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
 42static bool nowayout = WATCHDOG_NOWAYOUT;
 43module_param(nowayout, bool, 0000);
 44MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 45		 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 46
 47static struct resource gp_status_reg_227e_res =
 48	DEFINE_RES_IO_NAMED(GP_STATUS_REG_227E, SZ_1, KBUILD_MODNAME);
 49
 50static struct resource io_resource_enable =
 51	DEFINE_RES_IO_NAMED(WD_ENABLE_IOADR, SZ_1,
 52			    KBUILD_MODNAME " WD_ENABLE_IOADR");
 53
 54static 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 */
 59static struct resource mem_resource =
 60	DEFINE_RES_MEM_NAMED(0, 0, "WD_RESET_BASE_ADR");
 61
 62static u32 wd_timeout_table[] = {2, 4, 6, 8, 16, 32, 48, 64 };
 63static void __iomem *wd_reset_base_addr;
 64
 65static int wd_start(struct watchdog_device *wdd)
 66{
 67	outb(inb(WD_ENABLE_IOADR) | WD_ENABLED, WD_ENABLE_IOADR);
 68	return 0;
 69}
 70
 71static int wd_stop(struct watchdog_device *wdd)
 72{
 73	outb(inb(WD_ENABLE_IOADR) & ~WD_ENABLED, WD_ENABLE_IOADR);
 74	return 0;
 75}
 76
 77static int wd_ping(struct watchdog_device *wdd)
 78{
 79	inb(WD_TRIGGER_IOADR);
 80	return 0;
 81}
 82
 83static 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
 93static const struct watchdog_info wdt_ident = {
 94	.options	= WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING |
 95			  WDIOF_SETTIMEOUT,
 96	.identity	= KBUILD_MODNAME,
 97};
 98
 99static 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
107static 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
123static 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
142static 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
149static 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		res = &gp_status_reg_227e_res;
159		if (!request_muxed_region(res->start, resource_size(res), res->name)) {
160			dev_err(dev,
161				"Unable to register IO resource at %pR\n",
162				&gp_status_reg_227e_res);
163			return -EBUSY;
164		}
165		fallthrough;
166	case SIMATIC_IPC_DEVICE_427E:
167		wdd_data.parent = dev;
168		break;
169	default:
170		return -EINVAL;
171	}
172
173	if (!devm_request_region(dev, io_resource_enable.start,
174				 resource_size(&io_resource_enable),
175				 io_resource_enable.name)) {
176		dev_err(dev,
177			"Unable to register IO resource at %#x\n",
178			WD_ENABLE_IOADR);
179		return -EBUSY;
180	}
181
182	if (!devm_request_region(dev, io_resource_trigger.start,
183				 resource_size(&io_resource_trigger),
184				 io_resource_trigger.name)) {
185		dev_err(dev,
186			"Unable to register IO resource at %#x\n",
187			WD_TRIGGER_IOADR);
188		return -EBUSY;
189	}
190
191	if (plat->devmode == SIMATIC_IPC_DEVICE_427E) {
192		res = &mem_resource;
193
194		ret = p2sb_bar(NULL, 0, res);
195		if (ret)
196			return ret;
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 + SZ_4 - 1;
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	if (plat->devmode == SIMATIC_IPC_DEVICE_227E)
213		release_region(gp_status_reg_227e_res.start,
214			       resource_size(&gp_status_reg_227e_res));
215
216	watchdog_set_nowayout(&wdd_data, nowayout);
217	watchdog_stop_on_reboot(&wdd_data);
218	return devm_watchdog_register_device(dev, &wdd_data);
219}
220
221static struct platform_driver simatic_ipc_wdt_driver = {
222	.probe = simatic_ipc_wdt_probe,
223	.driver = {
224		.name = KBUILD_MODNAME,
225	},
226};
227
228module_platform_driver(simatic_ipc_wdt_driver);
229
230MODULE_LICENSE("GPL v2");
231MODULE_ALIAS("platform:" KBUILD_MODNAME);
232MODULE_AUTHOR("Gerd Haeussler <gerd.haeussler.ext@siemens.com>");