On 11/12/21 2:59 AM, Xiantao Hu wrote:
Sunplus SP7021 requires watchdog timer support.
Add watchdog driver to enable this.
Signed-off-by: Xiantao Hu <xt.hu@xxxxxxxxxxx>
---
MAINTAINERS | 6 +
drivers/watchdog/Kconfig | 11 ++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/sunplus_wdt.c | 297 +++++++++++++++++++++++++++++++++
4 files changed, 315 insertions(+)
create mode 100644 drivers/watchdog/sunplus_wdt.c
diff --git a/MAINTAINERS b/MAINTAINERS
index e0bca0de0..f6a328772 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17933,6 +17933,12 @@ L: netdev@xxxxxxxxxxxxxxx
S: Maintained
F: drivers/net/ethernet/dlink/sundance.c
+SUNPLUS WATCHDOG DRIVER
+M: Xiantao Hu <xt.hu@xxxxxxxxxxx>
+L: linux-watchdog@xxxxxxxxxxxxxxx
+S: Maintained
+F: drivers/watchdog/sunplus_wdt.c
+
SUPERH
M: Yoshinori Sato <ysato@xxxxxxxxxxxxxxxxxxxx>
M: Rich Felker <dalias@xxxxxxxx>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index bf59faeb3..1a95df8ed 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -990,6 +990,17 @@ config MSC313E_WATCHDOG
To compile this driver as a module, choose M here: the
module will be called msc313e_wdt.
+config SUNPLUS_WATCHDOG
+ tristate "Sunplus watchdog support"
+ depends on ARCH_SUNPLUS || COMPILE_TEST
+ select WATCHDOG_CORE
+ help
+ Say Y here to include support for the watchdog timer
+ in Sunplus SoCs.
+
+ To compile this driver as a module, choose M here: the
+ module will be called sunplus_wdt.
+
# X86 (i386 + ia64 + x86_64) Architecture
config ACQUIRE_WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 1bd2d6f37..d6a9e4d0e 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -94,6 +94,7 @@ obj-$(CONFIG_PM8916_WATCHDOG) += pm8916_wdt.o
obj-$(CONFIG_ARM_SMC_WATCHDOG) += arm_smc_wdt.o
obj-$(CONFIG_VISCONTI_WATCHDOG) += visconti_wdt.o
obj-$(CONFIG_MSC313E_WATCHDOG) += msc313e_wdt.o
+obj-$(CONFIG_SUNPLUS_WATCHDOG) += sunplus_wdt.o
# X86 (i386 + ia64 + x86_64) Architecture
obj-$(CONFIG_ACQUIRE_WDT) += acquirewdt.o
diff --git a/drivers/watchdog/sunplus_wdt.c b/drivers/watchdog/sunplus_wdt.c
new file mode 100644
index 000000000..27f22c518
--- /dev/null
+++ b/drivers/watchdog/sunplus_wdt.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * sunplus Watchdog Driver
+ *
+ * Copyright (C) 2021 Sunplus Technology Co., Ltd.
+ *
+ */
+
+#include <linux/clk.h>
+#include <linux/io.h>
+#include <linux/module.h>
+#include <linux/mod_devicetable.h>
+#include <linux/platform_device.h>
+#include <linux/reset.h>
+#include <linux/watchdog.h>
+
+#define WDT_CTRL 0x00
+#define WDT_CNT 0x04
+
+#define WDT_STOP 0x3877
+#define WDT_RESUME 0x4A4B
+#define WDT_CLRIRQ 0x7482
+#define WDT_UNLOCK 0xAB00
+#define WDT_LOCK 0xAB01
+#define WDT_CONMAX 0xDEAF
+
+#define RBUS_WDT_RST BIT(1)
+#define STC_WDT_RST BIT(4)
+
+#define MASK_SET(mask) ((mask) | (mask << 16))
+
+#define SP_WDT_MAX_TIMEOUT 11
+#define SP_WDT_MIN_TIMEOUT 1
+
+#define STC_CLK 90000
+
+#define DEVICE_NAME "sunplus-wdt"
+
+static unsigned int timeout;
+module_param(timeout, int, 0);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");
+
+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) ")");
+
+struct sp_wdt_priv {
+ struct watchdog_device wdev;
+ void __iomem *base;
+ void __iomem *miscellaneous;
Please find a better name for this variable. Also, unless I am
missing something, it is only used in the init function. That means
it can be passed to that function as parameter and doesn't need
to be stored in sp_wdt_priv.
