1 // SPDX-License-Identifier: GPL-2.0+
3 * Watchdog Device Driver for Xilinx axi/xps_timebase_wdt
5 * (C) Copyright 2013 - 2014 Xilinx, Inc.
6 * (C) Copyright 2011 (Alejandro Cabrera <aldaya@gmail.com>)
10 #include <linux/err.h>
11 #include <linux/module.h>
12 #include <linux/types.h>
13 #include <linux/kernel.h>
14 #include <linux/ioport.h>
15 #include <linux/watchdog.h>
18 #include <linux/of_device.h>
19 #include <linux/of_address.h>
21 /* Register offsets for the Wdt device */
22 #define XWT_TWCSR0_OFFSET 0x0 /* Control/Status Register0 */
23 #define XWT_TWCSR1_OFFSET 0x4 /* Control/Status Register1 */
24 #define XWT_TBR_OFFSET 0x8 /* Timebase Register Offset */
26 /* Control/Status Register Masks */
27 #define XWT_CSR0_WRS_MASK BIT(3) /* Reset status */
28 #define XWT_CSR0_WDS_MASK BIT(2) /* Timer state */
29 #define XWT_CSR0_EWDT1_MASK BIT(1) /* Enable bit 1 */
31 /* Control/Status Register 0/1 bits */
32 #define XWT_CSRX_EWDT2_MASK BIT(0) /* Enable bit 2 */
34 /* SelfTest constants */
35 #define XWT_MAX_SELFTEST_LOOP_COUNT 0x00010000
36 #define XWT_TIMER_FAILED 0xFFFFFFFF
38 #define WATCHDOG_NAME "Xilinx Watchdog"
43 spinlock_t spinlock; /* spinlock for register handling */
44 struct watchdog_device xilinx_wdt_wdd;
48 static int xilinx_wdt_start(struct watchdog_device *wdd)
51 u32 control_status_reg;
52 struct xwdt_device *xdev = watchdog_get_drvdata(wdd);
53 struct watchdog_device *xilinx_wdt_wdd = &xdev->xilinx_wdt_wdd;
55 ret = clk_enable(xdev->clk);
57 dev_err(wdd->parent, "Failed to enable clock\n");
61 spin_lock(&xdev->spinlock);
63 /* Clean previous status and enable the watchdog timer */
64 control_status_reg = ioread32(xdev->base + XWT_TWCSR0_OFFSET);
65 control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK);
67 iowrite32((control_status_reg | XWT_CSR0_EWDT1_MASK),
68 xdev->base + XWT_TWCSR0_OFFSET);
70 iowrite32(XWT_CSRX_EWDT2_MASK, xdev->base + XWT_TWCSR1_OFFSET);
72 spin_unlock(&xdev->spinlock);
74 dev_dbg(xilinx_wdt_wdd->parent, "Watchdog Started!\n");
79 static int xilinx_wdt_stop(struct watchdog_device *wdd)
81 u32 control_status_reg;
82 struct xwdt_device *xdev = watchdog_get_drvdata(wdd);
83 struct watchdog_device *xilinx_wdt_wdd = &xdev->xilinx_wdt_wdd;
85 spin_lock(&xdev->spinlock);
87 control_status_reg = ioread32(xdev->base + XWT_TWCSR0_OFFSET);
89 iowrite32((control_status_reg & ~XWT_CSR0_EWDT1_MASK),
90 xdev->base + XWT_TWCSR0_OFFSET);
92 iowrite32(0, xdev->base + XWT_TWCSR1_OFFSET);
94 spin_unlock(&xdev->spinlock);
96 clk_disable(xdev->clk);
98 dev_dbg(xilinx_wdt_wdd->parent, "Watchdog Stopped!\n");
103 static int xilinx_wdt_keepalive(struct watchdog_device *wdd)
105 u32 control_status_reg;
106 struct xwdt_device *xdev = watchdog_get_drvdata(wdd);
108 spin_lock(&xdev->spinlock);
110 control_status_reg = ioread32(xdev->base + XWT_TWCSR0_OFFSET);
111 control_status_reg |= (XWT_CSR0_WRS_MASK | XWT_CSR0_WDS_MASK);
112 iowrite32(control_status_reg, xdev->base + XWT_TWCSR0_OFFSET);
114 spin_unlock(&xdev->spinlock);
119 static const struct watchdog_info xilinx_wdt_ident = {
120 .options = WDIOF_MAGICCLOSE |
122 .firmware_version = 1,
123 .identity = WATCHDOG_NAME,
126 static const struct watchdog_ops xilinx_wdt_ops = {
127 .owner = THIS_MODULE,
128 .start = xilinx_wdt_start,
129 .stop = xilinx_wdt_stop,
130 .ping = xilinx_wdt_keepalive,
133 static u32 xwdt_selftest(struct xwdt_device *xdev)
139 spin_lock(&xdev->spinlock);
141 timer_value1 = ioread32(xdev->base + XWT_TBR_OFFSET);
142 timer_value2 = ioread32(xdev->base + XWT_TBR_OFFSET);
145 ((i <= XWT_MAX_SELFTEST_LOOP_COUNT) &&
146 (timer_value2 == timer_value1)); i++) {
147 timer_value2 = ioread32(xdev->base + XWT_TBR_OFFSET);
150 spin_unlock(&xdev->spinlock);
152 if (timer_value2 != timer_value1)
153 return ~XWT_TIMER_FAILED;
