Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 375 insertions, 0 deletions

diff --git a/drivers/watchdog/armada_37xx_wdt.c b/drivers/watchdog/armada_37xx_wdt.c
new file mode 100644
index 000000000..dcb3ffda3
--- /dev/null
+++ b/drivers/watchdog/armada_37xx_wdt.c
@@ -0,0 +1,375 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog driver for Marvell Armada 37xx SoCs
+ *
+ * Author: Marek Behun <marek.behun@nic.cz>
+ */
+
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+#include <linux/watchdog.h>
+
+/*
+ * There are four counters that can be used for watchdog on Armada 37xx.
+ * The addresses for counter control registers are register base plus ID*0x10,
+ * where ID is 0, 1, 2 or 3.
+ *
+ * In this driver we use IDs 0 and 1. Counter ID 1 is used as watchdog counter,
+ * while counter ID 0 is used to implement pinging the watchdog: counter ID 1 is
+ * set to restart counting from initial value on counter ID 0 end count event.
+ * Pinging is done by forcing immediate end count event on counter ID 0.
+ * If only one counter was used, pinging would have to be implemented by
+ * disabling and enabling the counter, leaving the system in a vulnerable state
+ * for a (really) short period of time.
+ *
+ * Counters ID 2 and 3 are enabled by default even before U-Boot loads,
+ * therefore this driver does not provide a way to use them, eg. by setting a
+ * property in device tree.
+ */
+
+#define CNTR_ID_RETRIGGER		0
+#define CNTR_ID_WDOG			1
+
+/* relative to cpu_misc */
+#define WDT_TIMER_SELECT		0x64
+#define WDT_TIMER_SELECT_MASK		0xf
+#define WDT_TIMER_SELECT_VAL		BIT(CNTR_ID_WDOG)
+
+/* relative to reg */
+#define CNTR_CTRL(id)			((id) * 0x10)
+#define CNTR_CTRL_ENABLE		0x0001
+#define CNTR_CTRL_ACTIVE		0x0002
+#define CNTR_CTRL_MODE_MASK		0x000c
+#define CNTR_CTRL_MODE_ONESHOT		0x0000
+#define CNTR_CTRL_MODE_HWSIG		0x000c
+#define CNTR_CTRL_TRIG_SRC_MASK		0x00f0
+#define CNTR_CTRL_TRIG_SRC_PREV_CNTR	0x0050
+#define CNTR_CTRL_PRESCALE_MASK		0xff00
+#define CNTR_CTRL_PRESCALE_MIN		2
+#define CNTR_CTRL_PRESCALE_SHIFT	8
+
+#define CNTR_COUNT_LOW(id)		(CNTR_CTRL(id) + 0x4)
+#define CNTR_COUNT_HIGH(id)		(CNTR_CTRL(id) + 0x8)
+
+#define WATCHDOG_TIMEOUT		120
+
+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 armada_37xx_watchdog {
+	struct watchdog_device wdt;
+	struct regmap *cpu_misc;
+	void __iomem *reg;
+	u64 timeout; /* in clock ticks */
+	unsigned long clk_rate;
+	struct clk *clk;
+};
+
+static u64 get_counter_value(struct armada_37xx_watchdog *dev, int id)
+{
+	u64 val;
+
+	/*
+	 * when low is read, high is latched into flip-flops so that it can be
+	 * read consistently without using software debouncing
+	 */
+	val = readl(dev->reg + CNTR_COUNT_LOW(id));
+	val |= ((u64)readl(dev->reg + CNTR_COUNT_HIGH(id))) << 32;
+
+	return val;
+}
+
+static void set_counter_value(struct armada_37xx_watchdog *dev, int id, u64 val)
+{
+	writel(val & 0xffffffff, dev->reg + CNTR_COUNT_LOW(id));
+	writel(val >> 32, dev->reg + CNTR_COUNT_HIGH(id));
+}
+
+static void counter_enable(struct armada_37xx_watchdog *dev, int id)
+{
+	u32 reg;
+
+	reg = readl(dev->reg + CNTR_CTRL(id));
+	reg |= CNTR_CTRL_ENABLE;
+	writel(reg, dev->reg + CNTR_CTRL(id));
+}
+
+static void counter_disable(struct armada_37xx_watchdog *dev, int id)
+{
+	u32 reg;
+
+	reg = readl(dev->reg + CNTR_CTRL(id));
+	reg &= ~CNTR_CTRL_ENABLE;
+	writel(reg, dev->reg + CNTR_CTRL(id));
+}
+
