On Wed, Sep 14, 2022 at 11:46:05AM +0200, David Müller wrote: > Simple driver for the watchdog present in some Exar/MaxLinear UART chips. > Please see https://www.maxlinear.com/product/interface/uarts/lpc-uarts/xr28v384 > for more info. > > Signed-off-by: David Müller <d.mueller@xxxxxxxxx> Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx> > --- > > v3: > - fix typo in comment > - use scnprintf() > > v2: > - removed pointless comments and debug output, fix and improve others > - removed checks already done by framework > - update hardware if new timeout value is set and watchdog is active > - separate init, probe and config code parts > - create watchdog devices for all active hardware instances > > drivers/watchdog/Kconfig | 11 + > drivers/watchdog/Makefile | 1 + > drivers/watchdog/exar_wdt.c | 427 ++++++++++++++++++++++++++++++++++++ > 3 files changed, 439 insertions(+) > create mode 100644 drivers/watchdog/exar_wdt.c > > diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig > index 9295492d24f7..72d8c3dc984b 100644 > --- a/drivers/watchdog/Kconfig > +++ b/drivers/watchdog/Kconfig > @@ -1089,6 +1089,17 @@ config EBC_C384_WDT > WinSystems EBC-C384 motherboard. The timeout may be configured via > the timeout module parameter. > > +config EXAR_WDT > + tristate "Exar Watchdog Timer" > + depends on X86 > + select WATCHDOG_CORE > + help > + Enables watchdog timer support for the watchdog timer present > + in some Exar/MaxLinear UART chips like the XR28V38x. > + > + To compile this driver as a module, choose M here: the > + module will be called exar_wdt. > + > config F71808E_WDT > tristate "Fintek F718xx, F818xx Super I/O Watchdog" > depends on X86 > diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile > index cdeb119e6e61..d41e5f830ae7 100644 > --- a/drivers/watchdog/Makefile > +++ b/drivers/watchdog/Makefile > @@ -105,6 +105,7 @@ obj-$(CONFIG_ADVANTECH_WDT) += advantechwdt.o > obj-$(CONFIG_ALIM1535_WDT) += alim1535_wdt.o > obj-$(CONFIG_ALIM7101_WDT) += alim7101_wdt.o > obj-$(CONFIG_EBC_C384_WDT) += ebc-c384_wdt.o > +obj-$(CONFIG_EXAR_WDT) += exar_wdt.o > obj-$(CONFIG_F71808E_WDT) += f71808e_wdt.o > obj-$(CONFIG_SP5100_TCO) += sp5100_tco.o > obj-$(CONFIG_GEODE_WDT) += geodewdt.o > diff --git a/drivers/watchdog/exar_wdt.c b/drivers/watchdog/exar_wdt.c > new file mode 100644 > index 000000000000..35058d8b21bc > --- /dev/null > +++ b/drivers/watchdog/exar_wdt.c > @@ -0,0 +1,427 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * exar_wdt.c - Driver for the watchdog present in some > + * Exar/MaxLinear UART chips like the XR28V38x. > + * > + * (c) Copyright 2022 D. Müller <d.mueller@xxxxxxxxx>. > + * > + */ > + > +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt > + > +#include <linux/io.h> > +#include <linux/list.h> > +#include <linux/module.h> > +#include <linux/platform_device.h> > +#include <linux/slab.h> > +#include <linux/watchdog.h> > + > +#define DRV_NAME "exar_wdt" > + > +static const unsigned short sio_config_ports[] = { 0x2e, 0x4e }; > +static const unsigned char sio_enter_keys[] = { 0x67, 0x77, 0x87, 0xA0 }; > +#define EXAR_EXIT_KEY 0xAA > + > +#define EXAR_LDN 0x07 > +#define EXAR_DID 0x20 > +#define EXAR_VID 0x23 > +#define EXAR_WDT 0x26 > +#define EXAR_ACT 0x30 > +#define EXAR_RTBASE 