[mirror_ubuntu-bionic-kernel.git] / drivers / watchdog / aspeed_wdt.c

/*
 * Copyright 2016 IBM Corporation
 *
 * Joel Stanley <joel@jms.id.au>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version
 * 2 of the License, or (at your option) any later version.
 */

#include <linux/delay.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/watchdog.h>

struct aspeed_wdt {
	struct watchdog_device	wdd;
	void __iomem		*base;
	u32			ctrl;
};

struct aspeed_wdt_config {
	u32 ext_pulse_width_mask;
};

static const struct aspeed_wdt_config ast2400_config = {
	.ext_pulse_width_mask = 0xff,
};

static const struct aspeed_wdt_config ast2500_config = {
	.ext_pulse_width_mask = 0xfffff,
};

static const struct of_device_id aspeed_wdt_of_table[] = {
	{ .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config },
	{ .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config },
	{ },
};
MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);

#define WDT_STATUS		0x00
#define WDT_RELOAD_VALUE	0x04
#define WDT_RESTART		0x08
#define WDT_CTRL		0x0C
#define   WDT_CTRL_BOOT_SECONDARY	BIT(7)
#define   WDT_CTRL_RESET_MODE_SOC	(0x00 << 5)
#define   WDT_CTRL_RESET_MODE_FULL_CHIP	(0x01 << 5)
#define   WDT_CTRL_RESET_MODE_ARM_CPU	(0x10 << 5)
#define   WDT_CTRL_1MHZ_CLK		BIT(4)
#define   WDT_CTRL_WDT_EXT		BIT(3)
#define   WDT_CTRL_WDT_INTR		BIT(2)
#define   WDT_CTRL_RESET_SYSTEM		BIT(1)
#define   WDT_CTRL_ENABLE		BIT(0)

/*
 * WDT_RESET_WIDTH controls the characteristics of the external pulse (if
 * enabled), specifically:
 *
 * * Pulse duration
 * * Drive mode: push-pull vs open-drain
 * * Polarity: Active high or active low
 *
 * Pulse duration configuration is available on both the AST2400 and AST2500,
 * though the field changes between SoCs:
 *
 * AST2400: Bits 7:0
 * AST2500: Bits 19:0
 *
 * This difference is captured in struct aspeed_wdt_config.
 *
 * The AST2500 exposes the drive mode and polarity options, but not in a
 * regular fashion. For read purposes, bit 31 represents active high or low,
 * and bit 30 represents push-pull or open-drain. With respect to write, magic
 * values need to be written to the top byte to change the state of the drive
 * mode and polarity bits. Any other value written to the top byte has no
 * effect on the state of the drive mode or polarity bits. However, the pulse
 * width value must be preserved (as desired) if written.
 */
#define WDT_RESET_WIDTH		0x18
#define   WDT_RESET_WIDTH_ACTIVE_HIGH	BIT(31)
#define     WDT_ACTIVE_HIGH_MAGIC	(0xA5 << 24)
#define     WDT_ACTIVE_LOW_MAGIC	(0x5A << 24)
#define   WDT_RESET_WIDTH_PUSH_PULL	BIT(30)
#define     WDT_PUSH_PULL_MAGIC		(0xA8 << 24)
#define     WDT_OPEN_DRAIN_MAGIC	(0x8A << 24)

#define WDT_RESTART_MAGIC	0x4755

/* 32 bits at 1MHz, in milliseconds */
#define WDT_MAX_TIMEOUT_MS	4294967
#define WDT_DEFAULT_TIMEOUT	30
#define WDT_RATE_1MHZ		1000000

static struct aspeed_wdt *to_aspeed_wdt(struct watchdog_device *wdd)
{
	return container_of(wdd, struct aspeed_wdt, wdd);
}

static void aspeed_wdt_enable(struct aspeed_wdt *wdt, int count)
{
	wdt->ctrl |= WDT_CTRL_ENABLE;

	writel(0, wdt->base + WDT_CTRL);
	writel(count, wdt->base + WDT_RELOAD_VALUE);
	writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
	writel(wdt->ctrl, wdt->base + WDT_CTRL);
}

static int aspeed_wdt_start(struct watchdog_device *wdd)
{
	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);

	aspeed_wdt_enable(wdt, wdd->timeout * WDT_RATE_1MHZ);

