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micropython/ports/stm32/usbd_cdc_interface.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* Taken from ST Cube library and heavily modified. See below for original
* copyright header.
*/
/**
******************************************************************************
* @file USB_Device/CDC_Standalone/Src/usbd_cdc_interface.c
* @author MCD Application Team
* @version V1.0.1
* @date 26-February-2014
* @brief Source file for USBD CDC interface
******************************************************************************
* @attention
*
* <h2><center>&copy; COPYRIGHT(c) 2014 STMicroelectronics</center></h2>
*
* Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
* You may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.st.com/software_license_agreement_liberty_v2
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
******************************************************************************
*/
/* Includes ------------------------------------------------------------------*/
#include <stdbool.h>
#include <stdint.h>
#include "usbd_cdc_msc_hid.h"
#include "usbd_cdc_interface.h"
#include "pendsv.h"
#include "py/obj.h"
#include "lib/utils/interrupt_char.h"
#include "irq.h"
#if MICROPY_HW_ENABLE_USB
// CDC control commands
#define CDC_SEND_ENCAPSULATED_COMMAND 0x00
#define CDC_GET_ENCAPSULATED_RESPONSE 0x01
#define CDC_SET_COMM_FEATURE 0x02
#define CDC_GET_COMM_FEATURE 0x03
#define CDC_CLEAR_COMM_FEATURE 0x04
#define CDC_SET_LINE_CODING 0x20
#define CDC_GET_LINE_CODING 0x21
#define CDC_SET_CONTROL_LINE_STATE 0x22
#define CDC_SEND_BREAK 0x23
// Used to control the connect_state variable when USB host opens the serial port
static uint8_t usbd_cdc_connect_tx_timer;
uint8_t *usbd_cdc_init(usbd_cdc_state_t *cdc_in) {
usbd_cdc_itf_t *cdc = (usbd_cdc_itf_t *)cdc_in;
// Reset the CDC state due to a new USB host connection
// Note: we don't reset tx_buf_ptr_* in order to allow the output buffer to
// be filled (by usbd_cdc_tx_always) before the USB device is connected, and
// to retain transmit buffer state across multiple USB connections (they will
// be 0 at MCU reset since the variables live in the BSS).
cdc->rx_buf_put = 0;
cdc->rx_buf_get = 0;
cdc->rx_buf_full = false;
cdc->tx_need_empty_packet = 0;
cdc->connect_state = USBD_CDC_CONNECT_STATE_DISCONNECTED;
if (cdc->attached_to_repl) {
// Default behavior is non-blocking when attached to repl
cdc->flow &= ~USBD_CDC_FLOWCONTROL_CTS;
} else {
cdc->flow |= USBD_CDC_FLOWCONTROL_CTS;
}
// Return the buffer to place the first USB OUT packet
return cdc->rx_packet_buf;
}
void usbd_cdc_deinit(usbd_cdc_state_t *cdc_in) {
usbd_cdc_itf_t *cdc = (usbd_cdc_itf_t *)cdc_in;
cdc->connect_state = USBD_CDC_CONNECT_STATE_DISCONNECTED;
}
// Manage the CDC class requests
// cmd: command code
// pbuf: buffer containing command data (request parameters)
// length: number of data to be sent (in bytes)
// Returns USBD_OK if all operations are OK else USBD_FAIL
int8_t usbd_cdc_control(usbd_cdc_state_t *cdc_in, uint8_t cmd, uint8_t *pbuf, uint16_t length) {
usbd_cdc_itf_t *cdc = (usbd_cdc_itf_t *)cdc_in;
switch (cmd) {
case CDC_SEND_ENCAPSULATED_COMMAND:
/* Add your code here */
break;
case CDC_GET_ENCAPSULATED_RESPONSE:
/* Add your code here */
break;
case CDC_SET_COMM_FEATURE:
/* Add your code here */
break;
case CDC_GET_COMM_FEATURE:
/* Add your code here */
break;
case CDC_CLEAR_COMM_FEATURE:
/* Add your code here */
break;
case CDC_SET_LINE_CODING:
#if 0
LineCoding.bitrate = (uint32_t)(pbuf[0] | (pbuf[1] << 8) | \
(pbuf[2] << 16) | (pbuf[3] << 24));
LineCoding.format = pbuf[4];
LineCoding.paritytype = pbuf[5];
LineCoding.datatype = pbuf[6];
/* Set the new configuration */
#endif
break;
case CDC_GET_LINE_CODING:
/* Add your code here */
pbuf[0] = (uint8_t)(115200);
pbuf[1] = (uint8_t)(115200 >> 8);
