[PATCH] watchdog: add in watchdog for nct6686
From: David Ober
Date: Thu Sep 07 2023 - 11:39:07 EST
This change adds in the watchdog timer support for the nct6686
chip so that it can be used on the Lenovo m90n IOT device
Signed-off-by: David Ober <dober6023@xxxxxxxxx>
---
drivers/watchdog/Kconfig | 11 +
drivers/watchdog/Makefile | 1 +
drivers/watchdog/nct6686_wdt.c | 492 +++++++++++++++++++++++++++++++++
3 files changed, 504 insertions(+)
create mode 100644 drivers/watchdog/nct6686_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 751458959411..64494f13e864 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -341,6 +341,17 @@ config RAVE_SP_WATCHDOG
help
Support for the watchdog on RAVE SP device.
+config NCT6686_WDT
+ tristate "NCT6686 Watchdog Timer"
+ depends on I2C
+ select WATCHDOG_CORE
+ help
+ Watchdog driver for the Nuvoton 6686 Watchdog
+ Processor.
+
+ To compile this driver as a module, choose M here: the
+ module will be called nct6686_wdt.
+
config MLX_WDT
tristate "Mellanox Watchdog"
depends on MELLANOX_PLATFORM || COMPILE_TEST
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 7eab9de311cb..6bcaedd5fc87 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -150,6 +150,7 @@ obj-$(CONFIG_INTEL_MEI_WDT) += mei_wdt.o
obj-$(CONFIG_NI903X_WDT) += ni903x_wdt.o
obj-$(CONFIG_NIC7018_WDT) += nic7018_wdt.o
obj-$(CONFIG_MLX_WDT) += mlx_wdt.o
+obj-$(CONFIG_NCT6686_WDT) += nct6686_wdt.o
obj-$(CONFIG_KEEMBAY_WATCHDOG) += keembay_wdt.o
obj-$(CONFIG_SIEMENS_SIMATIC_IPC_WDT) += simatic-ipc-wdt.o
diff --git a/drivers/watchdog/nct6686_wdt.c b/drivers/watchdog/nct6686_wdt.c
new file mode 100644
index 000000000000..e2125f56faf5
--- /dev/null
+++ b/drivers/watchdog/nct6686_wdt.c
@@ -0,0 +1,492 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * NCT6686D Watchdog Driver
+ */
+
+#define dev_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/acpi.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/iommu.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+
+static bool force;
+module_param(force, bool, 0);
+MODULE_PARM_DESC(force, "Set to one to enable support for unknown vendors");
+
+#define DRVNAME "nct6686_wdt"
+
+/*
+ * Super-I/O constants and functions
+ */
+#define NCT6686_LD_HWM 0x0b
+#define SIO_REG_LDSEL 0x07 /* Logical device select */
+#define SIO_REG_DEVID 0x20 /* Device ID (2 bytes) */
+#define SIO_REG_ENABLE 0x30 /* Logical device enable */
+#define SIO_REG_ADDR 0x60 /* Logical device address (2 bytes) */
+
+#define SIO_NCT6686_ID 0xd440
+#define SIO_ID_MASK 0xFFF0
+
+#define WDT_CFG 0x828 /* W/O Lock Watchdog Register */
+#define WDT_CNT 0x829 /* R/W Watchdog Timer Register */
+#define WDT_STS 0x82A /* R/O Watchdog Status Register */
+#define WDT_STS_EVT_POS (0)
+#define WDT_STS_EVT_MSK (0x3 << WDT_STS_EVT_POS)
+#define WDT_SOFT_EN 0x87 /* Enable soft watchdog timer */
+#define WDT_SOFT_DIS 0xAA /* Disable soft watchdog timer */
+
+#define WATCHDOG_TIMEOUT 60 /* 1 minute default timeout */
+
+/* The timeout range is 1-255 seconds */
+#define MIN_TIMEOUT 1
+#define MAX_TIMEOUT 255
+
+static int timeout;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds. 1 <= timeout <= 255, default="
+ __MODULE_STRING(WATCHDOG_TIMEOUT) ".");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static int early_disable;
+module_param(early_disable, int, 0);
+MODULE_PARM_DESC(early_disable, "Disable watchdog at boot time (default=0)");
+
+#define NCT6686_PAGE_REG_OFFSET 0
+#define NCT6686_ADDR_REG_OFFSET 1
+#define NCT6686_DATA_REG_OFFSET 2
+
+struct watchdog_device wdt;
+
+struct nct6686_sio_data {
+ int sioreg;
+};
+
+struct nct6686_data {
+ int addr; /* IO base of EC space */
+ struct nct6686_sio_data sio_data; /* SIO register */
+
+ struct watchdog_device wdt;
+ struct mutex update_lock; /* used to protect sensor updates */
+};
+
+static inline void
+superio_outb(int ioreg, int reg, int val)
+{
+ outb(reg, ioreg);
+ outb(val, ioreg + 1);
+}
+
+static inline int
+superio_inb(int ioreg, int reg)
+{
+ outb(reg, ioreg);
+ return inb(ioreg + 1);
+}
+
+static inline void
+superio_select(int ioreg, int ld)
+{
+ outb(SIO_REG_LDSEL, ioreg);
+ outb(ld, ioreg + 1);
+}
+
+static inline int
+superio_enter(int ioreg)
+{
+ /*
+ * Try to reserve <ioreg> and <ioreg + 1> for exclusive access.
