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From: Steffen Trumtrar <s.trumtrar@pengutronix.de>
To: barebox@lists.infradead.org
Subject: [PATCH 2/2] watchdog: add support for wdat_wdt
Date: Fri,  7 Jan 2022 14:42:19 +0100	[thread overview]
Message-ID: <20220107134219.1031552-2-s.trumtrar@pengutronix.de> (raw)
In-Reply-To: <20220107134219.1031552-1-s.trumtrar@pengutronix.de>

Add support for systems with the ACPI Watchdog Action Table (wdat).
Based on Linux v5.15-rc1 drivers/watchdog/wdat_wdt.c

Signed-off-by: Steffen Trumtrar <str@pengutronix.de>
---
 This patch depends on
  x86: <asm/io.h>: fix outl/outsl access size
  https://lore.barebox.org/20220107063644.22595-1-a.fatoum@pengutronix.de

 drivers/watchdog/Kconfig    |  10 +
 drivers/watchdog/Makefile   |   1 +
 drivers/watchdog/wdat_wdt.c | 496 ++++++++++++++++++++++++++++++++++++
 3 files changed, 507 insertions(+)
 create mode 100644 drivers/watchdog/wdat_wdt.c

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index f91a2571d9..68dbded3ec 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -149,4 +149,14 @@ config STARFIVE_WDT
 	  If you say yes here you get support for the watchdog device
 	  on StarFive SoCs.
 
+config WDAT_WDT
+	bool "ACPI Watchdog Action Table (WDAT)"
+	depends on X86
+	depends on ACPI
+	help
+	  This driver adds support for systems with ACPI Watchdog Action
+	  Table (WDAT) table. Servers typically have this but it can be
+	  found on some desktop machines as well. This driver will take
+	  over the native iTCO watchdog driver found on many Intel CPUs.
+
 endif
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 54a833447c..aaebc459e6 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -20,3 +20,4 @@ obj-$(CONFIG_F71808E_WDT) += f71808e_wdt.o
 obj-$(CONFIG_GPIO_WATCHDOG) += gpio_wdt.o
 obj-$(CONFIG_ITCO_WDT) += itco_wdt.o
 obj-$(CONFIG_STARFIVE_WDT) += starfive_wdt.o
+obj-$(CONFIG_WDAT_WDT) += wdat_wdt.o
diff --git a/drivers/watchdog/wdat_wdt.c b/drivers/watchdog/wdat_wdt.c
new file mode 100644
index 0000000000..39e8cc4a3d
--- /dev/null
+++ b/drivers/watchdog/wdat_wdt.c
@@ -0,0 +1,496 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * ACPI Hardware Watchdog (WDAT) driver.
+ *
+ * Copyright (C) 2016, Intel Corporation
+ * Author: Mika Westerberg <mika.westerberg@linux.intel.com>
+ */
+#include <common.h>
+#include <acpi.h>
+#include <errno.h>
+#include <init.h>
+#include <io.h>
+#include <malloc.h>
+#include <of.h>
+#include <watchdog.h>
+
+enum acpi_wdat_actions {
+	ACPI_WDAT_RESET = 1,
+	ACPI_WDAT_GET_CURRENT_COUNTDOWN = 4,
+	ACPI_WDAT_GET_COUNTDOWN = 5,
+	ACPI_WDAT_SET_COUNTDOWN = 6,
+	ACPI_WDAT_GET_RUNNING_STATE = 8,
+	ACPI_WDAT_SET_RUNNING_STATE = 9,
+	ACPI_WDAT_GET_STOPPED_STATE = 10,
+	ACPI_WDAT_SET_STOPPED_STATE = 11,
+	ACPI_WDAT_GET_REBOOT = 16,
+	ACPI_WDAT_SET_REBOOT = 17,
+	ACPI_WDAT_GET_SHUTDOWN = 18,
+	ACPI_WDAT_SET_SHUTDOWN = 19,
+	ACPI_WDAT_GET_STATUS = 32,
+	ACPI_WDAT_SET_STATUS = 33,
+	ACPI_WDAT_ACTION_RESERVED = 34	/* 34 and greater are reserved */
+};
+
