--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Siemens SIMATIC IPC driver for Watchdogs
+ *
+ * Copyright (c) Siemens AG, 2020-2021
+ *
+ * Authors:
+ * Gerd Haeussler <gerd.haeussler.ext@siemens.com>
+ */
+
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/ioport.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_data/x86/simatic-ipc-base.h>
+#include <linux/platform_device.h>
+#include <linux/sizes.h>
+#include <linux/util_macros.h>
+#include <linux/watchdog.h>
+
+#define WD_ENABLE_IOADR 0x62
+#define WD_TRIGGER_IOADR 0x66
+#define GPIO_COMMUNITY0_PORT_ID 0xaf
+#define PAD_CFG_DW0_GPP_A_23 0x4b8
+#define SAFE_EN_N_427E 0x01
+#define SAFE_EN_N_227E 0x04
+#define WD_ENABLED 0x01
+#define WD_TRIGGERED 0x80
+#define WD_MACROMODE 0x02
+
+#define TIMEOUT_MIN 2
+#define TIMEOUT_DEF 64
+#define TIMEOUT_MAX 64
+
+#define GP_STATUS_REG_227E 0x404D /* IO PORT for SAFE_EN_N on 227E */
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0000);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static struct resource gp_status_reg_227e_res =
+ DEFINE_RES_IO_NAMED(GP_STATUS_REG_227E, SZ_1, KBUILD_MODNAME);
+
+static struct resource io_resource_enable =
+ DEFINE_RES_IO_NAMED(WD_ENABLE_IOADR, SZ_1,
+ KBUILD_MODNAME " WD_ENABLE_IOADR");
+
+static struct resource io_resource_trigger =
+ DEFINE_RES_IO_NAMED(WD_TRIGGER_IOADR, SZ_1,
+ KBUILD_MODNAME " WD_TRIGGER_IOADR");
+
+/* the actual start will be discovered with pci, 0 is a placeholder */
+static struct resource mem_resource =
+ DEFINE_RES_MEM_NAMED(0, SZ_4, "WD_RESET_BASE_ADR");
+
+static u32 wd_timeout_table[] = {2, 4, 6, 8, 16, 32, 48, 64 };
+static void __iomem *wd_reset_base_addr;
+
+static int wd_start(struct watchdog_device *wdd)
+{
+ outb(inb(WD_ENABLE_IOADR) | WD_ENABLED, WD_ENABLE_IOADR);
+ return 0;
+}
+
+static int wd_stop(struct watchdog_device *wdd)
+{
+ outb(inb(WD_ENABLE_IOADR) & ~WD_ENABLED, WD_ENABLE_IOADR);
+ return 0;
+}
+
+static int wd_ping(struct watchdog_device *wdd)
+{
+ inb(WD_TRIGGER_IOADR);
+ return 0;
+}
+
+static int wd_set_timeout(struct watchdog_device *wdd, unsigned int t)
+{
+ int timeout_idx = find_closest(t, wd_timeout_table,
+ ARRAY_SIZE(wd_timeout_table));
+
+ outb((inb(WD_ENABLE_IOADR) & 0xc7) | timeout_idx << 3, WD_ENABLE_IOADR);
+ wdd->timeout = wd_timeout_table[timeout_idx];
+ return 0;
+}
+
+static const struct watchdog_info wdt_ident = {
+ .options = WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
+ WDIOF_SETTIMEOUT,
+ .identity = KBUILD_MODNAME,
+};
+
+static const struct watchdog_ops wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = wd_start,
+ .stop = wd_stop,
+ .ping = wd_ping,
+ .set_timeout = wd_set_timeout,
+};
+
+static void wd_secondary_enable(u32 wdtmode)
+{
+ u16 resetbit;
+
+ /* set safe_en_n so we are not just WDIOF_ALARMONLY */
+ if (wdtmode == SIMATIC_IPC_DEVICE_227E) {
+ /* enable SAFE_EN_N on GP_STATUS_REG_227E */
+ resetbit = inb(GP_STATUS_REG_227E);
+ outb(resetbit & ~SAFE_EN_N_227E, GP_STATUS_REG_227E);
