1 files changed, 98 insertions, 0 deletions
diff --git a/drivers/firmware/efi/libstub/riscv.c b/drivers/firmware/efi/libstub/riscv.c
new file mode 100644
index 0000000000..8022b104c3
--- /dev/null
+++ b/drivers/firmware/efi/libstub/riscv.c
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020 Western Digital Corporation or its affiliates.
+ */
+
+#include <linux/efi.h>
+#include <linux/libfdt.h>
+
+#include <asm/efi.h>
+#include <asm/unaligned.h>
+
+#include "efistub.h"
+
+typedef void __noreturn (*jump_kernel_func)(unsigned long, unsigned long);
+
+static unsigned long hartid;
+
+static int get_boot_hartid_from_fdt(void)
+{
+	const void *fdt;
+	int chosen_node, len;
+	const void *prop;
+
+	fdt = get_efi_config_table(DEVICE_TREE_GUID);
+	if (!fdt)
+		return -EINVAL;
+
+	chosen_node = fdt_path_offset(fdt, "/chosen");
+	if (chosen_node < 0)
+		return -EINVAL;
+
+	prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len);
+	if (!prop)
+		return -EINVAL;
+
+	if (len == sizeof(u32))
+		hartid = (unsigned long) fdt32_to_cpu(*(fdt32_t *)prop);
+	else if (len == sizeof(u64))
+		hartid = (unsigned long) fdt64_to_cpu(__get_unaligned_t(fdt64_t, prop));
+	else
+		return -EINVAL;
+
+	return 0;
+}
+
+static efi_status_t get_boot_hartid_from_efi(void)
+{
+	efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;
+	struct riscv_efi_boot_protocol *boot_protocol;
+	efi_status_t status;
+
+	status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL,
+			     (void **)&boot_protocol);
+	if (status != EFI_SUCCESS)
+		return status;
+	return efi_call_proto(boot_protocol, get_boot_hartid, &hartid);
+}
+
+efi_status_t check_platform_features(void)
+{
+	efi_status_t status;
+	int ret;
+
+	status = get_boot_hartid_from_efi();
+	if (status != EFI_SUCCESS) {
+		ret = get_boot_hartid_from_fdt();
+		if (ret) {
+			efi_err("Failed to get boot hartid!\n");
+			return EFI_UNSUPPORTED;
+		}
+	}
+	return EFI_SUCCESS;
+}
+
+unsigned long __weak stext_offset(void)
+{
+	/*
+	 * This fallback definition is used by the EFI zboot stub, which loads
+	 * the entire image so it can branch via the image header at offset #0.
+	 */
+	return 0;
+}
+
+void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt,
+				 unsigned long fdt_size)
+{
+	unsigned long kernel_entry = entrypoint + stext_offset();
+	jump_kernel_func jump_kernel = (jump_kernel_func)kernel_entry;
+
+	/*
+	 * Jump to real kernel here with following constraints.
+	 * 1. MMU should be disabled.
+	 * 2. a0 should contain hartid
+	 * 3. a1 should DT address
+	 */
+	csr_write(CSR_SATP, 0);
+	jump_kernel(hartid, fdt);
+}