+enum acpi_wdat_instructions {
+	ACPI_WDAT_READ_VALUE = 0,
+	ACPI_WDAT_READ_COUNTDOWN = 1,
+	ACPI_WDAT_WRITE_VALUE = 2,
+	ACPI_WDAT_WRITE_COUNTDOWN = 3,
+	ACPI_WDAT_INSTRUCTION_RESERVED = 4,	/* 4 and greater are reserved */
+	ACPI_WDAT_PRESERVE_REGISTER = 0x80	/* Except for this value */
+};
+
+#define MAX_WDAT_ACTIONS ACPI_WDAT_ACTION_RESERVED
+
+#define WDAT_DEFAULT_TIMEOUT	30
+
+/* WDAT Instruction Entries (actions) */
+
+struct __packed acpi_wdat_entry {
+	u8 				action;
+	u8 				instruction;
+	u16 				reserved;
+	struct acpi_generic_address 	register_region;
+	u32 				value;		/* Value used with Read/Write register */
+	u32 				mask;		/* Bitmask required for this register instruction */
+};
+
+/**
+ * struct wdat_instruction - Single ACPI WDAT instruction
+ * @entry: Copy of the ACPI table instruction
+ * @reg: Register the instruction is accessing
+ * @node: Next instruction in action sequence
+ */
+struct wdat_instruction {
+	struct acpi_wdat_entry entry;
+	void __iomem *reg;
+	struct list_head node;
+};
+
+/**
+ * struct wdat_wdt - ACPI WDAT watchdog device
+ * @dev: Parent platform device
+ * @wdd: Watchdog core device
+ * @period: How long is one watchdog period in ms
+ * @stopped_in_sleep: Is this watchdog stopped by the firmware in S1-S5
+ * @stopped: Was the watchdog stopped by the driver in suspend
+ * @instructions: An array of instruction lists indexed by an action number from
+ *                the WDAT table. There can be %NULL entries for not implemented
+ *                actions.
+ */
+struct wdat_wdt {
+	struct watchdog		wdd;
+	unsigned int		period;
+	bool 			stopped_in_sleep;
+	bool			stopped;
+	struct list_head	*instructions[MAX_WDAT_ACTIONS];
+};
+
+struct __packed acpi_table_wdat {
+	struct acpi_table_header header;	/* Common ACPI table header */
+	u32			 header_length;	/* Watchdog Header Length */
+	u16 			 pci_segment;	/* PCI Segment number */
+	u8 			 pci_bus;	/* PCI Bus number */
+	u8 			 pci_device;	/* PCI Device number */
+	u8 			 pci_function;	/* PCI Function number */
+	u8 			 reserved[3];
+	u32 			 timer_period;	/* Period of one timer count (msec) */
+	u32 			 max_count;	/* Maximum counter value supported */
+	u32 			 min_count;	/* Minimum counter value */
+	u8 			 flags;
+	u8 			 reserved2[3];
+	u32 			 nr_entries;	/* Number of watchdog entries that follow */
+	struct acpi_wdat_entry   entries[];
+};
+
+#define ACPI_WDAT_ENABLED           (1)
+#define ACPI_WDAT_STOPPED           0x80
+
+#define IO_COND(instr, is_pio, is_mmio) do {					\
+	const struct acpi_generic_address *gas = &instr->entry.register_region; \
+	unsigned long port = (unsigned long __force)instr->reg;			\
+	if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {			\
+		is_mmio;							\
+	} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {			\
+		is_pio;								\
+	}									\
+} while (0)
+
+static unsigned int read8(const struct wdat_instruction *instr)
+{
+	IO_COND(instr, return inb(port), return readb(instr->reg));
+	return 0xff;
+}
+
+static unsigned int read16(const struct wdat_instruction *instr)
