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rtl8169: AT93C56 EEPROM emulation
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- FreeBSD drivers read MAC address from EEPROM for whatever reason
- On RTL8169, EEPROM is accessed via bit-banging it's pins via MMIO register 0x50
- Either AT93C46 or AT93C56 can be present, the difference is addr length (6 vs 8 bits); FreeBSD driver distinguishes by determining which way reads Device ID (0x8129) successfully
- Also allow partial reads of MMIO registers, some drivers do this
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@LekKit
LekKit authored Feb 25, 2024
1 parent 974c4ea commit 60c5dae
Showing 1 changed file with 95 additions and 14 deletions.
109 changes: 95 additions & 14 deletions src/devices/rtl8169.c
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Original file line number Diff line number Diff line change
Expand Up @@ -91,6 +91,12 @@ along with this program. If not, see <https://www.gnu.org/licenses/>.
#define RTL8169_DESC_PAM 0x04000000
#define RTL8169_DESC_GRX 0x34000000 // Generic RX packet flags

#define RTL8169_EEPROM_DOU 0x01 // EEPROM Data out
#define RTL8169_EEPROM_DIN 0x02 // EEPROM Data in
#define RTL8169_EEPROM_CLK 0x04 // EEPROM Clock
#define RTL8169_EEPROM_SEL 0x08 // EEPROM Chip select
#define RTL8169_EEMODE_PRG 0x80 // EEPROM Programming mode

#define RTL8169_MAX_FIFO_SIZE 1024
#define RTL8169_MAC_SIZE 6

Expand All @@ -99,9 +105,19 @@ typedef struct {
uint32_t index;
} rtl8169_ring_t;

// 93C56 16-bit word EEPROM emulation for reading MAC
typedef struct {
uint8_t pins;
uint8_t addr;
uint16_t word;
bitcnt_t cur_bit;
bool addr_ok;
} at93c56_state_t;

typedef struct {
pci_dev_t* pci_dev;
tap_dev_t* tap;
at93c56_state_t eeprom;
rtl8169_ring_t rx;
rtl8169_ring_t tx;
rtl8169_ring_t txp;
Expand All @@ -117,12 +133,14 @@ typedef struct {
static void rtl8169_reset(rvvm_mmio_dev_t* dev)
{
rtl8169_dev_t* rtl8169 = dev->data;
memset(&rtl8169->eeprom, 0, sizeof(at93c56_state_t));
memset(&rtl8169->rx, 0, sizeof(rtl8169_ring_t));
memset(&rtl8169->tx, 0, sizeof(rtl8169_ring_t));
memset(&rtl8169->txp, 0, sizeof(rtl8169_ring_t));
rtl8169->isr = 0;
rtl8169->imr = 0;
rtl8169->cr = 0;
rtl8169->phyar = 0;
}

static void rtl8169_interrupt(rtl8169_dev_t* rtl8169, size_t irq)
Expand Down Expand Up @@ -164,6 +182,64 @@ static uint32_t rtl8169_handle_phy(uint32_t cmd)
return cmd ^ 0x80000000;
}

static void rtl8169_93c56_read_word(rtl8169_dev_t* rtl8169)
{
rtl8169->eeprom.word = 0;
switch (rtl8169->eeprom.addr) {
case 0x0: // Device ID
rtl8169->eeprom.word = 0x8129;
break;
case 0x7: // MAC words
case 0x8:
case 0x9:
tap_get_mac(rtl8169->tap, rtl8169->mac);
rtl8169->eeprom.word = read_uint16_le_m(rtl8169->mac + ((rtl8169->eeprom.addr - 7) << 1));
break;
default: // Unknown
rtl8169->eeprom.word = 0;
break;
}
}

static void rtl8169_93c56_pins_write(rtl8169_dev_t* rtl8169, uint8_t pins)
{
if (pins & RTL8169_EEMODE_PRG) {
if ((pins & RTL8169_EEPROM_CLK) && !(rtl8169->eeprom.pins & RTL8169_EEPROM_CLK)) {
// Clock pulled high
if (rtl8169->eeprom.addr_ok) {
// Push data bits
if (rtl8169->eeprom.cur_bit == 0) rtl8169_93c56_read_word(rtl8169);
if (rtl8169->eeprom.word & (0x8000 >> rtl8169->eeprom.cur_bit)) {
pins |= RTL8169_EEPROM_DOU;
} else {
pins &= ~RTL8169_EEPROM_DOU;
}
if (rtl8169->eeprom.cur_bit++ >= 15) {
rtl8169->eeprom.cur_bit = 0;
rtl8169->eeprom.addr++;
}
} else {
// Get starting addr, ignore command (Act as readonly eeprom)
if (rtl8169->eeprom.cur_bit >= 3) {
rtl8169->eeprom.addr <<= 1;
if (pins & RTL8169_EEPROM_DIN) rtl8169->eeprom.addr |= 1;
}
if (rtl8169->eeprom.cur_bit++ >= 11) {
rtl8169->eeprom.cur_bit = 0;
rtl8169->eeprom.addr_ok = true;
}
}
}
if (!(pins & RTL8169_EEPROM_SEL)) {
// End of transfer, request addr next time
rtl8169->eeprom.addr_ok = false;
rtl8169->eeprom.addr = 0;
rtl8169->eeprom.cur_bit = 0;
}
}
rtl8169->eeprom.pins = pins;
}

