On 11/30/2015 11:43 PM, Barry Song wrote:
From: Guo Zeng <Guo.Zeng@xxxxxxx>
This patch adds watchdog driver for CSRatlas7 platform.
On CSRatlas7, the 6th timer can act as a watchdog timer
when the Watchdog mode is enabled.
Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Guo Zeng <Guo.Zeng@xxxxxxx>
Signed-off-by: William Wang <William.Wang@xxxxxxx>
Signed-off-by: Barry Song <Baohua.Song@xxxxxxx>
Are those people all in the sign-off path, or just somehow involved
in writing the code ?
---
-v3: fix issues according to Guenter's comments
1. rename updatetimeout to ping
2. drop redundant calling ping in set_timeout
3. fix the error handler in probe
4. move to __maybe_unused for suspend/resume entries
5. fix the min and max timeout
6. clean up clear ugly codes for timeout set
drivers/watchdog/Kconfig | 10 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/atlas7_wdt.c | 249 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 260 insertions(+)
create mode 100644 drivers/watchdog/atlas7_wdt.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 1c427be..52b308f 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -578,6 +578,16 @@ config LPC18XX_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called lpc18xx_wdt.
+config ATLAS7_WATCHDOG
+ tristate "CSRatlas7 watchdog"
+ depends on ARCH_ATLAS7
+ help
+ Say Y here to include Watchdog timer support for the watchdog
+ existing on the CSRatlas7 series platforms.
+
+ To compile this driver as a module, choose M here: the
+ module will be called atlas7_wdt.
+
# AVR32 Architecture
config AT32AP700X_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 53d4827..e2bc52c 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -69,6 +69,7 @@ obj-$(CONFIG_MEDIATEK_WATCHDOG) += mtk_wdt.o
obj-$(CONFIG_DIGICOLOR_WATCHDOG) += digicolor_wdt.o
obj-$(CONFIG_LPC18XX_WATCHDOG) += lpc18xx_wdt.o
obj-$(CONFIG_BCM7038_WDT) += bcm7038_wdt.o
+obj-$(CONFIG_ATLAS7_WATCHDOG) += atlas7_wdt.o
# AVR32 Architecture
obj-$(CONFIG_AT32AP700X_WDT) += at32ap700x_wdt.o
diff --git a/drivers/watchdog/atlas7_wdt.c b/drivers/watchdog/atlas7_wdt.c
new file mode 100644
index 0000000..4f191fe
--- /dev/null
+++ b/drivers/watchdog/atlas7_wdt.c
@@ -0,0 +1,249 @@
+/*
+ * Watchdog driver for CSRatlas7
+ *
+ * Copyright (c) 2015 Cambridge Silicon Radio Limited, a CSR plc group company.
+ *
+ * Licensed under GPLv2 or later.
+ */
+
+#include <linux/module.h>
+#include <linux/watchdog.h>
+#include <linux/platform_device.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/io.h>
+#include <linux/uaccess.h>
Not required.
+#include <linux/clk.h>
+
Please order include files alphabetically.
+#define ATLAS7_TIMER_WDT_INDEX 5
+#define ATLAS7_WDT_DEFAULT_TIMEOUT 20 /* 20 secs */
+
+#define ATLAS7_WDT_CNT_CTRL 0
+#define ATLAS7_WDT_CNT_MATCH 0x18
+#define ATLAS7_WDT_CNT 0x48
Wondering - below you always add 4 * ATLAS7_TIMER_WDT_INDEX
to the WDT_CNT_CTRL, WDT_CNT_MATCH, and WDT_CNT registers.
Wouldn't it be easier to specify the final register offsets directly ?
#define ATLAS7_WDT_CNT_CTRL (0 + 4 * ATLAS7_TIMER_WDT_INDEX)
or even
#define ATLAS7_WDT_CNT_CTRL 0x14
The long expressions below just make the code more difficult to read.
+#define ATLAS7_WDT_CNT_EN (BIT(0) | BIT(1))
+#define ATLAS7_WDT_EN 0x64
+
+static unsigned int timeout = ATLAS7_WDT_DEFAULT_TIMEOUT;
This will cause a devicetree based initialization to be ignored.
It would be better to set this to 0 and initialize .timeout with
ATLAS7_WDT_DEFAULT_TIMEOUT prior to calling watchdog_init_timeout().