	return 0;
}

static int aspeed_wdt_stop(struct watchdog_device *wdd)
{
	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);

	wdt->ctrl &= ~WDT_CTRL_ENABLE;
	writel(wdt->ctrl, wdt->base + WDT_CTRL);

	return 0;
}

static int aspeed_wdt_ping(struct watchdog_device *wdd)
{
	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);

	writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);

	return 0;
}

static int aspeed_wdt_set_timeout(struct watchdog_device *wdd,
				  unsigned int timeout)
{
	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
	u32 actual;

	wdd->timeout = timeout;

	actual = min(timeout, wdd->max_hw_heartbeat_ms * 1000);

	writel(actual * WDT_RATE_1MHZ, wdt->base + WDT_RELOAD_VALUE);
	writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);

	return 0;
}

static int aspeed_wdt_restart(struct watchdog_device *wdd,
			      unsigned long action, void *data)
{
	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);

	wdt->ctrl &= ~WDT_CTRL_BOOT_SECONDARY;
	aspeed_wdt_enable(wdt, 128 * WDT_RATE_1MHZ / 1000);

	mdelay(1000);

	return 0;
}

static const struct watchdog_ops aspeed_wdt_ops = {
	.start		= aspeed_wdt_start,
	.stop		= aspeed_wdt_stop,
	.ping		= aspeed_wdt_ping,
	.set_timeout	= aspeed_wdt_set_timeout,
	.restart	= aspeed_wdt_restart,
	.owner		= THIS_MODULE,
};

static const struct watchdog_info aspeed_wdt_info = {
	.options	= WDIOF_KEEPALIVEPING
			| WDIOF_MAGICCLOSE
			| WDIOF_SETTIMEOUT,
	.identity	= KBUILD_MODNAME,
};

static int aspeed_wdt_probe(struct platform_device *pdev)
{
	const struct aspeed_wdt_config *config;
	const struct of_device_id *ofdid;
	struct aspeed_wdt *wdt;
	struct resource *res;
	struct device_node *np;
	const char *reset_type;
	u32 duration;
	int ret;

	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
	if (!wdt)
		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	wdt->base = devm_ioremap_resource(&pdev->dev, res);
	if (IS_ERR(wdt->base))
		return PTR_ERR(wdt->base);

	/*
	 * The ast2400 wdt can run at PCLK, or 1MHz. The ast2500 only
	 * runs at 1MHz. We chose to always run at 1MHz, as there's no
	 * good reason to have a faster watchdog counter.
	 */
	wdt->wdd.info = &aspeed_wdt_info;
	wdt->wdd.ops = &aspeed_wdt_ops;
	wdt->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;
	wdt->wdd.parent = &pdev->dev;

	wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
	watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);

	np = pdev->dev.of_node;

	ofdid = of_match_node(aspeed_wdt_of_table, np);
	if (!ofdid)
		return -EINVAL;
	config = ofdid->data;

	wdt->ctrl = WDT_CTRL_1MHZ_CLK;

	/*
	 * Control reset on a per-device basis to ensure the
	 * host is not affected by a BMC reboot
	 */
	ret = of_property_read_string(np, "aspeed,reset-type", &reset_type);
	if (ret) {
		wdt->ctrl |= WDT_CTRL_RESET_MODE_SOC | WDT_CTRL_RESET_SYSTEM;
	} else {
		if (!strcmp(reset_type, "cpu"))
			wdt->ctrl |= WDT_CTRL_RESET_MODE_ARM_CPU |
				     WDT_CTRL_RESET_SYSTEM;
		else if (!strcmp(reset_type, "soc"))
			wdt->ctrl |= WDT_CTRL_RESET_MODE_SOC |
				     WDT_CTRL_RESET_SYSTEM;
		else if (!strcmp(reset_type, "system"))
			wdt->ctrl |= WDT_CTRL_RESET_MODE_FULL_CHIP |
				     WDT_CTRL_RESET_SYSTEM;
		else if (strcmp(reset_type, "none"))
			return -EINVAL;
	}
	if (of_property_read_bool(np, "aspeed,external-signal"))
		wdt->ctrl |= WDT_CTRL_WDT_EXT;
	if (of_property_read_bool(np, "aspeed,alt-boot"))
		wdt->ctrl |= WDT_CTRL_BOOT_SECONDARY;

	writel(wdt->ctrl, wdt->base + WDT_CTRL);

