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feat(core): Retry getting Optiga response even when it doesn't seem to have one.

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This commit is contained in:
Andrew Kozlik 2024-04-30 10:35:27 +02:00 committed by Andrew Kozlik
parent 62e3a414ad
commit 594d7425cd
1 changed files with 14 additions and 3 deletions
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17
core/embed/trezorhal/optiga/optiga_transport.c
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@ -68,6 +68,10 @@ static const int I2C_MAX_RETRY_COUNT = 10;
// Maximum number of times to retry reading Optiga's response to a command.
static const int MAX_RETRY_READ = 10000;
// Maximum number of times to retry reading Optiga's response to a command when
// it claims it's not busy executing a command.
static const int MAX_RETRY_READ_NOT_BUSY = 10;
// Maximum number of packets per response. Used for flushing old reponses.
static const int MAX_RESPONSE_PACKET_COUNT = 15;
@ -371,6 +375,10 @@ optiga_result optiga_set_data_reg_len(size_t size) {
}
static optiga_result optiga_read(void) {
// The number of times we tried reading Optiga's response to a command while
// it claimed it's not busy executing a command.
int not_busy_count = 0;
for (int i = 0; i < MAX_RETRY_READ; ++i) {
optiga_result ret = optiga_i2c_write(&REG_I2C_STATE, 1);
if (OPTIGA_SUCCESS != ret) {
@ -410,9 +418,12 @@ static optiga_result optiga_read(void) {
if ((frame_buffer[0] & I2C_STATE_BYTE1_BUSY) == 0) {
// Optiga has no response ready and is not busy. This shouldn't happen if
// we are expecting to read a response, but Optiga occasionally fails to
// give any response to a command.
return OPTIGA_ERR_UNEXPECTED;
// we are expecting to read a response. However, we have observed that if
// we retry reading, then Optiga may return a response.
if (not_busy_count >= MAX_RETRY_READ_NOT_BUSY) {
return OPTIGA_ERR_UNEXPECTED;
}
not_busy_count += 1;
}
}