wdt: aspeed: Add AST2600 watchdog support

AST2600 has 8 watchdog timers including 8 sets of
32-bit decrement counters, based on 1MHz clock.

A 64-bit reset mask is also supported to specify
which controllers should be reset by the WDT reset.

Signed-off-by: Chia-Wei, Wang <chiawei_wang@aspeedtech.com>
Reviewed-by: Ryan Chen <ryan_chen@aspeedtech.com>

3 files changed, 120 insertions, 0 deletions

diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 4532a40e458..d5edabf3eff 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -86,6 +86,15 @@ config WDT_ASPEED
 	  It currently does not support Boot Flash Addressing Mode Detection or
 	  Second Boot.
 
+config WDT_AST2600
+	bool "Aspeed AST2600 watchdog timer support"
+	depends on WDT
+	default y if ASPEED_AST2600
+	help
+	  Select this to enable watchdog timer for Aspeed ast2500/ast2400 devices.
+	  The watchdog timer is stopped when initialized. It performs reset, either
+	  full SoC reset or CPU or just some peripherals, based on the flags.
+
 config WDT_AT91
 	bool "AT91 watchdog timer support"
 	depends on WDT
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 01b8231f2bf..cbb6d8407cc 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -19,6 +19,7 @@ obj-$(CONFIG_$(SPL_TPL_)WDT) += wdt-uclass.o
 obj-$(CONFIG_WDT_SANDBOX) += sandbox_wdt.o
 obj-$(CONFIG_WDT_ARMADA_37XX) += armada-37xx-wdt.o
 obj-$(CONFIG_WDT_ASPEED) += ast_wdt.o
+obj-$(CONFIG_WDT_AST2600) += ast2600_wdt.o
 obj-$(CONFIG_WDT_BCM6345) += bcm6345_wdt.o
 obj-$(CONFIG_WDT_CORTINA) += cortina_wdt.o
 obj-$(CONFIG_WDT_ORION) += orion_wdt.o
diff --git a/drivers/watchdog/ast2600_wdt.c b/drivers/watchdog/ast2600_wdt.c
new file mode 100644
index 00000000000..bc9842089be
--- /dev/null
+++ b/drivers/watchdog/ast2600_wdt.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (c) 2020 Aspeed Technology, Inc
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <log.h>
+#include <wdt.h>
+#include <asm/io.h>
+#include <asm/arch/wdt_ast2600.h>
+#include <linux/err.h>
+
+struct ast2600_wdt_priv {
+	struct ast2600_wdt *regs;
+};
+
+static int ast2600_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+	struct ast2600_wdt_priv *priv = dev_get_priv(dev);
+	struct ast2600_wdt *wdt = priv->regs;
+
+	/* WDT counts in the 1MHz frequency, namely 1us */
+	writel((u32)(timeout_ms * 1000), &wdt->counter_reload_val);
+	writel(WDT_COUNTER_RESTART_VAL, &wdt->counter_restart);
+	writel(WDT_CTRL_EN | WDT_CTRL_RESET, &wdt->ctrl);
+
+	return 0;
+}
+
+static int ast2600_wdt_stop(struct udevice *dev)
+{
+	struct ast2600_wdt_priv *priv = dev_get_priv(dev);
+	struct ast2600_wdt *wdt = priv->regs;
+
+	clrbits_le32(&wdt->ctrl, WDT_CTRL_EN);
+
+	writel(WDT_RESET_MASK1_DEFAULT, &wdt->reset_mask1);
+	writel(WDT_RESET_MASK2_DEFAULT, &wdt->reset_mask2);
+
+	return 0;
+}
+
+static int ast2600_wdt_reset(struct udevice *dev)
+{
+	struct ast2600_wdt_priv *priv = dev_get_priv(dev);
+	struct ast2600_wdt *wdt = priv->regs;
+
+	writel(WDT_COUNTER_RESTART_VAL, &wdt->counter_restart);
+
+	return 0;
+}
+
+static int ast2600_wdt_expire_now(struct udevice *dev, ulong flags)
+{
+	int ret;
+	struct ast2600_wdt_priv *priv = dev_get_priv(dev);
+	struct ast2600_wdt *wdt = priv->regs;
+
+	ret = ast2600_wdt_start(dev, 1, flags);
+	if (ret)
+		return ret;
+
+	while (readl(&wdt->ctrl) & WDT_CTRL_EN)
+		;
+
+	return ast2600_wdt_stop(dev);
+}
+
+static int ast2600_wdt_of_to_plat(struct udevice *dev)
+{
+	struct ast2600_wdt_priv *priv = dev_get_priv(dev);
+
+	priv->regs = dev_read_addr_ptr(dev);
+	if (!priv->regs)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct wdt_ops ast2600_wdt_ops = {
+	.start = ast2600_wdt_start,
+	.reset = ast2600_wdt_reset,
+	.stop = ast2600_wdt_stop,
+	.expire_now = ast2600_wdt_expire_now,
+};
+
+static const struct udevice_id ast2600_wdt_ids[] = {
+	{ .compatible = "aspeed,ast2600-wdt" },
+	{ }
+};
+
+static int ast2600_wdt_probe(struct udevice *dev)
+{
+	debug("%s() wdt%u\n", __func__, dev_seq(dev));
+	ast2600_wdt_stop(dev);
+
+	return 0;
+}
+
+U_BOOT_DRIVER(ast2600_wdt) = {
+	.name = "ast2600_wdt",
+	.id = UCLASS_WDT,
+	.of_match = ast2600_wdt_ids,
+	.probe = ast2600_wdt_probe,
+	.priv_auto = sizeof(struct ast2600_wdt_priv),
+	.of_to_plat = ast2600_wdt_of_to_plat,
+	.ops = &ast2600_wdt_ops,
+};