On 11/14/21 12:19, Mark Kettenis wrote:
This driver supports the watchdog timer found on Apple's M1 SoC.
On systems that use these SoC, the watchdog timer is the primary
way to reboot the system.
Signed-off-by: Mark Kettenis <kette...@openbsd.org>
---
MAINTAINERS | 1 +
drivers/watchdog/Kconfig | 9 +++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/apple_wdt.c | 111 +++++++++++++++++++++++++++++++++++
4 files changed, 122 insertions(+)
create mode 100644 drivers/watchdog/apple_wdt.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 00ff572d4d..fe56ffed60 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -115,6 +115,7 @@ F: arch/arm/include/asm/arch-m1/
F: arch/arm/mach-apple/
F: configs/apple_m1_defconfig
F: drivers/iommu/apple_dart.c
+F: drivers/watchdog/apple_wdt.c
F: include/configs/apple.h
ARM
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 1177f17fd8..cabac29053 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -81,6 +81,15 @@ config WDT
What exactly happens when the timer expires is up to a particular
device/driver.
+config WDT_APPLE
+ bool "Apple watchdog timer support"
+ depends on WDT
+ default y if ARCH_APPLE
+ help
+ Enable support for the watchdog timer on Apple SoCs.
+ The watchdog will perform a full SoC reset resulting in a
+ reboot of the entire system.
+
config WDT_ARMADA_37XX
bool "Marvell Armada 37xx watchdog timer support"
depends on WDT && ARMADA_3700
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index fa7ce583ce..6d2b3822c0 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -17,6 +17,7 @@ obj-$(CONFIG_DESIGNWARE_WATCHDOG) += designware_wdt.o
obj-$(CONFIG_ULP_WATCHDOG) += ulp_wdog.o
obj-$(CONFIG_$(SPL_TPL_)WDT) += wdt-uclass.o
obj-$(CONFIG_WDT_SANDBOX) += sandbox_wdt.o
+obj-$(CONFIG_WDT_APPLE) += apple_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
diff --git a/drivers/watchdog/apple_wdt.c b/drivers/watchdog/apple_wdt.c
new file mode 100644
index 0000000000..08eefcdaf9
--- /dev/null
+++ b/drivers/watchdog/apple_wdt.c
@@ -0,0 +1,111 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2021 Mark Kettenis <kette...@openbsd.org>
+ */
+
+#include <clk.h>
+#include <dm.h>
+#include <wdt.h>
+#include <asm/io.h>
+#include <linux/delay.h>
+
+#define APPLE_WDT_CUR_TIME 0x10
+#define APPLE_WDT_BARK_TIME 0x14
+#define APPLE_WDT_CTRL 0x1c
+#define APPLE_WDT_CTRL_RESET_EN BIT(2)
+
+struct apple_wdt_priv {
+ void *base;
+ ulong clk_rate;
+};
+
+static int apple_wdt_reset(struct udevice *dev)
+{
+ struct apple_wdt_priv *priv = dev_get_priv(dev);
+
+ writel(0, priv->base + APPLE_WDT_CUR_TIME);
+
+ return 0;
+}
+
+static int apple_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+ struct apple_wdt_priv *priv = dev_get_priv(dev);
+ u64 timeout;
+
+ timeout = (timeout_ms * priv->clk_rate) / 1000;
+ if (timeout > U32_MAX)
+ return -EINVAL;
+
+ writel(0, priv->base + APPLE_WDT_CUR_TIME);
+ writel(timeout, priv->base + APPLE_WDT_BARK_TIME);
+ writel(APPLE_WDT_CTRL_RESET_EN, priv->base + APPLE_WDT_CTRL);
+
+ return 0;
+}
+
+static int apple_wdt_stop(struct udevice *dev)
+{
+ struct apple_wdt_priv *priv = dev_get_priv(dev);
+
+ writel(0, priv->base + APPLE_WDT_CTRL);
+
+ return 0;
+}
+
+static int apple_wdt_expire_now(struct udevice *dev, ulong flags)
+{
+ int ret;
+
+ ret = apple_wdt_start(dev, 0, flags);
+ if (ret)
+ return ret;
+
+ mdelay(150);
Could you perhaps add a short comment here, why you chose 150ms?
Other than this:
Reviewed-by: Stefan Roese <s...@denx.de>
Thanks,
Stefan
+
+ return 0;
+}
+
+static const struct wdt_ops apple_wdt_ops = {
+ .reset = apple_wdt_reset,
+ .start = apple_wdt_start,
+ .stop = apple_wdt_stop,
+ .expire_now = apple_wdt_expire_now,
+};
+
+static const struct udevice_id apple_wdt_ids[] = {
+ { .compatible = "apple,wdt" },
+ { /* sentinel */ }
+};
+
+static int apple_wdt_probe(struct udevice *dev)
+{
+ struct apple_wdt_priv *priv = dev_get_priv(dev);
+ struct clk clk;
+ int ret;
+
+ priv->base = dev_read_addr_ptr(dev);
+ if (!priv->base)
+ return -EINVAL;
+
+ ret = clk_get_by_index(dev, 0, &clk);
+ if (ret)
+ return ret;
+
+ ret = clk_enable(&clk);
+ if (ret)
+ return ret;
+
+ priv->clk_rate = clk_get_rate(&clk);
+
+ return 0;
+}
+
+U_BOOT_DRIVER(apple_wdt) = {
+ .name = "apple_wdt",
+ .id = UCLASS_WDT,
+ .of_match = apple_wdt_ids,
+ .priv_auto = sizeof(struct apple_wdt_priv),
+ .probe = apple_wdt_probe,
+ .ops = &apple_wdt_ops,
+};
Viele Grüße,
Stefan Roese
--
DENX Software Engineering GmbH, Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-51 Fax: (+49)-8142-66989-80 Email: s...@denx.de
