1 files changed, 297 insertions, 0 deletions
diff --git a/drivers/watchdog/of_xilinx_wdt.c b/drivers/watchdog/of_xilinx_wdt.c
new file mode 100644
index 000000000..05657dc1d
--- /dev/null
+++ b/drivers/watchdog/of_xilinx_wdt.c
@@ -0,0 +1,297 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog Device Driver for Xilinx axi/xps_timebase_wdt
+ *
+ * (C) Copyright 2013 - 2014 Xilinx, Inc.
+ * (C) Copyright 2011 (Alejandro Cabrera <aldaya@gmail.com>)
+ */
+
+#include <linux/bits.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/ioport.h>
+#include <linux/watchdog.h>
+#include <linux/io.h>
+#include <linux/of.h>
+
+/* Register offsets for the Wdt device */
+#define XWT_TWCSR0_OFFSET   0x0 /* Control/Status Register0 */
+#define XWT_TWCSR1_OFFSET   0x4 /* Control/Status Register1 */
+#define XWT_TBR_OFFSET      0x8 /* Timebase Register Offset */
+
+/* Control/Status Register Masks  */
+#define XWT_CSR0_WRS_MASK	BIT(3) /* Reset status */
+#define XWT_CSR0_WDS_MASK	BIT(2) /* Timer state  */
+#define XWT_CSR0_EWDT1_MASK	BIT(1) /* Enable bit 1 */
+
+/* Control/Status Register 0/1 bits  */
+#define XWT_CSRX_EWDT2_MASK	BIT(0) /* Enable bit 2 */
+
+/* SelfTest constants */
+#define XWT_MAX_SELFTEST_LOOP_COUNT 0x00010000
+#define XWT_TIMER_FAILED            0xFFFFFFFF
+
+#define WATCHDOG_NAME     "Xilinx Watchdog"
+
+struct xwdt_device {
+	void __iomem *base;
+	u32 wdt_interval;
+	spinlock_t spinlock; /* spinlock for register handling */
+	struct watchdog_device xilinx_wdt_wdd;
+	struct clk		*clk;
+};
+
+static int xilinx_wdt_start(struct watchdog_device *wdd)
+{
+	int ret;
+	u32 control_status_reg;
+	struct xwdt_device *xdev = watchdog_get_drvdata(wdd);
+
+	ret = clk_enable(xdev->clk);
+	if (ret) {
+		dev_err(wdd->parent, "Failed to enable clock\n");
+		return ret;
+	}
+
+	spin_lock(&xdev->spinlock);
+
+	/* Clean previous status and enable the watchdog timer */
+	control_status_reg = ioread32(xdev->base + XWT_TWCSR0_OFFSET);
+	control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK);
+
+	iowrite32((control_status_reg | XWT_CSR0_EWDT1_MASK),
+		  xdev->base + XWT_TWCSR0_OFFSET);
+
+	iowrite32(XWT_CSRX_EWDT2_MASK, xdev->base + XWT_TWCSR1_OFFSET);
+
+	spin_unlock(&xdev->spinlock);
+
+	dev_dbg(wdd->parent, "Watchdog Started!\n");
+
+	return 0;
+}
+
+static int xilinx_wdt_stop(struct watchdog_device *wdd)
+{
+	u32 control_status_reg;
+	struct xwdt_device *xdev = watchdog_get_drvdata(wdd);
+
+	spin_lock(&xdev->spinlock);
+
+	control_status_reg = ioread32(xdev->base + XWT_TWCSR0_OFFSET);
+
+	iowrite32((control_status_reg & ~XWT_CSR0_EWDT1_MASK),
+		  xdev->base + XWT_TWCSR0_OFFSET);
+
+	iowrite32(0, xdev->base + XWT_TWCSR1_OFFSET);
+
+	spin_unlock(&xdev->spinlock);
+
+	clk_disable(xdev->clk);
+
+	dev_dbg(wdd->parent, "Watchdog Stopped!\n");
+
+	return 0;
+}
+
+static int xilinx_wdt_keepalive(struct watchdog_device *wdd)
+{
+	u32 control_status_reg;
+	struct xwdt_device *xdev = watchdog_get_drvdata(wdd);
+
+	spin_lock(&xdev->spinlock);
+
+	control_status_reg = ioread32(xdev->base + XWT_TWCSR0_OFFSET);
+	control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK);
+	iowrite32(control_status_reg, xdev->base + XWT_TWCSR0_OFFSET);
+
+	spin_unlock(&xdev->spinlock);
+
+	return 0;
+}
+
+static const struct watchdog_info xilinx_wdt_ident = {
+	.options =  WDIOF_MAGICCLOSE |
+		    WDIOF_KEEPALIVEPING,
+	.firmware_version =	1,
+	.identity =	WATCHDOG_NAME,
+};
+
+static const struct watchdog_ops xilinx_wdt_ops = {
+	.owner = THIS_MODULE,
+	.start = xilinx_wdt_start,
+	.stop = xilinx_wdt_stop,
+	.ping = xilinx_wdt_keepalive,
+};
+
+static u32 xwdt_selftest(struct xwdt_device *xdev)
+{
+	int i;
+	u32 timer_value1;
+	u32 timer_value2;
+
+	spin_lock(&xdev->spinlock);
+
+	timer_value1 = ioread32(xdev->base + XWT_TBR_OFFSET);
+	timer_value2 = ioread32(xdev->base + XWT_TBR_OFFSET);
+
+	for (i = 0;
+		((i <= XWT_MAX_SELFTEST_LOOP_COUNT) &&
