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path: root/drivers/watchdog/of_xilinx_wdt.c
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Diffstat (limited to 'drivers/watchdog/of_xilinx_wdt.c')
-rw-r--r--drivers/watchdog/of_xilinx_wdt.c312
1 files changed, 312 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..331854436
--- /dev/null
+++ b/drivers/watchdog/of_xilinx_wdt.c
@@ -0,0 +1,312 @@
+// 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/types.h>
+#include <linux/kernel.h>
+#include <linux/ioport.h>
+#include <linux/watchdog.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_address.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 void xwdt_clk_disable_unprepare(void *data)
+{
+ clk_disable_unprepare(data);
+}
+
+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(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);
+ rc = clk_prepare_enable(xdev->clk);
+ if (rc) {
+ dev_err(dev, "unable to enable clock\n");
+ return rc;
+ }
+ rc = devm_add_action_or_reset(dev, xwdt_clk_disable_unprepare,
+ xdev->clk);
+ if (rc)
+ return rc;
+ }
+
+ /*
+ * 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");