card_emu: Use USART timeout for waiting time

Instead of using the timer/counter peripheral to handle the waiting time
and corresponding timeout, the USART peripheral internal timeout
mechanism is used.

This is particularly important for the SIMtrace board since there
(contrary to other boards) the I/O signal is not wired to a TIO pin
of the timer/counter block, and hence Rx/Tx data cannot reset that
timer/counter.

As a result of this migration, cardem is now supported not only on
owhw + qmod, but also on the simtrace board.

The guts of this change have been lifted out of Change-Id
Ibcb2c8cace9137695adf5fb3de43566f7cfb93b5 by Kevin Redon, which was
unfortunately touching various different topics at the same time and
hence was split up. Some improvements are the introduction of the
ENABLE_TX_TIMER_ONLY mode, which avoids the USART interrupt handler
getting hammered with TXRDY between release of RST and start of the ATR.

Change-Id: Ibcb2c8cace9137695adf5fb3de43566f7cfb93b5
Related: OS#1704

1 files changed, 29 insertions, 19 deletions

diff --git a/firmware/libcommon/source/card_emu.c b/firmware/libcommon/source/card_emu.c
index 0ba6eb0..cefc957 100644
--- a/firmware/libcommon/source/card_emu.c
+++ b/firmware/libcommon/source/card_emu.c
@@ -27,7 +27,6 @@
 #include "utils.h"
 #include "trace.h"
 #include "iso7816_fidi.h"
-#include "tc_etu.h"
 #include "card_emu.h"
 #include "simtrace_prot.h"
 #include "usb_buf.h"
@@ -177,7 +176,6 @@ struct card_handle {
 	 *  \note this depends on Fi, Di, and WI if T=0 is used */
 	uint32_t waiting_time;	/* in etu */
 
-	uint8_t tc_chan;	/* TC channel number */
 	uint8_t uart_chan;	/* UART channel */
 
 	uint8_t in_ep;		/* USB IN EP */
@@ -222,7 +220,7 @@ static void card_handle_reset(struct card_handle *ch)
 {
 	struct msgb *msg;
 
-	tc_etu_disable(ch->tc_chan);
+	card_emu_uart_update_wt(ch->uart_chan, 0);
 
 	/* release any buffers we may still own */
 	if (ch->uart_tx_msg) {
@@ -383,8 +381,6 @@ static void emu_update_fidi(struct card_handle *ch)
 			   ch->F_index, ch->D_index, rc);
 		/* make sure UART uses new F/D ratio */
 		card_emu_uart_update_fidi(ch->uart_chan, rc);
-		/* notify ETU timer about this */
-		tc_etu_set_etu(ch->tc_chan, rc);
 	} else
 		TRACE_INFO("%u: computed F/D ratio %d unsupported\r\n",
 			   ch->num, rc);
@@ -408,6 +404,8 @@ static void card_set_state(struct card_handle *ch,
 	case ISO_S_WAIT_RST:
 		/* disable Rx and Tx of UART */
 		card_emu_uart_enable(ch->uart_chan, 0);
+		/* disable timeout */
+		card_emu_uart_update_wt(ch->uart_chan, 0);
 		break;
 	case ISO_S_WAIT_ATR:
 		/* Reset to initial Fi / Di ratio */
@@ -416,13 +414,13 @@ static void card_set_state(struct card_handle *ch,
 		ch->wi = ISO7816_3_DEFAULT_WI;
 		ch->waiting_time = ISO7816_3_INIT_WTIME;
 		emu_update_fidi(ch);
+		/* enable TX to be able to use the timeout */
+		card_emu_uart_enable(ch->uart_chan, ENABLE_TX_TIMER_ONLY);
 		/* the ATR should only be sent 400 to 40k clock cycles after the RESET.
-		 * we use the tc_etu mechanism to wait this time.
+		 * we use the UART timeout mechanism to wait this time.
 		 * since the initial ETU is Fd=372/Dd=1 clock cycles long, we have to wait 2-107 ETU.
 		 */
-		tc_etu_set_wtime(ch->tc_chan, 2);
-		/* enable the TC/ETU counter once reset has been released */
-		tc_etu_enable(ch->tc_chan);
+		card_emu_uart_update_wt(ch->uart_chan, 2);
 		break;
 	case ISO_S_IN_ATR:
 		/* initialize to default WI, this will be overwritten if we
@@ -432,7 +430,7 @@ static void card_set_state(struct card_handle *ch,
 		/* update waiting time to initial waiting time */
 		ch->waiting_time = ISO7816_3_INIT_WTIME;
 		/* set initial waiting time */
-		tc_etu_set_wtime(ch->tc_chan, ch->waiting_time);
+		card_emu_uart_update_wt(ch->uart_chan, ch->waiting_time);
 		/* Set ATR sub-state to initial state */
 		ch->atr.idx = 0;
 		/* enable USART transmission to reader */
@@ -509,7 +507,6 @@ static int tx_byte_atr(struct card_handle *ch)
 		}
 		/* update waiting time (see ISO 7816-3 10.2) */
 		ch->waiting_time = ch->wi * 960 * iso7816_3_fi_table[ch->F_index];
-		tc_etu_set_wtime(ch->tc_chan, ch->waiting_time);
 		/* go to next state */
 		card_set_state(ch, ISO_S_WAIT_TPDU);
 		return 0;
@@ -677,6 +674,7 @@ static int tx_byte_pts(struct card_handle *ch)
 		emu_update_fidi(ch);
 		/* Wait for the next TPDU */
 		card_set_state(ch, ISO_S_WAIT_TPDU);
+		set_pts_state(ch, PTS_S_WAIT_REQ_PTSS);
 		break;
 	default:
 		/* calculate the next state and set it */
@@ -752,14 +750,28 @@ static void set_tpdu_state(struct card_handle *ch, enum tpdu_state new_ts)
 