0x60 > + > +#define EXAR_WDT_LDEV 0x08 > + > +#define EXAR_VEN_ID 0x13A8 > +#define EXAR_DEV_382 0x0382 > +#define EXAR_DEV_384 0x0384 > + > +/* WDT runtime registers */ > +#define WDT_CTRL 0x00 > +#define WDT_VAL 0x01 > + > +#define WDT_UNITS_10MS 0x0 /* the 10 millisec unit of the HW is not used */ > +#define WDT_UNITS_SEC 0x2 > +#define WDT_UNITS_MIN 0x4 > + > +/* default WDT control for WDTOUT signal activ / rearm by read */ > +#define EXAR_WDT_DEF_CONF 0 > + > +struct wdt_pdev_node { > + struct list_head list; > + struct platform_device *pdev; > + const char name[16]; > +}; > + > +struct wdt_priv { > + /* the lock for WDT io operations */ > + spinlock_t io_lock; > + struct resource wdt_res; > + struct watchdog_device wdt_dev; > + unsigned short did; > + unsigned short config_port; > + unsigned char enter_key; > + unsigned char unit; > + unsigned char timeout; > +}; > + > +#define WATCHDOG_TIMEOUT 60 > + > +static int timeout = WATCHDOG_TIMEOUT; > +module_param(timeout, int, 0); > +MODULE_PARM_DESC(timeout, > + "Watchdog timeout in seconds. 1<=timeout<=15300, 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 exar_sio_enter(const unsigned short config_port, > + const unsigned char key) > +{ > + if (!request_muxed_region(config_port, 2, DRV_NAME)) > + return -EBUSY; > + > + /* write the ENTER-KEY twice */ > + outb(key, config_port); > + outb(key, config_port); > + > + return 0; > +} > + > +static void exar_sio_exit(const unsigned short config_port) > +{ > + outb(EXAR_EXIT_KEY, config_port); > + release_region(config_port, 2); > +} > + > +static unsigned char exar_sio_read(const unsigned short config_port, > + const unsigned char reg) > +{ > + outb(reg, config_port); > + return inb(config_port + 1); > +} > + > +static void exar_sio_write(const unsigned short config_port, > + const unsigned char reg, const unsigned char val) > +{ > + outb(reg, config_port); > + outb(val, config_port + 1); > +} > + > +static unsigned short exar_sio_read16(const unsigned short config_port, > + const unsigned char reg) > +{ > + unsigned char msb, lsb; > + > + msb = exar_sio_read(config_port, reg); > + lsb = exar_sio_read(config_port, reg + 1); > + > + return (msb << 8) | lsb; > +} > + > +static void exar_sio_select_wdt(const unsigned short config_port) > +{ > + exar_sio_write(config_port, EXAR_LDN, EXAR_WDT_LDEV); > +} > + > +static void exar_wdt_arm(const struct wdt_priv *priv) > +{ > + unsigned short rt_base = priv->wdt_res.start; > + > + /* write timeout value twice to arm watchdog */ > + outb(priv->timeout, rt_base + WDT_VAL); > + outb(priv->timeout, rt_base + WDT_VAL); > +} > + > +static void exar_wdt_disarm(const struct wdt_priv *priv) > +{ > + unsigned short rt_base = priv->wdt_res.start; > + > + /* > + * use two accesses with different values to make sure > + * that a combination of a previous single access and > + * the ones below with the same value are not falsely > + * interpreted as "arm watchdog" > + */ > + outb(0xFF, rt_base + WDT_VAL); > + outb(0, rt_base + WDT_VAL); > +} > + > +static int exar_wdt_start(struct watchdog_device *wdog) > +{ > + struct wdt_priv *priv = watchdog_get_drvdata(wdog); > + unsigned short rt_base = priv->wdt_res.start; > + > + spin_lock(&priv->io_lock); > + > + exar_wdt_disarm(priv); > + outb(priv->unit, rt_base + WDT_CTRL); > + exar_wdt_arm(priv); > + > + spin_unlock(&priv->io_lock); > + return 0; > +} > + > +static int exar_wdt_stop(struct watchdog_device *wdog) > +{ > + struct wdt_priv *priv = watchdog_get_drvdata(wdog); > + > + spin_lock(&priv->io_lock); > + > + exar_wdt_disarm(priv); > + > + spin_unlock(&priv->io_lock); > + return 0; > +} > + > +static int exar_wdt_keepalive(struct watchdog_device *wdog) > +{ > + struct wdt_priv *priv = watchdog_get_drvdata(wdog); > + unsigned short rt_base = priv->wdt_res.start; > + > + spin_lock(&priv->io_lock); > + > + /* reading the WDT_VAL reg will feed the watchdog */ > + inb(rt_base + WDT_VAL); > + > + spin_unlock(&priv->io_lock); > + return 0; > +} > + > +static int exar_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t) > +{ > + struct wdt_priv *priv = watchdog_get_drvdata(wdog); > + bool unit_min = false; > + > + /* > + * if new timeout is bigger then 255 seconds, change the > + * unit to minutes and round the timeout up to the next whole minute > + */ > + if (t > 255) { > + unit_min = true; > + t = DIV_ROUND_UP(t, 60); > + } > + > + /* save for later use in exar_wdt_start() */ > + priv->unit = unit_min ? WDT_UNITS_MIN : WDT_UNITS_SEC; > + priv->timeout = t; > + > + wdog->timeout = unit_min ? t * 60 : t; > + > + if (watchdog_hw_running(wdog)) > + exar_wdt_start(wdog); > + > + return 0; > +} > + > +static const struct watchdog_info exar_wdt_info = { > + .options = WDIOF_KEEPALIVEPING | > + WDIOF_SETTIMEOUT | > + WDIOF_MAGICCLOSE, > + .identity = "Exar/MaxLinear XR28V38x Watchdog", > +}; > + > +static const struct watchdog_ops exar_wdt_ops = { > + .owner = THIS_MODULE, > + .start = exar_wdt_start, > + .stop = exar_wdt_stop, > + .ping = exar_wdt_keepalive, > + .set_timeout = exar_wdt_set_timeout, > +}; > + > +static int exar_wdt_config(struct watchdog_device *wdog, > + const unsigned char conf) > +{ > + struct wdt_priv *priv = watchdog_get_drvdata(wdog); > + int ret; > + > + ret = exar_sio_enter(priv->config_port, priv->enter_key); > + if (ret) > + return ret; > + > + exar_sio_select_wdt(priv->config_port); > + exar_sio_write(priv->config_port, EXAR_WDT, conf); > + > + exar_sio_exit(priv->config_port); > + > + return 0; > +} > + > +static int __init exar_wdt_probe(struct platform_device *pdev) > +{ > + struct device *dev = &pdev->dev; > + struct wdt_priv *priv = dev->platform_data; > + struct watchdog_device *wdt_dev = &priv->wdt_dev; > + struct resource *res; > + int ret; > + > + res = platform_get_resource(pdev, IORESOURCE_IO, 0); > + if (!res) > + return -ENXIO; > + > + spin_lock_init(&priv->io_lock); > + > + wdt_dev->info = &exar_wdt_info; > + wdt_dev->ops = &exar_wdt_ops; > + wdt_dev->min_timeout = 1; > + wdt_dev->max_timeout = 255 * 60; > + > + watchdog_init_timeout(wdt_dev, timeout, NULL); > + watchdog_set_nowayout(wdt_dev, nowayout); > + watchdog_stop_on_reboot(wdt_dev); > + watchdog_stop_on_unregister(wdt_dev); > + watchdog_set_drvdata(wdt_dev, priv); > + > + ret = exar_wdt_config(wdt_dev, EXAR_WDT_DEF_CONF); > + if (ret) > + return ret; > + > + exar_wdt_set_timeout(wdt_dev, timeout); > + /* Make sure that the watchdog is not running */ > + exar_wdt_stop(wdt_dev); > + > + ret = devm_watchdog_register_device(dev, wdt_dev); > + if (ret) > + return ret; > + > + dev_info(dev, "XR28V%X WDT initialized. timeout=%d sec (nowayout=%d)\n", > + priv->did, timeout, nowayout); > + > + return 0; > +} > + > +static unsigned short __init exar_detect(const unsigned short config_port, > + const unsigned char key, > + unsigned short *rt_base) > +{ > + int ret; > + unsigned short base = 0; > + unsigned short vid, did; > + > + ret = exar_sio_enter(config_port, key); > + if (ret) > + return 0; > + > + vid = exar_sio_read16(config_port, EXAR_VID); > + did = exar_sio_read16(config_port, EXAR_DID); > + > + /* check for the vendor and device IDs we currently know about */ > + if (vid == EXAR_VEN_ID && > + (did == EXAR_DEV_382 || > + did == EXAR_DEV_384)) { > + exar_sio_select_wdt(config_port); > + /* is device active? */ > + if (exar_sio_read(config_port, EXAR_ACT) == 0x01) > + base = exar_sio_read16(config_port, EXAR_RTBASE); > + } > + > + exar_sio_exit(config_port); > + > + if (base) { > + pr_debug("Found a XR28V%X WDT (conf: 0x%x / rt: 0x%04x)\n", > + did, config_port, base); > + *rt_base = base; > + return did; > + } > + > + return 0; > +} > + > +static struct platform_driver exar_wdt_driver = { > + .driver = { > + .name = DRV_NAME, > + }, > +}; > + > +static LIST_HEAD(pdev_list); > + > +static int __init exar_wdt_register(struct wdt_priv *priv, const int idx) > +{ > + struct wdt_pdev_node *n; > + > + n = kzalloc(sizeof(*n), GFP_KERNEL); > + if (!n) > + return -ENOMEM; > + > + INIT_LIST_HEAD(&n->list); > + > + scnprintf((char *)n->name, sizeof(n->name), DRV_NAME ".%d", idx); > + priv->wdt_res.name = n->name; > + > + n->pdev = platform_device_register_resndata(NULL, DRV_NAME, idx, > + &priv->wdt_res, 1, > + priv, sizeof(*priv)); > + if (IS_ERR(n->pdev)) { > + kfree(n); > + return PTR_ERR(n->pdev); > + } > + > + list_add_tail(&n->list, &pdev_list); > + > + return 0; > +} > + > +static void exar_wdt_unregister(void) > +{ > + struct wdt_pdev_node *n, *t; > + > + list_for_each_entry_safe(n, t, &pdev_list, list) { > + platform_device_unregister(n->pdev); > + list_del(&n->list); > + kfree(n); > + } > +} > + > +static int __init exar_wdt_init(void) > +{ > + int ret, i, j, idx = 0; > + > + /* search for active Exar watchdogs on all possible locations */ > + for (i = 0; i < ARRAY_SIZE(sio_config_ports); i++) { > + for (j = 0; j < ARRAY_SIZE(sio_enter_keys); j++) { > + unsigned short did, rt_base = 0; > + > + did = exar_detect(sio_config_ports[i], > + sio_enter_keys[j], > + &rt_base); > + > + if (did) { > + struct wdt_priv priv = { > + .wdt_res = DEFINE_RES_IO(rt_base, 2), > + .did = did, > + .config_port = sio_config_ports[i], > + .enter_key = sio_enter_keys[j], > + }; > + > + ret = exar_wdt_register(&priv, idx); > + if (!ret) > + idx++; > + } > + } > + } > + > + if (!idx) > + return -ENODEV; > + > + ret = platform_driver_probe(&exar_wdt_driver, exar_wdt_probe); > + if (ret) > + exar_wdt_unregister(); > + > + return ret; > +} > + > +static void __exit exar_wdt_exit(void) > +{ > + exar_wdt_unregister(); > + platform_driver_unregister(&exar_wdt_driver); > +} > + > +module_init(exar_wdt_init); > +module_exit(exar_wdt_exit); > + > +MODULE_AUTHOR("David Müller <d.mueller@xxxxxxxxx>"); > +MODULE_DESCRIPTION("Exar/MaxLinear Watchdog Driver"); > +MODULE_LICENSE("GPL"); > -- > 2.30.2 >