+ */
+ if (!request_muxed_region(ioreg, 2, DRVNAME))
+ return -EBUSY;
+
+ outb(0x87, ioreg);
+ outb(0x87, ioreg);
+
+ return 0;
+}
+
+static inline void
+superio_exit(int ioreg)
+{
+ outb(0xaa, ioreg);
+ outb(0x02, ioreg);
+ outb(0x02, ioreg + 1);
+ release_region(ioreg, 2);
+}
+
+/*
+ * ISA constants
+ */
+
+#define IOREGION_ALIGNMENT (~7)
+#define IOREGION_OFFSET 4 /* Use EC port 1 */
+#define IOREGION_LENGTH 4
+
+#define EC_PAGE_REG 0
+#define EC_INDEX_REG 1
+#define EC_DATA_REG 2
+#define EC_EVENT_REG 3
+
+static inline void nct6686_wdt_set_bank(int base_addr, u16 reg)
+{
+ outb_p(0xFF, base_addr + NCT6686_PAGE_REG_OFFSET);
+ outb_p(reg >> 8, base_addr + NCT6686_PAGE_REG_OFFSET);
+}
+
+/* Not strictly necessary, but play it safe for now */
+static inline void nct6686_wdt_reset_bank(int base_addr, u16 reg)
+{
+ if (reg & 0xff00)
+ outb_p(0xFF, base_addr + NCT6686_PAGE_REG_OFFSET);
+}
+
+static u8 nct6686_read(struct nct6686_data *data, u16 reg)
+{
+ u8 res;
+
+ nct6686_wdt_set_bank(data->addr, reg);
+ outb_p(reg & 0xff, data->addr + NCT6686_ADDR_REG_OFFSET);
+ res = inb_p(data->addr + NCT6686_DATA_REG_OFFSET);
+
+ nct6686_wdt_reset_bank(data->addr, reg);
+ return res;
+}
+
+static void nct6686_write(struct nct6686_data *data, u16 reg, u8 value)
+{
+ nct6686_wdt_set_bank(data->addr, reg);
+ outb_p(reg & 0xff, data->addr + NCT6686_ADDR_REG_OFFSET);
+ outb_p(value & 0xff, data->addr + NCT6686_DATA_REG_OFFSET);
+ nct6686_wdt_reset_bank(data->addr, reg);
+}
+
+/*
+ * Watchdog Functions
+ */
+static int nct6686_wdt_enable(struct watchdog_device *wdog, bool enable)
+{
+ struct nct6686_data *data = watchdog_get_drvdata(wdog);
+
+ u_char reg;
+
+ mutex_lock(&data->update_lock);
+ reg = nct6686_read(data, WDT_CFG);
+
+ if (enable) {
+ nct6686_write(data, WDT_CFG, reg | 0x3);
+ mutex_unlock(&data->update_lock);
+ return 0;
+ }
+
+ nct6686_write(data, WDT_CFG, reg & ~BIT(0));
+ mutex_unlock(&data->update_lock);
+
+ return 0;
+}
+
+static int nct6686_wdt_set_time(struct watchdog_device *wdog)
+{
+ struct nct6686_data *data = watchdog_get_drvdata(wdog);
+
+ mutex_lock(&data->update_lock);
+ nct6686_write(data, WDT_CNT, wdog->timeout);
+ mutex_unlock(&data->update_lock);
+
+ if (wdog->timeout) {
+ nct6686_wdt_enable(wdog, true);
+ return 0;
+ }
+
+ nct6686_wdt_enable(wdog, false);
+ return 0;
+}
+
+static int nct6686_wdt_start(struct watchdog_device *wdt)
+{
+ struct nct6686_data *data = watchdog_get_drvdata(wdt);
+ u_char reg;
+
+ nct6686_wdt_set_time(wdt);
+
+ /* Enable soft watchdog timer */
+ mutex_lock(&data->update_lock);
+ /* reset trigger status */
+ reg = nct6686_read(data, WDT_STS);
+ nct6686_write(data, WDT_STS, reg & ~WDT_STS_EVT_MSK);
+ mutex_unlock(&data->update_lock);
+ return 0;
+}
+
+static int nct6686_wdt_stop(struct watchdog_device *wdt)
+{
+ struct nct6686_data *data = watchdog_get_drvdata(wdt);
+
+ mutex_lock(&data->update_lock);
+ nct6686_write(data, WDT_CFG, WDT_SOFT_DIS);
+ mutex_unlock(&data->update_lock);
+ return 0;
+}
+
+static int nct6686_wdt_set_timeout(struct watchdog_device *wdt,
+ unsigned int timeout)
+{
