/* DingusPPC - The Experimental PowerPC Macintosh emulator Copyright (C) 2018-23 divingkatae and maximum (theweirdo) spatium (Contact divingkatae#1017 or powermax#2286 on Discord for more info) 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, either version 3 of the License, or (at your option) any later version. 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, see . */ /** @file BigMac Ethernet controller emulation. */ #include #include #include BigMac::BigMac(uint8_t id) { set_name("BigMac"); supports_types(HWCompType::MMIO_DEV | HWCompType::ETHER_MAC); this->chip_id = id; this->phy_reset(); this->mii_reset(); } uint16_t BigMac::read(uint16_t reg_offset) { switch (reg_offset) { case BigMacReg::CHIP_ID: return this->chip_id; case BigMacReg::MIF_CSR: return (this->mif_csr_old & ~Mif_Data_In) | (this->mii_in_bit << 3); default: LOG_F(WARNING, "%s: unimplemented register at 0x%X", this->name.c_str(), reg_offset); } return 0; } void BigMac::write(uint16_t reg_offset, uint16_t value) { switch (reg_offset) { case BigMacReg::MIF_CSR: if (value & Mif_Data_Out_En) { // send bits one by one on each low-to-high transition of Mif_Clock if (((this->mif_csr_old ^ value) & Mif_Clock) && (value & Mif_Clock)) this->mii_xmit_bit(!!(value & Mif_Data_Out)); } else { if (((this->mif_csr_old ^ value) & Mif_Clock) && (value & Mif_Clock)) this->mii_rcv_bit(); } this->mif_csr_old = value; break; default: LOG_F(WARNING, "%s: unimplemented register at 0x%X is written with 0x%X", this->name.c_str(), reg_offset, value); } } // ================ Media Independent Interface (MII) emulation ================ bool BigMac::mii_rcv_value(uint16_t& var, uint8_t num_bits, uint8_t next_bit) { var = (var << 1) | (next_bit & 1); this->mii_bit_counter++; if (this->mii_bit_counter >= num_bits) { this->mii_bit_counter = 0; return true; // all bits have been received -> return true } return false; // more bits expected } void BigMac::mii_rcv_bit() { switch(this->mii_state) { case MII_FRAME_SM::Preamble: this->mii_in_bit = 1; // required for OSX this->mii_reset(); break; case MII_FRAME_SM::Turnaround: this->mii_in_bit = 0; this->mii_bit_counter = 16; this->mii_state = MII_FRAME_SM::Read_Data; break; case MII_FRAME_SM::Read_Data: if (this->mii_bit_counter) { --this->mii_bit_counter; this->mii_in_bit = (this->mii_data >> this->mii_bit_counter) & 1; if (!this->mii_bit_counter) { this->mii_state = MII_FRAME_SM::Preamble; } } else { // out of sync (shouldn't happen) this->mii_reset(); } break; default: LOG_F(ERROR, "%s: unhandled state %d in mii_rcv_bit", this->name.c_str(), this->mii_state); this->mii_reset(); } } void BigMac::mii_xmit_bit(const uint8_t bit_val) { switch(this->mii_state) { case MII_FRAME_SM::Preamble: if (bit_val) { this->mii_bit_counter++; if (this->mii_bit_counter >= 32) { this->mii_state = MII_FRAME_SM::Start; this->mii_in_bit = 1; // checked in OSX this->mii_bit_counter = 0; } } else { // zero bit -> out of sync this->mii_reset(); } break; case MII_FRAME_SM::Start: if (this->mii_rcv_value(this->mii_start, 2, bit_val)) { LOG_F(9, "MII_Start=0x%X", this->mii_start); this->mii_state = MII_FRAME_SM::Opcode; } break; case MII_FRAME_SM::Opcode: if (this->mii_rcv_value(this->mii_opcode, 2, bit_val)) { LOG_F(9, "MII_Opcode=0x%X", this->mii_opcode); this->mii_state = MII_FRAME_SM::Phy_Address; } break; case MII_FRAME_SM::Phy_Address: if (this->mii_rcv_value(this->mii_phy_address, 5, bit_val)) { LOG_F(9, "MII_PHY_Address=0x%X", this->mii_phy_address); this->mii_state = MII_FRAME_SM::Reg_Address; } break; case MII_FRAME_SM::Reg_Address: if (this->mii_rcv_value(this->mii_reg_address, 5, bit_val)) { LOG_F(9, "MII_REG_Address=0x%X", this->mii_reg_address); if (this->mii_start != 1) LOG_F(ERROR, "%s: unsupported frame type %d", this->name.c_str(), this->mii_start); if (this->mii_phy_address) LOG_F(ERROR, "%s: unsupported PHY address %d", this->name.c_str(), this->mii_phy_address); switch (this->mii_opcode) { case 1: // write this->mii_state = MII_FRAME_SM::Turnaround; break; case 2: // read this->mii_data = this->phy_reg_read(this->mii_reg_address); this->mii_state = MII_FRAME_SM::Turnaround; break; default: LOG_F(ERROR, "%s: invalid MII opcode %d", this->name.c_str(), this->mii_opcode); } } break; case MII_FRAME_SM::Turnaround: if (this->mii_rcv_value(this->mii_turnaround, 2, bit_val)) { if (this->mii_turnaround != 2) LOG_F(ERROR, "%s: unexpected turnaround 0x%X", this->name.c_str(), this->mii_turnaround); this->mii_state = MII_FRAME_SM::Write_Data; } break; case MII_FRAME_SM::Write_Data: if (this->mii_rcv_value(this->mii_data, 16, bit_val)) { LOG_F(9, "%s: MII data received = 0x%X", this->name.c_str(), this->mii_data); this->phy_reg_write(this->mii_reg_address, this->mii_data); this->mii_state = MII_FRAME_SM::Stop; } break; case MII_FRAME_SM::Stop: if (this->mii_rcv_value(this->mii_stop, 2, bit_val)) { LOG_F(9, "MII_Stop=0x%X", this->mii_stop); this->mii_reset(); } break; default: LOG_F(ERROR, "%s: unhandled state %d in mii_xmit_bit", this->name.c_str(), this->mii_state); this->mii_reset(); } } void BigMac::mii_reset() { mii_start = 0; mii_opcode = 0; mii_phy_address = 0; mii_reg_address = 0; mii_turnaround = 0; mii_data = 0; mii_stop = 0; this->mii_bit_counter = 0; this->mii_state = MII_FRAME_SM::Preamble; } // ===================== Ethernet PHY interface emulation ===================== void BigMac::phy_reset() { // TODO: add PHY type property to be able to select another PHY (DP83843) if (this->chip_id == EthernetCellId::Paddington) { this->phy_oui = 0x1E0400; // LXT970 aka ST10040 PHY this->phy_model = 0; this->phy_rev = 0; } else { // assume Heathrow with LXT907 PHY this->phy_oui = 0; // LXT907 doesn't support MII, MDIO is pulled low this->phy_model = 0; this->phy_rev = 0; } this->phy_anar = 0xA1; // tell the world we support 10BASE-T and 100BASE-TX } uint16_t BigMac::phy_reg_read(uint8_t reg_num) { switch(reg_num) { case PHY_ID1: return (this->phy_oui >> 6) & 0xFFFFU; case PHY_ID2: return ((this->phy_oui << 10) | (phy_model << 4) | phy_rev) & 0xFFFFU; case PHY_ANAR: return this->phy_anar; default: LOG_F(ERROR, "Reading unimplemented PHY register %d", reg_num); } return 0; } void BigMac::phy_reg_write(uint8_t reg_num, uint16_t value) { switch(reg_num) { case PHY_BMCR: this->phy_bmcr = value; break; case PHY_ANAR: this->phy_anar = value; break; default: LOG_F(ERROR, "Writing unimplemented PHY register %d", reg_num); } } static const DeviceDescription BigMac_Heathrow_Descriptor = { BigMac::create_for_heathrow, {}, {} }; static const DeviceDescription BigMac_Paddington_Descriptor = { BigMac::create_for_paddington, {}, {} }; REGISTER_DEVICE(BigMacHeathrow, BigMac_Heathrow_Descriptor); REGISTER_DEVICE(BigMacPaddington, BigMac_Paddington_Descriptor);