xref: /openbmc/qemu/hw/i2c/smbus_eeprom.c (revision 08a8a4d45050f837d560f1aa23ee0ffff4a2c1d7)
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 typedef struct SMBusEEPROMDevice {
36     SMBusDevice smbusdev;
37     void *data;
38     uint8_t offset;
39 } SMBusEEPROMDevice;
40 
41 static uint8_t eeprom_receive_byte(SMBusDevice *dev)
42 {
43     SMBusEEPROMDevice *eeprom = (SMBusEEPROMDevice *) dev;
44     uint8_t *data = eeprom->data;
45     uint8_t val = data[eeprom->offset++];
46 #ifdef DEBUG
47     printf("eeprom_receive_byte: addr=0x%02x val=0x%02x\n",
48            dev->i2c.address, val);
49 #endif
50     return val;
51 }
52 
53 static int eeprom_write_data(SMBusDevice *dev, uint8_t *buf, uint8_t len)
54 {
55     SMBusEEPROMDevice *eeprom = (SMBusEEPROMDevice *) dev;
56     uint8_t *data = eeprom->data;
57 
58 #ifdef DEBUG
59     printf("eeprom_write_byte: addr=0x%02x cmd=0x%02x val=0x%02x\n",
60            dev->i2c.address, buf[0], buf[1]);
61 #endif
62     /* len is guaranteed to be > 0 */
63     eeprom->offset = buf[0];
64     buf++;
65     len--;
66 
67     for (; len > 0; len--) {
68         data[eeprom->offset] = *buf++;
69         eeprom->offset = (eeprom->offset + 1) % 256;
70     }
71 
72     return 0;
73 }
74 
75 static void smbus_eeprom_realize(DeviceState *dev, Error **errp)
76 {
77     SMBusEEPROMDevice *eeprom = (SMBusEEPROMDevice *)dev;
78 
79     eeprom->offset = 0;
80 }
81 
82 static Property smbus_eeprom_properties[] = {
83     DEFINE_PROP_PTR("data", SMBusEEPROMDevice, data),
84     DEFINE_PROP_END_OF_LIST(),
85 };
86 
87 static void smbus_eeprom_class_initfn(ObjectClass *klass, void *data)
88 {
89     DeviceClass *dc = DEVICE_CLASS(klass);
90     SMBusDeviceClass *sc = SMBUS_DEVICE_CLASS(klass);
91 
92     dc->realize = smbus_eeprom_realize;
93     sc->receive_byte = eeprom_receive_byte;
94     sc->write_data = eeprom_write_data;
95     dc->props = smbus_eeprom_properties;
96     /* Reason: pointer property "data" */
97     dc->user_creatable = false;
98 }
99 
100 static const TypeInfo smbus_eeprom_info = {
101     .name          = "smbus-eeprom",
102     .parent        = TYPE_SMBUS_DEVICE,
103     .instance_size = sizeof(SMBusEEPROMDevice),
104     .class_init    = smbus_eeprom_class_initfn,
105 };
106 
107 static void smbus_eeprom_register_types(void)
108 {
109     type_register_static(&smbus_eeprom_info);
110 }
111 
112 type_init(smbus_eeprom_register_types)
113 
114 void smbus_eeprom_init_one(I2CBus *smbus, uint8_t address, uint8_t *eeprom_buf)
115 {
116     DeviceState *dev;
117 
118     dev = qdev_create((BusState *) smbus, "smbus-eeprom");
119     qdev_prop_set_uint8(dev, "address", address);
120     qdev_prop_set_ptr(dev, "data", eeprom_buf);
121     qdev_init_nofail(dev);
122 }
123 
124 void smbus_eeprom_init(I2CBus *smbus, int nb_eeprom,
125                        const uint8_t *eeprom_spd, int eeprom_spd_size)
126 {
127     int i;
128     uint8_t *eeprom_buf = g_malloc0(8 * 256); /* XXX: make this persistent */
129     if (eeprom_spd_size > 0) {
130         memcpy(eeprom_buf, eeprom_spd, eeprom_spd_size);
131     }
132 
133     for (i = 0; i < nb_eeprom; i++) {
134         smbus_eeprom_init_one(smbus, 0x50 + i, eeprom_buf + (i * 256));
135     }
136 }
137 
138 /* Generate SDRAM SPD EEPROM data describing a module of type and size */
139 uint8_t *spd_data_generate(enum sdram_type type, ram_addr_t ram_size,
140                            Error **errp)
141 {
142     uint8_t *spd;
143     uint8_t nbanks;
144     uint16_t density;
145     uint32_t size;
146     int min_log2, max_log2, sz_log2;
147     int i;
148 
149     switch (type) {
150     case SDR:
151         min_log2 = 2;
152         max_log2 = 9;
153         break;
154     case DDR:
155         min_log2 = 5;
156         max_log2 = 12;
157         break;
158     case DDR2:
159         min_log2 = 7;
