diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/southbridge/via/vt8231/vt8231_early_smbus.c | 150 |
1 files changed, 109 insertions, 41 deletions
diff --git a/src/southbridge/via/vt8231/vt8231_early_smbus.c b/src/southbridge/via/vt8231/vt8231_early_smbus.c index 1888176144..056c4b5b11 100644 --- a/src/southbridge/via/vt8231/vt8231_early_smbus.c +++ b/src/southbridge/via/vt8231/vt8231_early_smbus.c @@ -59,25 +59,54 @@ static inline void smbus_delay(void) outb(0x80, 0x80); } +static int smbus_wait_until_active(void) +{ + unsigned long loops; + loops = SMBUS_TIMEOUT; + do { + unsigned char val; + smbus_delay(); + val = inb(SMBUS_IO_BASE + SMBHSTSTAT); + if ((val & 1)) { + break; + } + } while(--loops); + return loops?0:-4; +} + static int smbus_wait_until_ready(void) { - unsigned char c; - unsigned long loops; - loops = SMBUS_TIMEOUT; - do { - unsigned char val; - smbus_delay(); - c = inb(SMBUS_IO_BASE + SMBHSTSTAT); - while((c & 1) == 1) { - print_debug("c is "); - print_debug_hex8(c); - print_debug("\r\n"); - c = inb(SMBUS_IO_BASE + SMBHSTSTAT); - /* nop */ - } - - } while(--loops); - return loops?0:-1; + unsigned long loops; + loops = SMBUS_TIMEOUT; + do { + unsigned char val; + smbus_delay(); + val = inb(SMBUS_IO_BASE + SMBHSTSTAT); + if ((val & 1) == 0) { + break; + } + if(loops == (SMBUS_TIMEOUT / 2)) { + outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), + SMBUS_IO_BASE + SMBHSTSTAT); + } + } while(--loops); + return loops?0:-2; +} + +static int smbus_wait_until_done(void) +{ + unsigned long loops; + loops = SMBUS_TIMEOUT; + do { + unsigned char val; + smbus_delay(); + + val = inb(SMBUS_IO_BASE + SMBHSTSTAT); + if ( (val & 1) == 0) { + break; + } + } while(--loops); + return loops?0:-3; } void smbus_reset(void) @@ -93,25 +122,6 @@ void smbus_reset(void) print_debug("\r\n"); } - - -static int smbus_wait_until_done(void) -{ - unsigned long loops; - unsigned char byte; - loops = SMBUS_TIMEOUT; - do { - unsigned char val; - smbus_delay(); - - byte = inb(SMBUS_IO_BASE + SMBHSTSTAT); - if (byte & 1) - break; - - } while(--loops); - return loops?0:-1; -} - static void smbus_print_error(unsigned char host_status_register) { @@ -135,13 +145,71 @@ static void smbus_print_error(unsigned char host_status_register) } } +/* + * Copied from intel/i82801dbm early smbus code - suggested by rgm. + * Modifications/check against i2c-viapro driver code from linux-2.4.22 + * and VT8231 Reference Docs - mw. + */ +static int smbus_read_byte(unsigned device, unsigned address) +{ + unsigned char global_control_register; + unsigned char global_status_register; + unsigned char byte; + + if (smbus_wait_until_ready() < 0) { + outb(inb(SMBUS_IO_BASE + SMBHSTSTAT), SMBUS_IO_BASE + SMBHSTSTAT); + if ( smbus_wait_until_ready() < 0 ) { + return -2; + } + } + + /* setup transaction */ + /* disable interrupts */ + outb(inb(SMBUS_IO_BASE + SMBHSTCTL) & 0xfe, SMBUS_IO_BASE + SMBHSTCTL); + /* set the device I'm talking too */ + outb(((device & 0x7f) << 1) | 1, SMBUS_IO_BASE + SMBXMITADD); + /* 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 a byte read, with interrupts disabled */ + outb((inb(SMBUS_IO_BASE + SMBHSTCTL) | 0x40), SMBUS_IO_BASE + SMBHSTCTL); + /* poll for it to start */ + if (smbus_wait_until_active() < 0) { + return -4; + } + + /* poll for transaction completion */ + if (smbus_wait_until_done() < 0) { + return -3; + } + /* Ignore the Host Busy & Command Complete ? */ + global_status_register = inb(SMBUS_IO_BASE + SMBHSTSTAT) & ~((1<<1)|(1<<0)); + + /* read results of transaction */ + byte = inb(SMBUS_IO_BASE + SMBHSTDAT0); + + if (global_status_register != 0) { + return -1; + } + return byte; +} + +#if 0 /* SMBus routines borrowed from VIA's Trident Driver */ /* this works, so I am not going to touch it for now -- rgm */ static unsigned char smbus_read_byte(unsigned char devAdr, unsigned char bIndex) { - unsigned short i; + unsigned int i; unsigned char bData; unsigned char sts = 0; @@ -149,10 +217,10 @@ static unsigned char smbus_read_byte(unsigned char devAdr, outb(0xff, SMBUS_IO_BASE); /* check SMBUS ready */ - for ( i = 0; i < 0xFFFF; i++ ) + for ( i = 0; i < SMBUS_TIMEOUT; i++ ) if ( (inb(SMBUS_IO_BASE) & 0x01) == 0 ) break; - + /* set host command */ outb(bIndex, SMBUS_IO_BASE+3); @@ -163,7 +231,7 @@ static unsigned char smbus_read_byte(unsigned char devAdr, outb(0x48, SMBUS_IO_BASE+2); /* SMBUS Wait Ready */ - for ( i = 0; i < 0xFFFF; i++ ) + for ( i = 0; i < SMBUS_TIMEOUT; i++ ) if ( ((sts = inb(SMBUS_IO_BASE)) & 0x01) == 0 ) break; if ((sts & ~3) != 0) { @@ -175,7 +243,7 @@ static unsigned char smbus_read_byte(unsigned char devAdr, return bData; } - +#endif /* for reference, here is the fancier version which we will use at some * point */ |