	if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
		aspeed_wdt_start(&wdt->wdd);
		set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
	}

	if (of_device_is_compatible(np, "aspeed,ast2500-wdt")) {
		u32 reg = readl(wdt->base + WDT_RESET_WIDTH);

		reg &= config->ext_pulse_width_mask;
		if (of_property_read_bool(np, "aspeed,ext-push-pull"))
			reg |= WDT_PUSH_PULL_MAGIC;
		else
			reg |= WDT_OPEN_DRAIN_MAGIC;

		writel(reg, wdt->base + WDT_RESET_WIDTH);

		reg &= config->ext_pulse_width_mask;
		if (of_property_read_bool(np, "aspeed,ext-active-high"))
			reg |= WDT_ACTIVE_HIGH_MAGIC;
		else
			reg |= WDT_ACTIVE_LOW_MAGIC;

		writel(reg, wdt->base + WDT_RESET_WIDTH);
	}

	if (!of_property_read_u32(np, "aspeed,ext-pulse-duration", &duration)) {
		u32 max_duration = config->ext_pulse_width_mask + 1;

		if (duration == 0 || duration > max_duration) {
			dev_err(&pdev->dev, "Invalid pulse duration: %uus\n",
					duration);
			duration = max(1U, min(max_duration, duration));
			dev_info(&pdev->dev, "Pulse duration set to %uus\n",
					duration);
		}

		/*
		 * The watchdog is always configured with a 1MHz source, so
		 * there is no need to scale the microsecond value. However we
		 * need to offset it - from the datasheet:
		 *
		 * "This register decides the asserting duration of wdt_ext and
		 * wdt_rstarm signal. The default value is 0xFF. It means the
		 * default asserting duration of wdt_ext and wdt_rstarm is
		 * 256us."
		 *
		 * This implies a value of 0 gives a 1us pulse.
		 */
		writel(duration - 1, wdt->base + WDT_RESET_WIDTH);
	}

	ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdd);
	if (ret) {
		dev_err(&pdev->dev, "failed to register\n");
		return ret;
	}

	return 0;
}

static struct platform_driver aspeed_watchdog_driver = {
	.probe = aspeed_wdt_probe,
	.driver = {
		.name = KBUILD_MODNAME,
		.of_match_table = of_match_ptr(aspeed_wdt_of_table),
	},
};
module_platform_driver(aspeed_watchdog_driver);

