xref: /openbmc/qemu/hw/i2c/smbus_eeprom.c (revision 0cf487e5bd802fccb7db9d47fdf3dad15deb273e)
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 #define SMBUS_EEPROM_SIZE 256
41 
42 typedef struct SMBusEEPROMDevice {
43     SMBusDevice smbusdev;
44     void *data;
45     uint8_t offset;
46 } SMBusEEPROMDevice;
47 
48 static uint8_t eeprom_receive_byte(SMBusDevice *dev)
49 {
50     SMBusEEPROMDevice *eeprom = SMBUS_EEPROM(dev);
51     uint8_t *data = eeprom->data;
52     uint8_t val = data[eeprom->offset++];
53 
54 #ifdef DEBUG
55     printf("eeprom_receive_byte: addr=0x%02x val=0x%02x\n",
56            dev->i2c.address, val);
57 #endif
58     return val;
59 }
60 
61 static int eeprom_write_data(SMBusDevice *dev, uint8_t *buf, uint8_t len)
62 {
63     SMBusEEPROMDevice *eeprom = SMBUS_EEPROM(dev);
64     uint8_t *data = eeprom->data;
65 
66 #ifdef DEBUG
67     printf("eeprom_write_byte: addr=0x%02x cmd=0x%02x val=0x%02x\n",
68            dev->i2c.address, buf[0], buf[1]);
69 #endif
70     /* len is guaranteed to be > 0 */
71     eeprom->offset = buf[0];
72     buf++;
73     len--;
74 
75     for (; len > 0; len--) {
76         data[eeprom->offset] = *buf++;
77         eeprom->offset = (eeprom->offset + 1) % SMBUS_EEPROM_SIZE;
78     }
79 
80     return 0;
81 }
82 
83 static void smbus_eeprom_realize(DeviceState *dev, Error **errp)
84 {
85     SMBusEEPROMDevice *eeprom = SMBUS_EEPROM(dev);
86 
87     eeprom->offset = 0;
88 }
89 
90 static Property smbus_eeprom_properties[] = {
91     DEFINE_PROP_PTR("data", SMBusEEPROMDevice, data),
92     DEFINE_PROP_END_OF_LIST(),
93 };
94 
95 static void smbus_eeprom_class_initfn(ObjectClass *klass, void *data)
96 {
97     DeviceClass *dc = DEVICE_CLASS(klass);
98     SMBusDeviceClass *sc = SMBUS_DEVICE_CLASS(klass);
99 
100     dc->realize = smbus_eeprom_realize;
101     sc->receive_byte = eeprom_receive_byte;
102     sc->write_data = eeprom_write_data;
103     dc->props = smbus_eeprom_properties;
104     /* Reason: pointer property "data" */
105     dc->user_creatable = false;
106 }
107 
108 static const TypeInfo smbus_eeprom_info = {
109     .name          = TYPE_SMBUS_EEPROM,
110     .parent        = TYPE_SMBUS_DEVICE,
111     .instance_size = sizeof(SMBusEEPROMDevice),
112     .class_init    = smbus_eeprom_class_initfn,
113 };
114 
115 static void smbus_eeprom_register_types(void)
116 {
117     type_register_static(&smbus_eeprom_info);
118 }
119 
120 type_init(smbus_eeprom_register_types)
121 
122 void smbus_eeprom_init_one(I2CBus *smbus, uint8_t address, uint8_t *eeprom_buf)
123 {
124     DeviceState *dev;
125 
126     dev = qdev_create((BusState *) smbus, TYPE_SMBUS_EEPROM);
127     qdev_prop_set_uint8(dev, "address", address);
128     qdev_prop_set_ptr(dev, "data", eeprom_buf);
129     qdev_init_nofail(dev);
130 }
131 
132 void smbus_eeprom_init(I2CBus *smbus, int nb_eeprom,
133                        const uint8_t *eeprom_spd, int eeprom_spd_size)
134 {
135     int i;
136      /* XXX: make this persistent */
137     uint8_t *eeprom_buf = g_malloc0(8 * SMBUS_EEPROM_SIZE);
138     if (eeprom_spd_size > 0) {
139         memcpy(eeprom_buf, eeprom_spd, eeprom_spd_size);
140     }
141 
142     for (i = 0; i < nb_eeprom; i++) {
143         smbus_eeprom_init_one(smbus, 0x50 + i,
144                               eeprom_buf + (i * SMBUS_EEPROM_SIZE));
145     }
146 }
147 
148 /* Generate SDRAM SPD EEPROM data describing a module of type and size */
149 uint8_t *spd_data_generate(enum sdram_type type, ram_addr_t ram_size,
150                            Error **errp)
151 {
152     uint8_t *spd;
153     uint8_t nbanks;
154     uint16_t density;
155     uint32_t size;
156     int min_log2, max_log2, sz_log2;
157     int i;
158 
159     switch (type) {
160     case SDR:
161         min_log2 = 2;
162         max_log2 = 9;
163         break;
164     case DDR:
165         min_log2 = 5;
166         max_log2 = 12;