+{
+	IO_COND(instr, return inw(port), return readw(instr->reg));
+	return 0xffff;
+}
+
+static unsigned int read32(const struct wdat_instruction *instr)
+{
+	IO_COND(instr, return inl(port), return readl(instr->reg));
+	return 0xffffffff;
+}
+
+static void write8(u8 val, const struct wdat_instruction *instr)
+{
+	IO_COND(instr, outb(val,port), writeb(val, instr->reg));
+}
+
+static void write16(u16 val, const struct wdat_instruction *instr)
+{
+	IO_COND(instr, outw(val,port), writew(val, instr->reg));
+}
+
+static void write32(u32 val, const struct wdat_instruction *instr)
+{
+	IO_COND(instr, outl(val,port), writel(val, instr->reg));
+}
+
+static int wdat_wdt_read(struct wdat_wdt *wdat,
+		       const struct wdat_instruction *instr, u32 *value)
+{
+	const struct acpi_generic_address *gas = &instr->entry.register_region;
+
+	switch (gas->access_width) {
+	case 1:
+		*value = read8(instr);
+		break;
+	case 2:
+		*value = read16(instr);
+		break;
+	case 3:
+		*value = read32(instr);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	dev_dbg(wdat->wdd.hwdev, "Read %#x from 0x%08llx\n", *value,
+		gas->address);
+
+	return 0;
+}
+
+static int wdat_wdt_write(struct wdat_wdt *wdat,
+			const struct wdat_instruction *instr, u32 value)
+{
+	const struct acpi_generic_address *gas = &instr->entry.register_region;
+
+	switch (gas->access_width) {
+	case 1:
+		write8((u8)value, instr);
+		break;
+	case 2:
+		write16((u16)value, instr);
+		break;
+	case 3:
+		write32(value, instr);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	dev_dbg(wdat->wdd.hwdev, "Wrote %#x to 0x%08llx\n", value,
+		gas->address);
+
+	return 0;
+}
+
+static int wdat_wdt_run_action(struct wdat_wdt *wdat, unsigned int action,
+			       u32 param, u32 *retval)
+{
+	struct wdat_instruction *instr;
+
+	if (action >= ARRAY_SIZE(wdat->instructions)) {
+		dev_dbg(wdat->wdd.hwdev, "Invalid action %#x\n", action);
+		return -EINVAL;
+	}
+
+	if (!wdat->instructions[action]) {
+		dev_dbg(wdat->wdd.hwdev, "Unsupported action %#x\n", action);
+		return -EOPNOTSUPP;
+	}
+
+	dev_dbg(wdat->wdd.hwdev, "Running action %#x\n", action);
+
+	/* Run each instruction sequentially */
+	list_for_each_entry(instr, wdat->instructions[action], node) {
+		const struct acpi_wdat_entry *entry = &instr->entry;
+		const struct acpi_generic_address *gas;
+		u32 flags, value, mask, x, y;
+		bool preserve;
+		int ret;
+
+		gas = &entry->register_region;
+
+		preserve = entry->instruction & ACPI_WDAT_PRESERVE_REGISTER;
+		flags = entry->instruction & ~ACPI_WDAT_PRESERVE_REGISTER;
+		value = entry->value;
+		mask = entry->mask;
+
+		switch (flags) {
+		case ACPI_WDAT_READ_VALUE:
+			ret = wdat_wdt_read(wdat, instr, &x);
+			if (ret)
+				return ret;
+			x >>= gas->bit_offset;
+			x &= mask;
+			if (retval)
+				*retval = x == value;
+			break;
+
+		case ACPI_WDAT_READ_COUNTDOWN:
+			ret = wdat_wdt_read(wdat, instr, &x);
+			if (ret)
+				return ret;
+			x >>= gas->bit_offset;
+			x &= mask;
+			if (retval)
+				*retval = x;
+			break;
+
