on 227E */
  40
  41 static bool nowayout = WATCHDOG_NOWAYOUT;
  42 module_param(nowayout, bool, 0000);
  43 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
  44                  __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
  45
  46 static struct resource gp_status_reg_227e_res =
  47         DEFINE_RES_IO_NAMED(GP_STATUS_REG_227E, SZ_1, KBUILD_MODNAME);
  48
  49 static struct resource io_resource_enable =
  50         DEFINE_RES_IO_NAMED(WD_ENABLE_IOADR, SZ_1,
  51                             KBUILD_MODNAME " WD_ENABLE_IOADR");
  52
  53 static struct resource io_resource_trigger =
  54         DEFINE_RES_IO_NAMED(WD_TRIGGER_IOADR, SZ_1,
  55                             KBUILD_MODNAME " WD_TRIGGER_IOADR");
  56
  57 /* the actual start will be discovered with pci, 0 is a placeholder */
  58 static struct resource mem_resource =
  59         DEFINE_RES_MEM_NAMED(0, SZ_4, "WD_RESET_BASE_ADR");
  60
  61 static u32 wd_timeout_table[] = {2, 4, 6, 8, 16, 32, 48, 64 };
  62 static void __iomem *wd_reset_base_addr;
  63
  64 static int wd_start(struct watchdog_device *wdd)
  65 {
  66         outb(inb(WD_ENABLE_IOADR) | WD_ENABLED, WD_ENABLE_IOADR);
  67         return 0;
  68 }
  69
  70 static int wd_stop(struct watchdog_device *wdd)
  71 {
  72         outb(inb(WD_ENABLE_IOADR) & ~WD_ENABLED, WD_ENABLE_IOADR);
  73         return 0;
  74 }
  75
  76 static int wd_ping(struct watchdog_device *wdd)
  77 {
  78         inb(WD_TRIGGER_IOADR);
  79         return 0;
  80 }
  81
  82 static int wd_set_timeout(struct watchdog_device *wdd, unsigned int t)
  83 {
  84         int timeout_idx = find_closest(t, wd_timeout_table,
  85                                        ARRAY_SIZE(wd_timeout_table));
  86
  87         outb((inb(WD_ENABLE_IOADR) & 0xc7) | timeout_idx << 3, WD_ENABLE_IOADR);
  88         wdd->timeout = wd_timeout_table[timeout_idx];
  89         return 0;
  90 }
  91
  92 static const struct watchdog_info wdt_ident = {
  93         .options        = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
  94                           WDIOF_SETTIMEOUT,
  95         .identity       = KBUILD_MODNAME,
  96 };
  97
  98 static const struct watchdog_ops wdt_ops = {
  99         .owner          = THIS_MODULE,
 100         .start          = wd_start,
 101         .stop           = wd_stop,
 102         .ping           = wd_ping,
 103         .set_timeout    = wd_set_timeout,
 104 };
 105
 106 static void wd_secondary_enable(u32 wdtmode)
 107 {
 108         u16 resetbit;
 109
 110         /* set safe_en_n so we are not just WDIOF_ALARMONLY */
 111         if (wdtmode == SIMATIC_IPC_DEVICE_227E) {
 112                 /* enable SAFE_EN_N on GP_STATUS_REG_227E */
 113                 resetbit = inb(GP_STATUS_REG_227E);
 114                 outb(resetbit & ~SAFE_EN_N_227E, GP_STATUS_REG_227E);
 115         } else {
 116                 /* enable SAFE_EN_N on PCH D1600 */
 117                 resetbit = ioread16(wd_reset_base_addr);
 118                 iowrite16(resetbit & ~SAFE_EN_N_427E, wd_reset_base_addr);
 119         }
 120 }
 121
 122 static int wd_setup(u32 wdtmode)
 123 {
 124         unsigned int bootstatus = 0;
 125         int timeout_idx;
 126
 127         timeout_idx = find_closest(TIMEOUT_DEF, wd_timeout_table,
 128                                    ARRAY_SIZE(wd_timeout_table));
 129
 130         if (inb(WD_ENABLE_IOADR) & WD_TRIGGERED)
 131                 bootstatus |= WDIOF_CARDRESET;
 132
 133         /* reset alarm bit, set macro mode, and set timeout */
 134         outb(WD_TRIGGERED | WD_MACROMODE | timeout_idx << 3, WD_ENABLE_IOADR);
 135
 136         wd_secondary_enable(wdtmode);
