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// SPDX-License-Identifier: GPL-2.0
/*
* omap_wdt.c
*
* (C) Copyright 2013
* Heiko Schocher, DENX Software Engineering, hs@denx.de.
*
* Based on:
*
* Watchdog driver for the TI OMAP 16xx & 24xx/34xx 32KHz (non-secure) watchdog
*
* commit 2d991a164a61858012651e13c59521975504e260
* Author: Bill Pemberton <wfp5p@virginia.edu>
* Date: Mon Nov 19 13:21:41 2012 -0500
*
* watchdog: remove use of __devinit
*
* CONFIG_HOTPLUG is going away as an option so __devinit is no longer
* needed.
*
* Author: MontaVista Software, Inc.
* <gdavis@mvista.com> or <source@mvista.com>
*
* History:
*
* 20030527: George G. Davis <gdavis@mvista.com>
* Initially based on linux-2.4.19-rmk7-pxa1/drivers/char/sa1100_wdt.c
* (c) Copyright 2000 Oleg Drokin <green@crimea.edu>
* Based on SoftDog driver by Alan Cox <alan@lxorguk.ukuu.org.uk>
*
* Copyright (c) 2004 Texas Instruments.
* 1. Modified to support OMAP1610 32-KHz watchdog timer
* 2. Ported to 2.6 kernel
*
* Copyright (c) 2005 David Brownell
* Use the driver model and standard identifiers; handle bigger timeouts.
*/
#include <common.h>
#include <log.h>
#include <watchdog.h>
#include <asm/arch/hardware.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/arch/cpu.h>
#include <wdt.h>
#include <dm.h>
#include <errno.h>
/* Hardware timeout in seconds */
#define WDT_HW_TIMEOUT 60
#if !CONFIG_IS_ENABLED(WDT)
static unsigned int wdt_trgr_pattern = 0x1234;
void hw_watchdog_reset(void)
{
struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
/*
* Somebody just triggered watchdog reset and write to WTGR register
* is in progress. It is resetting right now, no need to trigger it
* again
*/
if ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WTGR)
return;
wdt_trgr_pattern = ~wdt_trgr_pattern;
writel(wdt_trgr_pattern, &wdt->wdtwtgr);
/*
* Don't wait for posted write to complete, i.e. don't check
* WDT_WWPS_PEND_WTGR bit in WWPS register. There is no writes to
* WTGR register outside of this func, and if entering it
* we see WDT_WWPS_PEND_WTGR bit set, it means watchdog reset
* was just triggered. This prevents us from wasting time in busy
* polling of WDT_WWPS_PEND_WTGR bit.
*/
}
static int omap_wdt_set_timeout(unsigned int timeout)
{
struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
u32 pre_margin = GET_WLDR_VAL(timeout);
/* just count up at 32 KHz */
while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WLDR)
;
writel(pre_margin, &wdt->wdtwldr);
while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WLDR)
;
return 0;
}
void hw_watchdog_disable(void)
{
struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
/*
* Disable watchdog
*/
writel(0xAAAA, &wdt->wdtwspr);
while (readl(&wdt->wdtwwps) != 0x0)
;
writel(0x5555, &wdt->wdtwspr);
while (readl(&wdt->wdtwwps) != 0x0)
;
}
void hw_watchdog_init(void)
{
struct wd_timer *wdt = (struct wd_timer *)WDT_BASE;
/*
* Make sure the watchdog is disabled. This is unfortunately required
* because writing to various registers with the watchdog running has no
* effect.
