dingusppc/devices/ethernet/bigmac.cpp

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/*
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 <https://www.gnu.org/licenses/>.
*/
/** @file BigMac Ethernet controller emulation. */
#include <devices/deviceregistry.h>
#include <devices/ethernet/bigmac.h>
#include <loguru.hpp>
BigMac::BigMac(uint8_t id) {
set_name("BigMac");
supports_types(HWCompType::MMIO_DEV | HWCompType::ETHER_MAC);
this->chip_id = id;
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this->chip_reset();
}
void BigMac::chip_reset() {
this->event_mask = 0xFFFFU; // disable HW events causing on-chip interrupts
this->stat = 0;
this->phy_reset();
this->mii_reset();
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this->srom_reset();
}
uint16_t BigMac::read(uint16_t reg_offset) {
switch (reg_offset) {
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case BigMacReg::XIFC:
return this->tx_if_ctrl;
case BigMacReg::CHIP_ID:
return this->chip_id;
case BigMacReg::MIF_CSR:
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return (this->mif_csr_old & ~Mif_Data_In) | (this->mii_in_bit << 3);
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case BigMacReg::GLOB_STAT: {
uint16_t old_stat = this->stat;
this->stat = 0; // clear-on-read
return old_stat;
}
case BigMacReg::EVENT_MASK:
return this->event_mask;
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case BigMacReg::SROM_CSR:
return (this->srom_csr_old & ~Srom_Data_In) | (this->srom_in_bit << 2);
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case BigMacReg::TX_SW_RST:
return this->tx_reset;
case BigMacReg::TX_CONFIG:
return this->tx_config;
case BigMacReg::PEAK_ATT: {
uint8_t old_val = this->peak_attempts;
this->peak_attempts = 0; // clear-on-read
return old_val;
}
case BigMacReg::NC_CNT:
return this->norm_coll_cnt;
case BigMacReg::EX_CNT:
return this->excs_coll_cnt;
case BigMacReg::LT_CNT:
return this->late_coll_cnt;
case BigMacReg::RX_CONFIG:
return this->rx_config;
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) {
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case BigMacReg::XIFC:
this->tx_if_ctrl = value;
break;
case BigMacReg::TX_FIFO_CSR:
this->tx_fifo_enable = !!(value & 1);
this->tx_fifo_size = (((value >> 1) & 0xFF) + 1) << 7;
break;
case BigMacReg::TX_FIFO_TH:
this->tx_fifo_tresh = value;
break;
case BigMacReg::RX_FIFO_CSR:
this->rx_fifo_enable = !!(value & 1);
this->rx_fifo_size = (((value >> 1) & 0xFF) + 1) << 7;
break;
case BigMacReg::MIF_CSR:
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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 {
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if (((this->mif_csr_old ^ value) & Mif_Clock) && (value & Mif_Clock))
this->mii_rcv_bit();
}
this->mif_csr_old = value;
break;
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case BigMacReg::EVENT_MASK:
this->event_mask = value;
break;
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case BigMacReg::SROM_CSR:
if (value & Srom_Chip_Select) {
// exchange data on each low-to-high transition of Srom_Clock
if (((this->srom_csr_old ^ value) & Srom_Clock) && (value & Srom_Clock))
this->srom_xmit_bit(!!(value & Srom_Data_Out));
} else {
this->srom_reset();
}
this->srom_csr_old = value;
break;
case BigMacReg::TX_SW_RST:
if (value == 1) {
LOG_F(INFO, "%s: transceiver soft reset asserted", this->name.c_str());
this->tx_reset = 0; // acknowledge SW reset
}
break;
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case BigMacReg::TX_CONFIG:
this->tx_config = value;
break;
case BigMacReg::NC_CNT:
this->norm_coll_cnt = value;
break;
case BigMacReg::NT_CNT:
this->net_coll_cnt = value;
break;