 137
 138         return bootstatus;
 139 }
 140
 141 static struct watchdog_device wdd_data = {
 142         .info = &wdt_ident,
 143         .ops = &wdt_ops,
 144         .min_timeout = TIMEOUT_MIN,
 145         .max_timeout = TIMEOUT_MAX
 146 };
 147
 148 static int simatic_ipc_wdt_probe(struct platform_device *pdev)
 149 {
 150         struct simatic_ipc_platform *plat = pdev->dev.platform_data;
 151         struct device *dev = &pdev->dev;
 152         struct resource *res;
 153
 154         switch (plat->devmode) {
 155         case SIMATIC_IPC_DEVICE_227E:
 156                 if (!devm_request_region(dev, gp_status_reg_227e_res.start,
 157                                          resource_size(&gp_status_reg_227e_res),
 158                                          KBUILD_MODNAME)) {
 159                         dev_err(dev,
 160                                 "Unable to register IO resource at %pR\n",
 161                                 &gp_status_reg_227e_res);
 162                         return -EBUSY;
 163                 }
 164                 fallthrough;
 165         case SIMATIC_IPC_DEVICE_427E:
 166                 wdd_data.parent = dev;
 167                 break;
 168         default:
 169                 return -EINVAL;
 170         }
 171
 172         if (!devm_request_region(dev, io_resource_enable.start,
 173                                  resource_size(&io_resource_enable),
 174                                  io_resource_enable.name)) {
 175                 dev_err(dev,
 176                         "Unable to register IO resource at %#x\n",
 177                         WD_ENABLE_IOADR);
 178                 return -EBUSY;
 179         }
 180
 181         if (!devm_request_region(dev, io_resource_trigger.start,
 182                                  resource_size(&io_resource_trigger),
 183                                  io_resource_trigger.name)) {
 184                 dev_err(dev,
 185                         "Unable to register IO resource at %#x\n",
 186                         WD_TRIGGER_IOADR);
 187                 return -EBUSY;
 188         }
 189
 190         if (plat->devmode == SIMATIC_IPC_DEVICE_427E) {
 191                 res = &mem_resource;
 192
 193                 /* get GPIO base from PCI */
 194                 res->start = simatic_ipc_get_membase0(PCI_DEVFN(0x1f, 1));
 195                 if (res->start == 0)
 196                         return -ENODEV;
 197
 198                 /* do the final address calculation */
 199                 res->start = res->start + (GPIO_COMMUNITY0_PORT_ID << 16) +
 200                              PAD_CFG_DW0_GPP_A_23;
 201                 res->end += res->start;
 202
 203                 wd_reset_base_addr = devm_ioremap_resource(dev, res);
 204                 if (IS_ERR(wd_reset_base_addr))
 205                         return PTR_ERR(wd_reset_base_addr);
 206         }
 207
 208         wdd_data.bootstatus = wd_setup(plat->devmode);
 209         if (wdd_data.bootstatus)
 210                 dev_warn(dev, "last reboot caused by watchdog reset\n");
 211
 212         watchdog_set_nowayout(&wdd_data, nowayout);
 213         watchdog_stop_on_reboot(&wdd_data);
 214         return devm_watchdog_register_device(dev, &wdd_data);
 215 }
 216
 217 static struct platform_driver simatic_ipc_wdt_driver = {
 218         .probe = simatic_ipc_wdt_probe,
 219         .driver = {
 220                 .name = KBUILD_MODNAME,
 221         },
 222 };
 223
 224 module_platform_driver(simatic_ipc_wdt_driver);
 225
 226 MODULE_LICENSE("GPL v2");
 227 MODULE_ALIAS("platform:" KBUILD_MODNAME);
 228 MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");