[PATCH 03/17] aspeed: Watchdog Timer Driver
Maxim Sloyko
maxims at google.com
Fri Mar 17 08:36:10 AEDT 2017
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 at google.com>
---
arch/arm/include/asm/arch-aspeed/wdt.h | 53 ++++++++++++--
arch/arm/mach-aspeed/ast_wdt.c | 40 ++++++++---
drivers/watchdog/Kconfig | 13 ++++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/ast_wdt.c | 125 +++++++++++++++++++++++++++++++++
5 files changed, 219 insertions(+), 13 deletions(-)
create mode 100644 drivers/watchdog/ast_wdt.c
diff --git a/arch/arm/include/asm/arch-aspeed/wdt.h b/arch/arm/include/asm/arch-aspeed/wdt.h
index b292a0e67b..981fa05a56 100644
--- a/arch/arm/include/asm/arch-aspeed/wdt.h
+++ b/arch/arm/include/asm/arch-aspeed/wdt.h
@@ -67,15 +67,60 @@ struct ast_wdt {
u32 timeout_status;
u32 clr_timeout_status;
u32 reset_width;
-#ifdef CONFIG_ASPEED_AST2500
+ /* On pre-ast2500 SoCs this register is reserved. */
u32 reset_mask;
-#else
- u32 reserved0;
-#endif
};
+/**
+ * Given flags parameter passed to wdt_reset or wdt_start uclass functions,
+ * gets Reset Mode value from it.
+ *
+ * @flags: flags parameter passed into wdt_reset or wdt_start
+ * @return Reset Mode value
+ */
+u32 ast_reset_mode_from_flags(ulong flags);
+
+/**
+ * Given flags parameter passed to wdt_reset or wdt_start uclass functions,
+ * gets Reset Mask value from it. Reset Mask is only supported on ast2500
+ *
+ * @flags: flags parameter passed into wdt_reset or wdt_start
+ * @return Reset Mask value
+ */
+u32 ast_reset_mask_from_flags(ulong flags);
+
+/**
+ * Given Reset Mask and Reset Mode values, converts them to flags,
+ * suitable for passing into wdt_start or wdt_reset uclass functions.
+ *
+ * On ast2500 Reset Mask is 25 bits wide and Reset Mode is 2 bits wide, so they
+ * can both be packed into single 32 bits wide value.
+ *
+ * @reset_mode: Reset Mode
+ * @reset_mask: Reset Mask
+ */
+ulong ast_flags_from_reset_mode_mask(u32 reset_mode, u32 reset_mask);
+
+#ifndef CONFIG_WDT
+/**
+ * Stop WDT
+ *
+ * @wdt: watchdog to stop
+ *
+ * When using driver model this function has different signature
+ */
void wdt_stop(struct ast_wdt *wdt);
+
+/**
+ * Stop WDT
+ *
+ * @wdt: watchdog to start
+ * @timeout watchdog timeout in number of clock ticks
+ *
+ * When using driver model this function has different signature
+ */
void wdt_start(struct ast_wdt *wdt, u32 timeout);
+#endif /* CONFIG_WDT */
/**
* Reset peripherals specified by mask
diff --git a/arch/arm/mach-aspeed/ast_wdt.c b/arch/arm/mach-aspeed/ast_wdt.c
index 22481ab7ea..895fba3366 100644
--- a/arch/arm/mach-aspeed/ast_wdt.c
+++ b/arch/arm/mach-aspeed/ast_wdt.c
@@ -9,6 +9,27 @@
#include <asm/arch/wdt.h>
#include <linux/err.h>
+u32 ast_reset_mode_from_flags(ulong flags)
+{
+ return flags & WDT_CTRL_RESET_MASK;
+}
+
+u32 ast_reset_mask_from_flags(ulong flags)
+{
+ return flags >> 2;
+}
+
+ulong ast_flags_from_reset_mode_mask(u32 reset_mode, u32 reset_mask)
+{
+ ulong ret = reset_mode & WDT_CTRL_RESET_MASK;
+
+ if (ret == WDT_CTRL_RESET_SOC)
+ ret |= (reset_mask << 2);
+
+ return ret;
+}
+
+#ifndef CONFIG_WDT
void wdt_stop(struct ast_wdt *wdt)
{
clrbits_le32(&wdt->ctrl, WDT_CTRL_EN);
@@ -26,15 +47,7 @@ void wdt_start(struct ast_wdt *wdt, u32 timeout)
setbits_le32(&wdt->ctrl,
WDT_CTRL_EN | WDT_CTRL_RESET | WDT_CTRL_CLK1MHZ);
}
-
-struct ast_wdt *ast_get_wdt(u8 wdt_number)
-{
- if (wdt_number > CONFIG_WDT_NUM - 1)
- return ERR_PTR(-EINVAL);
-
- return (struct ast_wdt *)(WDT_BASE +
- sizeof(struct ast_wdt) * wdt_number);
-}
+#endif /* CONFIG_WDT */
int ast_wdt_reset_masked(struct ast_wdt *wdt, u32 mask)
{
@@ -57,3 +70,12 @@ int ast_wdt_reset_masked(struct ast_wdt *wdt, u32 mask)
return -EINVAL;
#endif
}
+
+struct ast_wdt *ast_get_wdt(u8 wdt_number)
+{
+ if (wdt_number > CONFIG_WDT_NUM - 1)
+ return ERR_PTR(-EINVAL);
+
+ return (struct ast_wdt *)(WDT_BASE +
+ sizeof(struct ast_wdt) * wdt_number);
+}
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 0d7366f3df..10f34f5efa 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -9,3 +9,16 @@ config WDT
start, restart, stop and reset (expire immediately).
What exactly happens when the timer expires is up to a particular
device/driver.
+
+config WDT_ASPEED
+ bool "Aspeed ast2400/ast2500 watchdog timer support"
+ depends on WDT
+ default y if ARCH_ASPEED
+ 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.
+ It currently does not support Boot Flash Addressing Mode Detection or
+ Second Boot.
+
+endmenu
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 1aabcb97ae..1d779a8446 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -16,3 +16,4 @@ obj-$(CONFIG_BFIN_WATCHDOG) += bfin_wdt.o
obj-$(CONFIG_OMAP_WATCHDOG) += omap_wdt.o
obj-$(CONFIG_DESIGNWARE_WATCHDOG) += designware_wdt.o
obj-$(CONFIG_WDT) += wdt-uclass.o
+obj-$(CONFIG_WDT_ASPEED) += ast_wdt.o
diff --git a/drivers/watchdog/ast_wdt.c b/drivers/watchdog/ast_wdt.c
new file mode 100644
index 0000000000..d53aada332
--- /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_restart(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_reset(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,
+ .restart = ast_wdt_restart,
+ .stop = ast_wdt_stop,
+ .reset = ast_wdt_reset,
+};
+
+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,
+};
--
2.12.0.367.g23dc2f6d3c-goog
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