case BigMacReg::EX_CNT:
this->excs_coll_cnt = value;
break;
case BigMacReg::LT_CNT:
this->late_coll_cnt = value;
break;
case BigMacReg::RNG_SEED:
this->rng_seed = value;
break;
case BigMacReg::RX_SW_RST:
if (!value) {
LOG_F(INFO, "%s: receiver soft reset asserted", this->name.c_str());
}
break;
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case BigMacReg::RX_CONFIG:
this->rx_config = value;
break;
case BigMacReg::MAC_ADDR_0:
case BigMacReg::MAC_ADDR_1:
case BigMacReg::MAC_ADDR_2:
this->mac_addr_flt[8 - ((reg_offset >> 4) & 0xF)] = value;
break;
case BigMacReg::RX_FRM_CNT:
this->rcv_frame_cnt = value;
break;
case BigMacReg::RX_LE_CNT:
this->len_err_cnt = value;
break;
case BigMacReg::RX_AE_CNT:
this->align_err_cnt = value;
break;
case BigMacReg::RX_FE_CNT:
this->fcs_err_cnt = value;
break;
case BigMacReg::RX_CVE_CNT:
this->cv_err_cnt = value;
break;
case BigMacReg::HASH_TAB_0:
case BigMacReg::HASH_TAB_1:
case BigMacReg::HASH_TAB_2:
case BigMacReg::HASH_TAB_3:
this->hash_table[(reg_offset >> 4) & 3] = 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;
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case MII_FRAME_SM::Stop:
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() {
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// 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
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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) {
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case PHY_BMCR:
return this->phy_bmcr;
case PHY_BMSR:
return 0x7809; // value from LXT970 datasheet
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:
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if (value & 0x8000) {
LOG_F(INFO, "PHY reset requested");
value &= ~0x8000; // Reset bit is self-clearing
}
this->phy_bmcr = value;
break;
case PHY_ANAR:
this->phy_anar = value;
break;
default:
LOG_F(ERROR, "Writing unimplemented PHY register %d", reg_num);
}
}
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// ======================== MAC Serial EEPROM emulation ========================
void BigMac::srom_reset() {
this->srom_csr_old = 0;
this->srom_bit_counter = 0;
this->srom_opcode = 0;
this->srom_address = 0;
this->srom_state = Srom_Start;
}
bool BigMac::srom_rcv_value(uint16_t& var, uint8_t num_bits, uint8_t next_bit) {
var = (var << 1) | (next_bit & 1);
this->srom_bit_counter++;
if (this->srom_bit_counter >= num_bits) {
this->srom_bit_counter = 0;
return true; // all bits have been received -> return true
}
return false; // more bits expected
}
void BigMac::srom_xmit_bit(const uint8_t bit_val) {
switch(this->srom_state) {
case Srom_Start:
if (bit_val)
this->srom_state = Srom_Opcode;
else
this->srom_reset();
break;
case Srom_Opcode:
if (this->srom_rcv_value(this->srom_opcode, 2, bit_val)) {
switch(this->srom_opcode) {
case 2: // read
this->srom_state = Srom_Address;
break;
default:
LOG_F(ERROR, "%s: unsupported SROM opcode %d", this->name.c_str(),
this->srom_opcode);
this->srom_reset();
}
}
break;
case Srom_Address:
if (this->srom_rcv_value(this->srom_address, 6, bit_val)) {
LOG_F(9, "SROM address received = 0x%X", this->srom_address);
this->srom_bit_counter = 16;
this->srom_state = Srom_Read_Data;
}
break;
case Srom_Read_Data:
if (this->srom_bit_counter) {
this->srom_bit_counter--;
this->srom_in_bit = (this->srom_data[this->srom_address] >> this->srom_bit_counter) & 1;
if (!this->srom_bit_counter) {
this->srom_address++;
this->srom_bit_counter = 16;
}
}
break;
default:
LOG_F(ERROR, "%s: unhandled state %d in srom_xmit_bit", this->name.c_str(),
this->srom_state);
this->srom_reset();
}
}
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);