--- /dev/null
+/*
+ * Watchdog Device Driver for Xilinx axi/xps_timebase_wdt
+ *
+ * (C) Copyright 2013 - 2014 Xilinx, Inc.
+ * (C) Copyright 2011 (Alejandro Cabrera <aldaya@gmail.com>)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#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 0x00000008 /* Reset status */
+#define XWT_CSR0_WDS_MASK 0x00000004 /* Timer state */
+#define XWT_CSR0_EWDT1_MASK 0x00000002 /* Enable bit 1 */
+
+/* Control/Status Register 0/1 bits */
+#define XWT_CSRX_EWDT2_MASK 0x00000001 /* 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;
+ struct watchdog_device xilinx_wdt_wdd;
+};
+
+static int xilinx_wdt_start(struct watchdog_device *wdd)
+{
+ u32 control_status_reg;
+ struct xwdt_device *xdev = watchdog_get_drvdata(wdd);
+
+ 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);
+
+ 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);
+ pr_info("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)
+{
+ int rc;
+ u32 pfreq = 0, enable_once = 0;
+ struct resource *res;
+ struct xwdt_device *xdev;
+ struct watchdog_device *xilinx_wdt_wdd;
+
+ xdev = devm_kzalloc(&pdev->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 = &pdev->dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ xdev->base = devm_ioremap_resource(&pdev->dev, res);
+ if (IS_ERR(xdev->base))
+ return PTR_ERR(xdev->base);
+
+ rc = of_property_read_u32(pdev->dev.of_node, "clock-frequency", &pfreq);
+ if (rc)
+ dev_warn(&pdev->dev,
+ "The watchdog clock frequency cannot be obtained\n");
+
+ rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-interval",
+ &xdev->wdt_interval);
+ if (rc)
+ dev_warn(&pdev->dev,
+ "Parameter \"xlnx,wdt-interval\" not found\n");
+
+ rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-enable-once",
+ &enable_once);
+ if (rc)
+ dev_warn(&pdev->dev,
+ "Parameter \"xlnx,wdt-enable-once\" not found\n");
+
+ watchdog_set_nowayout(xilinx_wdt_wdd, enable_once);
+
+ /*
+ * 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(&pdev->dev, "SelfTest routine error\n");
+ return rc;
+ }
+
+ rc = watchdog_register_device(xilinx_wdt_wdd);
+ if (rc) {
+ dev_err(&pdev->dev, "Cannot register watchdog (err=%d)\n", rc);
+ return rc;
+ }
+
+ dev_info(&pdev->dev, "Xilinx Watchdog Timer at %p with timeout %ds\n",
+ xdev->base, xilinx_wdt_wdd->timeout);
+
+ platform_set_drvdata(pdev, xdev);
+
+ return 0;
+}
+
+static int xwdt_remove(struct platform_device *pdev)
+{
+ struct xwdt_device *xdev = platform_get_drvdata(pdev);
+
+ watchdog_unregister_device(&xdev->xilinx_wdt_wdd);
+
+ return 0;
+}
+
+/* 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,
+ .remove = xwdt_remove,
+ .driver = {
+ .name = WATCHDOG_NAME,
+ .of_match_table = xwdt_of_match,
+ },
+};
+
+module_platform_driver(xwdt_driver);
+
+MODULE_AUTHOR("Alejandro Cabrera <aldaya@gmail.com>");
+MODULE_DESCRIPTION("Xilinx Watchdog driver");
+MODULE_LICENSE("GPL v2");
Code Review / kvmfornfv.git / blobdiff