+		case ACPI_WDAT_WRITE_VALUE:
+			x = value & mask;
+			x <<= gas->bit_offset;
+			if (preserve) {
+				ret = wdat_wdt_read(wdat, instr, &y);
+				if (ret)
+					return ret;
+				y = y & ~(mask << gas->bit_offset);
+				x |= y;
+			}
+			ret = wdat_wdt_write(wdat, instr, x);
+			if (ret)
+				return ret;
+			break;
+
+		case ACPI_WDAT_WRITE_COUNTDOWN:
+			x = param;
+			x &= mask;
+			x <<= gas->bit_offset;
+			if (preserve) {
+				ret = wdat_wdt_read(wdat, instr, &y);
+				if (ret)
+					return ret;
+				y = y & ~(mask << gas->bit_offset);
+				x |= y;
+			}
+			ret = wdat_wdt_write(wdat, instr, x);
+			if (ret)
+				return ret;
+			break;
+
+		default:
+			dev_err(wdat->wdd.hwdev, "Unknown instruction: %u\n",
+				flags);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+static void wdat_wdt_boot_status(struct wdat_wdt *wdat)
+{
+	u32 boot_status = 0;
+	int ret;
+
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_STATUS, 0, &boot_status);
+	if (ret && ret != -EOPNOTSUPP) {
+		dev_err(wdat->wdd.hwdev, "Failed to read boot status\n");
+		return;
+	}
+
+	/* Clear the boot status in case BIOS did not do it */
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_STATUS, 0, NULL);
+	if (ret && ret != -EOPNOTSUPP)
+		dev_err(wdat->wdd.hwdev, "Failed to clear boot status\n");
+}
+
+static int wdat_wdt_start(struct watchdog *wdd)
+{
+	struct wdat_wdt *wdat = container_of(wdd, struct wdat_wdt, wdd);
+
+	return wdat_wdt_run_action(wdat, ACPI_WDAT_SET_RUNNING_STATE, 0, NULL);
+}
+
+static int wdat_wdt_stop(struct watchdog *wdd)
+{
+	struct wdat_wdt *wdat = container_of(wdd, struct wdat_wdt, wdd);
+
+	return wdat_wdt_run_action(wdat, ACPI_WDAT_SET_STOPPED_STATE, 0, NULL);
+}
+
+static void wdat_wdt_set_running(struct wdat_wdt *wdat)
+{
+	u32 running = 0;
+	int ret;
+
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_GET_RUNNING_STATE, 0,
+				  &running);
+	if (ret && ret != -EOPNOTSUPP)
+		dev_err(wdat->wdd.hwdev, "Failed to read running state\n");
+
+	dev_dbg(wdat->wdd.hwdev, "Running state: %d\n", running);
+
+	wdat->wdd.running = running ? WDOG_HW_RUNNING : WDOG_HW_NOT_RUNNING;
+}
+
+static int wdat_wdt_set_timeout(struct watchdog *wdd, unsigned int timeout)
+{
+	struct wdat_wdt *wdat = container_of(wdd, struct wdat_wdt, wdd);
+	unsigned int periods;
+	int ret;
+
+	if (timeout == 0)
+		return wdat_wdt_stop(wdd);
+
+	periods = timeout * 1000 / wdat->period;
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_COUNTDOWN, periods, NULL);
+	if (ret)
+		return ret;
+
+	if (wdat->wdd.running == WDOG_HW_NOT_RUNNING) {
+		wdat_wdt_start(wdd);
+		wdat->wdd.running = WDOG_HW_RUNNING;
+	}
+
+	return wdat_wdt_run_action(wdat, ACPI_WDAT_RESET, 0, NULL);
+}
+
+static int wdat_wdt_enable_reboot(struct wdat_wdt *wdat)
+{
+	int ret;
+
+	/*
+	 * WDAT specification says that the watchdog is required to reboot
+	 * the system when it fires. However, it also states that it is
+	 * recommeded to make it configurable through hardware register. We
+	 * enable reboot now if it is configrable, just in case.