+static bool nowayout = WATCHDOG_NOWAYOUT;
+
+module_param(timeout, uint, 0);
+module_param(nowayout, bool, 0);
+
+MODULE_PARM_DESC(timeout, "Default watchdog timeout (in seconds)");
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
+ __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+struct atlas7_wdog {
+ struct device *dev;
+ void __iomem *base;
+ unsigned long tick_rate;
+ struct clk *clk;
+};
+
+static unsigned int atlas7_wdt_gettimeleft(struct watchdog_device *wdd)
+{
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+ u32 counter, match, delta;
+
+ counter = readl(wdt->base + ATLAS7_WDT_CNT +
+ 4 * ATLAS7_TIMER_WDT_INDEX);
+ match = readl(wdt->base + ATLAS7_WDT_CNT_MATCH +
+ 4 * ATLAS7_TIMER_WDT_INDEX);
In general, continuation lines should be aligned with '('.
On the other side, macros such as
#define WDT_CNT_REG(wdt) ((wdt)->base + ATLAS7_WDT_CNT + 4 * ATLAS7_TIMER_WDT_INDEX)
#define WDT_CNT_MATCH_REG(wdt) ((wdt)->base + ATLAS7_WDT_CNT_MATCH + 4 * ATLAS7_TIMER_WDT_INDEX)
#define WDT_CNT_CTRL_REG(wdt) ((wdt)->base + ATLAS7_WDT_CNT_CTRL + 4 * ATLAS7_TIMER_WDT_INDEX)
might be quite useful to avoid the repeated use of long expressions.
Or at least simplify the register definitions as suggested above.
+ delta = match - counter;
+
+ return delta / wdt->tick_rate;
+}
+
+static int atlas7_wdt_ping(struct watchdog_device *wdd)
+{
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+ u32 counter, match, delta;
+
+ counter = readl(wdt->base + ATLAS7_WDT_CNT +
+ 4 * ATLAS7_TIMER_WDT_INDEX);
+ delta = wdd->timeout * wdt->tick_rate;
+ match = counter + delta;
+
+ writel(match, wdt->base + ATLAS7_WDT_CNT_MATCH +
+ 4 * ATLAS7_TIMER_WDT_INDEX);
+
+ return 0;
+}
+
+static int atlas7_wdt_enable(struct watchdog_device *wdd)
+{
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+ void __iomem *ctrl_reg = wdt->base + ATLAS7_WDT_CNT_CTRL +
+ 4 * ATLAS7_TIMER_WDT_INDEX;
+
+ atlas7_wdt_ping(wdd);
+
+ writel(readl(ctrl_reg) | ATLAS7_WDT_CNT_EN, ctrl_reg);
+ writel(1, wdt->base + ATLAS7_WDT_EN);
+
+ return 0;
+}
+
+static int atlas7_wdt_disable(struct watchdog_device *wdd)
+{
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+ void __iomem *ctrl_reg = wdt->base + ATLAS7_WDT_CNT_CTRL +
+ 4 * ATLAS7_TIMER_WDT_INDEX;
+
+ writel(0, wdt->base + ATLAS7_WDT_EN);
+ writel(readl(ctrl_reg) & ~ATLAS7_WDT_CNT_EN, ctrl_reg);
+
+ return 0;
+}
+
+static int atlas7_wdt_settimeout(struct watchdog_device *wdd, unsigned int to)
+{
+ wdd->timeout = to;
+
+ return 0;
+}
+
+#define OPTIONS (WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE)
+
+static const struct watchdog_info atlas7_wdt_ident = {
+ .options = OPTIONS,
+ .firmware_version = 0,
+ .identity = "atlas7 Watchdog",
The tab after '=' is really unnecessary. I would suggest to replace it with a space.
