diff options
Diffstat (limited to 'src/southbridge/amd/cs5536/smbus.c')
| -rw-r--r-- | src/southbridge/amd/cs5536/smbus.c | 199 |
1 files changed, 199 insertions, 0 deletions
diff --git a/src/southbridge/amd/cs5536/smbus.c b/src/southbridge/amd/cs5536/smbus.c new file mode 100644 index 0000000000..3b948c4045 --- /dev/null +++ b/src/southbridge/amd/cs5536/smbus.c @@ -0,0 +1,199 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2007 Advanced Micro Devices, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <console/console.h> +#include <arch/io.h> +#include "cs5536.h" +#include "smbus.h" + +#define SMBUS_ERROR -1 +#define SMBUS_WAIT_UNTIL_READY_TIMEOUT -2 +#define SMBUS_WAIT_UNTIL_DONE_TIMEOUT -3 +#define SMBUS_TIMEOUT (1000) + +static void smbus_delay(void) +{ + /* inb(0x80); */ +} + +static int smbus_wait(unsigned smbus_io_base) +{ + unsigned long loops = SMBUS_TIMEOUT; + unsigned char val; + + do { + smbus_delay(); + val = inb(smbus_io_base + SMB_STS); + if ((val & SMB_STS_SDAST) != 0) + break; + if (val & (SMB_STS_BER | SMB_STS_NEGACK)) { + /*printk(BIOS_DEBUG, "SMBUS WAIT ERROR %x\n", val); */ + return SMBUS_ERROR; + } + } while (--loops); + return loops ? 0 : SMBUS_WAIT_UNTIL_READY_TIMEOUT; +} + +/* generate a smbus start condition */ +int smbus_start_condition(unsigned smbus_io_base) +{ + unsigned char val; + + /* issue a START condition */ + val = inb(smbus_io_base + SMB_CTRL1); + outb(val | SMB_CTRL1_START, smbus_io_base + SMB_CTRL1); + + /* check for bus conflict */ + val = inb(smbus_io_base + SMB_STS); + if ((val & SMB_STS_BER) != 0) + return SMBUS_ERROR; + + return smbus_wait(smbus_io_base); +} + +int smbus_check_stop_condition(unsigned smbus_io_base) +{ + unsigned char val; + unsigned long loops; + loops = SMBUS_TIMEOUT; + /* check for SDA status */ + do { + smbus_delay(); + val = inb(smbus_io_base + SMB_CTRL1); + if ((val & SMB_CTRL1_STOP) == 0) { + break; + } + outb((0x7F << 1) | SMB_CTRL2_ENABLE, smbus_io_base + SMB_CTRL2); + } while (--loops); + return loops ? 0 : SMBUS_WAIT_UNTIL_READY_TIMEOUT; +} + +int smbus_stop_condition(unsigned smbus_io_base) +{ + outb(SMB_CTRL1_STOP, smbus_io_base + SMB_CTRL1); + return smbus_wait(smbus_io_base); +} + +static int smbus_ack(unsigned smbus_io_base, int state) +{ + unsigned char val = inb(smbus_io_base + SMB_CTRL1); + +/* if (state) */ + outb(val | SMB_CTRL1_ACK, smbus_io_base + SMB_CTRL1); +/* else + outb(val & ~SMB_CTRL1_ACK, smbus_io_base + SMB_CTRL1); +*/ + return 0; +} + +int smbus_send_slave_address(unsigned smbus_io_base, + unsigned char device) +{ + unsigned char val; + + /* send the slave address */ + outb(device, smbus_io_base + SMB_SDA); + + /* check for bus conflict and NACK */ + val = inb(smbus_io_base + SMB_STS); + if (((val & SMB_STS_BER) != 0) || ((val & SMB_STS_NEGACK) != 0)) { + /* printk(BIOS_DEBUG, "SEND SLAVE ERROR (%x)\n", val); */ + return SMBUS_ERROR; + } + return smbus_wait(smbus_io_base); +} + +int smbus_send_command(unsigned smbus_io_base, unsigned char command) +{ + unsigned char val; + + /* send the command */ + outb(command, smbus_io_base + SMB_SDA); + + /* check for bus conflict and NACK */ + val = inb(smbus_io_base + SMB_STS); + if (((val & SMB_STS_BER) != 0) || ((val & SMB_STS_NEGACK) != 0)) + return SMBUS_ERROR; + + return smbus_wait(smbus_io_base); +} + +static unsigned char smbus_get_result(unsigned smbus_io_base) +{ + return inb(smbus_io_base + SMB_SDA); +} + +unsigned char do_smbus_read_byte(unsigned smbus_io_base, + unsigned char device, + unsigned char address) +{ + unsigned char error = 0; + + if ((smbus_check_stop_condition(smbus_io_base))) { + error = 1; + goto err; + } + + if ((smbus_start_condition(smbus_io_base))) { + error = 2; + goto err; + } + + if ((smbus_send_slave_address(smbus_io_base, device << 1))) { + error = 3; + goto err; + } + + smbus_ack(smbus_io_base, 1); + + if ((smbus_send_command(smbus_io_base, address))) { + error = 4; + goto err; + } + + if ((smbus_start_condition(smbus_io_base))) { + error = 5; + goto err; + } + + if ((smbus_send_slave_address(smbus_io_base, (device << 1) | 0x01))) { + error = 6; + goto err; + } + + if ((smbus_stop_condition(smbus_io_base))) { + error = 7; + goto err; + } + + return smbus_get_result(smbus_io_base); + +err: + print_debug("SMBUS READ ERROR:"); + print_debug_hex8(error); + print_debug(" device:"); + print_debug_hex8(device); + print_debug("\n"); + /* stop, clean up the error, and leave */ + smbus_stop_condition(smbus_io_base); + outb(inb(smbus_io_base + SMB_STS), smbus_io_base + SMB_STS); + outb(0x0, smbus_io_base + SMB_STS); + return 0xFF; +} + |