xref: /openbmc/u-boot/arch/x86/cpu/tangier/sdram.c (revision cd1cc31f)
1 /*
2  * Copyright (c) 2017 Intel Corporation
3  *
4  * SPDX-License-Identifier:	GPL-2.0+
5  */
6 
7 #include <common.h>
8 #include <asm/e820.h>
9 #include <asm/global_data.h>
10 #include <asm/sfi.h>
11 
12 DECLARE_GLOBAL_DATA_PTR;
13 
14 /*
15  * SFI tables are part of the first stage bootloader.
16  *
17  * U-Boot finds the System Table by searching 16-byte boundaries between
18  * physical address 0x000E0000 and 0x000FFFFF. U-Boot shall search this region
19  * starting at the low address and shall stop searching when the 1st valid SFI
20  * System Table is found.
21  */
22 #define SFI_BASE_ADDR		0x000E0000
23 #define SFI_LENGTH		0x00020000
24 #define SFI_TABLE_LENGTH	16
25 
26 static int sfi_table_check(struct sfi_table_header *sbh)
27 {
28 	char chksum = 0;
29 	char *pos = (char *)sbh;
30 	u32 i;
31 
32 	if (sbh->len < SFI_TABLE_LENGTH)
33 		return -ENXIO;
34 
35 	if (sbh->len > SFI_LENGTH)
36 		return -ENXIO;
37 
38 	for (i = 0; i < sbh->len; i++)
39 		chksum += *pos++;
40 
41 	if (chksum)
42 		pr_err("sfi: Invalid checksum\n");
43 
44 	/* Checksum is OK if zero */
45 	return chksum ? -EILSEQ : 0;
46 }
47 
48 static int sfi_table_is_type(struct sfi_table_header *sbh, const char *signature)
49 {
50 	return !strncmp(sbh->sig, signature, SFI_SIGNATURE_SIZE) &&
51 	       !sfi_table_check(sbh);
52 }
53 
54 static struct sfi_table_simple *sfi_get_table_by_sig(unsigned long addr,
55 						     const char *signature)
56 {
57 	struct sfi_table_simple *sb;
58 	u32 i;
59 
60 	for (i = 0; i < SFI_LENGTH; i += SFI_TABLE_LENGTH) {
61 		sb = (struct sfi_table_simple *)(addr + i);
62 		if (sfi_table_is_type(&sb->header, signature))
63 			return sb;
64 	}
65 
66 	return NULL;
67 }
68 
69 static struct sfi_table_simple *sfi_search_mmap(void)
70 {
71 	struct sfi_table_header *sbh;
72 	struct sfi_table_simple *sb;
73 	u32 sys_entry_cnt;
74 	u32 i;
75 
76 	/* Find SYST table */
77 	sb = sfi_get_table_by_sig(SFI_BASE_ADDR, SFI_SIG_SYST);
78 	if (!sb) {
79 		pr_err("sfi: failed to locate SYST table\n");
80 		return NULL;
81 	}
82 
83 	sys_entry_cnt = (sb->header.len - sizeof(*sbh)) / 8;
84 
85 	/* Search through each SYST entry for MMAP table */
86 	for (i = 0; i < sys_entry_cnt; i++) {
87 		sbh = (struct sfi_table_header *)(unsigned long)sb->pentry[i];
88 
89 		if (sfi_table_is_type(sbh, SFI_SIG_MMAP))
90 			return (struct sfi_table_simple *)sbh;
91 	}
92 
93 	pr_err("sfi: failed to locate SFI MMAP table\n");
94 	return NULL;
95 }
96 
97 #define sfi_for_each_mentry(i, sb, mentry)				\
98 	for (i = 0, mentry = (struct sfi_mem_entry *)sb->pentry;	\
99 	     i < SFI_GET_NUM_ENTRIES(sb, struct sfi_mem_entry);		\
100 	     i++, mentry++)						\
101 
102 static unsigned sfi_setup_e820(unsigned max_entries, struct e820entry *entries)
103 {
104 	struct sfi_table_simple *sb;
105 	struct sfi_mem_entry *mentry;
106 	unsigned long long start, end, size;
107 	int type, total = 0;
108 	u32 i;
109 
110 	sb = sfi_search_mmap();
111 	if (!sb)
112 		return 0;
113 
114 	sfi_for_each_mentry(i, sb, mentry) {
115 		start = mentry->phys_start;
116 		size = mentry->pages << 12;
117 		end = start + size;
118 
119 		if (start > end)
120 			continue;
121 
122 		/* translate SFI mmap type to E820 map type */
123 		switch (mentry->type) {
124 		case SFI_MEM_CONV:
125 			type = E820_RAM;
126 			break;
127 		case SFI_MEM_UNUSABLE:
128 		case SFI_RUNTIME_SERVICE_DATA:
129 			continue;
130 		default:
131 			type = E820_RESERVED;
132 		}
133 
134 		if (total == E820MAX)
135 			break;
136 		entries[total].addr = start;
137 		entries[total].size = size;
138 		entries[total].type = type;
139 
140 		total++;
141 	}
142 
143 	return total;
144 }
145 
146 static int sfi_get_bank_size(void)
147 {
148 	struct sfi_table_simple *sb;
149 	struct sfi_mem_entry *mentry;
150 	int bank = 0;
151 	u32 i;
152 
153 	sb = sfi_search_mmap();
154 	if (!sb)
155 		return 0;
156 
157 	sfi_for_each_mentry(i, sb, mentry) {
158 		if (mentry->type != SFI_MEM_CONV)
159 			continue;
160 
161 		gd->bd->bi_dram[bank].start = mentry->phys_start;
162 		gd->bd->bi_dram[bank].size = mentry->pages << 12;
163 		bank++;
164 	}
165 
166 	return bank;
167 }
168 
169 static phys_size_t sfi_get_ram_size(void)
170 {
171 	struct sfi_table_simple *sb;
172 	struct sfi_mem_entry *mentry;
173 	phys_size_t ram = 0;
174 	u32 i;
175 
176 	sb = sfi_search_mmap();
177 	if (!sb)
178 		return 0;
179 
180 	sfi_for_each_mentry(i, sb, mentry) {
181 		if (mentry->type != SFI_MEM_CONV)
182 			continue;
183 
184 		ram += mentry->pages << 12;
185 	}
186 
187 	debug("sfi: RAM size %llu\n", ram);
188 	return ram;
189 }
190 
191 unsigned install_e820_map(unsigned max_entries, struct e820entry *entries)
192 {
193 	return sfi_setup_e820(max_entries, entries);
194 }
195 
196 int dram_init_banksize(void)
197 {
198 	sfi_get_bank_size();
199 	return 0;
200 }
201 
202 int dram_init(void)
203 {
204 	gd->ram_size = sfi_get_ram_size();
205 	return 0;
206 }
207