150 lines
3.7 KiB
C
150 lines
3.7 KiB
C
/*
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* (c) 2012 Juergen Beisert <kernel@pengutronix.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* Note: this driver works for the i.MX28 SoC. It might work for the
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* i.MX23 Soc as well, but is not tested yet.
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*/
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#include <common.h>
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#include <init.h>
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#include <io.h>
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#include <errno.h>
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#include <malloc.h>
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#include <watchdog.h>
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#include <reset_source.h>
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#define MXS_RTC_CTRL 0x0
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#define MXS_RTC_SET_ADDR 0x4
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#define MXS_RTC_CLR_ADDR 0x8
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# define MXS_RTC_CTRL_WATCHDOGEN (1 << 4)
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#define MXS_RTC_STAT 0x10
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# define MXS_RTC_STAT_WD_PRESENT (1 << 29)
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#define MXS_RTC_WATCHDOG 0x50
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#define MXS_RTC_PERSISTENT0 0x60
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/* dubious meaning from inside the SoC's firmware ROM */
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# define MXS_RTC_PERSISTENT0_EXT_RST (1 << 21)
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/* dubious meaning from inside the SoC's firmware ROM */
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# define MXS_RTC_PERSISTENT0_THM_RST (1 << 20)
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#define MXS_RTC_PERSISTENT1 0x70
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/* dubious meaning from inside the SoC's firmware ROM */
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# define MXS_RTC_PERSISTENT1_FORCE_UPDATER (1 << 31)
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#define MXS_RTC_DEBUG 0xc0
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#define WDOG_TICK_RATE 1000 /* the watchdog uses a 1 kHz clock rate */
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struct imx28_wd {
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struct watchdog wd;
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void __iomem *regs;
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};
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#define to_imx28_wd(h) container_of(h, struct imx28_wd, wd)
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static int imx28_watchdog_set_timeout(struct watchdog *wd, unsigned timeout)
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{
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struct imx28_wd *pwd = (struct imx28_wd *)to_imx28_wd(wd);
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void __iomem *base;
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if (timeout > (ULONG_MAX / WDOG_TICK_RATE))
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return -EINVAL;
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if (timeout) {
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writel(timeout * WDOG_TICK_RATE, pwd->regs + MXS_RTC_WATCHDOG);
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base = pwd->regs + MXS_RTC_SET_ADDR;
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} else {
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base = pwd->regs + MXS_RTC_CLR_ADDR;
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}
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writel(MXS_RTC_CTRL_WATCHDOGEN, base + MXS_RTC_CTRL);
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writel(MXS_RTC_PERSISTENT1_FORCE_UPDATER, base + MXS_RTC_PERSISTENT1);
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return 0;
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}
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static void __maybe_unused imx28_detect_reset_source(const struct imx28_wd *p)
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{
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u32 reg;
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reg = readl(p->regs + MXS_RTC_PERSISTENT0);
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if (reg & MXS_RTC_PERSISTENT0_EXT_RST) {
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writel(MXS_RTC_PERSISTENT0_EXT_RST,
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p->regs + MXS_RTC_PERSISTENT0 + MXS_RTC_CLR_ADDR);
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set_reset_source(RESET_POR);
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return;
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}
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if (reg & MXS_RTC_PERSISTENT0_THM_RST) {
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writel(MXS_RTC_PERSISTENT0_THM_RST,
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p->regs + MXS_RTC_PERSISTENT0 + MXS_RTC_CLR_ADDR);
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set_reset_source(RESET_RST);
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return;
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}
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set_reset_source(RESET_RST);
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}
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static int imx28_wd_probe(struct device_d *dev)
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{
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struct imx28_wd *priv;
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int rc;
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priv = xzalloc(sizeof(struct imx28_wd));
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priv->regs = dev_request_mem_region(dev, 0);
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priv->wd.set_timeout = imx28_watchdog_set_timeout;
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if (!(readl(priv->regs + MXS_RTC_STAT) & MXS_RTC_STAT_WD_PRESENT)) {
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rc = -ENODEV;
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goto on_error;
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}
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/* disable the debug feature to ensure a working WD */
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writel(0x00000000, priv->regs + MXS_RTC_DEBUG);
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rc = watchdog_register(&priv->wd);
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if (rc != 0)
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goto on_error;
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if (IS_ENABLED(CONFIG_RESET_SOURCE))
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imx28_detect_reset_source(priv);
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dev->priv = priv;
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return 0;
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on_error:
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free(priv);
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return rc;
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}
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static void imx28_wd_remove(struct device_d *dev)
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{
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struct imx28_wd *priv= dev->priv;
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watchdog_deregister(&priv->wd);
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free(priv);
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}
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static struct driver_d imx28_wd_driver = {
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.name = "im28wd",
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.probe = imx28_wd_probe,
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.remove = imx28_wd_remove,
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};
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static int imx28_wd_init(void)
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{
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register_driver(&imx28_wd_driver);
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return 0;
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}
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device_initcall(imx28_wd_init);
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