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- // SPDX-License-Identifier: GPL-2.0+
- /*
- * [origin: Linux kernel drivers/watchdog/at91sam9_wdt.c]
- *
- * Watchdog driver for AT91SAM9x processors.
- *
- * Copyright (C) 2008 Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
- * Copyright (C) 2008 Renaud CERRATO r.cerrato@til-technologies.fr
- */
- /*
- * The Watchdog Timer Mode Register can be only written to once. If the
- * timeout need to be set from U-Boot, be sure that the bootstrap doesn't
- * write to this register. Inform Linux to it too
- */
- #include <log.h>
- #include <asm/io.h>
- #include <asm/arch/at91_wdt.h>
- #include <common.h>
- #include <div64.h>
- #include <dm.h>
- #include <errno.h>
- #include <wdt.h>
- DECLARE_GLOBAL_DATA_PTR;
- /*
- * AT91SAM9 watchdog runs a 12bit counter @ 256Hz,
- * use this to convert a watchdog
- * value from seconds.
- */
- #define WDT_SEC2TICKS(s) (((s) << 8) - 1)
- /*
- * Set the watchdog time interval in 1/256Hz (write-once)
- * Counter is 12 bit.
- */
- static int at91_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
- {
- struct at91_wdt_priv *priv = dev_get_priv(dev);
- u64 timeout;
- u32 ticks;
- /* Calculate timeout in seconds and the resulting ticks */
- timeout = timeout_ms;
- do_div(timeout, 1000);
- timeout = min_t(u64, timeout, WDT_MAX_TIMEOUT);
- ticks = WDT_SEC2TICKS(timeout);
- /* Check if disabled */
- if (readl(priv->regs + AT91_WDT_MR) & AT91_WDT_MR_WDDIS) {
- printf("sorry, watchdog is disabled\n");
- return -1;
- }
- /*
- * All counting occurs at SLOW_CLOCK / 128 = 256 Hz
- *
- * Since WDV is a 12-bit counter, the maximum period is
- * 4096 / 256 = 16 seconds.
- */
- priv->regval = AT91_WDT_MR_WDRSTEN /* causes watchdog reset */
- | AT91_WDT_MR_WDDBGHLT /* disabled in debug mode */
- | AT91_WDT_MR_WDD(0xfff) /* restart at any time */
- | AT91_WDT_MR_WDV(ticks); /* timer value */
- writel(priv->regval, priv->regs + AT91_WDT_MR);
- return 0;
- }
- static int at91_wdt_stop(struct udevice *dev)
- {
- struct at91_wdt_priv *priv = dev_get_priv(dev);
- /* Disable Watchdog Timer */
- priv->regval |= AT91_WDT_MR_WDDIS;
- writel(priv->regval, priv->regs + AT91_WDT_MR);
- return 0;
- }
- static int at91_wdt_reset(struct udevice *dev)
- {
- struct at91_wdt_priv *priv = dev_get_priv(dev);
- writel(AT91_WDT_CR_WDRSTT | AT91_WDT_CR_KEY, priv->regs + AT91_WDT_CR);
- return 0;
- }
- static const struct wdt_ops at91_wdt_ops = {
- .start = at91_wdt_start,
- .stop = at91_wdt_stop,
- .reset = at91_wdt_reset,
- };
- static const struct udevice_id at91_wdt_ids[] = {
- { .compatible = "atmel,at91sam9260-wdt" },
- {}
- };
- static int at91_wdt_probe(struct udevice *dev)
- {
- struct at91_wdt_priv *priv = dev_get_priv(dev);
- priv->regs = dev_remap_addr(dev);
- if (!priv->regs)
- return -EINVAL;
- debug("%s: Probing wdt%u\n", __func__, dev_seq(dev));
- return 0;
- }
- U_BOOT_DRIVER(atmel_at91sam9260_wdt) = {
- .name = "atmel_at91sam9260_wdt",
- .id = UCLASS_WDT,
- .of_match = at91_wdt_ids,
- .priv_auto = sizeof(struct at91_wdt_priv),
- .ops = &at91_wdt_ops,
- .probe = at91_wdt_probe,
- };
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