155 return XWT_TIMER_FAILED;
158 static int xwdt_probe(struct platform_device *pdev)
161 u32 pfreq = 0, enable_once = 0;
162 struct resource *res;
163 struct xwdt_device *xdev;
164 struct watchdog_device *xilinx_wdt_wdd;
166 xdev = devm_kzalloc(&pdev->dev, sizeof(*xdev), GFP_KERNEL);
170 xilinx_wdt_wdd = &xdev->xilinx_wdt_wdd;
171 xilinx_wdt_wdd->info = &xilinx_wdt_ident;
172 xilinx_wdt_wdd->ops = &xilinx_wdt_ops;
173 xilinx_wdt_wdd->parent = &pdev->dev;
175 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
176 xdev->base = devm_ioremap_resource(&pdev->dev, res);
177 if (IS_ERR(xdev->base))
178 return PTR_ERR(xdev->base);
180 rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-interval",
181 &xdev->wdt_interval);
184 "Parameter \"xlnx,wdt-interval\" not found\n");
186 rc = of_property_read_u32(pdev->dev.of_node, "xlnx,wdt-enable-once",
190 "Parameter \"xlnx,wdt-enable-once\" not found\n");
192 watchdog_set_nowayout(xilinx_wdt_wdd, enable_once);
194 xdev->clk = devm_clk_get(&pdev->dev, NULL);
195 if (IS_ERR(xdev->clk)) {
196 if (PTR_ERR(xdev->clk) != -ENOENT)
197 return PTR_ERR(xdev->clk);
200 * Clock framework support is optional, continue on
201 * anyways if we don't find a matching clock.
205 rc = of_property_read_u32(pdev->dev.of_node, "clock-frequency",
209 "The watchdog clock freq cannot be obtained\n");
211 pfreq = clk_get_rate(xdev->clk);
215 * Twice of the 2^wdt_interval / freq because the first wdt overflow is
216 * ignored (interrupt), reset is only generated at second wdt overflow
218 if (pfreq && xdev->wdt_interval)
219 xilinx_wdt_wdd->timeout = 2 * ((1 << xdev->wdt_interval) /
222 spin_lock_init(&xdev->spinlock);
223 watchdog_set_drvdata(xilinx_wdt_wdd, xdev);
225 rc = clk_prepare_enable(xdev->clk);
227 dev_err(&pdev->dev, "unable to enable clock\n");
231 rc = xwdt_selftest(xdev);
232 if (rc == XWT_TIMER_FAILED) {
233 dev_err(&pdev->dev, "SelfTest routine error\n");
234 goto err_clk_disable;
237 rc = watchdog_register_device(xilinx_wdt_wdd);
239 dev_err(&pdev->dev, "Cannot register watchdog (err=%d)\n", rc);
240 goto err_clk_disable;
243 clk_disable(xdev->clk);
245 dev_info(&pdev->dev, "Xilinx Watchdog Timer at %p with timeout %ds\n",
246 xdev->base, xilinx_wdt_wdd->timeout);
248 platform_set_drvdata(pdev, xdev);
252 clk_disable_unprepare(xdev->clk);
257 static int xwdt_remove(struct platform_device *pdev)
259 struct xwdt_device *xdev = platform_get_drvdata(pdev);
261 watchdog_unregister_device(&xdev->xilinx_wdt_wdd);
262 clk_disable_unprepare(xdev->clk);
268 * xwdt_suspend - Suspend the device.
270 * @dev: handle to the device structure.
273 static int __maybe_unused xwdt_suspend(struct device *dev)
275 struct xwdt_device *xdev = dev_get_drvdata(dev);
277 if (watchdog_active(&xdev->xilinx_wdt_wdd))
278 xilinx_wdt_stop(&xdev->xilinx_wdt_wdd);
284 * xwdt_resume - Resume the device.
286 * @dev: handle to the device structure.
287 * Return: 0 on success, errno otherwise.
289 static int __maybe_unused xwdt_resume(struct device *dev)
291 struct xwdt_device *xdev = dev_get_drvdata(dev);
294 if (watchdog_active(&xdev->xilinx_wdt_wdd))
295 ret = xilinx_wdt_start(&xdev->xilinx_wdt_wdd);
300 static SIMPLE_DEV_PM_OPS(xwdt_pm_ops, xwdt_suspend, xwdt_resume);
302 /* Match table for of_platform binding */
303 static const struct of_device_id xwdt_of_match[] = {
304 { .compatible = "xlnx,xps-timebase-wdt-1.00.a", },
305 { .compatible = "xlnx,xps-timebase-wdt-1.01.a", },
308 MODULE_DEVICE_TABLE(of, xwdt_of_match);
310 static struct platform_driver xwdt_driver = {
312 .remove = xwdt_remove,
314 .name = WATCHDOG_NAME,
315 .of_match_table = xwdt_of_match,
320 module_platform_driver(xwdt_driver);
322 MODULE_AUTHOR("Alejandro Cabrera <aldaya@gmail.com>");
323 MODULE_DESCRIPTION("Xilinx Watchdog driver");
324 MODULE_LICENSE("GPL");