diff options
Diffstat (limited to 'src')
| -rw-r--r-- | src/jtag/drivers/kitprog.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/src/jtag/drivers/kitprog.c b/src/jtag/drivers/kitprog.c index db5b62e2..522eb17b 100644 --- a/src/jtag/drivers/kitprog.c +++ b/src/jtag/drivers/kitprog.c @@ -741,12 +741,22 @@ static int kitprog_swd_run_queue(void) break; } - /* We use the maximum buffer size here because the KitProg sometimes - * doesn't like bulk reads of fewer than 62 bytes. (?!?!) + /* KitProg firmware does not send a zero length packet + * after the bulk-in transmission of a length divisible by bulk packet + * size (64 bytes) as required by the USB specification. + * Therefore libusb would wait for continuation of transmission. + * Workaround: Limit bulk read size to expected number of bytes + * for problematic tranfer sizes. Otherwise use the maximum buffer + * size here because the KitProg sometimes doesn't like bulk reads + * of fewer than 62 bytes. (?!?!) */ + size_t read_count_workaround = SWD_MAX_BUFFER_LENGTH; + if (read_count % 64 == 0) + read_count_workaround = read_count; + ret = jtag_libusb_bulk_read(kitprog_handle->usb_handle, BULK_EP_IN | LIBUSB_ENDPOINT_IN, (char *)buffer, - SWD_MAX_BUFFER_LENGTH, 0); + read_count_workaround, 1000); if (ret > 0) { /* Handle garbage data by offsetting the initial read index */ if ((unsigned int)ret > read_count) |