diff options
Diffstat (limited to 'hw/i2c')
| -rw-r--r-- | hw/i2c/smbus_eeprom.c | 129 |
1 files changed, 129 insertions, 0 deletions
diff --git a/hw/i2c/smbus_eeprom.c b/hw/i2c/smbus_eeprom.c index f18aa3d..01b9439 100644 --- a/hw/i2c/smbus_eeprom.c +++ b/hw/i2c/smbus_eeprom.c @@ -23,6 +23,8 @@ */ #include "qemu/osdep.h" +#include "qemu/units.h" +#include "qapi/error.h" #include "hw/hw.h" #include "hw/i2c/i2c.h" #include "hw/i2c/smbus.h" @@ -162,3 +164,130 @@ void smbus_eeprom_init(I2CBus *smbus, int nb_eeprom, smbus_eeprom_init_one(smbus, 0x50 + i, eeprom_buf + (i * 256)); } } + +/* Generate SDRAM SPD EEPROM data describing a module of type and size */ +uint8_t *spd_data_generate(enum sdram_type type, ram_addr_t ram_size, + Error **errp) +{ + uint8_t *spd; + uint8_t nbanks; + uint16_t density; + uint32_t size; + int min_log2, max_log2, sz_log2; + int i; + + switch (type) { + case SDR: + min_log2 = 2; + max_log2 = 9; + break; + case DDR: + min_log2 = 5; + max_log2 = 12; + break; + case DDR2: + min_log2 = 7; + max_log2 = 14; + break; + default: + g_assert_not_reached(); + } + size = ram_size >> 20; /* work in terms of megabytes */ + if (size < 4) { + error_setg(errp, "SDRAM size is too small"); + return NULL; + } + sz_log2 = 31 - clz32(size); + size = 1U << sz_log2; + if (ram_size > size * MiB) { + error_setg(errp, "SDRAM size 0x"RAM_ADDR_FMT" is not a power of 2, " + "truncating to %u MB", ram_size, size); + } + if (sz_log2 < min_log2) { + error_setg(errp, + "Memory size is too small for SDRAM type, adjusting type"); + if (size >= 32) { + type = DDR; + min_log2 = 5; + max_log2 = 12; + } else { + type = SDR; + min_log2 = 2; + max_log2 = 9; + } + } + + nbanks = 1; + while (sz_log2 > max_log2 && nbanks < 8) { + sz_log2--; + nbanks++; + } + + if (size > (1ULL << sz_log2) * nbanks) { + error_setg(errp, "Memory size is too big for SDRAM, truncating"); + } + + /* split to 2 banks if possible to avoid a bug in MIPS Malta firmware */ + if (nbanks == 1 && sz_log2 > min_log2) { + sz_log2--; + nbanks++; + } + + density = 1ULL << (sz_log2 - 2); + switch (type) { + case DDR2: + density = (density & 0xe0) | (density >> 8 & 0x1f); + break; + case DDR: + density = (density & 0xf8) | (density >> 8 & 0x07); + break; + case SDR: + default: + density &= 0xff; + break; + } + + spd = g_malloc0(256); + spd[0] = 128; /* data bytes in EEPROM */ + spd[1] = 8; /* log2 size of EEPROM */ + spd[2] = type; + spd[3] = 13; /* row address bits */ + spd[4] = 10; /* column address bits */ + spd[5] = (type == DDR2 ? nbanks - 1 : nbanks); + spd[6] = 64; /* module data width */ + /* reserved / data width high */ + spd[8] = 4; /* interface voltage level */ + spd[9] = 0x25; /* highest CAS latency */ + spd[10] = 1; /* access time */ + /* DIMM configuration 0 = non-ECC */ + spd[12] = 0x82; /* refresh requirements */ + spd[13] = 8; /* primary SDRAM width */ + /* ECC SDRAM width */ + spd[15] = (type == DDR2 ? 0 : 1); /* reserved / delay for random col rd */ + spd[16] = 12; /* burst lengths supported */ + spd[17] = 4; /* banks per SDRAM device */ + spd[18] = 12; /* ~CAS latencies supported */ + spd[19] = (type == DDR2 ? 0 : 1); /* reserved / ~CS latencies supported */ + spd[20] = 2; /* DIMM type / ~WE latencies */ + /* module features */ + /* memory chip features */ + spd[23] = 0x12; /* clock cycle time @ medium CAS latency */ + /* data access time */ + /* clock cycle time @ short CAS latency */ + /* data access time */ + spd[27] = 20; /* min. row precharge time */ + spd[28] = 15; /* min. row active row delay */ + spd[29] = 20; /* min. ~RAS to ~CAS delay */ + spd[30] = 45; /* min. active to precharge time */ + spd[31] = density; + spd[32] = 20; /* addr/cmd setup time */ + spd[33] = 8; /* addr/cmd hold time */ + spd[34] = 20; /* data input setup time */ + spd[35] = 8; /* data input hold time */ + + /* checksum */ + for (i = 0; i < 63; i++) { + spd[63] += spd[i]; + } + return spd; +} |