3 files changed, 176 insertions, 0 deletions

diff --git a/lib/utils/reset/Kconfig b/lib/utils/reset/Kconfig
index 4748cc85..c0b96406 100644
--- a/lib/utils/reset/Kconfig
+++ b/lib/utils/reset/Kconfig
@@ -33,6 +33,11 @@ config FDT_RESET_SUNXI_WDT
 	bool "Sunxi WDT FDT reset driver"
 	default n
 
+config FDT_RESET_SYSCON
+	bool "Syscon FDT reset driver"
+	depends on FDT_REGMAP
+	default n
+
 config FDT_RESET_THEAD
 	bool "T-HEAD FDT reset driver"
 	default n
diff --git a/lib/utils/reset/fdt_reset_syscon.c b/lib/utils/reset/fdt_reset_syscon.c
new file mode 100644
index 00000000..bae9ec58
--- /dev/null
+++ b/lib/utils/reset/fdt_reset_syscon.c
@@ -0,0 +1,167 @@
+/*
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2023 Ventana Micro Systems Inc.
+ *
+ * Authors:
+ *   Anup Patel <[email protected]>
+ */
+
+#include <libfdt.h>
+#include <sbi/sbi_ecall_interface.h>
+#include <sbi/sbi_error.h>
+#include <sbi/sbi_hart.h>
+#include <sbi/sbi_system.h>
+#include <sbi_utils/fdt/fdt_helper.h>
+#include <sbi_utils/regmap/fdt_regmap.h>
+#include <sbi_utils/reset/fdt_reset.h>
+
+struct syscon_reset {
+	struct regmap *rmap;
+	u32 priority;
+	u32 offset;
+	u32 value;
+	u32 mask;
+};
+
+static struct syscon_reset poweroff;
+static struct syscon_reset reboot;
+
+static struct syscon_reset *syscon_reset_get(bool is_reboot, u32 type)
+{
+	struct syscon_reset *reset = NULL;
+
+	switch (type) {
+	case SBI_SRST_RESET_TYPE_SHUTDOWN:
+		if (!is_reboot)
+			reset = &poweroff;
+		break;
+	case SBI_SRST_RESET_TYPE_COLD_REBOOT:
+	case SBI_SRST_RESET_TYPE_WARM_REBOOT:
+		if (is_reboot)
+			reset = &reboot;
+		break;
+	}
+
+	if (reset && !reset->rmap)
+		reset = NULL;
+
+	return reset;
+}
+
+static void syscon_reset_exec(struct syscon_reset *reset)
+{
+	/* Issue the reset through regmap */
+	if (reset)
+		regmap_update_bits(reset->rmap, reset->offset,
+				   reset->mask, reset->value);
+
+	/* hang !!! */
+	sbi_hart_hang();
+}
+
+static int syscon_poweroff_check(u32 type, u32 reason)
+{
+	struct syscon_reset *reset = syscon_reset_get(false, type);
+
+	return (reset) ? reset->priority : 0;
+}
+
+static void syscon_do_poweroff(u32 type, u32 reason)
+{
+	syscon_reset_exec(syscon_reset_get(false, type));
+}
+
+static struct sbi_system_reset_device syscon_poweroff = {
+	.name = "syscon-poweroff",
+	.system_reset_check = syscon_poweroff_check,
+	.system_reset = syscon_do_poweroff
+};
+
+static int syscon_reboot_check(u32 type, u32 reason)
+{
+	struct syscon_reset *reset = syscon_reset_get(true, type);
+
+	return (reset) ? reset->priority : 0;
+}
+
+static void syscon_do_reboot(u32 type, u32 reason)
+{
+	syscon_reset_exec(syscon_reset_get(true, type));
+}
+
+static struct sbi_system_reset_device syscon_reboot = {
