On 10/20/2016 10:45 PM, Yang Ling wrote:
Add watchdog timer specific driver for Loongson1 SoC.
Signed-off-by: Yang Ling <gnaygnil@xxxxxxxxx>
---
V2.1 from Kelvin Cheung:
Use max_hw_heartbeat_ms instead of max_timeout.
V2:
Increase the value of the default heartbeat.
Modify the setup process for register.
Order include files and Makefile alphabetically.
V1.1:
Add a little debugging information.
---
drivers/watchdog/Kconfig | 7 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/loongson1_wdt.c | 158 +++++++++++++++++++++++++++++++++++++++
3 files changed, 166 insertions(+)
create mode 100644 drivers/watchdog/loongson1_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 50dbaa8..6707d43 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1513,6 +1513,13 @@ config LANTIQ_WDT
help
Hardware driver for the Lantiq SoC Watchdog Timer.
+config LOONGSON1_WDT
+ tristate "Loongson1 SoC hardware watchdog"
+ depends on MACH_LOONGSON32
+ select WATCHDOG_CORE
+ help
+ Hardware driver for the Loongson1 SoC Watchdog Timer.
+
config RALINK_WDT
tristate "Ralink SoC watchdog"
select WATCHDOG_CORE
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index cba0043..b6a8d70 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -157,6 +157,7 @@ obj-$(CONFIG_TXX9_WDT) += txx9wdt.o
obj-$(CONFIG_OCTEON_WDT) += octeon-wdt.o
octeon-wdt-y := octeon-wdt-main.o octeon-wdt-nmi.o
obj-$(CONFIG_LANTIQ_WDT) += lantiq_wdt.o
+obj-$(CONFIG_LOONGSON1_WDT) += loongson1_wdt.o
obj-$(CONFIG_RALINK_WDT) += rt2880_wdt.o
obj-$(CONFIG_IMGPDC_WDT) += imgpdc_wdt.o
obj-$(CONFIG_MT7621_WDT) += mt7621_wdt.o
diff --git a/drivers/watchdog/loongson1_wdt.c b/drivers/watchdog/loongson1_wdt.c
new file mode 100644
index 0000000..f885294
--- /dev/null
+++ b/drivers/watchdog/loongson1_wdt.c
@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2016 Yang Ling <gnaygnil@xxxxxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
Odd spacing.
+ */
+
+#include <linux/clk.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/watchdog.h>
+#include <loongson1.h>
+
+#define DEFAULT_HEARTBEAT 30
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, 0444);
+
+static unsigned int heartbeat = DEFAULT_HEARTBEAT;
+module_param(heartbeat, uint, 0444);
+
+struct ls1x_wdt_drvdata {
+ void __iomem *base;
+ struct clk *clk;
+ unsigned int counts_per_second;
+ struct watchdog_device wdt;
+};
+
+static int ls1x_wdt_ping(struct watchdog_device *wdt_dev)
+{
+ struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+
+ writel(0x1, drvdata->base + WDT_SET);
+
+ return 0;
+}
+
+static int ls1x_wdt_set_timeout(struct watchdog_device *wdt_dev,
+ unsigned int timeout)
+{
+ struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+ unsigned int counts;
+
+ wdt_dev->timeout = min(timeout, wdt_dev->max_hw_heartbeat_ms / 1000);
The point of using max_hw_heartbeat_ms is that the watchdog core takes care of
timeouts larger than the maximum supported by the hardware. What you should do
here is something along the line of
wdt_dev->timeout = timeout;
counts = drvdata->counts_per_second * min(timeout, wdt_dev->max_hw_heartbeat_ms / 1000);
+ counts = drvdata->counts_per_second * wdt_dev->timeout;
+
+ writel(counts, drvdata->base + WDT_TIMER);
+
+ return 0;
+}
+
+static int ls1x_wdt_start(struct watchdog_device *wdt_dev)
+{
+ struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+
+ writel(0x1, drvdata->base + WDT_EN);
+
+ return 0;
+}
+
+static int ls1x_wdt_stop(struct watchdog_device *wdt_dev)
+{
+ struct ls1x_wdt_drvdata *drvdata = watchdog_get_drvdata(wdt_dev);
+
+ writel(0x0, drvdata->base + WDT_EN);
+
+ return 0;
+}
+
+static const struct watchdog_info ls1x_wdt_info = {
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+ .identity = "Loongson1 Watchdog",
+};
+
+static const struct watchdog_ops ls1x_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = ls1x_wdt_start,
+ .stop = ls1x_wdt_stop,
+ .ping = ls1x_wdt_ping,
+ .set_timeout = ls1x_wdt_set_timeout,
+};
+
+static int ls1x_wdt_probe(struct platform_device *pdev)
+{
+ struct ls1x_wdt_drvdata *drvdata;
+ struct watchdog_device *ls1x_wdt;
+ struct resource *res;
+ int ret;
+
+ drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
+ if (!drvdata)
+ return -ENOMEM;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ drvdata->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(drvdata->base))
+ return PTR_ERR(drvdata->base);
+
+ drvdata->clk = devm_clk_get(&pdev->dev, pdev->name);
+ if (IS_ERR(drvdata->clk)) {
+ dev_err(&pdev->dev, "failed to get %s clock\n", pdev->name);
+ return PTR_ERR(drvdata->clk);
+ }
+ clk_prepare_enable(drvdata->clk);
+
+ drvdata->counts_per_second = clk_get_rate(drvdata->clk);
clk_get_rate() can at least in theory return 0,
+
+ ls1x_wdt = &drvdata->wdt;
+ ls1x_wdt->info = &ls1x_wdt_info;
+ ls1x_wdt->ops = &ls1x_wdt_ops;
+ ls1x_wdt->min_timeout = 1;
+ ls1x_wdt->max_hw_heartbeat_ms = U32_MAX / drvdata->counts_per_second *
+ 1000;
which would result in a crash here.
+ ls1x_wdt->parent = &pdev->dev;
+
+ watchdog_init_timeout(ls1x_wdt, heartbeat, &pdev->dev);
+ watchdog_set_nowayout(ls1x_wdt, nowayout);
+ watchdog_set_drvdata(ls1x_wdt, drvdata);
+
+ ret = watchdog_register_device(&drvdata->wdt);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "failed to register watchdog device\n");
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, drvdata);
+
+ dev_info(&pdev->dev, "Loongson1 Watchdog driver registered\n");
+
+ return 0;
+}
+
+static int ls1x_wdt_remove(struct platform_device *pdev)
+{
+ struct ls1x_wdt_drvdata *drvdata = platform_get_drvdata(pdev);
+
+ ls1x_wdt_stop(&drvdata->wdt);
This should not be necessary. If the watchdog device is open (meaning the
watchdog may be running), you should not be able to unload the driver.
Can you test ?
+ watchdog_unregister_device(&drvdata->wdt);
+ clk_disable_unprepare(drvdata->clk);
+
+ return 0;
+}
+
+static struct platform_driver ls1x_wdt_driver = {
+ .probe = ls1x_wdt_probe,
+ .remove = ls1x_wdt_remove,
+ .driver = {
+ .name = "ls1x-wdt",
+ },
+};
+
+module_platform_driver(ls1x_wdt_driver);
+
+MODULE_AUTHOR("Yang Ling <gnaygnil@xxxxxxxxx>");
+MODULE_DESCRIPTION("Loongson1 Watchdog Driver");
+MODULE_LICENSE("GPL");