+ struct nct6686_data *data = watchdog_get_drvdata(wdt);
+
+ wdt->timeout = timeout;
+ mutex_lock(&data->update_lock);
+ nct6686_write(data, WDT_CNT, timeout);
+ mutex_unlock(&data->update_lock);
+ return 0;
+}
+
+static int nct6686_wdt_ping(struct watchdog_device *wdt)
+{
+ struct nct6686_data *data = watchdog_get_drvdata(wdt);
+ int timeout;
+
+ /*
+ * Note:
+ * NCT6686 does not support refreshing WDT_TIMER_REG register when
+ * the watchdog is active. Please disable watchdog before feeding
+ * the watchdog and enable it again.
+ */
+ /* Disable soft watchdog timer */
+ nct6686_wdt_enable(wdt, false);
+
+ /* feed watchdog */
+ timeout = wdt->timeout;
+ mutex_lock(&data->update_lock);
+ nct6686_write(data, WDT_CNT, timeout);
+ mutex_unlock(&data->update_lock);
+
+ /* Enable soft watchdog timer */
+ nct6686_wdt_enable(wdt, true);
+ return 0;
+}
+
+static unsigned int nct6686_wdt_get_timeleft(struct watchdog_device *wdt)
+{
+ struct nct6686_data *data = watchdog_get_drvdata(wdt);
+ int ret;
+
+ mutex_lock(&data->update_lock);
+ ret = nct6686_read(data, WDT_CNT);
+ mutex_unlock(&data->update_lock);
+ if (ret < 0)
+ return 0;
+
+ return ret;
+}
+
+static const struct watchdog_info nct6686_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING |
+ WDIOF_MAGICCLOSE,
+ .identity = "nct6686 watchdog",
+};
+
+static const struct watchdog_ops nct6686_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = nct6686_wdt_start,
+ .stop = nct6686_wdt_stop,
+ .ping = nct6686_wdt_ping,
+ .set_timeout = nct6686_wdt_set_timeout,
+ .get_timeleft = nct6686_wdt_get_timeleft,
+};
+
+static int nct6686_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct watchdog_device *wdt;
+ struct resource *res;
+ struct nct6686_data *data;
+ struct nct6686_sio_data *sio_data = dev->platform_data;
+ int ret;
+ u_char reg;
+
+ dev_dbg(&pdev->dev, "Probe NCT6686 called\n");
+ res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+ if (!devm_request_region(dev, res->start, IOREGION_LENGTH, DRVNAME))
+ return -EBUSY;
+
+ data = devm_kzalloc(dev, sizeof(struct nct6686_data), GFP_KERNEL);
+ if (!data)
+ return -ENOMEM;
+
+ data->sio_data.sioreg = sio_data->sioreg;
+ data->addr = res->start;
+ mutex_init(&data->update_lock);
+ platform_set_drvdata(pdev, data);
+
+ /* Watchdog initialization */
+ data->wdt.ops = &nct6686_wdt_ops;
+ data->wdt.info = &nct6686_wdt_info;
+
+ data->wdt.timeout = WATCHDOG_TIMEOUT; /* Set default timeout */
+ data->wdt.min_timeout = MIN_TIMEOUT;
+ data->wdt.max_timeout = MAX_TIMEOUT;
+ data->wdt.parent = &pdev->dev;
+
+ watchdog_init_timeout(&data->wdt, timeout, &pdev->dev);
+ watchdog_set_nowayout(&data->wdt, nowayout);
+ watchdog_set_drvdata(&data->wdt, data);
+
+ /* reset trigger status */
+ reg = nct6686_read(data, WDT_STS);
+ nct6686_write(data, WDT_STS, reg & ~WDT_STS_EVT_MSK);
+
+ watchdog_stop_on_unregister(&data->wdt);
+
+ ret = devm_watchdog_register_device(dev, &data->wdt);
+
+ dev_dbg(&pdev->dev, "initialized. timeout=%d sec (nowayout=%d)\n",
+ wdt->timeout, nowayout);
+
+ return ret;
+}
+
+static struct platform_driver nct6686_driver = {
+ .driver = {
