167 lines
3.9 KiB
C
167 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Watchdog driver for the MEN z069 IP-Core
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*
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* Copyright (C) 2018 Johannes Thumshirn <jth@kernel.org>
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*/
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/mcb.h>
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#include <linux/module.h>
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#include <linux/watchdog.h>
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struct men_z069_drv {
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struct watchdog_device wdt;
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void __iomem *base;
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struct resource *mem;
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};
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#define MEN_Z069_WTR 0x10
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#define MEN_Z069_WTR_WDEN BIT(15)
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#define MEN_Z069_WTR_WDET_MASK 0x7fff
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#define MEN_Z069_WVR 0x14
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#define MEN_Z069_TIMER_FREQ 500 /* 500 Hz */
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#define MEN_Z069_WDT_COUNTER_MIN 1
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#define MEN_Z069_WDT_COUNTER_MAX 0x7fff
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#define MEN_Z069_DEFAULT_TIMEOUT 30
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static bool nowayout = WATCHDOG_NOWAYOUT;
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module_param(nowayout, bool, 0);
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MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
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__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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static int men_z069_wdt_start(struct watchdog_device *wdt)
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{
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struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
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u16 val;
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val = readw(drv->base + MEN_Z069_WTR);
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val |= MEN_Z069_WTR_WDEN;
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writew(val, drv->base + MEN_Z069_WTR);
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return 0;
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}
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static int men_z069_wdt_stop(struct watchdog_device *wdt)
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{
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struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
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u16 val;
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val = readw(drv->base + MEN_Z069_WTR);
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val &= ~MEN_Z069_WTR_WDEN;
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writew(val, drv->base + MEN_Z069_WTR);
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return 0;
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}
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static int men_z069_wdt_ping(struct watchdog_device *wdt)
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{
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struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
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u16 val;
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/* The watchdog trigger value toggles between 0x5555 and 0xaaaa */
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val = readw(drv->base + MEN_Z069_WVR);
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val ^= 0xffff;
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writew(val, drv->base + MEN_Z069_WVR);
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return 0;
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}
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static int men_z069_wdt_set_timeout(struct watchdog_device *wdt,
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unsigned int timeout)
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{
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struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
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u16 reg, val, ena;
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wdt->timeout = timeout;
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val = timeout * MEN_Z069_TIMER_FREQ;
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reg = readw(drv->base + MEN_Z069_WTR);
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ena = reg & MEN_Z069_WTR_WDEN;
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reg = ena | val;
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writew(reg, drv->base + MEN_Z069_WTR);
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return 0;
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}
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static const struct watchdog_info men_z069_info = {
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
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.identity = "MEN z069 Watchdog",
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};
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static const struct watchdog_ops men_z069_ops = {
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.owner = THIS_MODULE,
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.start = men_z069_wdt_start,
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.stop = men_z069_wdt_stop,
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.ping = men_z069_wdt_ping,
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.set_timeout = men_z069_wdt_set_timeout,
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};
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static int men_z069_probe(struct mcb_device *dev,
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const struct mcb_device_id *id)
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{
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struct men_z069_drv *drv;
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struct resource *mem;
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drv = devm_kzalloc(&dev->dev, sizeof(struct men_z069_drv), GFP_KERNEL);
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if (!drv)
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return -ENOMEM;
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mem = mcb_request_mem(dev, "z069-wdt");
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if (IS_ERR(mem))
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return PTR_ERR(mem);
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drv->base = devm_ioremap(&dev->dev, mem->start, resource_size(mem));
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if (drv->base == NULL)
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goto release_mem;
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drv->mem = mem;
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drv->wdt.info = &men_z069_info;
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drv->wdt.ops = &men_z069_ops;
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drv->wdt.timeout = MEN_Z069_DEFAULT_TIMEOUT;
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drv->wdt.min_timeout = 1;
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drv->wdt.max_timeout = MEN_Z069_WDT_COUNTER_MAX / MEN_Z069_TIMER_FREQ;
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watchdog_init_timeout(&drv->wdt, 0, &dev->dev);
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watchdog_set_nowayout(&drv->wdt, nowayout);
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watchdog_set_drvdata(&drv->wdt, drv);
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drv->wdt.parent = &dev->dev;
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mcb_set_drvdata(dev, drv);
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return watchdog_register_device(&drv->wdt);
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release_mem:
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mcb_release_mem(mem);
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return -ENOMEM;
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}
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static void men_z069_remove(struct mcb_device *dev)
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{
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struct men_z069_drv *drv = mcb_get_drvdata(dev);
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watchdog_unregister_device(&drv->wdt);
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mcb_release_mem(drv->mem);
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}
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static const struct mcb_device_id men_z069_ids[] = {
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{ .device = 0x45 },
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{ }
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};
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MODULE_DEVICE_TABLE(mcb, men_z069_ids);
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static struct mcb_driver men_z069_driver = {
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.driver = {
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.name = "z069-wdt",
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},
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.probe = men_z069_probe,
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.remove = men_z069_remove,
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.id_table = men_z069_ids,
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};
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module_mcb_driver(men_z069_driver);
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MODULE_AUTHOR("Johannes Thumshirn <jth@kernel.org>");
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MODULE_LICENSE("GPL v2");
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MODULE_ALIAS("mcb:16z069");
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MODULE_IMPORT_NS(MCB);
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