+ struct clk *clk;
+ struct reset_control *rstc;
+};
+
+static int sp_wdt_restart(struct watchdog_device *wdev,
+ unsigned long action, void *data)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base;
+
+ base = priv->base;
+ writel(WDT_STOP, base + WDT_CTRL);
+ writel(WDT_UNLOCK, base + WDT_CTRL);
+ writel(0x0001, base + WDT_CNT);
+ writel(WDT_RESUME, base + WDT_CTRL);
+
+ return 0;
+}
+
+/* TIMEOUT_MAX = ffff0/90kHz =11.65,so longer than 11 seconds will time out */
+static int sp_wdt_ping(struct watchdog_device *wdev)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base = priv->base;
+ u32 count;
+
+ writel(WDT_STOP, base + WDT_CTRL);
+ writel(WDT_UNLOCK, base + WDT_CTRL);
+ /* tiemrw_cnt[3:0]cant be write,only [19:4] can be write. */
+ count = (wdev->timeout * STC_CLK) >> 4;
+ writel(count, base + WDT_CNT);
+ writel(WDT_RESUME, base + WDT_CTRL);
+
+ return 0;
+}
+
+static int sp_wdt_set_timeout(struct watchdog_device *wdev,
+ unsigned int timeout)
+{
+ wdev->timeout = timeout;
+
I would assume this also needs to set the new timeout in HW if
the watchdog is running, or the watchdog could time out before
userspace sends another ping.
+ return 0;
+}
+
+static int sp_wdt_stop(struct watchdog_device *wdev)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base = priv->base;
+
+ writel(WDT_STOP, base + WDT_CTRL);
+
+ return 0;
+}
+
+static int sp_wdt_start(struct watchdog_device *wdev)
+{
+ int ret;
+
+ ret = sp_wdt_set_timeout(wdev, wdev->timeout);
That function never returns an error, so checking for it is
pointless here.
+ if (ret < 0)
+ return ret;
+
+ sp_wdt_ping(wdev);
+
+ return 0;
+}
+
+static unsigned int sp_wdt_get_timeleft(struct watchdog_device *wdev)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base = priv->base;
+ u32 val;
+
+ val = readl(base + WDT_CNT);
+ val &= 0xffff;
+ val = val << 4;
+
+ return val;
+}
+
+/*
+ * 1.We need to reset watchdog flag(clear watchdog interrupt) here
+ * because watchdog timer driver does not have an interrupt handler,
+ * and before enalbe STC and RBUS watchdog timeout. Otherwise,
enable
+ * the intr is always in the triggered state.
+ * 2.enable STC and RBUS watchdog timeout trigger.
+ * 3.watchdog conuter is running, need to be stopped.
counter
+ */
+static int sp_wdt_hw_init(struct watchdog_device *wdev)
+{
+ struct sp_wdt_priv *priv = watchdog_get_drvdata(wdev);
+ void __iomem *base = priv->base;
+ void __iomem *miscellaneous = priv->miscellaneous;
+ u32 val;
+
+ writel(WDT_CLRIRQ, base + WDT_CTRL);
+ val = readl(miscellaneous);
+ val |= MASK_SET(STC_WDT_RST);
+ val |= MASK_SET(RBUS_WDT_RST);
+ writel(val, miscellaneous);
+
+ sp_wdt_stop(wdev);
+
+ return 0;
+}
+
+static const struct watchdog_info sp_wdt_info = {
+ .identity = DEVICE_NAME,
+ .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+};
+
+static const struct watchdog_ops sp_wdt_ops = {
+ .owner = THIS_MODULE,
+ .start = sp_wdt_start,
+ .stop = sp_wdt_stop,
+ .ping = sp_wdt_ping,
+ .set_timeout = sp_wdt_set_timeout,
+ .get_timeleft = sp_wdt_get_timeleft,
+ .restart = sp_wdt_restart,
+};
+
+static int sp_wdt_probe(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+ struct sp_wdt_priv *priv;
+ struct resource *wdt_res;
+ struct clk *clk;
+ int err;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ priv->clk = devm_clk_get(dev, NULL);
+ if (IS_ERR(priv->clk)) {
+ dev_err(dev, "Can't find clock source\n");
+ return PTR_ERR(priv->clk);
+ }
+
+ err = clk_prepare_enable(clk);
+ if (err) {
+ dev_err(dev, "Clock can't be enabled correctly\n");
+ return err;
+ }
+
+ priv->rstc = devm_reset_control_get_exclusive(dev, NULL);
+ if (!IS_ERR(priv->rstc))
+ reset_control_deassert(priv->rstc);
+
+ platform_set_drvdata(pdev, priv);
+
+ priv->base = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(priv->base))
+ return PTR_ERR(priv->base);
+
+ wdt_res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+ priv->miscellaneous =
+ devm_ioremap(dev, wdt_res->start, resource_size(wdt_res));
Why not use devm_ioremap_resource() ? Or, for that matter,
devm_platform_ioremap_resource() like above ?
