/* SPDX-License-Identifier: GPL-2.0-only */ #include #include #include #include #include #include #include #include /* * readspd - Read one or more SPD bytes from a DIMM. * Start with offset zero and read sequentially. * Optimization relies on autoincrement to avoid * sending offset for every byte. * Reads 128 bytes in 7-8 ms at 400 KHz. */ static int readspd(uint8_t SmbusSlaveAddress, char *buffer, size_t count) { uint8_t dev_addr; size_t index; int error; char *pbuf = buffer; printk(BIOS_SPEW, "-------------READING SPD-----------\n"); printk(BIOS_SPEW, "SmbusSlave: 0x%08X, count: %zd\n", SmbusSlaveAddress, count); /* * Convert received device address to the format accepted by * do_smbus_read_byte and do_smbus_recv_byte. */ dev_addr = (SmbusSlaveAddress >> 1); /* Read the first SPD byte */ error = do_smbus_read_byte((uintptr_t)acpimmio_smbus, dev_addr, 0); if (error < 0) { printk(BIOS_ERR, "-------------SPD READ ERROR-----------\n"); return error; } *pbuf = (char)error; pbuf++; /* Read the remaining SPD bytes using do_smbus_recv_byte for speed */ for (index = 1 ; index < count ; index++) { error = do_smbus_recv_byte((uintptr_t)acpimmio_smbus, dev_addr); if (error < 0) { printk(BIOS_ERR, "-------------SPD READ ERROR-----------\n"); return error; } *pbuf = (char)error; pbuf++; } printk(BIOS_SPEW, "\n"); printk(BIOS_SPEW, "-------------FINISHED READING SPD-----------\n"); return 0; } int sb_read_spd(uint8_t spdAddress, char *buf, size_t len) { return readspd(spdAddress, buf, len); }