minor add comments

this is just to better understand the flow

Change-Id: I045286836176da729cc8c863866d6f6aa3836592
This commit is contained in:
Kévin Redon
2020-03-26 01:46:45 +01:00
committed by Eric Wild
parent 9dd4dc287d
commit ae28d5a4c5

View File

@@ -1,7 +1,7 @@
/* card emulation mode
*
* (C) 2015-2017 by Harald Welte <laforge@gnumonks.org>
* (C) 2018 by sysmocom -s.f.m.c. GmbH, Author: Kevin Redon <kredon@sysmocom.de>
* (C) 2018-2019 by sysmocom -s.f.m.c. GmbH, Author: Kevin Redon <kredon@sysmocom.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
@@ -202,32 +202,33 @@ static void usart_irq_rx(uint8_t inst_num)
uint32_t csr;
uint8_t byte = 0;
csr = usart->US_CSR & usart->US_IMR;
csr = usart->US_CSR & usart->US_IMR; // save state/flags before they get changed
if (csr & US_CSR_RXRDY) {
byte = (usart->US_RHR) & 0xFF;
if (rbuf_write(&ci->rb, byte) < 0)
TRACE_ERROR("rbuf overrun\r\n");
if (csr & US_CSR_RXRDY) { // bytes has been received
byte = (usart->US_RHR) & 0xFF; // ready out byte
if (rbuf_write(&ci->rb, byte) < 0) // store byte in buffer
TRACE_ERROR("rbuf overrun\r\n"); // error if could not store in buffer
}
if (csr & US_CSR_TXRDY) {
if (card_emu_tx_byte(ci->ch) == 0)
USART_DisableIt(usart, US_IER_TXRDY);
if (csr & US_CSR_TXRDY) { // ready to transmit the next byte
if (card_emu_tx_byte(ci->ch) == 0) // transmit next byte, and check if a byte is being transmitted
USART_DisableIt(usart, US_IER_TXRDY); // stop the TX ready signal if not byte has been transmitted
}
if (csr & (US_CSR_OVRE|US_CSR_FRAME|US_CSR_PARE|
US_CSR_TIMEOUT|US_CSR_NACK|(1<<10))) {
usart->US_CR = US_CR_RSTSTA | US_CR_RSTIT | US_CR_RSTNACK;
TRACE_ERROR("%u e 0x%x st: 0x%lx\n", ci->num, byte, csr);
if (csr & (US_CSR_OVRE|US_CSR_FRAME|US_CSR_PARE|US_CSR_TIMEOUT|US_CSR_NACK|(1<<10))) { // error flag set
usart->US_CR = US_CR_RSTSTA | US_CR_RSTIT | US_CR_RSTNACK; // reset UART state to clear flag
TRACE_ERROR("%u USART error on 0x%x status: 0x%lx\n", ci->num, byte, csr); // warn user about error
}
}
/*! ISR called for USART0 */
void mode_cardemu_usart0_irq(void)
{
/* USART0 == Instance 1 == USIM 2 */
usart_irq_rx(1);
}
/*! ISR called for USART1 */
void mode_cardemu_usart1_irq(void)
{
/* USART1 == Instance 0 == USIM 1 */
@@ -419,15 +420,21 @@ void mode_cardemu_init(void)
INIT_LLIST_HEAD(&cardem_inst[0].usb_out_queue);
rbuf_reset(&cardem_inst[0].rb);
PIO_Configure(pins_usim1, PIO_LISTSIZE(pins_usim1));
/* configure USART as ISO-7816 slave (e.g. card) */
ISO7816_Init(&cardem_inst[0].usart_info, CLK_SLAVE);
NVIC_EnableIRQ(USART1_IRQn);
PIO_ConfigureIt(&pin_usim1_rst, usim1_rst_irqhandler);
PIO_EnableIt(&pin_usim1_rst);
usim1_rst_irqhandler(&pin_usim1_rst); /* obtain current RST state */
/* obtain current RST state */
usim1_rst_irqhandler(&pin_usim1_rst);
#ifndef DETECT_VCC_BY_ADC
PIO_ConfigureIt(&pin_usim1_vcc, usim1_vcc_irqhandler);
PIO_EnableIt(&pin_usim1_vcc);
usim1_vcc_irqhandler(&pin_usim1_vcc); /* obtain current VCC state */
/* obtain current VCC state */
usim1_vcc_irqhandler(&pin_usim1_vcc);
#else
do {} while (!adc_triggered); /* wait for first ADC reading */
#endif /* DETECT_VCC_BY_ADC */
@@ -442,6 +449,7 @@ void mode_cardemu_init(void)
rbuf_reset(&cardem_inst[1].rb);
PIO_Configure(pins_usim2, PIO_LISTSIZE(pins_usim2));
ISO7816_Init(&cardem_inst[1].usart_info, CLK_SLAVE);
// TODO enable timeout
NVIC_EnableIRQ(USART0_IRQn);
PIO_ConfigureIt(&pin_usim2_rst, usim2_rst_irqhandler);
PIO_EnableIt(&pin_usim2_rst);
@@ -458,6 +466,7 @@ void mode_cardemu_init(void)
SIMTRACE_CARDEM_USB_EP_USIM2_INT, cardem_inst[1].vcc_active,
cardem_inst[1].rst_active, cardem_inst[1].vcc_active);
sim_switch_use_physical(1, 1);
// TODO check rst and vcc
#endif /* CARDEMU_SECOND_UART */
}