xref: /openbmc/qemu/hw/i2c/smbus_eeprom.c (revision 8b38e532b58d9e314d95aa9845cc89243ee60acc)
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 
47 #ifdef DEBUG
48     printf("eeprom_receive_byte: addr=0x%02x val=0x%02x\n",
49            dev->i2c.address, val);
50 #endif
51     return val;
52 }
53 
54 static int eeprom_write_data(SMBusDevice *dev, uint8_t *buf, uint8_t len)
55 {
56     SMBusEEPROMDevice *eeprom = (SMBusEEPROMDevice *) dev;
57     uint8_t *data = eeprom->data;
58 
59 #ifdef DEBUG
60     printf("eeprom_write_byte: addr=0x%02x cmd=0x%02x val=0x%02x\n",
61            dev->i2c.address, buf[0], buf[1]);
62 #endif
63     /* len is guaranteed to be > 0 */
64     eeprom->offset = buf[0];
65     buf++;
66     len--;
67 
68     for (; len > 0; len--) {
69         data[eeprom->offset] = *buf++;
70         eeprom->offset = (eeprom->offset + 1) % 256;
71     }
72 
73     return 0;
74 }
75 
76 static void smbus_eeprom_realize(DeviceState *dev, Error **errp)
77 {
78     SMBusEEPROMDevice *eeprom = (SMBusEEPROMDevice *)dev;
79 
80     eeprom->offset = 0;
81 }
82 
83 static Property smbus_eeprom_properties[] = {
84     DEFINE_PROP_PTR("data", SMBusEEPROMDevice, data),
85     DEFINE_PROP_END_OF_LIST(),
86 };
87 
88 static void smbus_eeprom_class_initfn(ObjectClass *klass, void *data)
89 {
90     DeviceClass *dc = DEVICE_CLASS(klass);
91     SMBusDeviceClass *sc = SMBUS_DEVICE_CLASS(klass);
92 
93     dc->realize = smbus_eeprom_realize;
94     sc->receive_byte = eeprom_receive_byte;
95     sc->write_data = eeprom_write_data;
96     dc->props = smbus_eeprom_properties;
97     /* Reason: pointer property "data" */
98     dc->user_creatable = false;
99 }
100 
101 static const TypeInfo smbus_eeprom_info = {
102     .name          = "smbus-eeprom",
103     .parent        = TYPE_SMBUS_DEVICE,
104     .instance_size = sizeof(SMBusEEPROMDevice),
105     .class_init    = smbus_eeprom_class_initfn,
106 };
107 
108 static void smbus_eeprom_register_types(void)
109 {
110     type_register_static(&smbus_eeprom_info);
111 }
112 
113 type_init(smbus_eeprom_register_types)
114 
115 void smbus_eeprom_init_one(I2CBus *smbus, uint8_t address, uint8_t *eeprom_buf)
116 {
117     DeviceState *dev;
118 
119     dev = qdev_create((BusState *) smbus, "smbus-eeprom");
120     qdev_prop_set_uint8(dev, "address", address);
121     qdev_prop_set_ptr(dev, "data", eeprom_buf);
122     qdev_init_nofail(dev);
123 }
124 
125 void smbus_eeprom_init(I2CBus *smbus, int nb_eeprom,
126                        const uint8_t *eeprom_spd, int eeprom_spd_size)
127 {
128     int i;
129     uint8_t *eeprom_buf = g_malloc0(8 * 256); /* XXX: make this persistent */
130     if (eeprom_spd_size > 0) {
131         memcpy(eeprom_buf, eeprom_spd, eeprom_spd_size);
132     }
133 
134     for (i = 0; i < nb_eeprom; i++) {
135         smbus_eeprom_init_one(smbus, 0x50 + i, eeprom_buf + (i * 256));
136     }
137 }
138 
139 /* Generate SDRAM SPD EEPROM data describing a module of type and size */
140 uint8_t *spd_data_generate(enum sdram_type type, ram_addr_t ram_size,
141                            Error **errp)
142 {
143     uint8_t *spd;
144     uint8_t nbanks;
145     uint16_t density;
146     uint32_t size;
147     int min_log2, max_log2, sz_log2;
148     int i;
149 
150     switch (type) {
151     case SDR:
152         min_log2 = 2;
153         max_log2 = 9;
154         break;
155     case DDR:
156         min_log2 = 5;
157         max_log2 = 12;
158         break;
159     case DDR2:
160         min_log2 = 7;
161         max_log2 = 14;
162         break;
163     default:
164         g_assert_not_reached();
165     }
166     size = ram_size >> 20; /* work in terms of megabytes */
