[PATCH 4/4] lib: sbi: Add ecall handler for SBI watchdog

[Prajwal N]

Update the Kconfig and build infrastructure to include
SBI ecall handler for watchdog.

Implement ecall handler functionality to delegate the
ecall to SBI watchdog framework

Signed-off-by: Prajwal N <prajwal.n at oss.qualcomm.com>
---
 lib/sbi/Kconfig         |  4 +++
 lib/sbi/objects.mk      |  3 ++
 lib/sbi/sbi_ecall_wdt.c | 79 +++++++++++++++++++++++++++++++++++++++++
 3 files changed, 86 insertions(+)
 create mode 100644 lib/sbi/sbi_ecall_wdt.c

diff --git a/lib/sbi/Kconfig b/lib/sbi/Kconfig
index 24132eaa..6fd965d5 100644
--- a/lib/sbi/Kconfig
+++ b/lib/sbi/Kconfig
@@ -95,4 +95,8 @@ config SBI_ECALL_SSE
 config SBI_ECALL_MPXY
 	bool "MPXY extension"
 	default y
+
+config SBI_ECALL_WDT
+	bool "WDT extension"
+	default y
 endmenu
diff --git a/lib/sbi/objects.mk b/lib/sbi/objects.mk
index c8bdc94a..847aee89 100644
--- a/lib/sbi/objects.mk
+++ b/lib/sbi/objects.mk
@@ -46,6 +46,9 @@ libsbi-objs-$(CONFIG_SBI_ECALL_DBCN) += sbi_ecall_dbcn.o
 carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_CPPC) += ecall_cppc
 libsbi-objs-$(CONFIG_SBI_ECALL_CPPC) += sbi_ecall_cppc.o
 
+carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_WDT) += ecall_wdt
+libsbi-objs-$(CONFIG_SBI_ECALL_WDT) += sbi_ecall_wdt.o
+
 carray-sbi_ecall_exts-$(CONFIG_SBI_ECALL_FWFT) += ecall_fwft
 libsbi-objs-$(CONFIG_SBI_ECALL_FWFT) += sbi_ecall_fwft.o
 
diff --git a/lib/sbi/sbi_ecall_wdt.c b/lib/sbi/sbi_ecall_wdt.c
new file mode 100644
index 00000000..81b3e174
--- /dev/null
+++ b/lib/sbi/sbi_ecall_wdt.c
@@ -0,0 +1,79 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2026 Qualcomm Inc.
+ *
+ * Authors:
+ *   Prajwal N <prajwal.n at oss.qualcomm.com>
+ */
+
+#include <sbi/sbi_ecall.h>
+#include <sbi/sbi_ecall_interface.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_trap.h>
+#include <sbi/sbi_wdt.h>
+
+/**
+ * OpenSBI watchdog ecall handler
+ * @param extid OpenSBI extension ID
+ * @param funcid OpenSBI function ID corresponding to the extension ID
+ * @param regs Trap registers for arguments
+ * @param out Carry the return value
+ * @return integer error value
+ */
+static int sbi_ecall_wdt_handler(unsigned long extid, unsigned long funcid,
+			                        struct sbi_trap_regs *regs,
+	                                struct sbi_ecall_return *out)
+{
+	int ret;
+	u32 attribute_value = 0;
+	ret = SBI_ERR_FAILED;
+
+	switch (funcid) {
+	case SBI_EXT_WATCHDOG_READ_ATTRIBUTE:
+		ret = sbi_watchdog_read_attribute(regs->a0, &attribute_value);
+		out->value = attribute_value;
+		break;
+
+	case SBI_EXT_WATCHDOG_WRITE_ATTRIBUTE:
+		ret = sbi_watchdog_write_attribute(regs->a0, regs->a1);
+		break;
+
+	case SBI_EXT_WATCHDOG_WRITE_NOTIF_MSI_MESSAGE:
+		ret = sbi_watchdog_write_notif_msi_message(regs->a0, regs->a1, regs->a2);
+		break;
+
+	case SBI_EXT_WATCHDOG_START:
+		ret = sbi_watchdog_start();
+		break;
+
+	case SBI_EXT_WATCHDOG_STOP:
+		ret = sbi_watchdog_stop();
+		break;
+
+	case SBI_EXT_WATCHDOG_PAT:
+		ret = sbi_watchdog_pat();
+		break;
+
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+struct sbi_ecall_extension ecall_wdt;
+
+static int sbi_ecall_wdt_register_extensions(void)
+{
+	return sbi_ecall_register_extension(&ecall_wdt);
+}
+
+struct sbi_ecall_extension ecall_wdt = {
+	.name                   = "sbi-wdt",
+	.extid_start            = SBI_EXT_WDT,
+	.extid_end              = SBI_EXT_WDT,
+	.experimental           = true,
+	.register_extensions    = sbi_ecall_wdt_register_extensions,
+	.handle                 = sbi_ecall_wdt_handler,
+};
-- 
2.43.0