Hoernchen has uploaded this change for review. ( https://gerrit.osmocom.org/c/simtrace2/+/43125?usp=email )
Change subject: firmware: use the full 11 bit US_FIDI.FI_DI_RATIO ......................................................................
firmware: use the full 11 bit US_FIDI.FI_DI_RATIO
US_FIDI_FI_DI_RATIO_Msk is 0x7ff, cemu rejected >= 0x400 in emu_update_fidi() and masked with 0x3ff in card_emu_uart_update_fidi(), but update_fidi() used by the sniffer already used 0x7ff.
-> ratios 1024..2047 are unusable in cemu, which is the entire upper half of ISO 7816-3 Table 7 at Di=1.
A reader trying one of those in a PPS gets the proposal echoed and accepted, after which the card keeps transmitting at the old rate.
FI_DI_RATIO is clock periods per bit -> larger ratio is a SLOWER link. The old check rejected slow values but accepted Fi=372/Di=64, ratio 5 !?
Unify and use the register mask (= shifed by 0 so usable as value) and reject ratios that do not fit rather than truncating to garbage dividers.
Change-Id: I6211dd5be7c5c5d2150af2aa37a403b33e6d340d --- M firmware/libcommon/source/card_emu.c M firmware/libcommon/source/mode_cardemu.c M firmware/libcommon/source/simtrace_iso7816.c 3 files changed, 4 insertions(+), 4 deletions(-)
git pull ssh://gerrit.osmocom.org:29418/simtrace2 refs/changes/25/43125/1
diff --git a/firmware/libcommon/source/card_emu.c b/firmware/libcommon/source/card_emu.c index ab54fc5..e6c119a 100644 --- a/firmware/libcommon/source/card_emu.c +++ b/firmware/libcommon/source/card_emu.c @@ -376,7 +376,7 @@ int rc;
rc = iso7816_3_compute_fd_ratio(ch->F_index, ch->D_index); - if (rc > 0 && rc < 0x400) { + if (rc > 0 && rc <= US_FIDI_FI_DI_RATIO_Msk) { TRACE_INFO("%u: computed F(%u)/D(%u) ratio: %d\r\n", ch->num, ch->F_index, ch->D_index, rc); /* make sure UART uses new F/D ratio */ diff --git a/firmware/libcommon/source/mode_cardemu.c b/firmware/libcommon/source/mode_cardemu.c index a5485e4..77f7454 100644 --- a/firmware/libcommon/source/mode_cardemu.c +++ b/firmware/libcommon/source/mode_cardemu.c @@ -387,7 +387,7 @@ Usart *usart = get_usart_by_chan(uart_chan);
usart->US_CR |= US_CR_RXDIS | US_CR_RSTRX; - usart->US_FIDI = fidi & 0x3ff; + usart->US_FIDI = fidi & US_FIDI_FI_DI_RATIO_Msk; usart->US_CR |= US_CR_RXEN | US_CR_STTTO; return 0; } diff --git a/firmware/libcommon/source/simtrace_iso7816.c b/firmware/libcommon/source/simtrace_iso7816.c index 27677a6..a2446a3 100644 --- a/firmware/libcommon/source/simtrace_iso7816.c +++ b/firmware/libcommon/source/simtrace_iso7816.c @@ -127,14 +127,14 @@ uint8_t di = fidi & 0xf; int ratio = iso7816_3_compute_fd_ratio(fi, di);
- if (ratio > 0 && ratio < 0x8000) { + if (ratio > 0 && ratio <= US_FIDI_FI_DI_RATIO_Msk) { /* make sure USART uses new F/D ratio */ usart->base->US_CR |= US_CR_RXDIS | US_CR_RSTRX; /* disable write protection */ if (usart->base->US_WPMR) { usart->base->US_WPMR = US_WPMR_WPKEY(0x555341); } - usart->base->US_FIDI = (ratio & 0x7ff); + usart->base->US_FIDI = (ratio & US_FIDI_FI_DI_RATIO_Msk); usart->base->US_CR |= US_CR_RXEN | US_CR_STTTO; //TRACE_INFO("updated USART(%u) Fi(%u)/Di(%u) ratio(%d): %u\n\r", usart->id, fi, di, ratio, usart->base->US_FIDI); } else {
-
Hoernchen