diff options
Diffstat (limited to 'src/southbridge/intel/i82801er/i82801er_smbus.c')
-rw-r--r-- | src/southbridge/intel/i82801er/i82801er_smbus.c | 92 |
1 files changed, 92 insertions, 0 deletions
diff --git a/src/southbridge/intel/i82801er/i82801er_smbus.c b/src/southbridge/intel/i82801er/i82801er_smbus.c new file mode 100644 index 0000000000..fd06871234 --- /dev/null +++ b/src/southbridge/intel/i82801er/i82801er_smbus.c @@ -0,0 +1,92 @@ +#include <smbus.h> +#include <pci.h> +#include <arch/io.h> + +#define PM_BUS 0 +#define PM_DEVFN PCI_DEVFN(0x1f,3) + +#define SMBUS_IO_BASE 0x1000 +#define SMBHSTSTAT 0 +#define SMBHSTCTL 2 +#define SMBHSTCMD 3 +#define SMBHSTADD 4 +#define SMBHSTDAT0 5 +#define SMBHSTDAT1 6 +#define SMBBLKDAT 7 + +void smbus_enable(void) +{ + unsigned char byte; + /* iobase addr */ + pcibios_write_config_dword(PM_BUS, PM_DEVFN, 0x20, SMBUS_IO_BASE | 1); + /* smbus enable */ + pcibios_write_config_byte(PM_BUS, PM_DEVFN, 0x40, 1); + /* iospace enable */ + pcibios_write_config_word(PM_BUS, PM_DEVFN, 0x4, 1); + + /* Disable interrupt generation */ + outb(0, SMBUS_IO_BASE + SMBHSTCTL); + +} + +void smbus_setup(void) +{ + outb(0, SMBUS_IO_BASE + SMBHSTSTAT); +} + +static void smbus_wait_until_ready(void) +{ + while((inb(SMBUS_IO_BASE + SMBHSTSTAT) & 1) == 1) { + /* nop */ + } +} + +static void smbus_wait_until_done(void) +{ + unsigned char byte; + do { + byte = inb(SMBUS_IO_BASE + SMBHSTSTAT); + } + while((byte &1) == 1); + while( (byte & ~1) == 0) { + byte = inb(SMBUS_IO_BASE + SMBHSTSTAT); + } +} + +int smbus_read_byte(unsigned device, unsigned address, unsigned char *result) +{ + unsigned char host_status_register; + unsigned char byte; + + smbus_wait_until_ready(); + + /* setup transaction */ + /* disable interrupts */ + outb(inb(SMBUS_IO_BASE + SMBHSTCTL) & (~1), SMBUS_IO_BASE + SMBHSTCTL); + /* set the device I'm talking too */ + outb(((device & 0x7f) << 1) | 1, SMBUS_IO_BASE + SMBHSTADD); + /* set the command/address... */ + outb(address & 0xFF, SMBUS_IO_BASE + SMBHSTCMD); + /* set up for a byte data read */ + outb((inb(SMBUS_IO_BASE + SMBHSTCTL) & 0xE3) | (0x2 << 2), SMBUS_IO_BASE + SMBHSTCTL); + + /* clear any lingering errors, so the transaction will run */ + outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), SMBUS_IO_BASE + SMBHSTSTAT); + + /* clear the data byte...*/ + outb(0, SMBUS_IO_BASE + SMBHSTDAT0); + + /* start the command */ + outb((inb(SMBUS_IO_BASE + SMBHSTCTL) | 0x40), SMBUS_IO_BASE + SMBHSTCTL); + + /* poll for transaction completion */ + smbus_wait_until_done(); + + host_status_register = inb(SMBUS_IO_BASE + SMBHSTSTAT); + + /* read results of transaction */ + byte = inb(SMBUS_IO_BASE + SMBHSTDAT0); + + *result = byte; + return host_status_register != 0x02; +} |