xref: /openbmc/qemu/hw/i2c/smbus_eeprom.c (revision b398a92440ef8283532b0cd3ec0197993232f28f)
1 /*
2  * QEMU SMBus EEPROM device
3  *
4  * Copyright (c) 2007 Arastra, Inc.
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 
25 #include "qemu/osdep.h"
26 #include "qemu/units.h"
27 #include "qapi/error.h"
28 #include "hw/hw.h"
29 #include "hw/i2c/i2c.h"
30 #include "hw/i2c/smbus_slave.h"
31 #include "hw/i2c/smbus_eeprom.h"
32 
33 //#define DEBUG
34 
35 #define TYPE_SMBUS_EEPROM "smbus-eeprom"
36 
37 #define SMBUS_EEPROM(obj) \
38     OBJECT_CHECK(SMBusEEPROMDevice, (obj), TYPE_SMBUS_EEPROM)
39 
40 typedef struct SMBusEEPROMDevice {
41     SMBusDevice smbusdev;
42     void *data;
43     uint8_t offset;
44 } SMBusEEPROMDevice;
45 
46 static uint8_t eeprom_receive_byte(SMBusDevice *dev)
47 {
48     SMBusEEPROMDevice *eeprom = SMBUS_EEPROM(dev);
49     uint8_t *data = eeprom->data;
50     uint8_t val = data[eeprom->offset++];
51 
52 #ifdef DEBUG
53     printf("eeprom_receive_byte: addr=0x%02x val=0x%02x\n",
54            dev->i2c.address, val);
55 #endif
56     return val;
57 }
58 
59 static int eeprom_write_data(SMBusDevice *dev, uint8_t *buf, uint8_t len)
60 {
61     SMBusEEPROMDevice *eeprom = SMBUS_EEPROM(dev);
62     uint8_t *data = eeprom->data;
63 
64 #ifdef DEBUG
65     printf("eeprom_write_byte: addr=0x%02x cmd=0x%02x val=0x%02x\n",
66            dev->i2c.address, buf[0], buf[1]);
67 #endif
68     /* len is guaranteed to be > 0 */
69     eeprom->offset = buf[0];
70     buf++;
71     len--;
72 
73     for (; len > 0; len--) {
74         data[eeprom->offset] = *buf++;
75         eeprom->offset = (eeprom->offset + 1) % 256;
76     }
77 
78     return 0;
79 }
80 
81 static void smbus_eeprom_realize(DeviceState *dev, Error **errp)
82 {
83     SMBusEEPROMDevice *eeprom = SMBUS_EEPROM(dev);
84 
85     eeprom->offset = 0;
86 }
87 
88 static Property smbus_eeprom_properties[] = {
89     DEFINE_PROP_PTR("data", SMBusEEPROMDevice, data),
90     DEFINE_PROP_END_OF_LIST(),
91 };
92 
93 static void smbus_eeprom_class_initfn(ObjectClass *klass, void *data)
94 {
95     DeviceClass *dc = DEVICE_CLASS(klass);
96     SMBusDeviceClass *sc = SMBUS_DEVICE_CLASS(klass);
97 
98     dc->realize = smbus_eeprom_realize;
99     sc->receive_byte = eeprom_receive_byte;
100     sc->write_data = eeprom_write_data;
101     dc->props = smbus_eeprom_properties;
102     /* Reason: pointer property "data" */
103     dc->user_creatable = false;
104 }
105 
106 static const TypeInfo smbus_eeprom_info = {
107     .name          = TYPE_SMBUS_EEPROM,
108     .parent        = TYPE_SMBUS_DEVICE,
109     .instance_size = sizeof(SMBusEEPROMDevice),
110     .class_init    = smbus_eeprom_class_initfn,
111 };
112 
113 static void smbus_eeprom_register_types(void)
114 {
115     type_register_static(&smbus_eeprom_info);
116 }
117 
118 type_init(smbus_eeprom_register_types)
119 
120 void smbus_eeprom_init_one(I2CBus *smbus, uint8_t address, uint8_t *eeprom_buf)
121 {
122     DeviceState *dev;
123 
124     dev = qdev_create((BusState *) smbus, TYPE_SMBUS_EEPROM);
125     qdev_prop_set_uint8(dev, "address", address);
126     qdev_prop_set_ptr(dev, "data", eeprom_buf);
127     qdev_init_nofail(dev);
128 }
129 
130 void smbus_eeprom_init(I2CBus *smbus, int nb_eeprom,
131                        const uint8_t *eeprom_spd, int eeprom_spd_size)
132 {
133     int i;
134     uint8_t *eeprom_buf = g_malloc0(8 * 256); /* XXX: make this persistent */
135     if (eeprom_spd_size > 0) {
136         memcpy(eeprom_buf, eeprom_spd, eeprom_spd_size);
137     }
138 
139     for (i = 0; i < nb_eeprom; i++) {
140         smbus_eeprom_init_one(smbus, 0x50 + i, eeprom_buf + (i * 256));
141     }
142 }
143 
144 /* Generate SDRAM SPD EEPROM data describing a module of type and size */
145 uint8_t *spd_data_generate(enum sdram_type type, ram_addr_t ram_size,
146                            Error **errp)
147 {
148     uint8_t *spd;
149     uint8_t nbanks;
150     uint16_t density;
151     uint32_t size;
152     int min_log2, max_log2, sz_log2;
153     int i;
154 
