1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2020 Western Digital Corporation or its affiliates.
4 */
5
6#include <linux/efi.h>
7#include <linux/libfdt.h>
8
9#include <asm/efi.h>
10#include <asm/unaligned.h>
11
12#include "efistub.h"
13
14typedef void __noreturn (*jump_kernel_func)(unsigned long, unsigned long);
15
16static unsigned long hartid;
17
18static int get_boot_hartid_from_fdt(void)
19{
20	const void *fdt;
21	int chosen_node, len;
22	const void *prop;
23
24	fdt = get_efi_config_table(DEVICE_TREE_GUID);
25	if (!fdt)
26		return -EINVAL;
27
28	chosen_node = fdt_path_offset(fdt, "/chosen");
29	if (chosen_node < 0)
30		return -EINVAL;
31
32	prop = fdt_getprop((void *)fdt, chosen_node, "boot-hartid", &len);
33	if (!prop)
34		return -EINVAL;
35
36	if (len == sizeof(u32))
37		hartid = (unsigned long) fdt32_to_cpu(*(fdt32_t *)prop);
38	else if (len == sizeof(u64))
39		hartid = (unsigned long) fdt64_to_cpu(__get_unaligned_t(fdt64_t, prop));
40	else
41		return -EINVAL;
42
43	return 0;
44}
45
46static efi_status_t get_boot_hartid_from_efi(void)
47{
48	efi_guid_t boot_protocol_guid = RISCV_EFI_BOOT_PROTOCOL_GUID;
49	struct riscv_efi_boot_protocol *boot_protocol;
50	efi_status_t status;
51
52	status = efi_bs_call(locate_protocol, &boot_protocol_guid, NULL,
53			     (void **)&boot_protocol);
54	if (status != EFI_SUCCESS)
55		return status;
56	return efi_call_proto(boot_protocol, get_boot_hartid, &hartid);
57}
58
59efi_status_t check_platform_features(void)
60{
61	efi_status_t status;
62	int ret;
63
64	status = get_boot_hartid_from_efi();
65	if (status != EFI_SUCCESS) {
66		ret = get_boot_hartid_from_fdt();
67		if (ret) {
68			efi_err("Failed to get boot hartid!\n");
69			return EFI_UNSUPPORTED;
70		}
71	}
72	return EFI_SUCCESS;
73}
74
75unsigned long __weak stext_offset(void)
76{
77	/*
78	 * This fallback definition is used by the EFI zboot stub, which loads
79	 * the entire image so it can branch via the image header at offset #0.
80	 */
81	return 0;
82}
83
84void __noreturn efi_enter_kernel(unsigned long entrypoint, unsigned long fdt,
85				 unsigned long fdt_size)
86{
87	unsigned long kernel_entry = entrypoint + stext_offset();
88	jump_kernel_func jump_kernel = (jump_kernel_func)kernel_entry;
89
90	/*
91	 * Jump to real kernel here with following constraints.
92	 * 1. MMU should be disabled.
93	 * 2. a0 should contain hartid
94	 * 3. a1 should DT address
95	 */
96	csr_write(CSR_SATP, 0);
97	jump_kernel(hartid, fdt);
98}
99