167         break;
168     case DDR2:
169         min_log2 = 7;
170         max_log2 = 14;
171         break;
172     default:
173         g_assert_not_reached();
174     }
175     size = ram_size >> 20; /* work in terms of megabytes */
176     if (size < 4) {
177         error_setg(errp, "SDRAM size is too small");
178         return NULL;
179     }
180     sz_log2 = 31 - clz32(size);
181     size = 1U << sz_log2;
182     if (ram_size > size * MiB) {
183         error_setg(errp, "SDRAM size 0x"RAM_ADDR_FMT" is not a power of 2, "
184                    "truncating to %u MB", ram_size, size);
185     }
186     if (sz_log2 < min_log2) {
187         error_setg(errp,
188                    "Memory size is too small for SDRAM type, adjusting type");
189         if (size >= 32) {
190             type = DDR;
191             min_log2 = 5;
192             max_log2 = 12;
193         } else {
194             type = SDR;
195             min_log2 = 2;
196             max_log2 = 9;
197         }
198     }
199 
200     nbanks = 1;
201     while (sz_log2 > max_log2 && nbanks < 8) {
202         sz_log2--;
203         nbanks++;
204     }
205 
206     if (size > (1ULL << sz_log2) * nbanks) {
207         error_setg(errp, "Memory size is too big for SDRAM, truncating");
208     }
209 
210     /* split to 2 banks if possible to avoid a bug in MIPS Malta firmware */
211     if (nbanks == 1 && sz_log2 > min_log2) {
212         sz_log2--;
213         nbanks++;
214     }
215 
216     density = 1ULL << (sz_log2 - 2);
217     switch (type) {
218     case DDR2:
219         density = (density & 0xe0) | (density >> 8 & 0x1f);
220         break;
221     case DDR:
222         density = (density & 0xf8) | (density >> 8 & 0x07);
223         break;
224     case SDR:
225     default:
226         density &= 0xff;
227         break;
228     }
229 
230     spd = g_malloc0(256);
231     spd[0] = 128;   /* data bytes in EEPROM */
232     spd[1] = 8;     /* log2 size of EEPROM */
233     spd[2] = type;
234     spd[3] = 13;    /* row address bits */
235     spd[4] = 10;    /* column address bits */
236     spd[5] = (type == DDR2 ? nbanks - 1 : nbanks);
237     spd[6] = 64;    /* module data width */
238                     /* reserved / data width high */
239     spd[8] = 4;     /* interface voltage level */
240     spd[9] = 0x25;  /* highest CAS latency */
241     spd[10] = 1;    /* access time */
242                     /* DIMM configuration 0 = non-ECC */
243     spd[12] = 0x82; /* refresh requirements */
244     spd[13] = 8;    /* primary SDRAM width */
245                     /* ECC SDRAM width */
246     spd[15] = (type == DDR2 ? 0 : 1); /* reserved / delay for random col rd */
247     spd[16] = 12;   /* burst lengths supported */
248     spd[17] = 4;    /* banks per SDRAM device */
249     spd[18] = 12;   /* ~CAS latencies supported */
250     spd[19] = (type == DDR2 ? 0 : 1); /* reserved / ~CS latencies supported */
251     spd[20] = 2;    /* DIMM type / ~WE latencies */
252                     /* module features */
253                     /* memory chip features */
254     spd[23] = 0x12; /* clock cycle time @ medium CAS latency */
255                     /* data access time */
256                     /* clock cycle time @ short CAS latency */
257                     /* data access time */
258     spd[27] = 20;   /* min. row precharge time */
259     spd[28] = 15;   /* min. row active row delay */
260     spd[29] = 20;   /* min. ~RAS to ~CAS delay */
261     spd[30] = 45;   /* min. active to precharge time */
262     spd[31] = density;
263     spd[32] = 20;   /* addr/cmd setup time */
264     spd[33] = 8;    /* addr/cmd hold time */
265     spd[34] = 20;   /* data input setup time */
266     spd[35] = 8;    /* data input hold time */
267 
268     /* checksum */
269     for (i = 0; i < 63; i++) {
270         spd[63] += spd[i];
271     }
272     return spd;
273 }
274