MODULE_DESCRIPTION("Aspeed Watchdog Driver");
MODULE_LICENSE("GPL");
Commit	Line	Data
efa859f7 JS	1	/*
	2	* Copyright 2016 IBM Corporation
	3	*
	4	* Joel Stanley <joel@jms.id.au>
	5	*
	6	* This program is free software; you can redistribute it and/or
	7	* modify it under the terms of the GNU General Public License
	8	* as published by the Free Software Foundation; either version
	9	* 2 of the License, or (at your option) any later version.
	10	*/
	11
	12	#include <linux/delay.h>
	13	#include <linux/io.h>
	14	#include <linux/kernel.h>
	15	#include <linux/module.h>
	16	#include <linux/of.h>
	17	#include <linux/platform_device.h>
	18	#include <linux/watchdog.h>
	19
	20	struct aspeed_wdt {
	21	struct watchdog_device wdd;
	22	void __iomem *base;
	23	u32 ctrl;
	24	};
	25
012c0460 AJ	26	struct aspeed_wdt_config {
	27	u32 ext_pulse_width_mask;
	28	};
	29
	30	static const struct aspeed_wdt_config ast2400_config = {
	31	.ext_pulse_width_mask = 0xff,
	32	};
	33
	34	static const struct aspeed_wdt_config ast2500_config = {
	35	.ext_pulse_width_mask = 0xfffff,
	36	};
	37
efa859f7	38	static const struct of_device_id aspeed_wdt_of_table[] = {
012c0460 AJ	39	{ .compatible = "aspeed,ast2400-wdt", .data = &ast2400_config },
012c0460 AJ	40	{ .compatible = "aspeed,ast2500-wdt", .data = &ast2500_config },
efa859f7 JS	41	{ },
	42	};
	43	MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
	44
	45	#define WDT_STATUS 0x00
	46	#define WDT_RELOAD_VALUE 0x04
	47	#define WDT_RESTART 0x08
	48	#define WDT_CTRL 0x0C
7b2c229a	49	#define WDT_CTRL_BOOT_SECONDARY BIT(7)
efa859f7 JS	50	#define WDT_CTRL_RESET_MODE_SOC (0x00 << 5)
efa859f7 JS	51	#define WDT_CTRL_RESET_MODE_FULL_CHIP (0x01 << 5)
b7f0b8ad	52	#define WDT_CTRL_RESET_MODE_ARM_CPU (0x10 << 5)
efa859f7 JS	53	#define WDT_CTRL_1MHZ_CLK BIT(4)
	54	#define WDT_CTRL_WDT_EXT BIT(3)
	55	#define WDT_CTRL_WDT_INTR BIT(2)
	56	#define WDT_CTRL_RESET_SYSTEM BIT(1)
	57	#define WDT_CTRL_ENABLE BIT(0)
	58
012c0460 AJ	59	/*
	60	* WDT_RESET_WIDTH controls the characteristics of the external pulse (if
	61	* enabled), specifically:
	62	*
	63	* * Pulse duration
	64	* * Drive mode: push-pull vs open-drain
	65	* * Polarity: Active high or active low
	66	*
	67	* Pulse duration configuration is available on both the AST2400 and AST2500,
	68	* though the field changes between SoCs:
	69	*
	70	* AST2400: Bits 7:0
	71	* AST2500: Bits 19:0
	72	*
	73	* This difference is captured in struct aspeed_wdt_config.
	74	*
	75	* The AST2500 exposes the drive mode and polarity options, but not in a
	76	* regular fashion. For read purposes, bit 31 represents active high or low,
	77	* and bit 30 represents push-pull or open-drain. With respect to write, magic
	78	* values need to be written to the top byte to change the state of the drive
	79	* mode and polarity bits. Any other value written to the top byte has no
	80	* effect on the state of the drive mode or polarity bits. However, the pulse
	81	* width value must be preserved (as desired) if written.
	82	*/
	83	#define WDT_RESET_WIDTH 0x18
	84	#define WDT_RESET_WIDTH_ACTIVE_HIGH BIT(31)
	85	#define WDT_ACTIVE_HIGH_MAGIC (0xA5 << 24)
	86	#define WDT_ACTIVE_LOW_MAGIC (0x5A << 24)
	87	#define WDT_RESET_WIDTH_PUSH_PULL BIT(30)
	88	#define WDT_PUSH_PULL_MAGIC (0xA8 << 24)
	89	#define WDT_OPEN_DRAIN_MAGIC (0x8A << 24)
	90
efa859f7 JS	91	#define WDT_RESTART_MAGIC 0x4755
	92
	93	/* 32 bits at 1MHz, in milliseconds */
	94	#define WDT_MAX_TIMEOUT_MS 4294967
	95	#define WDT_DEFAULT_TIMEOUT 30
	96	#define WDT_RATE_1MHZ 1000000
	97
	98	static struct aspeed_wdt to_aspeed_wdt(struct watchdog_device wdd)
	99	{