+	.name = "syscon-reboot",
+	.system_reset_check = syscon_reboot_check,
+	.system_reset = syscon_do_reboot
+};
+
+static int syscon_reset_init(void *fdt, int nodeoff,
+			   const struct fdt_match *match)
+{
+	int rc, len;
+	const fdt32_t *val, *mask;
+	bool is_reboot = (ulong)match->data;
+	struct syscon_reset *reset = (is_reboot) ? &reboot : &poweroff;
+
+	if (reset->rmap)
+		return SBI_EALREADY;
+
+	rc = fdt_regmap_get(fdt, nodeoff, &reset->rmap);
+	if (rc)
+		return rc;
+
+	val = fdt_getprop(fdt, nodeoff, "priority", &len);
+	reset->priority = (val && len > 0) ? fdt32_to_cpu(*val) : 192;
+
+	val = fdt_getprop(fdt, nodeoff, "offset", &len);
+	if (val && len > 0)
+		reset->offset = fdt32_to_cpu(*val);
+	else
+		return SBI_EINVAL;
+
+	val = fdt_getprop(fdt, nodeoff, "value", &len);
+	mask = fdt_getprop(fdt, nodeoff, "mask", &len);
+	if (!val && !mask)
+		return SBI_EINVAL;
+
+	if (!val) {
+		/* support old binding */
+		reset->value = fdt32_to_cpu(*mask);
+		reset->mask = 0xFFFFFFFF;
+	} else if (!mask) {
+		/* support value without mask */
+		reset->value = fdt32_to_cpu(*val);
+		reset->mask = 0xFFFFFFFF;
+	} else {
+		reset->value = fdt32_to_cpu(*val);
+		reset->mask = fdt32_to_cpu(*mask);
+	}
+
+	if (is_reboot)
+		sbi_system_reset_add_device(&syscon_reboot);
+	else
+		sbi_system_reset_add_device(&syscon_poweroff);
+
+	return 0;
+}
+
+static const struct fdt_match syscon_poweroff_match[] = {
+	{ .compatible = "syscon-poweroff", .data = (const void *)false },
+	{ },
+};
+
+struct fdt_reset fdt_syscon_poweroff = {
+	.match_table = syscon_poweroff_match,
+	.init = syscon_reset_init,
+};
+
+static const struct fdt_match syscon_reboot_match[] = {
+	{ .compatible = "syscon-reboot", .data = (const void *)true },
+	{ },
+};
+
+struct fdt_reset fdt_syscon_reboot = {
+	.match_table = syscon_reboot_match,
+	.init = syscon_reset_init,
+};
diff --git a/lib/utils/reset/objects.mk b/lib/utils/reset/objects.mk
index c9f851cd..17287a5e 100644
--- a/lib/utils/reset/objects.mk
+++ b/lib/utils/reset/objects.mk
@@ -26,6 +26,10 @@ libsbiutils-objs-$(CONFIG_FDT_RESET_SIFIVE_TEST) += reset/fdt_reset_sifive_test.
 carray-fdt_reset_drivers-$(CONFIG_FDT_RESET_SUNXI_WDT) += fdt_reset_sunxi_wdt
 libsbiutils-objs-$(CONFIG_FDT_RESET_SUNXI_WDT) += reset/fdt_reset_sunxi_wdt.o
 
+carray-fdt_reset_drivers-$(CONFIG_FDT_RESET_SYSCON) += fdt_syscon_poweroff
+carray-fdt_reset_drivers-$(CONFIG_FDT_RESET_SYSCON) += fdt_syscon_reboot
+libsbiutils-objs-$(CONFIG_FDT_RESET_SYSCON) += reset/fdt_reset_syscon.o
+
 carray-fdt_reset_drivers-$(CONFIG_FDT_RESET_THEAD) += fdt_reset_thead
 libsbiutils-objs-$(CONFIG_FDT_RESET_THEAD) += reset/fdt_reset_thead.o
 libsbiutils-objs-$(CONFIG_FDT_RESET_THEAD) += reset/fdt_reset_thead_asm.o