diff options
Diffstat (limited to 'src/southbridge/amd/cimx/sb800/smbus_spd.c')
-rw-r--r-- | src/southbridge/amd/cimx/sb800/smbus_spd.c | 123 |
1 files changed, 123 insertions, 0 deletions
diff --git a/src/southbridge/amd/cimx/sb800/smbus_spd.c b/src/southbridge/amd/cimx/sb800/smbus_spd.c new file mode 100644 index 0000000000..e3f5acc95b --- /dev/null +++ b/src/southbridge/amd/cimx/sb800/smbus_spd.c @@ -0,0 +1,123 @@ +/* + * This file is part of the coreboot project. + * + * Copyright (C) 2011 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 as published by + * the Free Software Foundation; version 2 of the License. + * + * 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 <device/pci_def.h> +#include <device/device.h> +#include <stdlib.h> +#include "OEM.h" /* SMBUS0_BASE_ADDRESS */ + +/* warning: Porting.h includes an open #pragma pack(1) */ +#include "Porting.h" +#include "AGESA.h" +#include "chip.h" +#include "smbus_spd.h" + +#include <northbridge/amd/agesa/dimmSpd.h> + +/* uncomment for source level debug - GDB gets really confused otherwise. */ +//#pragma optimize ("", off) + +/** + * Read a single SPD byte. If the first byte is being read, set up the + * address and offset. Following bytes auto increment. + */ +static UINT8 readSmbusByte(UINT16 iobase, UINT8 address, char *buffer, + int offset, int initial_offset) +{ + unsigned int status = -1; + UINT64 time_limit; + + /* clear status register */ + __outbyte(iobase + SMBUS_STATUS_REG, 0x1E); + + if (offset == initial_offset) { + /* Clear slave status, set offset, set slave address and start reading */ + __outbyte(iobase + SMBUS_SLAVE_STATUS_REG, 0x3E); + __outbyte(iobase + SMBUS_CONTROL_REG, offset); + __outbyte(iobase + SMBUS_HOST_CMD_REG, address | READ_BIT); + __outbyte(iobase + SMBUS_COMMAND_REG, SMBUS_READ_BYTE_COMMAND); + } else { + /* Issue read command - auto increments to next byte */ + __outbyte(iobase + SMBUS_COMMAND_REG, SMBUS_READ_COMMAND); + } + /* time limit to avoid hanging for unexpected error status */ + time_limit = __rdtsc() + MAX_READ_TSC_COUNT; + while (__rdtsc() <= time_limit) { + status = __inbyte(iobase + SMBUS_STATUS_REG); + if ((status & SMBUS_INTERRUPT_MASK) == 0) + continue; /* SMBusInterrupt not set, keep waiting */ + if ((status & HOSTBUSY_MASK) != 0) + continue; /* HostBusy set, keep waiting */ + break; + } + + if (status != STATUS__COMPLETED_SUCCESSFULLY) + return AGESA_ERROR; + + buffer[0] = __inbyte(iobase + SMBUS_DATA0_REG); + return AGESA_SUCCESS; +} + +static void writePmReg(UINT8 reg, UINT8 data) +{ + __outbyte(PMIO_INDEX_REG, reg); + __outbyte(PMIO_DATA_REG, data); +} + +static void setupFch(UINT16 ioBase) +{ + /* set up SMBUS - Set to SMBUS 0 & set base address */ + /* For SB800 & Hudson1 to SB900 & Hudson 2/3 */ + writePmReg(SMBUS_BAR_HIGH_BYTE, ioBase >> 8); + writePmReg(SMBUS_BAR_LOW_BYTE, (ioBase & 0xe0) | 1); + + /* set SMBus clock to 400 KHz */ + __outbyte(ioBase + SMBUS_CLOCK_REG, SMBUS_FREQUENCY_CONST / 400000); +} + +/** + * Read one or more SPD bytes from a DIMM. + * Start with offset zero and read sequentially. + * Reads 128 bytes in 7-8 ms at 400 KHz. + */ +static UINT8 readspd(UINT16 iobase, UINT8 SmbusSlaveAddress, char *buffer, + UINT16 count) +{ + UINT16 index; + UINT8 status; + UINT8 initial_offset = 0; + + setupFch(iobase); + + for (index = initial_offset; index < count; index++) { + status = readSmbusByte(iobase, SmbusSlaveAddress, &buffer[index], index, + initial_offset); + if (status != AGESA_SUCCESS) + return status; + } + + return status; +} + +int smbus_readSpd(int spdAddress, char *buf, size_t len) +{ + int ioBase = SMBUS0_BASE_ADDRESS; + setupFch (ioBase); + return readspd (ioBase, spdAddress, buf, len); +} |