+			(timer_value2 == timer_value1)); i++) {
+		timer_value2 = ioread32(xdev->base + XWT_TBR_OFFSET);
+	}
+
+	spin_unlock(&xdev->spinlock);
+
+	if (timer_value2 != timer_value1)
+		return ~XWT_TIMER_FAILED;
+	else
+		return XWT_TIMER_FAILED;
+}
+
+static int xwdt_probe(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	int rc;
+	u32 pfreq = 0, enable_once = 0;
+	struct xwdt_device *xdev;
+	struct watchdog_device *xilinx_wdt_wdd;
+
+	xdev = devm_kzalloc(dev, sizeof(*xdev), GFP_KERNEL);
+	if (!xdev)
+		return -ENOMEM;
+
+	xilinx_wdt_wdd = &xdev->xilinx_wdt_wdd;
+	xilinx_wdt_wdd->info = &xilinx_wdt_ident;
+	xilinx_wdt_wdd->ops = &xilinx_wdt_ops;
+	xilinx_wdt_wdd->parent = dev;
+
+	xdev->base = devm_platform_ioremap_resource(pdev, 0);
+	if (IS_ERR(xdev->base))
+		return PTR_ERR(xdev->base);
+
+	rc = of_property_read_u32(dev->of_node, "xlnx,wdt-interval",
+				  &xdev->wdt_interval);
+	if (rc)
+		dev_warn(dev, "Parameter \"xlnx,wdt-interval\" not found\n");
+
+	rc = of_property_read_u32(dev->of_node, "xlnx,wdt-enable-once",
+				  &enable_once);
+	if (rc)
+		dev_warn(dev,
+			 "Parameter \"xlnx,wdt-enable-once\" not found\n");
+
+	watchdog_set_nowayout(xilinx_wdt_wdd, enable_once);
+
+	xdev->clk = devm_clk_get_enabled(dev, NULL);
+	if (IS_ERR(xdev->clk)) {
+		if (PTR_ERR(xdev->clk) != -ENOENT)
+			return PTR_ERR(xdev->clk);
+
+		/*
+		 * Clock framework support is optional, continue on
+		 * anyways if we don't find a matching clock.
+		 */
+		xdev->clk = NULL;
+
+		rc = of_property_read_u32(dev->of_node, "clock-frequency",
+					  &pfreq);
+		if (rc)
+			dev_warn(dev,
+				 "The watchdog clock freq cannot be obtained\n");
+	} else {
+		pfreq = clk_get_rate(xdev->clk);
+	}
+
+	/*
+	 * Twice of the 2^wdt_interval / freq  because the first wdt overflow is
+	 * ignored (interrupt), reset is only generated at second wdt overflow
+	 */
+	if (pfreq && xdev->wdt_interval)
+		xilinx_wdt_wdd->timeout = 2 * ((1 << xdev->wdt_interval) /
+					  pfreq);
+
+	spin_lock_init(&xdev->spinlock);
+	watchdog_set_drvdata(xilinx_wdt_wdd, xdev);
+
+	rc = xwdt_selftest(xdev);
+	if (rc == XWT_TIMER_FAILED) {
+		dev_err(dev, "SelfTest routine error\n");
+		return rc;
+	}
+
+	rc = devm_watchdog_register_device(dev, xilinx_wdt_wdd);
+	if (rc)
+		return rc;
+
+	clk_disable(xdev->clk);
+
+	dev_info(dev, "Xilinx Watchdog Timer with timeout %ds\n",
+		 xilinx_wdt_wdd->timeout);
+
+	platform_set_drvdata(pdev, xdev);
+
+	return 0;
+}
+
+/**
+ * xwdt_suspend - Suspend the device.
+ *
+ * @dev: handle to the device structure.
+ * Return: 0 always.
+ */
+static int __maybe_unused xwdt_suspend(struct device *dev)
+{
+	struct xwdt_device *xdev = dev_get_drvdata(dev);
+
+	if (watchdog_active(&xdev->xilinx_wdt_wdd))
+		xilinx_wdt_stop(&xdev->xilinx_wdt_wdd);
+
+	return 0;
+}
+
+/**
+ * xwdt_resume - Resume the device.
+ *
+ * @dev: handle to the device structure.
+ * Return: 0 on success, errno otherwise.
+ */
+static int __maybe_unused xwdt_resume(struct device *dev)
+{
+	struct xwdt_device *xdev = dev_get_drvdata(dev);
+	int ret = 0;
+
+	if (watchdog_active(&xdev->xilinx_wdt_wdd))
+		ret = xilinx_wdt_start(&xdev->xilinx_wdt_wdd);
+
+	return ret;
+}
+
+static SIMPLE_DEV_PM_OPS(xwdt_pm_ops, xwdt_suspend, xwdt_resume);
+
+/* Match table for of_platform binding */
+static const struct of_device_id xwdt_of_match[] = {
+	{ .compatible = "xlnx,xps-timebase-wdt-1.00.a", },
+	{ .compatible = "xlnx,xps-timebase-wdt-1.01.a", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, xwdt_of_match);
+
+static struct platform_driver xwdt_driver = {
+	.probe       = xwdt_probe,
+	.driver = {
+		.name  = WATCHDOG_NAME,
+		.of_match_table = xwdt_of_match,
+		.pm = &xwdt_pm_ops,
+	},
+};
+
+module_platform_driver(xwdt_driver);
+
+MODULE_AUTHOR("Alejandro Cabrera <aldaya@gmail.com>");
+MODULE_DESCRIPTION("Xilinx Watchdog driver");
+MODULE_LICENSE("GPL");