diff options
author | Kévin Redon <kredon@sysmocom.de> | 2020-03-26 01:46:45 +0100 |
---|---|---|
committer | Eric Wild <ewild@sysmocom.de> | 2020-04-10 02:08:59 +0200 |
commit | ae28d5a4c5fe3ab26eba09b1f861c0b67803200b (patch) | |
tree | 3b7ddde67a932ccce27a9af17977c67c231fb5ed | |
parent | 9dd4dc287d1f937da0094bd2dd5e4b19091f57fe (diff) |
minor add comments
this is just to better understand the flow
Change-Id: I045286836176da729cc8c863866d6f6aa3836592
-rw-r--r-- | firmware/libcommon/source/mode_cardemu.c | 39 |
1 files changed, 24 insertions, 15 deletions
diff --git a/firmware/libcommon/source/mode_cardemu.c b/firmware/libcommon/source/mode_cardemu.c index 6a8d98f..7a37317 100644 --- a/firmware/libcommon/source/mode_cardemu.c +++ b/firmware/libcommon/source/mode_cardemu.c @@ -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 */ } |