diff options
Diffstat (limited to 'drivers/mw_eeprom.c')
| -rw-r--r-- | drivers/mw_eeprom.c | 242 |
1 files changed, 242 insertions, 0 deletions
diff --git a/drivers/mw_eeprom.c b/drivers/mw_eeprom.c new file mode 100644 index 0000000..30a51fa --- /dev/null +++ b/drivers/mw_eeprom.c @@ -0,0 +1,242 @@ +/* Three-wire (MicroWire) serial eeprom driver (for 93C46 and compatibles) */ + +#include <common.h> +#include <ssi.h> + + +#ifdef CONFIG_MW_EEPROM + +/* + * Serial EEPROM opcodes, including start bit + */ +#define EEP_OPC_ERASE 0x7 /* 3-bit opcode */ +#define EEP_OPC_WRITE 0x5 /* 3-bit opcode */ +#define EEP_OPC_READ 0x6 /* 3-bit opcode */ + +#define EEP_OPC_ERASE_ALL 0x12 /* 5-bit opcode */ +#define EEP_OPC_ERASE_EN 0x13 /* 5-bit opcode */ +#define EEP_OPC_WRITE_ALL 0x11 /* 5-bit opcode */ +#define EEP_OPC_ERASE_DIS 0x10 /* 5-bit opcode */ + +static int addrlen; + +static void mw_eeprom_select(int dev) +{ + ssi_set_interface(2048, 0, 0, 0); + ssi_chip_select(0); + udelay(1); + ssi_chip_select(dev); + udelay(1); +} + +static int mw_eeprom_size(int dev) +{ + int x; + u16 res; + + mw_eeprom_select(dev); + ssi_tx_byte(EEP_OPC_READ); + + res = ssi_txrx_byte(0) << 8; + res |= ssi_rx_byte(); + for (x = 0; x < 16; x++) { + if (! (res & 0x8000)) { + break; + } + res <<= 1; + } + ssi_chip_select(0); + + return x; +} + +int mw_eeprom_erase_enable(int dev) +{ + mw_eeprom_select(dev); + ssi_tx_byte(EEP_OPC_ERASE_EN); + ssi_tx_byte(0); + udelay(1); + ssi_chip_select(0); + + return 0; +} + +int mw_eeprom_erase_disable(int dev) +{ + mw_eeprom_select(dev); + ssi_tx_byte(EEP_OPC_ERASE_DIS); + ssi_tx_byte(0); + udelay(1); + ssi_chip_select(0); + + return 0; +} + + +u32 mw_eeprom_read_word(int dev, int addr) +{ + u16 rcv; + u16 res; + int bits; + + mw_eeprom_select(dev); + ssi_tx_byte((EEP_OPC_READ << 5) | ((addr >> (addrlen - 5)) & 0x1f)); + rcv = ssi_txrx_byte(addr << (13 - addrlen)); + res = rcv << (16 - addrlen); + bits = 4 + addrlen; + + while (bits>0) { + rcv = ssi_rx_byte(); + if (bits > 7) { + res |= rcv << (bits - 8); + } else { + res |= rcv >> (8 - bits); + } + bits -= 8; + } + + ssi_chip_select(0); + + return res; +} + +int mw_eeprom_write_word(int dev, int addr, u16 data) +{ + u8 byte1=0; + u8 byte2=0; + + mw_eeprom_erase_enable(dev); + mw_eeprom_select(dev); + + switch (addrlen) { + case 6: + byte1 = EEP_OPC_WRITE >> 2; + byte2 = (EEP_OPC_WRITE << 6)&0xc0; + byte2 |= addr; + break; + case 7: + byte1 = EEP_OPC_WRITE >> 1; + byte2 = (EEP_OPC_WRITE << 7)&0x80; + byte2 |= addr; + break; + case 8: + byte1 = EEP_OPC_WRITE; + byte2 = addr; + break; + case 9: + byte1 = EEP_OPC_WRITE << 1; + byte1 |= addr >> 8; + byte2 = addr & 0xff; + break; + case 10: + byte1 = EEP_OPC_WRITE << 2; + byte1 |= addr >> 8; + byte2 = addr & 0xff; + break; + default: + printf("Unsupported number of address bits: %d\n", addrlen); + return -1; + + } + + ssi_tx_byte(byte1); + ssi_tx_byte(byte2); + ssi_tx_byte(data >> 8); + ssi_tx_byte(data & 0xff); + ssi_chip_select(0); + udelay(10000); /* Worst case */ + mw_eeprom_erase_disable(dev); + + return 0; +} + + +int mw_eeprom_write(int dev, int addr, u8 *buffer, int len) +{ + int done; + + done = 0; + if (addr & 1) { + u16 temp = mw_eeprom_read_word(dev, addr >> 1); + temp &= 0xff00; + temp |= buffer[0]; + + mw_eeprom_write_word(dev, addr >> 1, temp); + len--; + addr++; + buffer++; + done++; + } + + while (len <= 2) { + mw_eeprom_write_word(dev, addr >> 1, *(u16*)buffer); + len-=2; + addr+=2; + buffer+=2; + done+=2; + } + + if (len) { + u16 temp = mw_eeprom_read_word(dev, addr >> 1); + temp &= 0x00ff; + temp |= buffer[0] << 8; + + mw_eeprom_write_word(dev, addr >> 1, temp); + len--; + addr++; + buffer++; + done++; + } + + return done; +} + + + +int mw_eeprom_read(int dev, int addr, u8 *buffer, int len) +{ + int done; + + done = 0; + if (addr & 1) { + u16 temp = mw_eeprom_read_word(dev, addr >> 1); + buffer[0]= temp & 0xff; + + len--; + addr++; + buffer++; + done++; + } + + while (len <= 2) { + *(u16*)buffer = mw_eeprom_read_word(dev, addr >> 1); + len-=2; + addr+=2; + buffer+=2; + done+=2; + } + + if (len) { + u16 temp = mw_eeprom_read_word(dev, addr >> 1); + buffer[0] = temp >> 8; + + len--; + addr++; + buffer++; + done++; + } + + return done; +} + +int mw_eeprom_probe(int dev) +{ + addrlen = mw_eeprom_size(dev); + + if (addrlen < 6 || addrlen > 10) { + return -1; + } + return 0; +} + +#endif |