watchdog: tqmx86: Add watchdog driver for the IO controller

Some TQ-Systems ComExpress modules have an IO controller with a
watchdog timer.

Signed-off-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

3 files changed, 139 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 6dcd5603a3e4..57f017d74a97 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1316,6 +1316,18 @@ config SMSC37B787_WDT
 
           Most people will say N.
 
+config TQMX86_WDT
+        tristate "TQ-Systems TQMX86 Watchdog Timer"
+        depends on X86
+        help
+        This is the driver for the hardware watchdog timer in the TQMX86 IO
+        controller found on some of their ComExpress Modules.
+
+        To compile this driver as a module, choose M here; the module
+        will be called tqmx86_wdt.
+
+        Most people will say N.
+
 config VIA_WDT
         tristate "VIA Watchdog Timer"
         depends on X86 && PCI
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index cc90e723135e..a0917ef28e07 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -130,6 +130,7 @@ obj-$(CONFIG_SBC7240_WDT) += sbc7240_wdt.o
 obj-$(CONFIG_CPU5_WDT) += cpu5wdt.o
 obj-$(CONFIG_SMSC_SCH311X_WDT) += sch311x_wdt.o
 obj-$(CONFIG_SMSC37B787_WDT) += smsc37b787_wdt.o
+obj-$(CONFIG_TQMX86_WDT) += tqmx86_wdt.o
 obj-$(CONFIG_VIA_WDT) += via_wdt.o
 obj-$(CONFIG_W83627HF_WDT) += w83627hf_wdt.o
 obj-$(CONFIG_W83877F_WDT) += w83877f_wdt.o
diff --git a/drivers/watchdog/tqmx86_wdt.c b/drivers/watchdog/tqmx86_wdt.c
new file mode 100644
index 000000000000..0d3a0fbbd7a5
--- /dev/null
+++ b/drivers/watchdog/tqmx86_wdt.c
@@ -0,0 +1,126 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog driver for TQMx86 PLD.
+ *
+ * The watchdog supports power of 2 timeouts from 1 to 4096sec.
+ * Once started, it cannot be stopped.
+ *
+ * Based on the vendor code written by Vadim V.Vlasov
+ * <vvlasov@dev.rtsoft.ru>
+ */
+
+#include <linux/io.h>
+#include <linux/log2.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/timer.h>
+#include <linux/watchdog.h>
+
+/* default timeout (secs) */
+#define WDT_TIMEOUT 32
+
+static unsigned int timeout;
+module_param(timeout, uint, 0);
+MODULE_PARM_DESC(timeout,
+        "Watchdog timeout in seconds. (1<=timeout<=4096, default="
+                                __MODULE_STRING(WDT_TIMEOUT) ")");
+struct tqmx86_wdt {
+        struct watchdog_device wdd;
+        void __iomem *io_base;
+};
+
+#define TQMX86_WDCFG    0x00 /* Watchdog Configuration Register */
+#define TQMX86_WDCS     0x01 /* Watchdog Config/Status Register */
+
+static int tqmx86_wdt_start(struct watchdog_device *wdd)
+{
+        struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
+
+        iowrite8(0x81, priv->io_base + TQMX86_WDCS);
+
+        return 0;
+}
+
+static int tqmx86_wdt_set_timeout(struct watchdog_device *wdd, unsigned int t)
+{
+        struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
+        u8 val;
+
+        t = roundup_pow_of_two(t);
+        val = ilog2(t) | 0x90;
+        val += 3; /* values 0,1,2 correspond to 0.125,0.25,0.5s timeouts */
+        iowrite8(val, priv->io_base + TQMX86_WDCFG);
+
+        wdd->timeout = t;
+
+        return 0;
+}
+
+static const struct watchdog_info tqmx86_wdt_info = {
+        .options        = WDIOF_SETTIMEOUT |
+                          WDIOF_KEEPALIVEPING,
+        .identity       = "TQMx86 Watchdog",
+};
+
+static struct watchdog_ops tqmx86_wdt_ops = {
+        .owner          = THIS_MODULE,
+        .start          = tqmx86_wdt_start,
+        .set_timeout    = tqmx86_wdt_set_timeout,
+};
+
+static int tqmx86_wdt_probe(struct platform_device *pdev)
+{
+        struct tqmx86_wdt *priv;
+        struct resource *res;
+        int err;
+
+        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+        if (!priv)
+                return -ENOMEM;
+
+        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
+        if (IS_ERR(res))
+                return PTR_ERR(res);
+
+        priv->io_base = devm_ioport_map(&pdev->dev, res->start,
+                                        resource_size(res));
+        if (IS_ERR(priv->io_base))
+                return PTR_ERR(priv->io_base);
+
+        watchdog_set_drvdata(&priv->wdd, priv);
+
+        priv->wdd.parent = &pdev->dev;
+        priv->wdd.info = &tqmx86_wdt_info;
+        priv->wdd.ops = &tqmx86_wdt_ops;
+        priv->wdd.min_timeout = 1;
+        priv->wdd.max_timeout = 4096;
+        priv->wdd.max_hw_heartbeat_ms = 4096*1000;
+        priv->wdd.timeout = WDT_TIMEOUT;
+
+        watchdog_init_timeout(&priv->wdd, timeout, &pdev->dev);
+        watchdog_set_nowayout(&priv->wdd, WATCHDOG_NOWAYOUT);
+
+        tqmx86_wdt_set_timeout(&priv->wdd, priv->wdd.timeout);
+
+        err = devm_watchdog_register_device(&pdev->dev, &priv->wdd);
+        if (err)
+                return err;
+
+        dev_info(&pdev->dev, "TQMx86 watchdog\n");
+
+        return 0;
+}
+
+static struct platform_driver tqmx86_wdt_driver = {
+        .driver         = {
+                .name   = "tqmx86-wdt",
+        },
+        .probe          = tqmx86_wdt_probe,
+};
+
+module_platform_driver(tqmx86_wdt_driver);
+
+MODULE_AUTHOR("Andrew Lunn <andrew@lunn.ch>");
+MODULE_DESCRIPTION("TQMx86 Watchdog");
+MODULE_ALIAS("platform:tqmx86-wdt");
+MODULE_LICENSE("GPL");