155     switch (type) {
156     case SDR:
157         min_log2 = 2;
158         max_log2 = 9;
159         break;
160     case DDR:
161         min_log2 = 5;
162         max_log2 = 12;
163         break;
164     case DDR2:
165         min_log2 = 7;
166         max_log2 = 14;
167         break;
168     default:
169         g_assert_not_reached();
170     }
171     size = ram_size >> 20; /* work in terms of megabytes */
172     if (size < 4) {
173         error_setg(errp, "SDRAM size is too small");
174         return NULL;
175     }
176     sz_log2 = 31 - clz32(size);
177     size = 1U << sz_log2;
178     if (ram_size > size * MiB) {
179         error_setg(errp, "SDRAM size 0x"RAM_ADDR_FMT" is not a power of 2, "
180                    "truncating to %u MB", ram_size, size);
181     }
182     if (sz_log2 < min_log2) {
183         error_setg(errp,
184                    "Memory size is too small for SDRAM type, adjusting type");
185         if (size >= 32) {
186             type = DDR;
187             min_log2 = 5;
188             max_log2 = 12;
189         } else {
190             type = SDR;
191             min_log2 = 2;
192             max_log2 = 9;
193         }
194     }
195 
196     nbanks = 1;
197     while (sz_log2 > max_log2 && nbanks < 8) {
198         sz_log2--;
199         nbanks++;
200     }
201 
202     if (size > (1ULL << sz_log2) * nbanks) {
203         error_setg(errp, "Memory size is too big for SDRAM, truncating");
204     }
205 
206     /* split to 2 banks if possible to avoid a bug in MIPS Malta firmware */
207     if (nbanks == 1 && sz_log2 > min_log2) {
208         sz_log2--;
209         nbanks++;
210     }
211 
212     density = 1ULL << (sz_log2 - 2);
213     switch (type) {
214     case DDR2:
215         density = (density & 0xe0) | (density >> 8 & 0x1f);
216         break;
217     case DDR:
218         density = (density & 0xf8) | (density >> 8 & 0x07);
219         break;
220     case SDR:
221     default:
222         density &= 0xff;
223         break;
224     }
225 
226     spd = g_malloc0(256);
227     spd[0] = 128;   /* data bytes in EEPROM */
228     spd[1] = 8;     /* log2 size of EEPROM */
229     spd[2] = type;
230     spd[3] = 13;    /* row address bits */
231     spd[4] = 10;    /* column address bits */
232     spd[5] = (type == DDR2 ? nbanks - 1 : nbanks);
233     spd[6] = 64;    /* module data width */
234                     /* reserved / data width high */
235     spd[8] = 4;     /* interface voltage level */
236     spd[9] = 0x25;  /* highest CAS latency */
237     spd[10] = 1;    /* access time */
238                     /* DIMM configuration 0 = non-ECC */
239     spd[12] = 0x82; /* refresh requirements */
240     spd[13] = 8;    /* primary SDRAM width */
241                     /* ECC SDRAM width */
242     spd[15] = (type == DDR2 ? 0 : 1); /* reserved / delay for random col rd */
243     spd[16] = 12;   /* burst lengths supported */
244     spd[17] = 4;    /* banks per SDRAM device */
245     spd[18] = 12;   /* ~CAS latencies supported */
246     spd[19] = (type == DDR2 ? 0 : 1); /* reserved / ~CS latencies supported */
247     spd[20] = 2;    /* DIMM type / ~WE latencies */
248                     /* module features */
249                     /* memory chip features */
250     spd[23] = 0x12; /* clock cycle time @ medium CAS latency */
251                     /* data access time */
252                     /* clock cycle time @ short CAS latency */
253                     /* data access time */
254     spd[27] = 20;   /* min. row precharge time */
255     spd[28] = 15;   /* min. row active row delay */
256     spd[29] = 20;   /* min. ~RAS to ~CAS delay */
257     spd[30] = 45;   /* min. active to precharge time */
258     spd[31] = density;
259     spd[32] = 20;   /* addr/cmd setup time */
260     spd[33] = 8;    /* addr/cmd hold time */
261     spd[34] = 20;   /* data input setup time */
262     spd[35] = 8;    /* data input hold time */
263 
264     /* checksum */
265     for (i = 0; i < 63; i++) {
266         spd[63] += spd[i];
267     }
268     return spd;
269 }
270