On 12/8/18 8:13 AM, Andrew Lunn wrote:
Some TQ-Systems ComExpress modules have an IO controller with a
watchdog time.
Signed-off-by: Andrew Lunn <andrew@xxxxxxx>
---
drivers/watchdog/Kconfig | 12 +++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/tqmx86_wdt.c | 157 ++++++++++++++++++++++++++++++++++
3 files changed, 170 insertions(+)
create mode 100644 drivers/watchdog/tqmx86_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 2d64333f4782..1c99238c2f32 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1308,6 +1308,18 @@ 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 TQMN86 IO
+ on controller found on some of their ComExpress Modules.
"on controller" ? Should that be just "controller" ?
+
+ To compile this driver as a module, choose M here; the module
+ will be called via_wdt.
via_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 f69cdff5ad7f..b077e35414e2 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -129,6 +129,7 @@ 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..9f5d4612b97a
--- /dev/null
+++ b/drivers/watchdog/tqmx86_wdt.c
@@ -0,0 +1,157 @@
+// 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.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#include <linux/timer.h>
+#include <linux/io.h>
+#include <linux/log2.h>
+
Alphabetic order, please.
+/* default timeout (secs) */
+#define WDT_TIMEOUT 32
+
+static unsigned int timeout = WDT_TIMEOUT;
Please set to 0 (ie don't set it) and use watchdog_init_timeout() in the probe
function to override the default.
+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_stop(struct watchdog_device *wdd)
+{
+ return -EINVAL;
+}
This is quite pointless. If there is no means to stop the watchdog,
just don't provide a stop function.
+
+static int tqmx86_wdt_ping(struct watchdog_device *wdd)
+{
+ struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
+
+ iowrite8(0x81, priv->io_base + TQMX86_WDCS);
+
If the start and the ping function are the same, the ping function
can be omitted.
+ return 0;
+}
+
+static int tqmx86_wdt_set_timeout(struct watchdog_device *wdd,
+ unsigned int new_timeout)
+{
+ struct tqmx86_wdt *priv = watchdog_get_drvdata(wdd);
+ u8 val;
+
+ if (new_timeout < 1 || new_timeout > 4096) {
+ dev_info(wdd->parent, "Timeout must be between 1 and 4096\n");
+ return -EINVAL;
+ }
Not necessary; checked by infrastructure.
+
+ timeout = roundup_pow_of_two(new_timeout);
+ val = ilog2(timeout) | 0x90;
+ val += 3; /* vallues 0,1,2 correspond to 0.125,0.25,0.5s timeouts */
values
+ iowrite8(val, priv->io_base + TQMX86_WDCFG);
+
+ wdd->timeout = timeout;
+
+ 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,
+ .stop = tqmx86_wdt_stop,
+ .ping = tqmx86_wdt_ping,
+ .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);
+
+ if (timeout < 1 || timeout > 4096) {
+ timeout = WDT_TIMEOUT;
+ dev_warn(&pdev->dev,
+ "timeout value must be 1<=x<=4096, using %d\n",
+ timeout);
+ }
+
You should set the default in the wdd structure and call watchdog_init_timeout()
to update it.
+ platform_set_drvdata(pdev, priv);
+ watchdog_set_drvdata(&priv->wdd, priv);
+
+ tqmx86_wdt_set_timeout(&priv->wdd, timeout);
+
+ priv->wdd.parent = &pdev->dev;
+ priv->wdd.info = &tqmx86_wdt_info;
+ priv->wdd.ops = &tqmx86_wdt_ops;
+
You should also specify minimum and maximum timeout
to enable boundary checking by the watchdog core.
+ watchdog_set_nowayout(&priv->wdd, 1);
Why not use CONFIG_WATCHDOG_NOWAYOUT and WATCHDOG_NOWAYOUT ?
+
+ err = watchdog_register_device(&priv->wdd);
+ if (err)
+ return err;
+
+ dev_info(&pdev->dev, "TQMx86 watchdog\n");
+
+ return 0;
+}
+
+static int tqmx86_wdt_remove(struct platform_device *pdev)
+{
+ struct tqmx86_wdt *priv = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&priv->wdd);
+ return 0;
If the remove function only removes the watchdog, you can use
devm_watchdog_register_device() to register it and drop the remove function.
+}
+
+static struct platform_driver tqmx86_wdt_driver = {
+ .driver = {
+ .name = "tqmx86-wdt",
+ },
+ .probe = tqmx86_wdt_probe,
+ .remove = tqmx86_wdt_remove,
+};
+
+module_platform_driver(tqmx86_wdt_driver);
+
+MODULE_AUTHOR("Vadim V.Vlasov <vvlasov@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("TQMx86 Watchdog");
+MODULE_ALIAS("platform:tqmx86-wdt");
+MODULE_LICENSE("GPL");
