watchdog: add sl28cpld watchdog driver
The watchdog timer is part of the sl28cpld management controller. The
watchdog timer usually supervises the bootloader boot-up and if it bites
the failsafe bootloader will be activated. Apart from that it supports
the usual board level reset and one SMARC speciality: driving the
WDT_TIMEOUT# signal.
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Priyanka Jain <priyanka.jain@nxp.com>
diff --git a/drivers/watchdog/sl28cpld-wdt.c b/drivers/watchdog/sl28cpld-wdt.c
new file mode 100644
index 0000000..af5a6b1
--- /dev/null
+++ b/drivers/watchdog/sl28cpld-wdt.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Watchdog driver for the sl28cpld
+ *
+ * Copyright (c) 2021 Michael Walle <michael@walle.cc>
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <wdt.h>
+#include <sl28cpld.h>
+#include <div64.h>
+
+#define SL28CPLD_WDT_CTRL 0x00
+#define WDT_CTRL_EN0 BIT(0)
+#define WDT_CTRL_EN1 BIT(1)
+#define WDT_CTRL_EN_MASK GENMASK(1, 0)
+#define WDT_CTRL_LOCK BIT(2)
+#define WDT_CTRL_ASSERT_SYS_RESET BIT(6)
+#define WDT_CTRL_ASSERT_WDT_TIMEOUT BIT(7)
+#define SL28CPLD_WDT_TIMEOUT 0x01
+#define SL28CPLD_WDT_KICK 0x02
+#define WDT_KICK_VALUE 0x6b
+
+static int sl28cpld_wdt_reset(struct udevice *dev)
+{
+ return sl28cpld_write(dev, SL28CPLD_WDT_KICK, WDT_KICK_VALUE);
+}
+
+static int sl28cpld_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
+{
+ int ret, val;
+
+ val = sl28cpld_read(dev, SL28CPLD_WDT_CTRL);
+ if (val < 0)
+ return val;
+
+ /* (1) disable watchdog */
+ val &= ~WDT_CTRL_EN_MASK;
+ ret = sl28cpld_write(dev, SL28CPLD_WDT_CTRL, val);
+ if (ret)
+ return ret;
+
+ /* (2) set timeout */
+ ret = sl28cpld_write(dev, SL28CPLD_WDT_TIMEOUT, lldiv(timeout, 1000));
+ if (ret)
+ return ret;
+
+ /* (3) kick it, will reset timer to the timeout value */
+ ret = sl28cpld_wdt_reset(dev);
+ if (ret)
+ return ret;
+
+ /* (4) enable either recovery or normal one */
+ if (flags & BIT(0))
+ val |= WDT_CTRL_EN1;
+ else
+ val |= WDT_CTRL_EN0;
+
+ if (flags & BIT(1))
+ val |= WDT_CTRL_LOCK;
+
+ if (flags & BIT(2))
+ val &= ~WDT_CTRL_ASSERT_SYS_RESET;
+ else
+ val |= WDT_CTRL_ASSERT_SYS_RESET;
+
+ if (flags & BIT(3))
+ val |= WDT_CTRL_ASSERT_WDT_TIMEOUT;
+ else
+ val &= ~WDT_CTRL_ASSERT_WDT_TIMEOUT;
+
+ return sl28cpld_write(dev, SL28CPLD_WDT_CTRL, val);
+}
+
+static int sl28cpld_wdt_stop(struct udevice *dev)
+{
+ int val;
+
+ val = sl28cpld_read(dev, SL28CPLD_WDT_CTRL);
+ if (val < 0)
+ return val;
+
+ return sl28cpld_write(dev, SL28CPLD_WDT_CTRL, val & ~WDT_CTRL_EN_MASK);
+}
+
+static int sl28cpld_wdt_expire_now(struct udevice *dev, ulong flags)
+{
+ return sl28cpld_wdt_start(dev, 0, flags);
+}
+
+static const struct wdt_ops sl28cpld_wdt_ops = {
+ .start = sl28cpld_wdt_start,
+ .reset = sl28cpld_wdt_reset,
+ .stop = sl28cpld_wdt_stop,
+ .expire_now = sl28cpld_wdt_expire_now,
+};
+
+static const struct udevice_id sl28cpld_wdt_ids[] = {
+ { .compatible = "kontron,sl28cpld-wdt", },
+ {}
+};
+
+U_BOOT_DRIVER(sl28cpld_wdt) = {
+ .name = "sl28cpld-wdt",
+ .id = UCLASS_WDT,
+ .of_match = sl28cpld_wdt_ids,
+ .ops = &sl28cpld_wdt_ops,
+};