xref: /openbmc/u-boot/arch/x86/lib/sfi.c (revision 6d97dc10)
1 /*
2  * Copyright (c) 2015 Google, Inc
3  * Written by Simon Glass <sjg@chromium.org>
4  *
5  * SPDX-License-Identifier:	GPL-2.0+
6  */
7 
8 /*
9  * Intel Simple Firmware Interface (SFI)
10  *
11  * Yet another way to pass information to the Linux kernel.
12  *
13  * See https://simplefirmware.org/ for details
14  */
15 
16 #include <common.h>
17 #include <cpu.h>
18 #include <dm.h>
19 #include <asm/cpu.h>
20 #include <asm/ioapic.h>
21 #include <asm/sfi.h>
22 #include <asm/tables.h>
23 #include <dm/uclass-internal.h>
24 
25 struct table_info {
26 	u32 base;
27 	int ptr;
28 	u32 entry_start;
29 	u64 table[SFI_TABLE_MAX_ENTRIES];
30 	int count;
31 };
32 
33 static void *get_entry_start(struct table_info *tab)
34 {
35 	if (tab->count == SFI_TABLE_MAX_ENTRIES)
36 		return NULL;
37 	tab->entry_start = tab->base + tab->ptr;
38 	tab->table[tab->count] = tab->entry_start;
39 	tab->entry_start += sizeof(struct sfi_table_header);
40 
41 	return (void *)tab->entry_start;
42 }
43 
44 static void finish_table(struct table_info *tab, const char *sig, void *entry)
45 {
46 	struct sfi_table_header *hdr;
47 
48 	hdr = (struct sfi_table_header *)(tab->base + tab->ptr);
49 	strcpy(hdr->sig, sig);
50 	hdr->len = sizeof(*hdr) + ((ulong)entry - tab->entry_start);
51 	hdr->rev = 1;
52 	strncpy(hdr->oem_id, "U-Boot", SFI_OEM_ID_SIZE);
53 	strncpy(hdr->oem_table_id, "Table v1", SFI_OEM_TABLE_ID_SIZE);
54 	hdr->csum = 0;
55 	hdr->csum = table_compute_checksum(hdr, hdr->len);
56 	tab->ptr += hdr->len;
57 	tab->ptr = ALIGN(tab->ptr, 16);
58 	tab->count++;
59 }
60 
61 static int sfi_write_system_header(struct table_info *tab)
62 {
63 	u64 *entry = get_entry_start(tab);
64 	int i;
65 
66 	if (!entry)
67 		return -ENOSPC;
68 
69 	for (i = 0; i < tab->count; i++)
70 		*entry++ = tab->table[i];
71 	finish_table(tab, SFI_SIG_SYST, entry);
72 
73 	return 0;
74 }
75 
76 static int sfi_write_cpus(struct table_info *tab)
77 {
78 	struct sfi_cpu_table_entry *entry = get_entry_start(tab);
79 	struct udevice *dev;
80 	int count = 0;
81 
82 	if (!entry)
83 		return -ENOSPC;
84 
85 	for (uclass_find_first_device(UCLASS_CPU, &dev);
86 	     dev;
87 	     uclass_find_next_device(&dev)) {
88 		struct cpu_platdata *plat = dev_get_parent_platdata(dev);
89 
90 		if (!device_active(dev))
91 			continue;
92 		entry->apic_id = plat->cpu_id;
93 		entry++;
94 		count++;
95 	}
96 
97 	/* Omit the table if there is only one CPU */
98 	if (count > 1)
99 		finish_table(tab, SFI_SIG_CPUS, entry);
100 
101 	return 0;
102 }
103 
104 static int sfi_write_apic(struct table_info *tab)
105 {
106 	struct sfi_apic_table_entry *entry = get_entry_start(tab);
107 
108 	if (!entry)
109 		return -ENOSPC;
110 
111 	entry->phys_addr = IO_APIC_ADDR;
112 	entry++;
113 	finish_table(tab, SFI_SIG_APIC, entry);
114 
115 	return 0;
116 }
117 
118 static int sfi_write_xsdt(struct table_info *tab)
119 {
120 	struct sfi_xsdt_header *entry = get_entry_start(tab);
121 
122 	if (!entry)
123 		return -ENOSPC;
124 
125 	entry->oem_revision = 1;
126 	entry->creator_id = 1;
127 	entry->creator_revision = 1;
128 	entry++;
129 	finish_table(tab, SFI_SIG_XSDT, entry);
130 
131 	return 0;
132 }
133 
134 u32 write_sfi_table(u32 base)
135 {
136 	struct table_info table;
137 
138 	table.base = base;
139 	table.ptr = 0;
140 	table.count = 0;
141 	sfi_write_cpus(&table);
142 	sfi_write_apic(&table);
143 
144 	/*
145 	 * The SFI specification marks the XSDT table as option, but Linux 4.0
146 	 * crashes on start-up when it is not provided.
147 	 */
148 	sfi_write_xsdt(&table);
149 
150 	/* Finally, write out the system header which points to the others */
151 	sfi_write_system_header(&table);
152 
153 	return base + table.ptr;
154 }
155