wdt: imx8qxp: add option to control external PMIC wdt via IMX8 SCU
Driver for a PMIC watchdog timer controlled via Siemens SCU firmware
extensions. Only useful on some Siemens i.MX8-based platforms as
special SCFW is needed which provides the needed SCU API.
Signed-off-by: Andrej Valek <andrej.valek@siemens.com>
Signed-off-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Alexander Sverdlin <alexander.sverdlin@siemens.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 0e45f0a..b39b254 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -351,6 +351,13 @@
In the single stage mode, when the timeout is reached, your system
will be reset by WS1. The first signal (WS0) is ignored.
+config WDT_SIEMENS_PMIC
+ bool "Enable PMIC Watchdog Timer support for Siemens platforms"
+ depends on ARCH_IMX8 && WDT
+ help
+ Select this to enable the PMIC watchdog driver controlled via
+ IMX8 SCU API found on Siemens platforms.
+
config WDT_SL28CPLD
bool "sl28cpld watchdog timer support"
depends on WDT && SL28CPLD
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 0b107c0..9b6b1a8 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -45,6 +45,7 @@
obj-$(CONFIG_WDT_OMAP3) += omap_wdt.o
obj-$(CONFIG_WDT_SBSA) += sbsa_gwdt.o
obj-$(CONFIG_WDT_K3_RTI) += rti_wdt.o
+obj-$(CONFIG_WDT_SIEMENS_PMIC) += siemens_pmic_wdt.o
obj-$(CONFIG_WDT_SL28CPLD) += sl28cpld-wdt.o
obj-$(CONFIG_WDT_SP805) += sp805_wdt.o
obj-$(CONFIG_WDT_STARFIVE) += starfive_wdt.o
diff --git a/drivers/watchdog/siemens_pmic_wdt.c b/drivers/watchdog/siemens_pmic_wdt.c
new file mode 100644
index 0000000..87e817b
--- /dev/null
+++ b/drivers/watchdog/siemens_pmic_wdt.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Driver for a PMIC watchdog timer controlled via Siemens SCU firmware
+ * extensions. Only useful on some Siemens i.MX8-based platforms as
+ * special NXP SCFW is needed which provides the needed SCU API.
+ *
+ * Copyright (C) 2024 Siemens AG
+ */
+
+#include <dm.h>
+#include <wdt.h>
+#include <firmware/imx/sci/sci.h>
+
+/* watchdog commands */
+#define CMD_START_WDT 0x55
+#define CMD_STOP_WDT 0x45
+#define CMD_PING_WDT 0x35
+
+static int scu_wdt_start(struct udevice *dev, u64 timeout_ms, ulong flags)
+{
+ /* start external watchdog via Timer API */
+ return sc_timer_control_siemens_pmic_wdog(-1, CMD_START_WDT);
+}
+
+static int scu_wdt_stop(struct udevice *dev)
+{
+ /* stop external watchdog via Timer API */
+ return sc_timer_control_siemens_pmic_wdog(-1, CMD_STOP_WDT);
+}
+
+static int scu_wdt_reset(struct udevice *dev)
+{
+ return sc_timer_control_siemens_pmic_wdog(-1, CMD_PING_WDT);
+}
+
+static int scu_wdt_probe(struct udevice *dev)
+{
+ debug("%s(dev=%p)\n", __func__, dev);
+ return 0;
+}
+
+static const struct wdt_ops scu_wdt_ops = {
+ .reset = scu_wdt_reset,
+ .start = scu_wdt_start,
+ .stop = scu_wdt_stop,
+};
+
+static const struct udevice_id scu_wdt_ids[] = {
+ { .compatible = "siemens,scu-wdt" },
+ { }
+};
+
+U_BOOT_DRIVER(scu_wdt) = {
+ .name = "scu_wdt",
+ .id = UCLASS_WDT,
+ .of_match = scu_wdt_ids,
+ .probe = scu_wdt_probe,
+ .ops = &scu_wdt_ops,
+};