+};
+
+static struct watchdog_ops atlas7_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = atlas7_wdt_enable,
+ .stop = atlas7_wdt_disable,
+ .get_timeleft = atlas7_wdt_gettimeleft,
+ .ping = atlas7_wdt_ping,
+ .set_timeout = atlas7_wdt_settimeout,
+};
+
+static struct watchdog_device atlas7_wdd = {
+ .info = &atlas7_wdt_ident,
+ .ops = &atlas7_wdt_ops,
+ .timeout = ATLAS7_WDT_DEFAULT_TIMEOUT,
+};
+
+static const struct of_device_id atlas7_wdt_ids[] = {
+ { .compatible = "sirf,atlas7-tick"},
+ {}
+};
+
+static int atlas7_wdt_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct atlas7_wdog *wdt;
+ struct resource *res;
+ struct clk *clk;
+ int ret;
+
+ wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
+ if (!wdt)
+ return -ENOMEM;
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ wdt->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(wdt->base))
+ return PTR_ERR(wdt->base);
+
+ clk = of_clk_get(np, 0);
+ if (IS_ERR(clk)) {
+ ret = PTR_ERR(clk);
+ goto err;
You can just return PTR_ERR(clk) here.
The "err:" label, just to return, is unnecessary.
+ }
+ ret = clk_prepare_enable(clk);
+ if (ret) {
+ pr_err("wdt clk enable failed\n");
+ goto err1;
wdt->clk is not yet set here, meaning the clk_put() below won't work.
+ }
+
+ /* disable watchdog hardware */
+ writel(0, wdt->base + ATLAS7_WDT_CNT_CTRL +
+ 4 * ATLAS7_TIMER_WDT_INDEX);
+
+ wdt->tick_rate = clk_get_rate(clk);
+ wdt->clk = clk;
+ atlas7_wdd.min_timeout = 1;
+ atlas7_wdd.max_timeout = UINT_MAX / wdt->tick_rate;
+
+ watchdog_init_timeout(&atlas7_wdd, timeout, &pdev->dev);
+ watchdog_set_nowayout(&atlas7_wdd, nowayout);
+
+ watchdog_set_drvdata(&atlas7_wdd, wdt);
+ platform_set_drvdata(pdev, &atlas7_wdd);
+
+ ret = watchdog_register_device(&atlas7_wdd);
+ if (ret)
+ goto err2;
+
+ return 0;
+
+err2:
+ clk_disable_unprepare(wdt->clk);
+err1:
+ clk_put(wdt->clk);
+err:
+ return ret;
+}
+
+static void atlas7_wdt_shutdown(struct platform_device *pdev)
+{
+ struct watchdog_device *wdd = platform_get_drvdata(pdev);
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+
+ atlas7_wdt_disable(wdd);
+ clk_disable_unprepare(wdt->clk);
+}
+
+static int atlas7_wdt_remove(struct platform_device *pdev)
+{
+ struct watchdog_device *wdd = platform_get_drvdata(pdev);
+ struct atlas7_wdog *wdt = watchdog_get_drvdata(wdd);
+
+ atlas7_wdt_shutdown(pdev);
+ clk_put(wdt->clk);
+ return 0;
+}
+
+static int __maybe_unused atlas7_wdt_suspend(struct device *dev)
+{
+ return 0;
Is it not necessary to stop the watchdog ? If the watchdog is disabled
elsewhere, a similar comment to the one below would help.
+}
+
+static int __maybe_unused atlas7_wdt_resume(struct device *dev)
+{
+ struct watchdog_device *wdd = dev_get_drvdata(dev);
+
+ /*
+ * NOTE: Since timer controller registers settings are saved
+ * and restored back by the timer-atlas7.c, so we need not
+ * update WD settings except refreshing timeout.
+ */
+ atlas7_wdt_ping(wdd);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(atlas7_wdt_pm_ops,
+ atlas7_wdt_suspend, atlas7_wdt_resume);
+
+MODULE_DEVICE_TABLE(of, atlas7_wdt_ids);
+
+static struct platform_driver atlas7_wdt_driver = {
+ .driver = {
+ .name = "atlas7-wdt",
+ .pm = &atlas7_wdt_pm_ops,
+ .of_match_table = atlas7_wdt_ids,
+ },
+ .probe = atlas7_wdt_probe,
+ .remove = atlas7_wdt_remove,
+ .shutdown = atlas7_wdt_shutdown,
+};
+module_platform_driver(atlas7_wdt_driver);
+
+MODULE_DESCRIPTION("CSRatlas7 watchdog driver");
+MODULE_AUTHOR("Guo Zeng <Guo.Zeng@xxxxxxx>");
+MODULE_LICENSE("GPL v2");
This contradicts "GPL v2 or later" in the comments at the beginning of the file.
+MODULE_ALIAS("platform:atlas7-wdt");
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