167     if (size < 4) {
168         error_setg(errp, "SDRAM size is too small");
169         return NULL;
170     }
171     sz_log2 = 31 - clz32(size);
172     size = 1U << sz_log2;
173     if (ram_size > size * MiB) {
174         error_setg(errp, "SDRAM size 0x"RAM_ADDR_FMT" is not a power of 2, "
175                    "truncating to %u MB", ram_size, size);
176     }
177     if (sz_log2 < min_log2) {
178         error_setg(errp,
179                    "Memory size is too small for SDRAM type, adjusting type");
180         if (size >= 32) {
181             type = DDR;
182             min_log2 = 5;
183             max_log2 = 12;
184         } else {
185             type = SDR;
186             min_log2 = 2;
187             max_log2 = 9;
188         }
189     }
190 
191     nbanks = 1;
192     while (sz_log2 > max_log2 && nbanks < 8) {
193         sz_log2--;
194         nbanks++;
195     }
196 
197     if (size > (1ULL << sz_log2) * nbanks) {
198         error_setg(errp, "Memory size is too big for SDRAM, truncating");
199     }
200 
201     /* split to 2 banks if possible to avoid a bug in MIPS Malta firmware */
202     if (nbanks == 1 && sz_log2 > min_log2) {
203         sz_log2--;
204         nbanks++;
205     }
206 
207     density = 1ULL << (sz_log2 - 2);
208     switch (type) {
209     case DDR2:
210         density = (density & 0xe0) | (density >> 8 & 0x1f);
211         break;
212     case DDR:
213         density = (density & 0xf8) | (density >> 8 & 0x07);
214         break;
215     case SDR:
216     default:
217         density &= 0xff;
218         break;
219     }
220 
221     spd = g_malloc0(256);
222     spd[0] = 128;   /* data bytes in EEPROM */
223     spd[1] = 8;     /* log2 size of EEPROM */
224     spd[2] = type;
225     spd[3] = 13;    /* row address bits */
226     spd[4] = 10;    /* column address bits */
227     spd[5] = (type == DDR2 ? nbanks - 1 : nbanks);
228     spd[6] = 64;    /* module data width */
229                     /* reserved / data width high */
230     spd[8] = 4;     /* interface voltage level */
231     spd[9] = 0x25;  /* highest CAS latency */
232     spd[10] = 1;    /* access time */
233                     /* DIMM configuration 0 = non-ECC */
234     spd[12] = 0x82; /* refresh requirements */
235     spd[13] = 8;    /* primary SDRAM width */
236                     /* ECC SDRAM width */
237     spd[15] = (type == DDR2 ? 0 : 1); /* reserved / delay for random col rd */
238     spd[16] = 12;   /* burst lengths supported */
239     spd[17] = 4;    /* banks per SDRAM device */
240     spd[18] = 12;   /* ~CAS latencies supported */
241     spd[19] = (type == DDR2 ? 0 : 1); /* reserved / ~CS latencies supported */
242     spd[20] = 2;    /* DIMM type / ~WE latencies */
243                     /* module features */
244                     /* memory chip features */
245     spd[23] = 0x12; /* clock cycle time @ medium CAS latency */
246                     /* data access time */
247                     /* clock cycle time @ short CAS latency */
248                     /* data access time */
249     spd[27] = 20;   /* min. row precharge time */
250     spd[28] = 15;   /* min. row active row delay */
251     spd[29] = 20;   /* min. ~RAS to ~CAS delay */
252     spd[30] = 45;   /* min. active to precharge time */
253     spd[31] = density;
254     spd[32] = 20;   /* addr/cmd setup time */
255     spd[33] = 8;    /* addr/cmd hold time */
256     spd[34] = 20;   /* data input setup time */
257     spd[35] = 8;    /* data input hold time */
258 
259     /* checksum */
260     for (i = 0; i < 63; i++) {
261         spd[63] += spd[i];
262     }
263     return spd;
264 }
265