 	switch (new_ts) {
 	case TPDU_S_WAIT_CLA:
+		/* switch back to receiving mode */
+		card_emu_uart_enable(ch->uart_chan, ENABLE_RX);
+		/* disable waiting time since we don't expect any data */
+		card_emu_uart_update_wt(ch->uart_chan, 0);
+		break;
+	case TPDU_S_WAIT_INS:
+		/* start waiting for the rest of the header/body */
+		card_emu_uart_update_wt(ch->uart_chan, ch->waiting_time);
+		break;
 	case TPDU_S_WAIT_RX:
+		/* switch to receive mode to receive the body */
 		card_emu_uart_enable(ch->uart_chan, ENABLE_RX);
+		/* start waiting for the body */
+		card_emu_uart_update_wt(ch->uart_chan, ch->waiting_time);
 		break;
 	case TPDU_S_WAIT_PB:
 		/* we just completed the TPDU header from reader to card
 		 * and now need to disable the receiver, enable the
 		 * transmitter and transmit the procedure byte */
 		card_emu_uart_enable(ch->uart_chan, ENABLE_TX);
+		/* prepare to extend the waiting time once half of it is reached */
+		card_emu_uart_update_wt(ch->uart_chan, ch->waiting_time);
 		break;
 	default:
 		break;
@@ -1103,8 +1115,6 @@ void card_emu_io_statechg(struct card_handle *ch, enum card_io io, int active)
 		if (active == 0 && ch->in_reset) {
 			TRACE_INFO("%u: RST released\r\n", ch->num);
 			if (ch->vcc_active && ch->clocked && ch->state == ISO_S_WAIT_RST) {
-				/* enable the TC/ETU counter once reset has been released */
-				tc_etu_enable(ch->tc_chan);
 				/* prepare to send the ATR */
 				card_set_state(ch, ISO_S_WAIT_ATR);
 			}
@@ -1163,7 +1173,7 @@ int card_emu_set_atr(struct card_handle *ch, const uint8_t *atr, uint8_t len)
 }
 
 /* hardware driver informs us that one (more) ETU has expired */
-void tc_etu_wtime_half_expired(void *handle)
+void card_emu_wtime_half_expired(void *handle)
 {
 	struct card_handle *ch = handle;
 	/* transmit NULL procedure byte well before waiting time expires */
@@ -1173,7 +1183,10 @@ void tc_etu_wtime_half_expired(void *handle)
 		case TPDU_S_WAIT_PB:
 		case TPDU_S_WAIT_TX:
 			putchar('N');
+			/* we are waiting for data from the user. Send a procedure byte to ask the
+			 * reader to wait more time */
 			card_emu_uart_tx(ch->uart_chan, ISO7816_3_PB_NULL);
+			card_emu_uart_reset_wt(ch->uart_chan);
 			break;
 		default:
 			break;
@@ -1185,7 +1198,7 @@ void tc_etu_wtime_half_expired(void *handle)
 }
 
 /* hardware driver informs us that one (more) ETU has expired */
-void tc_etu_wtime_expired(void *handle)
+void card_emu_wtime_expired(void *handle)
 {
 	struct card_handle *ch = handle;
 	switch (ch->state) {
@@ -1231,7 +1244,7 @@ int card_emu_set_config(struct card_handle *ch, const struct cardemu_usb_msg_con
 	return 0;
 }
 
-struct card_handle *card_emu_init(uint8_t slot_num, uint8_t tc_chan, uint8_t uart_chan, uint8_t in_ep, uint8_t irq_ep, bool vcc_active, bool in_reset, bool clocked)
+struct card_handle *card_emu_init(uint8_t slot_num, uint8_t uart_chan, uint8_t in_ep, uint8_t irq_ep, bool vcc_active, bool in_reset, bool clocked)
 {
 	struct card_handle *ch;
 
@@ -1256,7 +1269,6 @@ struct card_handle *card_emu_init(uint8_t slot_num, uint8_t tc_chan, uint8_t uar
 	ch->Di_index = ch->D_index = 1;
 	ch->wi = ISO7816_3_DEFAULT_WI;
 
-	ch->tc_chan = tc_chan;
 	ch->uart_chan = uart_chan;
 	ch->waiting_time = ISO7816_3_INIT_WTIME;
 
@@ -1269,7 +1281,5 @@ struct card_handle *card_emu_init(uint8_t slot_num, uint8_t tc_chan, uint8_t uar
 
 	card_handle_reset(ch);
 
-	tc_etu_init(ch->tc_chan, ch);
-
 	return ch;
 }