	100	return container_of(wdd, struct aspeed_wdt, wdd);
	101	}
	102
	103	static void aspeed_wdt_enable(struct aspeed_wdt *wdt, int count)
	104	{
	105	wdt->ctrl \|= WDT_CTRL_ENABLE;
	106
	107	writel(0, wdt->base + WDT_CTRL);
	108	writel(count, wdt->base + WDT_RELOAD_VALUE);
	109	writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
	110	writel(wdt->ctrl, wdt->base + WDT_CTRL);
	111	}
	112
	113	static int aspeed_wdt_start(struct watchdog_device *wdd)
	114	{
	115	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
	116
	117	aspeed_wdt_enable(wdt, wdd->timeout * WDT_RATE_1MHZ);
	118
	119	return 0;
	120	}
	121
	122	static int aspeed_wdt_stop(struct watchdog_device *wdd)
	123	{
	124	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
	125
	126	wdt->ctrl &= ~WDT_CTRL_ENABLE;
	127	writel(wdt->ctrl, wdt->base + WDT_CTRL);
	128
	129	return 0;
	130	}
	131
	132	static int aspeed_wdt_ping(struct watchdog_device *wdd)
	133	{
	134	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
	135
	136	writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
	137
	138	return 0;
	139	}
	140
	141	static int aspeed_wdt_set_timeout(struct watchdog_device *wdd,
	142	unsigned int timeout)
	143	{
	144	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
	145	u32 actual;
	146
	147	wdd->timeout = timeout;
	148
	149	actual = min(timeout, wdd->max_hw_heartbeat_ms * 1000);
	150
	151	writel(actual * WDT_RATE_1MHZ, wdt->base + WDT_RELOAD_VALUE);
	152	writel(WDT_RESTART_MAGIC, wdt->base + WDT_RESTART);
	153
	154	return 0;
155	}
156
157	static int aspeed_wdt_restart(struct watchdog_device *wdd,
158	unsigned long action, void *data)
159	{
160	struct aspeed_wdt *wdt = to_aspeed_wdt(wdd);
161
7b2c229a	162	wdt->ctrl &= ~WDT_CTRL_BOOT_SECONDARY;
efa859f7 JS	163	aspeed_wdt_enable(wdt, 128 * WDT_RATE_1MHZ / 1000);
	164
	165	mdelay(1000);
	166
	167	return 0;
	168	}
	169
	170	static const struct watchdog_ops aspeed_wdt_ops = {
	171	.start = aspeed_wdt_start,
	172	.stop = aspeed_wdt_stop,
	173	.ping = aspeed_wdt_ping,
	174	.set_timeout = aspeed_wdt_set_timeout,
	175	.restart = aspeed_wdt_restart,
	176	.owner = THIS_MODULE,
	177	};
	178
	179	static const struct watchdog_info aspeed_wdt_info = {
	180	.options = WDIOF_KEEPALIVEPING
	181	\| WDIOF_MAGICCLOSE
	182	\| WDIOF_SETTIMEOUT,
	183	.identity = KBUILD_MODNAME,
	184	};
	185
efa859f7 JS	186	static int aspeed_wdt_probe(struct platform_device *pdev)
efa859f7 JS	187	{
012c0460 AJ	188	const struct aspeed_wdt_config *config;
012c0460 AJ	189	const struct of_device_id *ofdid;
efa859f7 JS	190	struct aspeed_wdt *wdt;
efa859f7 JS	191	struct resource *res;
b7f0b8ad CB	192	struct device_node *np;
b7f0b8ad CB	193	const char *reset_type;
012c0460	194	u32 duration;
efa859f7 JS	195	int ret;
	196
	197	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
	198	if (!wdt)
	199	return -ENOMEM;
	200
	201	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	202	wdt->base = devm_ioremap_resource(&pdev->dev, res);
	203	if (IS_ERR(wdt->base))
	204	return PTR_ERR(wdt->base);
	205
	206	/*
	207	* The ast2400 wdt can run at PCLK, or 1MHz. The ast2500 only
	208	* runs at 1MHz. We chose to always run at 1MHz, as there's no
	209	* good reason to have a faster watchdog counter.
	210	*/
	211	wdt->wdd.info = &aspeed_wdt_info;
	212	wdt->wdd.ops = &aspeed_wdt_ops;
	213	wdt->wdd.max_hw_heartbeat_ms = WDT_MAX_TIMEOUT_MS;
	214	wdt->wdd.parent = &pdev->dev;
	215
	216	wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
	217	watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
	218
012c0460 AJ	219	np = pdev->dev.of_node;
	220
	221	ofdid = of_match_node(aspeed_wdt_of_table, np);
