circuitpython/atmel-samd/mphalport.c

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#include <string.h>
#include "compiler.h"
#include "asf/common/services/sleepmgr/sleepmgr.h"
#include "asf/common/services/usb/class/cdc/device/udi_cdc.h"
#include "asf/common2/services/delay/delay.h"
#include "asf/sam0/drivers/port/port.h"
#include "asf/sam0/drivers/sercom/usart/usart.h"
#include "py/mphal.h"
#include "py/mpstate.h"
#include "mpconfigboard.h"
#include "mphalport.h"
// Store received characters on our own so that we can filter control characters
// and act immediately on CTRL-C for example.
// This is adapted from asf/thirdparty/wireless/addons/sio2host
// Receive buffer
static uint8_t usb_rx_buf[USB_RX_BUF_SIZE];
// Receive buffer head
static volatile uint8_t usb_rx_buf_head;
// Receive buffer tail
static volatile uint8_t usb_rx_buf_tail;
// Number of bytes in receive buffer
static volatile uint8_t usb_rx_count;
static volatile bool mp_cdc_enabled = false;
void mp_keyboard_interrupt(void);
int interrupt_char;
extern struct usart_module usart_instance;
static volatile bool mp_msc_enabled = false;
bool mp_msc_enable()
{
mp_msc_enabled = true;
return true;
}
void mp_msc_disable()
{
mp_msc_enabled = false;
}
bool mp_cdc_enable(uint8_t port)
{
mp_cdc_enabled = true;
return true;
}
void mp_cdc_disable(uint8_t port)
{
mp_cdc_enabled = false;
}
void usb_rx_notify(void)
{
irqflags_t flags;
if (mp_cdc_enabled) {
while (udi_cdc_is_rx_ready()) {
uint8_t c;
// Introduce a critical section to avoid buffer corruption. We use
// cpu_irq_save instead of cpu_irq_disable because we don't know the
// current state of IRQs. They may have been turned off already and
// we don't want to accidentally turn them back on.
flags = cpu_irq_save();
// If our buffer is full, then don't get another character otherwise
// we'll lose a previous character.
if (usb_rx_count >= USB_RX_BUF_SIZE) {
cpu_irq_restore(flags);
break;
}
uint8_t current_tail = usb_rx_buf_tail;
// Pretend we've received a character so that any nested calls to
// this function have to consider the spot we've reserved.
if ((USB_RX_BUF_SIZE - 1) == usb_rx_buf_tail) {
// Reached the end of buffer, revert back to beginning of
// buffer.
usb_rx_buf_tail = 0x00;
} else {
usb_rx_buf_tail++;
}
// The count of characters present in receive buffer is
// incremented.
usb_rx_count++;
// WARNING(tannewt): This call can call us back with the next
// character!
c = udi_cdc_getc();
if (c == interrupt_char) {
// We consumed a character rather than adding it to the rx
// buffer so undo the modifications we made to count and the
// tail.
usb_rx_count--;
usb_rx_buf_tail = current_tail;
cpu_irq_restore(flags);
mp_keyboard_interrupt();
// Don't put the interrupt into the buffer, just continue.
continue;
}
// We put the next character where we expected regardless of whether
// the next character was already loaded in the buffer.
usb_rx_buf[current_tail] = c;
cpu_irq_restore(flags);
}
}
}
int receive_usb() {
if (usb_rx_count == 0) {
return 0;
}
// Copy from head.
cpu_irq_disable();
int data = usb_rx_buf[usb_rx_buf_head];
usb_rx_buf_head++;
usb_rx_count--;
if ((USB_RX_BUF_SIZE) == usb_rx_buf_head) {
usb_rx_buf_head = 0;
}
cpu_irq_enable();
// Call usb_rx_notify if we just emptied a spot in the buffer.
if (usb_rx_count == USB_RX_BUF_SIZE - 1) {
usb_rx_notify();
}
return data;
}
int mp_hal_stdin_rx_chr(void) {
for (;;) {
// Process any mass storage transfers.
if (mp_msc_enabled) {
udi_msc_process_trans();
}
#ifdef USB_REPL
if (mp_cdc_enabled && usb_rx_count > 0) {
#ifdef MICROPY_HW_LED_RX
port_pin_toggle_output_level(MICROPY_HW_LED_RX);
#endif
return receive_usb();
}
#endif
#ifdef UART_REPL
uint16_t temp;
if (usart_read_wait(&usart_instance, &temp) == STATUS_OK) {
#ifdef MICROPY_HW_LED_RX
port_pin_toggle_output_level(MICROPY_HW_LED_RX);
#endif
return temp;
}
#endif
// TODO(tannewt): Switch to callback/interrupt based UART so it can work
// with the sleepmgr.
sleepmgr_enter_sleep();
}
}
void mp_hal_stdout_tx_strn(const char *str, size_t len) {
#ifdef MICROPY_HW_LED_TX
port_pin_toggle_output_level(MICROPY_HW_LED_TX);
#endif
#ifdef UART_REPL
usart_write_buffer_wait(&usart_instance, (uint8_t*) str, len);
#endif
#ifdef USB_REPL
if (mp_cdc_enabled && udi_cdc_is_tx_ready()) {
udi_cdc_write_buf(str, len);
}
#endif
}
void mp_hal_set_interrupt_char(int c) {
if (c != -1) {
mp_obj_exception_clear_traceback(MP_STATE_PORT(mp_kbd_exception));
}
extern int interrupt_char;
interrupt_char = c;
}
void mp_hal_delay_ms(mp_uint_t delay) {
// Process any mass storage transfers.
// TODO(tannewt): Actually account for how long the processing takes and
// subtract it from the delay.
if (mp_msc_enabled) {
udi_msc_process_trans();
}
delay_ms(delay);
}
void mp_hal_delay_us(mp_uint_t delay) {
// Process any mass storage transfers.
// TODO(tannewt): Actually account for how long the processing takes and
// subtract it from the delay.
if (mp_msc_enabled) {
udi_msc_process_trans();
}
delay_us(delay);
}
// Global millisecond tick count (driven by SysTick interrupt handler).
volatile uint32_t systick_ticks_ms = 0;
void SysTick_Handler(void) {
// SysTick interrupt handler called when the SysTick timer reaches zero
// (every millisecond).
systick_ticks_ms += 1;
// Keep the counter within the range of 31 bit uint values since that's the
// max value for micropython 'small' ints.
systick_ticks_ms = systick_ticks_ms > (0xFFFFFFFF >> 1) ? 0 : systick_ticks_ms;
}
// Interrupt flags that will be saved and restored during disable/Enable
// interrupt functions below.
static irqflags_t irq_flags;
void mp_hal_disable_all_interrupts(void) {
// Disable all interrupt sources for timing critical sections.
// Disable ASF-based interrupts.
irq_flags = cpu_irq_save();
// Disable SysTick interrupt.
SysTick->CTRL &= ~SysTick_CTRL_TICKINT_Msk;
}
void mp_hal_enable_all_interrupts(void) {
// Enable all interrupt sources after timing critical sections.
// Restore SysTick interrupt.
SysTick->CTRL |= SysTick_CTRL_TICKINT_Msk;
// Restore ASF-based interrupts.
cpu_irq_restore(irq_flags);
}