+static void init_counter(struct armada_37xx_watchdog *dev, int id, u32 mode,
+			 u32 trig_src)
+{
+	u32 reg;
+
+	reg = readl(dev->reg + CNTR_CTRL(id));
+
+	reg &= ~(CNTR_CTRL_MODE_MASK | CNTR_CTRL_PRESCALE_MASK |
+		 CNTR_CTRL_TRIG_SRC_MASK);
+
+	/* set mode */
+	reg |= mode & CNTR_CTRL_MODE_MASK;
+
+	/* set prescaler to the min value */
+	reg |= CNTR_CTRL_PRESCALE_MIN << CNTR_CTRL_PRESCALE_SHIFT;
+
+	/* set trigger source */
+	reg |= trig_src & CNTR_CTRL_TRIG_SRC_MASK;
+
+	writel(reg, dev->reg + CNTR_CTRL(id));
+}
+
+static int armada_37xx_wdt_ping(struct watchdog_device *wdt)
+{
+	struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt);
+
+	/* counter 1 is retriggered by forcing end count on counter 0 */
+	counter_disable(dev, CNTR_ID_RETRIGGER);
+	counter_enable(dev, CNTR_ID_RETRIGGER);
+
+	return 0;
+}
+
+static unsigned int armada_37xx_wdt_get_timeleft(struct watchdog_device *wdt)
+{
+	struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt);
+	u64 res;
+
+	res = get_counter_value(dev, CNTR_ID_WDOG) * CNTR_CTRL_PRESCALE_MIN;
+	do_div(res, dev->clk_rate);
+
+	return res;
+}
+
+static int armada_37xx_wdt_set_timeout(struct watchdog_device *wdt,
+				       unsigned int timeout)
+{
+	struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt);
+
+	wdt->timeout = timeout;
+
+	/*
+	 * Compute the timeout in clock rate. We use smallest possible
+	 * prescaler, which divides the clock rate by 2
+	 * (CNTR_CTRL_PRESCALE_MIN).
+	 */
+	dev->timeout = (u64)dev->clk_rate * timeout;
+	do_div(dev->timeout, CNTR_CTRL_PRESCALE_MIN);
+
+	return 0;
+}
+
+static bool armada_37xx_wdt_is_running(struct armada_37xx_watchdog *dev)
+{
+	u32 reg;
+
+	regmap_read(dev->cpu_misc, WDT_TIMER_SELECT, &reg);
+	if ((reg & WDT_TIMER_SELECT_MASK) != WDT_TIMER_SELECT_VAL)
+		return false;
+
+	reg = readl(dev->reg + CNTR_CTRL(CNTR_ID_WDOG));
+	return !!(reg & CNTR_CTRL_ACTIVE);
+}
+
+static int armada_37xx_wdt_start(struct watchdog_device *wdt)
+{
+	struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt);
+
+	/* select counter 1 as watchdog counter */
+	regmap_write(dev->cpu_misc, WDT_TIMER_SELECT, WDT_TIMER_SELECT_VAL);
+
+	/* init counter 0 as retrigger counter for counter 1 */
+	init_counter(dev, CNTR_ID_RETRIGGER, CNTR_CTRL_MODE_ONESHOT, 0);
+	set_counter_value(dev, CNTR_ID_RETRIGGER, 0);
+
+	/* init counter 1 to be retriggerable by counter 0 end count */
+	init_counter(dev, CNTR_ID_WDOG, CNTR_CTRL_MODE_HWSIG,
+		     CNTR_CTRL_TRIG_SRC_PREV_CNTR);
+	set_counter_value(dev, CNTR_ID_WDOG, dev->timeout);
+
+	/* enable counter 1 */
+	counter_enable(dev, CNTR_ID_WDOG);
+
+	/* start counter 1 by forcing immediate end count on counter 0 */
+	counter_enable(dev, CNTR_ID_RETRIGGER);
+
+	return 0;
+}
+
+static int armada_37xx_wdt_stop(struct watchdog_device *wdt)
+{
+	struct armada_37xx_watchdog *dev = watchdog_get_drvdata(wdt);
+
+	counter_disable(dev, CNTR_ID_WDOG);
+	counter_disable(dev, CNTR_ID_RETRIGGER);
+	regmap_write(dev->cpu_misc, WDT_TIMER_SELECT, 0);
+
+	return 0;
+}
+
+static const struct watchdog_info armada_37xx_wdt_info = {
+	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
+	.identity = "Armada 37xx Watchdog",
+};
+
+static const struct watchdog_ops armada_37xx_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = armada_37xx_wdt_start,
+	.stop = armada_37xx_wdt_stop,
+	.ping = armada_37xx_wdt_ping,
+	.set_timeout = armada_37xx_wdt_set_timeout,
+	.get_timeleft = armada_37xx_wdt_get_timeleft,
+};
+