	222	if (!ofdid)
	223	return -EINVAL;
	224	config = ofdid->data;
	225
b7f0b8ad CB	226	wdt->ctrl = WDT_CTRL_1MHZ_CLK;
b7f0b8ad CB	227
efa859f7 JS	228	/*
efa859f7 JS	229	* Control reset on a per-device basis to ensure the
b7f0b8ad	230	* host is not affected by a BMC reboot
efa859f7	231	*/
b7f0b8ad CB	232	ret = of_property_read_string(np, "aspeed,reset-type", &reset_type);
	233	if (ret) {
	234	wdt->ctrl \|= WDT_CTRL_RESET_MODE_SOC \| WDT_CTRL_RESET_SYSTEM;
	235	} else {
	236	if (!strcmp(reset_type, "cpu"))
afd2a5d9 MM	237	wdt->ctrl \|= WDT_CTRL_RESET_MODE_ARM_CPU \|
afd2a5d9 MM	238	WDT_CTRL_RESET_SYSTEM;
b7f0b8ad	239	else if (!strcmp(reset_type, "soc"))
afd2a5d9 MM	240	wdt->ctrl \|= WDT_CTRL_RESET_MODE_SOC \|
afd2a5d9 MM	241	WDT_CTRL_RESET_SYSTEM;
b7f0b8ad	242	else if (!strcmp(reset_type, "system"))
afd2a5d9 MM	243	wdt->ctrl \|= WDT_CTRL_RESET_MODE_FULL_CHIP \|
afd2a5d9 MM	244	WDT_CTRL_RESET_SYSTEM;
b7f0b8ad CB	245	else if (strcmp(reset_type, "none"))
	246	return -EINVAL;
	247	}
	248	if (of_property_read_bool(np, "aspeed,external-signal"))
	249	wdt->ctrl \|= WDT_CTRL_WDT_EXT;
7b2c229a MM	250	if (of_property_read_bool(np, "aspeed,alt-boot"))
7b2c229a MM	251	wdt->ctrl \|= WDT_CTRL_BOOT_SECONDARY;
b7f0b8ad CB	252
b7f0b8ad CB	253	writel(wdt->ctrl, wdt->base + WDT_CTRL);
efa859f7 JS	254
	255	if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE) {
	256	aspeed_wdt_start(&wdt->wdd);
	257	set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
	258	}
	259
012c0460 AJ	260	if (of_device_is_compatible(np, "aspeed,ast2500-wdt")) {
	261	u32 reg = readl(wdt->base + WDT_RESET_WIDTH);
	262
	263	reg &= config->ext_pulse_width_mask;
	264	if (of_property_read_bool(np, "aspeed,ext-push-pull"))
	265	reg \|= WDT_PUSH_PULL_MAGIC;
	266	else
	267	reg \|= WDT_OPEN_DRAIN_MAGIC;
	268
	269	writel(reg, wdt->base + WDT_RESET_WIDTH);
	270
	271	reg &= config->ext_pulse_width_mask;
	272	if (of_property_read_bool(np, "aspeed,ext-active-high"))
	273	reg \|= WDT_ACTIVE_HIGH_MAGIC;
	274	else
	275	reg \|= WDT_ACTIVE_LOW_MAGIC;
	276
	277	writel(reg, wdt->base + WDT_RESET_WIDTH);
	278	}
	279
	280	if (!of_property_read_u32(np, "aspeed,ext-pulse-duration", &duration)) {
	281	u32 max_duration = config->ext_pulse_width_mask + 1;
	282
	283	if (duration == 0 \|\| duration > max_duration) {
	284	dev_err(&pdev->dev, "Invalid pulse duration: %uus\n",
	285	duration);
	286	duration = max(1U, min(max_duration, duration));
	287	dev_info(&pdev->dev, "Pulse duration set to %uus\n",
	288	duration);
	289	}
	290
	291	/*
	292	* The watchdog is always configured with a 1MHz source, so
	293	* there is no need to scale the microsecond value. However we
	294	* need to offset it - from the datasheet:
	295	*
	296	* "This register decides the asserting duration of wdt_ext and
	297	* wdt_rstarm signal. The default value is 0xFF. It means the
	298	* default asserting duration of wdt_ext and wdt_rstarm is
	299	* 256us."
	300	*
	301	* This implies a value of 0 gives a 1us pulse.
	302	*/
	303	writel(duration - 1, wdt->base + WDT_RESET_WIDTH);
	304	}
	305
7db1634d	306	ret = devm_watchdog_register_device(&pdev->dev, &wdt->wdd);
efa859f7 JS	307	if (ret) {
	308	dev_err(&pdev->dev, "failed to register\n");
	309	return ret;
	310	}
	311
efa859f7 JS	312	return 0;
	313	}
	314
	315	static struct platform_driver aspeed_watchdog_driver = {
	316	.probe = aspeed_wdt_probe,
efa859f7 JS	317	.driver = {
	318	.name = KBUILD_MODNAME,
	319	.of_match_table = of_match_ptr(aspeed_wdt_of_table),
	320	},
	321	};
	322	module_platform_driver(aspeed_watchdog_driver);
	323
	324	MODULE_DESCRIPTION("Aspeed Watchdog Driver");
	325	MODULE_LICENSE("GPL");