160         max_log2 = 14;
161         break;
162     default:
163         g_assert_not_reached();
164     }
165     size = ram_size >> 20; /* work in terms of megabytes */
166     if (size < 4) {
167         error_setg(errp, "SDRAM size is too small");
168         return NULL;
169     }
170     sz_log2 = 31 - clz32(size);
171     size = 1U << sz_log2;
172     if (ram_size > size * MiB) {
173         error_setg(errp, "SDRAM size 0x"RAM_ADDR_FMT" is not a power of 2, "
174                    "truncating to %u MB", ram_size, size);
175     }
176     if (sz_log2 < min_log2) {
177         error_setg(errp,
178                    "Memory size is too small for SDRAM type, adjusting type");
179         if (size >= 32) {
180             type = DDR;
181             min_log2 = 5;
182             max_log2 = 12;
183         } else {
184             type = SDR;
185             min_log2 = 2;
186             max_log2 = 9;
187         }
188     }
189 
190     nbanks = 1;
191     while (sz_log2 > max_log2 && nbanks < 8) {
192         sz_log2--;
193         nbanks++;
194     }
195 
196     if (size > (1ULL << sz_log2) * nbanks) {
197         error_setg(errp, "Memory size is too big for SDRAM, truncating");
198     }
199 
200     /* split to 2 banks if possible to avoid a bug in MIPS Malta firmware */
201     if (nbanks == 1 && sz_log2 > min_log2) {
202         sz_log2--;
203         nbanks++;
204     }
205 
206     density = 1ULL << (sz_log2 - 2);
207     switch (type) {
208     case DDR2:
209         density = (density & 0xe0) | (density >> 8 & 0x1f);
210         break;
211     case DDR:
212         density = (density & 0xf8) | (density >> 8 & 0x07);
213         break;
214     case SDR:
215     default:
216         density &= 0xff;
217         break;
218     }
219 
220     spd = g_malloc0(256);
221     spd[0] = 128;   /* data bytes in EEPROM */
222     spd[1] = 8;     /* log2 size of EEPROM */
223     spd[2] = type;
224     spd[3] = 13;    /* row address bits */
225     spd[4] = 10;    /* column address bits */
226     spd[5] = (type == DDR2 ? nbanks - 1 : nbanks);
227     spd[6] = 64;    /* module data width */
228                     /* reserved / data width high */
229     spd[8] = 4;     /* interface voltage level */
230     spd[9] = 0x25;  /* highest CAS latency */
231     spd[10] = 1;    /* access time */
232                     /* DIMM configuration 0 = non-ECC */
233     spd[12] = 0x82; /* refresh requirements */
234     spd[13] = 8;    /* primary SDRAM width */
235                     /* ECC SDRAM width */
236     spd[15] = (type == DDR2 ? 0 : 1); /* reserved / delay for random col rd */
237     spd[16] = 12;   /* burst lengths supported */
238     spd[17] = 4;    /* banks per SDRAM device */
239     spd[18] = 12;   /* ~CAS latencies supported */
240     spd[19] = (type == DDR2 ? 0 : 1); /* reserved / ~CS latencies supported */
241     spd[20] = 2;    /* DIMM type / ~WE latencies */
242                     /* module features */
243                     /* memory chip features */
244     spd[23] = 0x12; /* clock cycle time @ medium CAS latency */
245                     /* data access time */
246                     /* clock cycle time @ short CAS latency */
247                     /* data access time */
248     spd[27] = 20;   /* min. row precharge time */
249     spd[28] = 15;   /* min. row active row delay */
250     spd[29] = 20;   /* min. ~RAS to ~CAS delay */
251     spd[30] = 45;   /* min. active to precharge time */
252     spd[31] = density;
253     spd[32] = 20;   /* addr/cmd setup time */
254     spd[33] = 8;    /* addr/cmd hold time */
255     spd[34] = 20;   /* data input setup time */
256     spd[35] = 8;    /* data input hold time */
257 
258     /* checksum */
259     for (i = 0; i < 63; i++) {
260         spd[63] += spd[i];
261     }
262     return spd;
263 }
264