+	 */
+	ret = wdat_wdt_run_action(wdat, ACPI_WDAT_SET_REBOOT, 0, NULL);
+	if (ret && ret != -EOPNOTSUPP) {
+		dev_err(wdat->wdd.hwdev,
+			"Failed to enable reboot when watchdog triggers\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int wdat_wdt_probe(struct device_d *const dev)
+{
+	const struct acpi_wdat_entry *entries;
+	struct acpi_table_wdat *tbl;
+	struct wdat_wdt *wdat;
+	int i, ret;
+
+	dev_dbg(dev, "driver initializing...\n");
+
+	tbl = (struct acpi_table_wdat __force *)dev_request_mem_region_by_name(dev, "SDT");
+	if (IS_ERR(tbl)) {
+		dev_err(dev, "no SDT resource available: %pe\n", tbl);
+		return PTR_ERR(tbl);
+	}
+
+	dev_dbg(dev, "SDT is at 0x%p\n", tbl);
+
+	wdat = xzalloc(sizeof(*wdat));
+
+	/* WDAT specification wants to have >= 1ms period */
+	if (tbl->timer_period < 1) {
+		dev_dbg(dev, "timer_period is less than 1: %d\n", tbl->timer_period);
+		return -EINVAL;
+	}
+	if (tbl->min_count > tbl->max_count) {
+		dev_dbg(dev, "min_count must be greater than max_count\n");
+		return -EINVAL;
+	}
+
+	wdat->period = tbl->timer_period;
+	wdat->stopped_in_sleep = tbl->flags & ACPI_WDAT_STOPPED;
+	wdat->wdd.set_timeout = wdat_wdt_set_timeout;
+	wdat->wdd.hwdev = dev;
+	wdat->wdd.timeout_max = U32_MAX;
+
+	entries = tbl->entries;
+
+	for (i = 0; i < tbl->nr_entries; i++) {
+		const struct acpi_generic_address *gas;
+		struct wdat_instruction *instr;
+		struct list_head *instructions;
+		struct resource *res;
+		unsigned int action;
+		struct resource r;
+
+		action = entries[i].action;
+		if (action >= MAX_WDAT_ACTIONS) {
+			dev_dbg(dev, "Skipping unknown action: %u\n", action);
+			continue;
+		}
+
+		instr = xzalloc(sizeof(*instr));
+
+		INIT_LIST_HEAD(&instr->node);
+		instr->entry = entries[i];
+
+		gas = &entries[i].register_region;
+
+		memset(&r, 0, sizeof(r));
+		r.start = gas->address;
+		r.end = r.start + ACPI_ACCESS_BYTE_WIDTH(gas->access_width) - 1;
+		if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
+			res = request_iomem_region(dev_name(dev), r.start, r.end);
+		} else if (gas->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
+			res = request_ioport_region(dev_name(dev), r.start, r.end);
+		} else {
+			dev_dbg(dev, "Unsupported address space: %d\n",
+				gas->space_id);
+			continue;
+		}
+
+		/*
+		 * Some entries have the same gas->address.
+		 * We want the action but can't request the region multiple times.
+		 */
+		if (IS_ERR(res) && (PTR_ERR(res) != -EBUSY))
+			return PTR_ERR(res);
+
+		instr->reg = IOMEM(r.start);
+
+		instructions = wdat->instructions[action];
+		if (!instructions) {
+			instructions = xzalloc(sizeof(*instructions));
+			if (!instructions)
+				return -ENOMEM;
+
+			INIT_LIST_HEAD(instructions);
+			wdat->instructions[action] = instructions;
+		}
+
+		list_add_tail(&instr->node, instructions);
+	}
+
+	wdat_wdt_boot_status(wdat);
+	wdat_wdt_set_running(wdat);
+
+	ret = wdat_wdt_enable_reboot(wdat);
+	if (ret)
+		return ret;
+
+	return watchdog_register(&wdat->wdd);
+}
+
+
+static struct acpi_driver wdat_wdt_driver = {
+	.signature = "WDAT",
+	.driver = {
+		.name = "wdat-wdt",
+		.probe = wdat_wdt_probe,
+	}
+};
+device_acpi_driver(wdat_wdt_driver);
-- 
2.30.2


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  reply	other threads:[~2022-01-07 13:44 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-07 13:42 [PATCH 1/2] acpi.h: add defines for adr_space and gas Steffen Trumtrar
2022-01-07 13:42 ` Steffen Trumtrar [this message]
2022-01-10  8:42 ` Sascha Hauer

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