sysreset: psci: support system reset in a generic way with PSCI

If the system is running PSCI firmware, the System Reset function
(func ID: 0x80000009) is supposed to be handled by PSCI, that is,
the SoC/board specific reset implementation should be moved to PSCI.
U-Boot should call the PSCI service according to the arm-smccc
manner.

The arm-smccc is supported on ARMv7 or later.  Especially, ARMv8
generation SoCs are likely to run ARM Trusted Firmware BL31.  In
this case, U-Boot is a non-secure world boot loader, so it should
not be able to reset the system directly.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

1 files changed, 41 insertions, 0 deletions

diff --git a/drivers/sysreset/sysreset_psci.c b/drivers/sysreset/sysreset_psci.c
new file mode 100644
index 0000000..a4911b7
--- /dev/null
+++ b/drivers/sysreset/sysreset_psci.c
@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 Masahiro Yamada <yamada.masahiro@socionext.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <dm/device.h>
+#include <sysreset.h>
+#include <linux/errno.h>
+#include <linux/psci.h>
+
+static int psci_sysreset_request(struct udevice *dev, enum sysreset_t type)
+{
+	unsigned long function_id;
+
+	switch (type) {
+	case SYSRESET_WARM:
+	case SYSRESET_COLD:
+		function_id = PSCI_0_2_FN_SYSTEM_RESET;
+		break;
+	case SYSRESET_POWER:
+		function_id = PSCI_0_2_FN_SYSTEM_OFF;
+		break;
+	default:
+		return -ENOSYS;
+	}
+
+	invoke_psci_fn(function_id, 0, 0, 0);
+
+	return -EINPROGRESS;
+}
+
+static struct sysreset_ops psci_sysreset_ops = {
+	.request = psci_sysreset_request,
+};
+
+U_BOOT_DRIVER(psci_sysreset) = {
+	.name = "psci-sysreset",
+	.id = UCLASS_SYSRESET,
+	.ops = &psci_sysreset_ops,
+};