+static void armada_clk_disable_unprepare(void *data)
+{
+	clk_disable_unprepare(data);
+}
+
+static int armada_37xx_wdt_probe(struct platform_device *pdev)
+{
+	struct armada_37xx_watchdog *dev;
+	struct resource *res;
+	struct regmap *regmap;
+	int ret;
+
+	dev = devm_kzalloc(&pdev->dev, sizeof(struct armada_37xx_watchdog),
+			   GFP_KERNEL);
+	if (!dev)
+		return -ENOMEM;
+
+	dev->wdt.info = &armada_37xx_wdt_info;
+	dev->wdt.ops = &armada_37xx_wdt_ops;
+
+	regmap = syscon_regmap_lookup_by_phandle(pdev->dev.of_node,
+						 "marvell,system-controller");
+	if (IS_ERR(regmap))
+		return PTR_ERR(regmap);
+	dev->cpu_misc = regmap;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+	dev->reg = devm_ioremap(&pdev->dev, res->start, resource_size(res));
+	if (!dev->reg)
+		return -ENOMEM;
+
+	/* init clock */
+	dev->clk = devm_clk_get(&pdev->dev, NULL);
+	if (IS_ERR(dev->clk))
+		return PTR_ERR(dev->clk);
+
+	ret = clk_prepare_enable(dev->clk);
+	if (ret)
+		return ret;
+	ret = devm_add_action_or_reset(&pdev->dev,
+				       armada_clk_disable_unprepare, dev->clk);
+	if (ret)
+		return ret;
+
+	dev->clk_rate = clk_get_rate(dev->clk);
+	if (!dev->clk_rate)
+		return -EINVAL;
+
+	/*
+	 * Since the timeout in seconds is given as 32 bit unsigned int, and
+	 * the counters hold 64 bit values, even after multiplication by clock
+	 * rate the counter can hold timeout of UINT_MAX seconds.
+	 */
+	dev->wdt.min_timeout = 1;
+	dev->wdt.max_timeout = UINT_MAX;
+	dev->wdt.parent = &pdev->dev;
+
+	/* default value, possibly override by module parameter or dtb */
+	dev->wdt.timeout = WATCHDOG_TIMEOUT;
+	watchdog_init_timeout(&dev->wdt, timeout, &pdev->dev);
+
+	platform_set_drvdata(pdev, &dev->wdt);
+	watchdog_set_drvdata(&dev->wdt, dev);
+
+	armada_37xx_wdt_set_timeout(&dev->wdt, dev->wdt.timeout);
+
+	if (armada_37xx_wdt_is_running(dev))
+		set_bit(WDOG_HW_RUNNING, &dev->wdt.status);
+
+	watchdog_set_nowayout(&dev->wdt, nowayout);
+	watchdog_stop_on_reboot(&dev->wdt);
+	ret = devm_watchdog_register_device(&pdev->dev, &dev->wdt);
+	if (ret)
+		return ret;
+
+	dev_info(&pdev->dev, "Initial timeout %d sec%s\n",
+		 dev->wdt.timeout, nowayout ? ", nowayout" : "");
+
+	return 0;
+}
+
+static int __maybe_unused armada_37xx_wdt_suspend(struct device *dev)
+{
+	struct watchdog_device *wdt = dev_get_drvdata(dev);
+
+	return armada_37xx_wdt_stop(wdt);
+}
+
+static int __maybe_unused armada_37xx_wdt_resume(struct device *dev)
+{
+	struct watchdog_device *wdt = dev_get_drvdata(dev);
+
+	if (watchdog_active(wdt))
+		return armada_37xx_wdt_start(wdt);
+
+	return 0;
+}
+
+static const struct dev_pm_ops armada_37xx_wdt_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(armada_37xx_wdt_suspend,
+				armada_37xx_wdt_resume)
+};
+
+#ifdef CONFIG_OF
+static const struct of_device_id armada_37xx_wdt_match[] = {
+	{ .compatible = "marvell,armada-3700-wdt", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, armada_37xx_wdt_match);
+#endif
+
+static struct platform_driver armada_37xx_wdt_driver = {
+	.probe		= armada_37xx_wdt_probe,
+	.driver		= {
+		.name	= "armada_37xx_wdt",
+		.of_match_table = of_match_ptr(armada_37xx_wdt_match),
+		.pm = &armada_37xx_wdt_dev_pm_ops,
+	},
+};
+
+module_platform_driver(armada_37xx_wdt_driver);
+
+MODULE_AUTHOR("Marek Behun <marek.behun@nic.cz>");
+MODULE_DESCRIPTION("Armada 37xx CPU Watchdog");
+
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("platform:armada_37xx_wdt");