+ } else {
+ /* enable SAFE_EN_N on PCH D1600 */
+ resetbit = ioread16(wd_reset_base_addr);
+ iowrite16(resetbit & ~SAFE_EN_N_427E, wd_reset_base_addr);
+ }
+}
+
+static int wd_setup(u32 wdtmode)
+{
+ unsigned int bootstatus = 0;
+ int timeout_idx;
+
+ timeout_idx = find_closest(TIMEOUT_DEF, wd_timeout_table,
+ ARRAY_SIZE(wd_timeout_table));
+
+ if (inb(WD_ENABLE_IOADR) & WD_TRIGGERED)
+ bootstatus |= WDIOF_CARDRESET;
+
+ /* reset alarm bit, set macro mode, and set timeout */
+ outb(WD_TRIGGERED | WD_MACROMODE | timeout_idx << 3, WD_ENABLE_IOADR);
+
+ wd_secondary_enable(wdtmode);
+
+ return bootstatus;
+}
+
+static struct watchdog_device wdd_data = {
+ .info = &wdt_ident,
+ .ops = &wdt_ops,
+ .min_timeout = TIMEOUT_MIN,
+ .max_timeout = TIMEOUT_MAX
+};
+
+static int simatic_ipc_wdt_probe(struct platform_device *pdev)
+{
+ struct simatic_ipc_platform *plat = pdev->dev.platform_data;
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+
+ switch (plat->devmode) {
+ case SIMATIC_IPC_DEVICE_227E:
+ if (!devm_request_region(dev, gp_status_reg_227e_res.start,
+ resource_size(&gp_status_reg_227e_res),
+ KBUILD_MODNAME)) {
+ dev_err(dev,
+ "Unable to register IO resource at %pR\n",
+ &gp_status_reg_227e_res);
+ return -EBUSY;
+ }
+ fallthrough;
+ case SIMATIC_IPC_DEVICE_427E:
+ wdd_data.parent = dev;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ if (!devm_request_region(dev, io_resource_enable.start,
+ resource_size(&io_resource_enable),
+ io_resource_enable.name)) {
+ dev_err(dev,
+ "Unable to register IO resource at %#x\n",
+ WD_ENABLE_IOADR);
+ return -EBUSY;
+ }
+
+ if (!devm_request_region(dev, io_resource_trigger.start,
+ resource_size(&io_resource_trigger),
+ io_resource_trigger.name)) {
+ dev_err(dev,
+ "Unable to register IO resource at %#x\n",
+ WD_TRIGGER_IOADR);
+ return -EBUSY;
+ }
+
+ if (plat->devmode == SIMATIC_IPC_DEVICE_427E) {
+ res = &mem_resource;
+
+ /* get GPIO base from PCI */
+ res->start = simatic_ipc_get_membase0(PCI_DEVFN(0x1f, 1));
+ if (res->start == 0)
+ return -ENODEV;
+
+ /* do the final address calculation */
+ res->start = res->start + (GPIO_COMMUNITY0_PORT_ID << 16) +
+ PAD_CFG_DW0_GPP_A_23;
+ res->end += res->start;
+
+ wd_reset_base_addr = devm_ioremap_resource(dev, res);
+ if (IS_ERR(wd_reset_base_addr))
+ return PTR_ERR(wd_reset_base_addr);
+ }
+
+ wdd_data.bootstatus = wd_setup(plat->devmode);
+ if (wdd_data.bootstatus)
+ dev_warn(dev, "last reboot caused by watchdog reset\n");
+
+ watchdog_set_nowayout(&wdd_data, nowayout);
+ watchdog_stop_on_reboot(&wdd_data);
+ return devm_watchdog_register_device(dev, &wdd_data);
+}
+
+static struct platform_driver simatic_ipc_wdt_driver = {
+ .probe = simatic_ipc_wdt_probe,
+ .driver = {
+ .name = KBUILD_MODNAME,
+ },
+};
+
+module_platform_driver(simatic_ipc_wdt_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:" KBUILD_MODNAME);
+MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");
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