aspeed: Watchdog Timer Driver
This driver supports ast2500 and ast2400 SoCs.
Only ast2500 supports reset_mask and thus the option of resettting
individual peripherals using WDT.
Signed-off-by: Maxim Sloyko <maxims@google.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/watchdog/ast_wdt.c b/drivers/watchdog/ast_wdt.c
new file mode 100644
index 0000000..b2bd912
--- /dev/null
+++ b/drivers/watchdog/ast_wdt.c
@@ -0,0 +1,125 @@
+/*
+ * Copyright 2017 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <wdt.h>
+#include <asm/io.h>
+#include <asm/arch/wdt.h>
+
+#define WDT_AST2500 2500
+#define WDT_AST2400 2400
+
+DECLARE_GLOBAL_DATA_PTR;
+
+struct ast_wdt_priv {
+ struct ast_wdt *regs;
+};
+
+static int ast_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
+{
+ struct ast_wdt_priv *priv = dev_get_priv(dev);
+ ulong driver_data = dev_get_driver_data(dev);
+ u32 reset_mode = ast_reset_mode_from_flags(flags);
+
+ clrsetbits_le32(&priv->regs->ctrl,
+ WDT_CTRL_RESET_MASK << WDT_CTRL_RESET_MODE_SHIFT,
+ reset_mode << WDT_CTRL_RESET_MODE_SHIFT);
+
+ if (driver_data >= WDT_AST2500 && reset_mode == WDT_CTRL_RESET_SOC)
+ writel(ast_reset_mask_from_flags(flags),
+ &priv->regs->reset_mask);
+
+ writel((u32) timeout, &priv->regs->counter_reload_val);
+ writel(WDT_COUNTER_RESTART_VAL, &priv->regs->counter_restart);
+ /*
+ * Setting CLK1MHZ bit is just for compatibility with ast2400 part.
+ * On ast2500 watchdog timer clock is fixed at 1MHz and the bit is
+ * read-only
+ */
+ setbits_le32(&priv->regs->ctrl,
+ WDT_CTRL_EN | WDT_CTRL_RESET | WDT_CTRL_CLK1MHZ);
+
+ return 0;
+}
+
+static int ast_wdt_stop(struct udevice *dev)
+{
+ struct ast_wdt_priv *priv = dev_get_priv(dev);
+
+ clrbits_le32(&priv->regs->ctrl, WDT_CTRL_EN);
+
+ return 0;
+}
+
+static int ast_wdt_reset(struct udevice *dev)
+{
+ struct ast_wdt_priv *priv = dev_get_priv(dev);
+
+ writel(WDT_COUNTER_RESTART_VAL, &priv->regs->counter_restart);
+
+ return 0;
+}
+
+static int ast_wdt_expire_now(struct udevice *dev, ulong flags)
+{
+ struct ast_wdt_priv *priv = dev_get_priv(dev);
+ int ret;
+
+ ret = ast_wdt_start(dev, 1, flags);
+ if (ret)
+ return ret;
+
+ while (readl(&priv->regs->ctrl) & WDT_CTRL_EN)
+ ;
+
+ return ast_wdt_stop(dev);
+}
+
+static int ast_wdt_ofdata_to_platdata(struct udevice *dev)
+{
+ struct ast_wdt_priv *priv = dev_get_priv(dev);
+
+ priv->regs = dev_get_addr_ptr(dev);
+ if (IS_ERR(priv->regs))
+ return PTR_ERR(priv->regs);
+
+ return 0;
+}
+
+static const struct wdt_ops ast_wdt_ops = {
+ .start = ast_wdt_start,
+ .reset = ast_wdt_reset,
+ .stop = ast_wdt_stop,
+ .expire_now = ast_wdt_expire_now,
+};
+
+static const struct udevice_id ast_wdt_ids[] = {
+ { .compatible = "aspeed,wdt", .data = WDT_AST2500 },
+ { .compatible = "aspeed,ast2500-wdt", .data = WDT_AST2500 },
+ { .compatible = "aspeed,ast2400-wdt", .data = WDT_AST2400 },
+ {}
+};
+
+static int ast_wdt_probe(struct udevice *dev)
+{
+ debug("%s() wdt%u\n", __func__, dev->seq);
+ ast_wdt_stop(dev);
+
+ return 0;
+}
+
+U_BOOT_DRIVER(ast_wdt) = {
+ .name = "ast_wdt",
+ .id = UCLASS_WDT,
+ .of_match = ast_wdt_ids,
+ .probe = ast_wdt_probe,
+ .priv_auto_alloc_size = sizeof(struct ast_wdt_priv),
+ .ofdata_to_platdata = ast_wdt_ofdata_to_platdata,
+ .ops = &ast_wdt_ops,
+ .flags = DM_FLAG_PRE_RELOC,
+};