From: Guenter Roeck <linux@roeck-us.net>
To: "David Müller" <d.mueller@elsoft.ch>
Cc: linux-watchdog@vger.kernel.org
Subject: Re: [PATCH v3] watchdog: Exar/MaxLinear XR28V38x driver
Date: Thu, 15 Sep 2022 01:06:38 -0700 [thread overview]
Message-ID: <20220915080638.GB109875@roeck-us.net> (raw)
In-Reply-To: <20220914094605.93377-1-d.mueller@elsoft.ch>
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@elsoft.ch>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
>
> 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@elsoft.ch>.
> + *
> + */
> +
> +#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@elsoft.ch>");
> +MODULE_DESCRIPTION("Exar/MaxLinear Watchdog Driver");
> +MODULE_LICENSE("GPL");
> --
> 2.30.2
>
prev parent reply other threads:[~2022-09-15 8:27 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-14 9:46 [PATCH v3] watchdog: Exar/MaxLinear XR28V38x driver David Müller
2022-09-15 8:06 ` Guenter Roeck [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220915080638.GB109875@roeck-us.net \
--to=linux@roeck-us.net \
--cc=d.mueller@elsoft.ch \
--cc=linux-watchdog@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).