1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2015 Google, Inc
4  * Written by Simon Glass <sjg@chromium.org>
5  */
6 
7 /*
8  * Intel Simple Firmware Interface (SFI)
9  *
10  * Yet another way to pass information to the Linux kernel.
11  *
12  * See https://simplefirmware.org/ for details
13  */
14 
15 #include <common.h>
16 #include <cpu.h>
17 #include <dm.h>
18 #include <asm/cpu.h>
19 #include <asm/ioapic.h>
20 #include <asm/sfi.h>
21 #include <asm/tables.h>
22 #include <dm/uclass-internal.h>
23 
24 struct table_info {
25 	u32 base;
26 	int ptr;
27 	u32 entry_start;
28 	u64 table[SFI_TABLE_MAX_ENTRIES];
29 	int count;
30 };
31 
get_entry_start(struct table_info * tab)32 static void *get_entry_start(struct table_info *tab)
33 {
34 	if (tab->count == SFI_TABLE_MAX_ENTRIES)
35 		return NULL;
36 	tab->entry_start = tab->base + tab->ptr;
37 	tab->table[tab->count] = tab->entry_start;
38 	tab->entry_start += sizeof(struct sfi_table_header);
39 
40 	return (void *)(uintptr_t)tab->entry_start;
41 }
42 
finish_table(struct table_info * tab,const char * sig,void * entry)43 static void finish_table(struct table_info *tab, const char *sig, void *entry)
44 {
45 	struct sfi_table_header *hdr;
46 
47 	hdr = (struct sfi_table_header *)(uintptr_t)(tab->base + tab->ptr);
48 	strcpy(hdr->sig, sig);
49 	hdr->len = sizeof(*hdr) + ((ulong)entry - tab->entry_start);
50 	hdr->rev = 1;
51 	strncpy(hdr->oem_id, "U-Boot", SFI_OEM_ID_SIZE);
52 	strncpy(hdr->oem_table_id, "Table v1", SFI_OEM_TABLE_ID_SIZE);
53 	hdr->csum = 0;
54 	hdr->csum = table_compute_checksum(hdr, hdr->len);
55 	tab->ptr += hdr->len;
56 	tab->ptr = ALIGN(tab->ptr, 16);
57 	tab->count++;
58 }
59 
sfi_write_system_header(struct table_info * tab)60 static int sfi_write_system_header(struct table_info *tab)
61 {
62 	u64 *entry = get_entry_start(tab);
63 	int i;
64 
65 	if (!entry)
66 		return -ENOSPC;
67 
68 	for (i = 0; i < tab->count; i++)
69 		*entry++ = tab->table[i];
70 	finish_table(tab, SFI_SIG_SYST, entry);
71 
72 	return 0;
73 }
74 
sfi_write_cpus(struct table_info * tab)75 static int sfi_write_cpus(struct table_info *tab)
76 {
77 	struct sfi_cpu_table_entry *entry = get_entry_start(tab);
78 	struct udevice *dev;
79 	int count = 0;
80 
81 	if (!entry)
82 		return -ENOSPC;
83 
84 	for (uclass_find_first_device(UCLASS_CPU, &dev);
85 	     dev;
86 	     uclass_find_next_device(&dev)) {
87 		struct cpu_plat *plat = dev_get_parent_plat(dev);
88 
89 		if (!device_active(dev))
90 			continue;
91 		entry->apic_id = plat->cpu_id;
92 		entry++;
93 		count++;
94 	}
95 
96 	/* Omit the table if there is only one CPU */
97 	if (count > 1)
98 		finish_table(tab, SFI_SIG_CPUS, entry);
99 
100 	return 0;
101 }
102 
sfi_write_apic(struct table_info * tab)103 static int sfi_write_apic(struct table_info *tab)
104 {
105 	struct sfi_apic_table_entry *entry = get_entry_start(tab);
106 
107 	if (!entry)
108 		return -ENOSPC;
109 
110 	entry->phys_addr = IO_APIC_ADDR;
111 	entry++;
112 	finish_table(tab, SFI_SIG_APIC, entry);
113 
114 	return 0;
115 }
116 
sfi_write_xsdt(struct table_info * tab)117 static int sfi_write_xsdt(struct table_info *tab)
118 {
119 	struct sfi_xsdt_header *entry = get_entry_start(tab);
120 
121 	if (!entry)
122 		return -ENOSPC;
123 
124 	entry->oem_revision = 1;
125 	entry->creator_id = 1;
126 	entry->creator_revision = 1;
127 	entry++;
128 	finish_table(tab, SFI_SIG_XSDT, entry);
129 
130 	return 0;
131 }
132 
write_sfi_table(ulong base)133 ulong write_sfi_table(ulong base)
134 {
135 	struct table_info table;
136 
137 	table.base = base;
138 	table.ptr = 0;
139 	table.count = 0;
140 	sfi_write_cpus(&table);
141 	sfi_write_apic(&table);
142 
143 	/*
144 	 * The SFI specification marks the XSDT table as option, but Linux 4.0
145 	 * crashes on start-up when it is not provided.
146 	 */
147 	sfi_write_xsdt(&table);
148 
149 	/* Finally, write out the system header which points to the others */
150 	sfi_write_system_header(&table);
151 
152 	return base + table.ptr;
153 }
154