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hw/ssi/esp32_spi: fix RX bounds check and add dummy cycle handling (QEMU-282) #144

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hw/ssi/esp32_spi: fix RX bounds check and add dummy cycle handling (QEMU-282) #144

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23e56be
hw/ssi/esp32_spi: fix RX bounds check and add dummy cycle handling
Ahmad-myenergi Feb 28, 2026
cb39a40
Align implementation with esp32c2_spic and esp32s3_spi files
Ahmad-myenergi Feb 28, 2026
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30 changes: 28 additions & 2 deletions hw/ssi/esp32_spi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -146,6 +146,7 @@ typedef struct Esp32SpiTransaction {
uint32_t cmd;
int addr_bytes;
uint32_t addr;
int dummy_bytes;
int data_tx_bytes;
int data_rx_bytes;
uint32_t* data;
Expand All @@ -157,11 +158,11 @@ static void esp32_spi_txrx_buffer(Esp32SpiState *s, void *buf, int tx_bytes, int
uint8_t *c_buf = (uint8_t*) buf;
for (int i = 0; i < bytes; ++i) {
uint8_t byte = 0;
if (byte < tx_bytes) {
if (i < tx_bytes) {
memcpy(&byte, c_buf + i, 1);
}
uint32_t res = ssi_transfer(s->spi, byte);
if (byte < rx_bytes) {
if (i < rx_bytes) {
memcpy(c_buf + i, &res, 1);
}
}
Expand All @@ -174,11 +175,19 @@ static void esp32_spi_cs_set(Esp32SpiState *s, int value)
}
}

static void esp32_spi_dummy_cycles(Esp32SpiState *s, int dummy_bytes)
{
for (int i = 0; i < dummy_bytes; i++) {
ssi_transfer(s->spi, 0);
}
}

static void esp32_spi_transaction(Esp32SpiState *s, Esp32SpiTransaction *t)
{
esp32_spi_cs_set(s, 0);
esp32_spi_txrx_buffer(s, &t->cmd, t->cmd_bytes, 0);
esp32_spi_txrx_buffer(s, &t->addr, t->addr_bytes, 0);
esp32_spi_dummy_cycles(s, t->dummy_bytes);
esp32_spi_txrx_buffer(s, t->data, t->data_tx_bytes, t->data_rx_bytes);
esp32_spi_cs_set(s, 1);
}
Expand Down Expand Up @@ -285,6 +294,23 @@ static void esp32_spi_do_command(Esp32SpiState* s, uint32_t cmd_reg)
t.addr_bytes = bitlen_to_bytes(FIELD_EX32(s->user1_reg, SPI_USER1, ADDR_BITLEN));
t.addr = bswap32(s->addr_reg);
}
/* Inject 1 dummy byte for SPI flash fast-read commands when DUMMY
* phase is enabled. The m25p80 flash model expects this byte
* between address and data for DOR/QOR/FastRead etc.
* PSRAM commands handle dummy internally - don't inject for them. */
if (FIELD_EX32(s->user_reg, SPI_USER, DUMMY)) {
switch (FIELD_EX32(s->user2_reg, SPI_USER2, COMMAND_VALUE)) {
case 0x0b: case 0x0c: /* Fast Read / Fast Read 4B */
case 0x3b: case 0x3c: /* DOR / DOR 4B */
case 0x6b: case 0x6c: /* QOR / QOR 4B */
case 0xbb: case 0xbc: /* DIOR / DIOR 4B */
case 0xeb: case 0xec: /* QIOR / QIOR 4B */
t.dummy_bytes = 1;
break;
default:
break;
}
}
if (FIELD_EX32(s->user_reg, SPI_USER, MOSI)) {
t.data = &s->data_reg[0];
t.data_tx_bytes = bitlen_to_bytes(s->mosi_dlen_reg);
Expand Down
4 changes: 2 additions & 2 deletions hw/ssi/esp32c3_spi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -127,11 +127,11 @@ static void esp32c3_spi_txrx_buffer(ESP32C3SpiState *s,
int bytes = MAX(tx_bytes, rx_bytes);
for (int i = 0; i < bytes; ++i) {
uint8_t byte = 0;
if (byte < tx_bytes) {
if (i < tx_bytes) {
memcpy(&byte, tx + i, 1);
}
uint32_t res = ssi_transfer(s->spi, byte);
if (byte < rx_bytes) {
if (i < rx_bytes) {
memcpy(rx + i, &res, 1);
}
}
Expand Down
4 changes: 2 additions & 2 deletions hw/ssi/esp32s3_spi.c
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Original file line number Diff line number Diff line change
Expand Up @@ -142,11 +142,11 @@ static void esp32s3_spi_txrx_buffer(ESP32S3SpiState *s,
int bytes = MAX(tx_bytes, rx_bytes);
for (int i = 0; i < bytes; ++i) {
uint8_t byte = 0;
if (byte < tx_bytes) {
if (i < tx_bytes) {
memcpy(&byte, tx + i, 1);
}
uint32_t res = ssi_transfer(s->spi, byte);
if (byte < rx_bytes) {
if (i < rx_bytes) {
memcpy(rx + i, &res, 1);
}
}
Expand Down