*/
hw_watchdog_disable();
/* initialize prescaler */
while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WCLR)
;
writel(WDT_WCLR_PRE | (PTV << WDT_WCLR_PTV_OFF), &wdt->wdtwclr);
while (readl(&wdt->wdtwwps) & WDT_WWPS_PEND_WCLR)
;
omap_wdt_set_timeout(WDT_HW_TIMEOUT);
/* Sequence to enable the watchdog */
writel(0xBBBB, &wdt->wdtwspr);
while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WSPR)
;
writel(0x4444, &wdt->wdtwspr);
while ((readl(&wdt->wdtwwps)) & WDT_WWPS_PEND_WSPR)
;
}
void watchdog_reset(void)
{
hw_watchdog_reset();
}
#else
static int omap3_wdt_reset(struct udevice *dev)
{
struct omap3_wdt_priv *priv = dev_get_priv(dev);
/*
* Somebody just triggered watchdog reset and write to WTGR register
* is in progress. It is resetting right now, no need to trigger it
* again
*/
if ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
return 0;
priv->wdt_trgr_pattern = ~(priv->wdt_trgr_pattern);
writel(priv->wdt_trgr_pattern, &priv->regs->wdtwtgr);
/*
* Don't wait for posted write to complete, i.e. don't check
* WDT_WWPS_PEND_WTGR bit in WWPS register. There is no writes to
* WTGR register outside of this func, and if entering it
* we see WDT_WWPS_PEND_WTGR bit set, it means watchdog reset
* was just triggered. This prevents us from wasting time in busy
* polling of WDT_WWPS_PEND_WTGR bit.
*/
return 0;
}
static int omap3_wdt_stop(struct udevice *dev)
{
struct omap3_wdt_priv *priv = dev_get_priv(dev);
/* disable watchdog */
writel(0xAAAA, &priv->regs->wdtwspr);
while (readl(&priv->regs->wdtwwps) != 0x0)
;
writel(0x5555, &priv->regs->wdtwspr);
while (readl(&priv->regs->wdtwwps) != 0x0)
;
return 0;
}
static int omap3_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
{
struct omap3_wdt_priv *priv = dev_get_priv(dev);
u32 pre_margin = GET_WLDR_VAL(timeout_ms / 1000);
/*
* Make sure the watchdog is disabled. This is unfortunately required
* because writing to various registers with the watchdog running has
* no effect.
*/
omap3_wdt_stop(dev);
/* initialize prescaler */
while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WCLR)
;
writel(WDT_WCLR_PRE | (PTV << WDT_WCLR_PTV_OFF), &priv->regs->wdtwclr);
while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WCLR)
;
/* just count up at 32 KHz */
while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WLDR)
;
writel(pre_margin, &priv->regs->wdtwldr);
while (readl(&priv->regs->wdtwwps) & WDT_WWPS_PEND_WLDR)
;
/* Sequence to enable the watchdog */
writel(0xBBBB, &priv->regs->wdtwspr);
while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WSPR)
;
writel(0x4444, &priv->regs->wdtwspr);
while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WSPR)
;
/* Trigger the watchdog to actually reload the counter. */
while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
;
priv->wdt_trgr_pattern = ~(priv->wdt_trgr_pattern);
writel(priv->wdt_trgr_pattern, &priv->regs->wdtwtgr);
while ((readl(&priv->regs->wdtwwps)) & WDT_WWPS_PEND_WTGR)
;
return 0;
}
static int omap3_wdt_probe(struct udevice *dev)
{
struct omap3_wdt_priv *priv = dev_get_priv(dev);
priv->regs = dev_read_addr_ptr(dev);
if (!priv->regs)
return -EINVAL;
priv->wdt_trgr_pattern = 0x1234;
debug("%s: Probing wdt%u\n", __func__, dev_seq(dev));
return 0;
}
static const struct wdt_ops omap3_wdt_ops = {
.start = omap3_wdt_start,
.stop = omap3_wdt_stop,
.reset = omap3_wdt_reset,
};
static const struct udevice_id omap3_wdt_ids[] = {
{ .compatible = "ti,omap3-wdt" },
{ }
};
U_BOOT_DRIVER(omap3_wdt) = {
.name = "omap3_wdt",
.id = UCLASS_WDT,
.of_match = omap3_wdt_ids,
.ops = &omap3_wdt_ops,
.probe = omap3_wdt_probe,
.priv_auto = sizeof(struct omap3_wdt_priv),
};
#endif /* !CONFIG_IS_ENABLED(WDT) */
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