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ot_spi_device: discard all packets for a failed transaction #263

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Merged
merged 2 commits into from
Oct 30, 2025
Merged

ot_spi_device: discard all packets for a failed transaction #263

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e60b225
[ot] hw/opentitan: spi_device: correctly adjust for discarded bytes
jwnrt Oct 28, 2025
8a9f6c3
[ot] hw/opentitan: spi_device: discard all packets in failed transaction
jwnrt Oct 28, 2025
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13 changes: 12 additions & 1 deletion hw/opentitan/ot_spi_device.c
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Original file line number Diff line number Diff line change
Expand Up @@ -458,6 +458,7 @@ typedef struct {
Fifo8 chr_fifo; /* QEMU protocol input FIFO */
uint8_t mode; /* Polarity/phase mismatch */
bool release; /* Whether to release /CS on last byte */
bool failed_transaction; /* Whether to discard until /CS is deasserted */
bool rev_rx; /* Reverse RX bits */
bool rev_tx; /* Reverse TX bits */
} SpiDeviceBus;
Expand Down Expand Up @@ -876,6 +877,7 @@ static void ot_spi_device_release(OtSPIDeviceState *s)

BUS_CHANGE_STATE(s, IDLE);
bus->byte_count = 0u;
bus->failed_transaction = false;

bool update_irq = false;
switch (ot_spi_device_get_mode(s)) {
Expand Down Expand Up @@ -2028,6 +2030,12 @@ static void ot_spi_device_chr_handle_header(OtSPIDeviceState *s)
return;
}

/* discard the packet if we're within a failed transaction */
if (bus->failed_transaction) {
BUS_CHANGE_STATE(s, DISCARD);
return;
}

/* @todo: Check that the tpm chip-select was assigned.*/
if (ot_spi_device_is_tpm_enabled(s)) {
ot_spi_device_tpm_init_buffers(s);
Expand Down Expand Up @@ -2064,6 +2072,7 @@ static void ot_spi_device_chr_recv_discard(OtSPIDeviceState *s,
(void)buf;

ot_spi_device_chr_send_discard(s, size);
s->bus.byte_count -= size;
}

static void ot_spi_device_chr_recv_flash(OtSPIDeviceState *s,
Expand Down Expand Up @@ -2291,13 +2300,15 @@ static void ot_spi_device_chr_receive(void *opaque, const uint8_t *buf,
case SPI_BUS_DISCARD:
case SPI_BUS_ERROR:
ot_spi_device_chr_recv_discard(s, buf, (unsigned)size);
/* we need to discard the other packets in this transaction */
bus->failed_transaction = true;
break;
default:
g_assert_not_reached();
break;
}

if (!bus->byte_count) {
if (!bus->byte_count && bus->state != SPI_BUS_ERROR) {
if (bus->release) {
ot_spi_device_release(s);
} else {
Expand Down
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