+ if (IS_ERR(priv->miscellaneous))
+ return PTR_ERR(priv->miscellaneous);
+
+ priv->wdev.info = &sp_wdt_info;
+ priv->wdev.ops = &sp_wdt_ops;
+ priv->wdev.timeout = SP_WDT_MAX_TIMEOUT;
+ priv->wdev.max_timeout = SP_WDT_MAX_TIMEOUT;
+ priv->wdev.min_timeout = SP_WDT_MIN_TIMEOUT;
THis should really use max_hw_heartbeat_ms to let the core
ping the watchdog if larger timeouts are desired.
+ priv->wdev.parent = dev;
+
+ watchdog_set_drvdata(&priv->wdev, priv);
+ sp_wdt_hw_init(&priv->wdev);
+
+ watchdog_init_timeout(&priv->wdev, timeout, dev);
+ watchdog_set_nowayout(&priv->wdev, nowayout);
+ watchdog_stop_on_reboot(&priv->wdev);
+
+ err = devm_watchdog_register_device(dev, &priv->wdev);
Since you call watchdog_unregister_device() below you can not use
the devm_ function here.
+ if (unlikely(err))
This is not time critical. Drop the unlikely.
+ return err;
+
+ dev_info(dev, "Watchdog enabled (timeout=%d sec%s.)\n",
+ priv->wdev.timeout, nowayout ? ", nowayout" : "");
+
+ return 0;
+}
+
+static int sp_wdt_remove(struct platform_device *pdev)
+{
+ struct sp_wdt_priv *priv = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&priv->wdev);
+
+ reset_control_assert(priv->rstc);
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static const struct of_device_id sp_wdt_of_match[] = {
+ {.compatible = "sunplus,sp7021-wdt", },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sp_wdt_of_match);
+
+static int __maybe_unused sp_wdt_suspend(struct device *dev)
+{
+ struct sp_wdt_priv *priv = dev_get_drvdata(dev);
+
+ if (watchdog_active(&priv->wdev))
+ sp_wdt_stop(&priv->wdev);
+
+ reset_control_assert(priv->rstc);
+ clk_disable_unprepare(priv->clk);
+
+ return 0;
+}
+
+static int __maybe_unused sp_wdt_resume(struct device *dev)
+{
+ struct sp_wdt_priv *priv = dev_get_drvdata(dev);
+
+ if (watchdog_active(&priv->wdev))
+ sp_wdt_start(&priv->wdev);
+
Shouldn't the order be the opposite of the order in the suspend function ?
+ reset_control_deassert(priv->rstc);
+ clk_prepare_enable(priv->clk);
+
+ return 0;
+}
+
+static SIMPLE_DEV_PM_OPS(sp_wdt_pm_ops, sp_wdt_suspend, sp_wdt_resume);
+
+static struct platform_driver sp_wdt_driver = {
+ .probe = sp_wdt_probe,
+ .remove = sp_wdt_remove,
+ .driver = {
+ .name = DEVICE_NAME,
+ .of_match_table = sp_wdt_of_match,
+ .pm = &sp_wdt_pm_ops,
+ },
+};
+
+module_platform_driver(sp_wdt_driver);
+
+MODULE_AUTHOR("Xiantao Hu <xt.hu@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Sunplus Watchdog Timer Driver");
+MODULE_LICENSE("GPL v2");
