GK SDK 源码库: XMIPCLinuxV100R005C00SPC030 (kernel/tools/open_source excluded)

2026-09-06 03:52:57 +08:00
commit b1928b41c0
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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 <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);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(at91_wdt) = {
+	.name = "at91_wdt",
+	.id = UCLASS_WDT,
+	.of_match = at91_wdt_ids,
+	.priv_auto_alloc_size = sizeof(struct at91_wdt_priv),
+	.ops = &at91_wdt_ops,
+	.probe = at91_wdt_probe,
+};