static bool rtl8169_feed_rx(void* net_dev, const void* data, size_t size)
{
rtl8169_dev_t* rtl8169 = net_dev;
Expand Down Expand Up @@ -245,24 +321,28 @@ static bool rtl8169_pci_read(rvvm_mmio_dev_t* dev, void* data, size_t offset, ui
rtl8169_dev_t* rtl8169 = dev->data;
uint8_t tmp[4] = {0};
spin_lock(&rtl8169->lock);
if (offset < RTL8169_MAC_SIZE) {
size_t size_clamp = (offset + size > RTL8169_MAC_SIZE)
? (RTL8169_MAC_SIZE - offset) : size;
tap_get_mac(rtl8169->tap, rtl8169->mac);
memcpy(tmp, rtl8169->mac + offset, size_clamp);
} else switch (offset) {
case RTL8169_REG_ISR:
write_uint16_le(tmp, atomic_load_uint32(&rtl8169->isr));
switch (offset & (~0x3)) {
case RTL8169_REG_IDR0:
tap_get_mac(rtl8169->tap, rtl8169->mac);
memcpy(tmp, rtl8169->mac, 4);
break;
case RTL8169_REG_IDR4:
tap_get_mac(rtl8169->tap, rtl8169->mac);
memcpy(tmp, rtl8169->mac + 4, 2);
break;
case RTL8169_REG_IMR:
write_uint16_le(tmp, atomic_load_uint32(&rtl8169->imr));
write_uint16_le(tmp + 2, atomic_load_uint32(&rtl8169->isr));
break;
case RTL8169_REG_CR:
write_uint8(tmp, atomic_load_uint32(&rtl8169->cr));
case RTL8169_REG_CR - 3:
write_uint8(tmp + 3, atomic_load_uint32(&rtl8169->cr));
break;
case RTL8169_REG_TCR:
write_uint32_le(tmp, 0x3810700); // RTL8169S XID
break;
case RTL8169_REG_9346:
tmp[0] = rtl8169->eeprom.pins;
break;
case RTL8169_REG_PHYAR:
write_uint32_le(tmp, rtl8169->phyar);
break;
Expand Down Expand Up @@ -295,17 +375,17 @@ static bool rtl8169_pci_read(rvvm_mmio_dev_t* dev, void* data, size_t offset, ui
break;
}
spin_unlock(&rtl8169->lock);
memcpy(data, tmp, size);
//rvvm_warn("rtl8169 read %08x from %08zx", read_uint32_le(data), offset);
memcpy(data, tmp + (offset & 0x3), size);
//rvvm_warn("rtl8169 read %08x from %08zx", read_uint32_le(tmp), offset & (~0x3));
return true;
}

static bool rtl8169_pci_write(rvvm_mmio_dev_t* dev, void* data, size_t offset, uint8_t size)
{
rtl8169_dev_t* rtl8169 = dev->data;
UNUSED(size);
//rvvm_warn("rtl8169 write %08x to %08zx", read_uint32_le(data), offset);
spin_lock(&rtl8169->lock);
// I don't even know how to refactor this...
if (offset == RTL8169_REG_TPOLL) {
uint8_t flags = read_uint8(data);
if (flags & RTL8169_TPOLL_HPQ) rtl8169_handle_tx(rtl8169, &rtl8169->txp);
Expand All @@ -319,7 +399,8 @@ static bool rtl8169_pci_write(rvvm_mmio_dev_t* dev, void* data, size_t offset, u
? (RTL8169_MAC_SIZE - offset) : size;
memcpy(rtl8169->mac + offset, data, size_clamp);
tap_set_mac(rtl8169->tap, rtl8169->mac);
}
} else if (offset == RTL8169_REG_9346) rtl8169_93c56_pins_write(rtl8169, read_uint8(data));

if (size >= 2) {
switch (offset) {
case RTL8169_REG_IMR:
Expand Down

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