+ .name = DRVNAME,
+ },
+ .probe = nct6686_probe,
+};
+
+static int __init nct6686_find(int sioaddr, u_long *base_phys)
+{
+ u16 val;
+ int err = 0;
+ u_long addr;
+
+ err = superio_enter(sioaddr);
+ if (err)
+ return err;
+
+ val = (superio_inb(sioaddr, SIO_REG_DEVID) << 8)
+ | superio_inb(sioaddr, SIO_REG_DEVID + 1);
+
+ if ((val & SIO_ID_MASK) != SIO_NCT6686_ID)
+ goto fail;
+
+ /* We have a known chip, find the HWM I/O address */
+ superio_select(sioaddr, NCT6686_LD_HWM);
+ val = (superio_inb(sioaddr, SIO_REG_ADDR) << 8)
+ | superio_inb(sioaddr, SIO_REG_ADDR + 1);
+ addr = val & IOREGION_ALIGNMENT;
+ if (addr == 0) {
+ pr_err("EC base I/O port unconfigured\n");
+ goto fail;
+ }
+
+ /* Activate logical device if needed */
+ val = superio_inb(sioaddr, SIO_REG_ENABLE);
+ if (!(val & 0x01)) {
+ pr_warn("Forcibly enabling EC access. Data may be unusable.\n");
+ superio_outb(sioaddr, SIO_REG_ENABLE, val | 0x01);
+ }
+
+ superio_exit(sioaddr);
+ *base_phys = addr;
+
+ return 0;
+
+fail:
+ superio_exit(sioaddr);
+ return -ENODEV;
+}
+
+static struct platform_device *pdev;
+
+static int __init nct6686_init(void)
+{
+ struct nct6686_sio_data sio_data;
+ int sioaddr[2] = { 0x2e, 0x4e };
+ struct resource res;
+ int err;
+ u_long addr;
+
+ /*
+ * when Super-I/O functions move to a separate file, the Super-I/O
+ * driver will probe 0x2e and 0x4e and auto-detect the presence of a
+ * nct6686 hardware monitor, and call probe()
+ */
+ err = nct6686_find(sioaddr[0], &addr);
+ if (err) {
+ err = nct6686_find(sioaddr[1], &addr);
+ if (err)
+ return -ENODEV;
+ }
+
+ pdev = platform_device_alloc(DRVNAME, addr);
+ if (!pdev) {
+ err = -ENOMEM;
+ goto exit_device_unregister;
+ }
+
+ err = platform_device_add_data(pdev, &sio_data,
+ sizeof(struct nct6686_sio_data));
+ if (err)
+ goto exit_device_put;
+
+ memset(&res, 0, sizeof(res));
+ res.name = DRVNAME;
+ res.start = addr + IOREGION_OFFSET;
+ res.end = addr + IOREGION_OFFSET + IOREGION_LENGTH - 1;
+ res.flags = IORESOURCE_IO;
+
+ err = acpi_check_resource_conflict(&res);
+ if (err)
+ return err;
+
+ platform_driver_register(&nct6686_driver);
+
+ pdev = platform_device_alloc(DRVNAME, addr);
+ if (!pdev) {
+ err = -ENOMEM;
+ goto exit_device_unregister;
+ }
+ err = platform_device_add_data(pdev, &sio_data,
+ sizeof(struct nct6686_sio_data));
+ if (err)
+ goto exit_device_put;
+
+ err = platform_device_add_resources(pdev, &res, 1);
+ if (err)
+ goto exit_device_put;
+
+ dev_info(&pdev->dev, "NCT6686 device found\n");
+ /* platform_device_add calls probe() */
+ err = platform_device_add(pdev);
+ if (err)
+ goto exit_device_put;
+
+ return 0;
+exit_device_put:
+ platform_device_put(pdev);
+ platform_device_unregister(pdev);
+exit_device_unregister:
+ platform_driver_unregister(&nct6686_driver);
+ return err;
+}
+
+static void __exit nct6686_exit(void)
+{
+ platform_device_unregister(pdev);
+ platform_driver_unregister(&nct6686_driver);
+}
+
+MODULE_AUTHOR("David Ober <dober@xxxxxxxxxx>");
+MODULE_DESCRIPTION("NCT6686D driver");
+MODULE_LICENSE("GPL");
+
+module_init(nct6686_init);
+module_exit(nct6686_exit);
--
2.34.1