diff --git a/hw/mips_malta.c b/hw/mips_malta.c index eeb351387656c3dcd184be4335e8ee4e5ac9dd44..e7327983585b94df16bca7938c8f738559817f72 100644 --- a/hw/mips_malta.c +++ b/hw/mips_malta.c @@ -49,6 +49,7 @@ typedef struct { uint32_t leds; uint32_t brk; uint32_t gpout; + uint32_t i2cin; uint32_t i2coe; uint32_t i2cout; uint32_t i2csel; @@ -83,6 +84,124 @@ static void malta_fpga_update_display(void *opaque) qemu_chr_printf(s->display, "\n\n\n\n|\e[31m%-8.8s\e[00m|", s->display_text); } +/* + * EEPROM 24C01 / 24C02 emulation. + * + * Emulation for serial EEPROMs: + * 24C01 - 1024 bit (128 x 8) + * 24C02 - 2048 bit (256 x 8) + * + * Typical device names include Microchip 24C02SC or SGS Thomson ST24C02. + */ + +//~ #define DEBUG + +#if defined(DEBUG) +# define logout(fmt, args...) fprintf(stderr, "MALTA\t%-24s" fmt, __func__, ##args) +#else +# define logout(fmt, args...) ((void)0) +#endif + +struct _eeprom24c0x_t { + uint8_t tick; + uint8_t address; + uint8_t command; + uint8_t ack; + uint8_t scl; + uint8_t sda; + uint8_t data; + //~ uint16_t size; + uint8_t contents[256]; +}; + +typedef struct _eeprom24c0x_t eeprom24c0x_t; + +static eeprom24c0x_t eeprom = { + contents: { + /* 00000000: */ 0x80,0x08,0x04,0x0D,0x0A,0x01,0x40,0x00, + /* 00000008: */ 0x01,0x75,0x54,0x00,0x82,0x08,0x00,0x01, + /* 00000010: */ 0x8F,0x04,0x02,0x01,0x01,0x00,0x0E,0x00, + /* 00000018: */ 0x00,0x00,0x00,0x14,0x0F,0x14,0x2D,0x40, + /* 00000020: */ 0x15,0x08,0x15,0x08,0x00,0x00,0x00,0x00, + /* 00000028: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, + /* 00000030: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, + /* 00000038: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x12,0xD0, + /* 00000040: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, + /* 00000048: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, + /* 00000050: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, + /* 00000058: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, + /* 00000060: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, + /* 00000068: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, + /* 00000070: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00, + /* 00000078: */ 0x00,0x00,0x00,0x00,0x00,0x00,0x64,0xF4, + }, +}; + +static uint8_t eeprom24c0x_read() +{ + logout("%u: scl = %u, sda = %u, data = 0x%02x\n", + eeprom.tick, eeprom.scl, eeprom.sda, eeprom.data); + return eeprom.sda; +} + +static void eeprom24c0x_write(int scl, int sda) +{ + if (eeprom.scl && scl && (eeprom.sda != sda)) { + logout("%u: scl = %u->%u, sda = %u->%u i2c %s\n", + eeprom.tick, eeprom.scl, scl, eeprom.sda, sda, sda ? "stop" : "start"); + if (!sda) { + eeprom.tick = 1; + eeprom.command = 0; + } + } else if (eeprom.tick == 0 && !eeprom.ack) { + /* Waiting for start. */ + logout("%u: scl = %u->%u, sda = %u->%u wait for i2c start\n", + eeprom.tick, eeprom.scl, scl, eeprom.sda, sda); + } else if (!eeprom.scl && scl) { + logout("%u: scl = %u->%u, sda = %u->%u trigger bit\n", + eeprom.tick, eeprom.scl, scl, eeprom.sda, sda); + if (eeprom.ack) { + logout("\ti2c ack bit = 0\n"); + sda = 0; + eeprom.ack = 0; + } else if (eeprom.sda == sda) { + uint8_t bit = (sda != 0); + logout("\ti2c bit = %d\n", bit); + if (eeprom.tick < 9) { + eeprom.command <<= 1; + eeprom.command += bit; + eeprom.tick++; + if (eeprom.tick == 9) { + logout("\tcommand 0x%04x, %s\n", eeprom.command, bit ? "read" : "write"); + eeprom.ack = 1; + } + } else if (eeprom.tick < 17) { + if (eeprom.command & 1) { + sda = ((eeprom.data & 0x80) != 0); + } + eeprom.address <<= 1; + eeprom.address += bit; + eeprom.tick++; + eeprom.data <<= 1; + if (eeprom.tick == 17) { + eeprom.data = eeprom.contents[eeprom.address]; + logout("\taddress 0x%04x, data 0x%02x\n", eeprom.address, eeprom.data); + eeprom.ack = 1; + eeprom.tick = 0; + } + } else if (eeprom.tick >= 17) { + sda = 0; + } + } else { + logout("\tsda changed with raising scl\n"); + } + } else { + logout("%u: scl = %u->%u, sda = %u->%u\n", eeprom.tick, eeprom.scl, scl, eeprom.sda, sda); + } + eeprom.scl = scl; + eeprom.sda = sda; +} + static uint32_t malta_fpga_readl(void *opaque, target_phys_addr_t addr) { MaltaFPGAState *s = opaque; @@ -140,7 +259,7 @@ static uint32_t malta_fpga_readl(void *opaque, target_phys_addr_t addr) /* I2CINP Register */ case 0x00b00: - val = 0x00000003; + val = ((s->i2cin & ~1) | eeprom24c0x_read()); break; /* I2COE Register */ @@ -155,7 +274,7 @@ static uint32_t malta_fpga_readl(void *opaque, target_phys_addr_t addr) /* I2CSEL Register */ case 0x00b18: - val = s->i2cout; + val = s->i2csel; break; default: @@ -234,12 +353,13 @@ static void malta_fpga_writel(void *opaque, target_phys_addr_t addr, /* I2COUT Register */ case 0x00b10: - s->i2cout = val & 0x03; + eeprom24c0x_write(val & 0x02, val & 0x01); + s->i2cout = val; break; /* I2CSEL Register */ case 0x00b18: - s->i2cout = val & 0x01; + s->i2csel = val & 0x01; break; default: @@ -270,6 +390,7 @@ void malta_fpga_reset(void *opaque) s->leds = 0x00; s->brk = 0x0a; s->gpout = 0x00; + s->i2cin = 0x3; s->i2coe = 0x0; s->i2cout = 0x3; s->i2csel = 0x1;