/* * 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");