pbuf[2] = (uint8_t)(115200 >> 16);
pbuf[3] = (uint8_t)(115200 >> 24);
pbuf[4] = 0; // stop bits (1)
pbuf[5] = 0; // parity (none)
pbuf[6] = 8; // number of bits (8)
break;
case CDC_SET_CONTROL_LINE_STATE: {
// wValue, indicating the state, is passed in length (bit of a hack)
if (length & 1) {
// The actual connection state is delayed to give the host a chance to
// configure its serial port (in most cases to disable local echo)
cdc->connect_state = USBD_CDC_CONNECT_STATE_CONNECTING;
usbd_cdc_connect_tx_timer = 8; // wait for 8 SOF IRQs
#if !MICROPY_HW_USB_IS_MULTI_OTG
USB->CNTR |= USB_CNTR_SOFM;
#else
PCD_HandleTypeDef *hpcd = cdc->base.usbd->pdev->pData;
hpcd->Instance->GINTMSK |= USB_OTG_GINTMSK_SOFM;
#endif
} else {
cdc->connect_state = USBD_CDC_CONNECT_STATE_DISCONNECTED;
}
break;
}
case CDC_SEND_BREAK:
/* Add your code here */
break;
default:
break;
}
return USBD_OK;
}
// Called when the USB IN endpoint is ready to receive more data
// (cdc.base.tx_in_progress must be 0)
void usbd_cdc_tx_ready(usbd_cdc_state_t *cdc_in) {
usbd_cdc_itf_t *cdc = (usbd_cdc_itf_t *)cdc_in;
cdc->tx_buf_ptr_out = cdc->tx_buf_ptr_out_shadow;
if (cdc->tx_buf_ptr_out == cdc->tx_buf_ptr_in && !cdc->tx_need_empty_packet) {
// No outstanding data to send
return;
}
uint32_t len;
if (cdc->tx_buf_ptr_out > cdc->tx_buf_ptr_in) { // rollback
len = USBD_CDC_TX_DATA_SIZE - cdc->tx_buf_ptr_out;
} else {
len = cdc->tx_buf_ptr_in - cdc->tx_buf_ptr_out;
}
// Should always succeed because cdc.base.tx_in_progress==0
USBD_CDC_TransmitPacket(&cdc->base, len, &cdc->tx_buf[cdc->tx_buf_ptr_out]);
cdc->tx_buf_ptr_out_shadow += len;
if (cdc->tx_buf_ptr_out_shadow == USBD_CDC_TX_DATA_SIZE) {
cdc->tx_buf_ptr_out_shadow = 0;
}
// According to the USB specification, a packet size of 64 bytes (CDC_DATA_FS_MAX_PACKET_SIZE)
// gets held at the USB host until the next packet is sent. This is because a
// packet of maximum size is considered to be part of a longer chunk of data, and
// the host waits for all data to arrive (ie, waits for a packet < max packet size).
// To flush a packet of exactly max packet size, we need to send a zero-size packet.
// See eg http://www.cypress.com/?id=4&rID=92719
cdc->tx_need_empty_packet = (len > 0 && len % usbd_cdc_max_packet(cdc->base.usbd->pdev) == 0 && cdc->tx_buf_ptr_out_shadow == cdc->tx_buf_ptr_in);
}
// Attempt to queue data on the USB IN endpoint
static void usbd_cdc_try_tx(usbd_cdc_itf_t *cdc) {
uint32_t basepri = raise_irq_pri(IRQ_PRI_OTG_FS);
if (cdc == NULL || cdc->connect_state == USBD_CDC_CONNECT_STATE_DISCONNECTED) {
// CDC device is not connected to a host, so we are unable to send any data
} else if (cdc->base.tx_in_progress) {
// USB driver will call callback when ready
} else {
usbd_cdc_tx_ready(&cdc->base);
}
restore_irq_pri(basepri);
}
void HAL_PCD_SOFCallback(PCD_HandleTypeDef *hpcd) {
if (usbd_cdc_connect_tx_timer > 0) {
--usbd_cdc_connect_tx_timer;
} else {
usbd_cdc_msc_hid_state_t *usbd = ((USBD_HandleTypeDef *)hpcd->pData)->pClassData;
#if !MICROPY_HW_USB_IS_MULTI_OTG
USB->CNTR &= ~USB_CNTR_SOFM;
#else
hpcd->Instance->GINTMSK &= ~USB_OTG_GINTMSK_SOFM;
#endif
for (int i = 0; i < MICROPY_HW_USB_CDC_NUM; ++i) {
usbd_cdc_itf_t *cdc = (usbd_cdc_itf_t *)usbd->cdc[i];
if (cdc->connect_state == USBD_CDC_CONNECT_STATE_CONNECTING) {
cdc->connect_state = USBD_CDC_CONNECT_STATE_CONNECTED;
usbd_cdc_try_tx(cdc);
}
}
}
}
bool usbd_cdc_rx_buffer_full(usbd_cdc_itf_t *cdc) {
int get = cdc->rx_buf_get, put = cdc->rx_buf_put;
int remaining = (get - put) + (-((int)(get <= put)) & USBD_CDC_RX_DATA_SIZE);
return remaining < CDC_DATA_MAX_PACKET_SIZE + 1;
}
void usbd_cdc_rx_check_resume(usbd_cdc_itf_t *cdc) {
uint32_t irq_state = disable_irq();
if (cdc->rx_buf_full) {
if (!usbd_cdc_rx_buffer_full(cdc)) {
cdc->rx_buf_full = false;
enable_irq(irq_state);
USBD_CDC_ReceivePacket(&cdc->base, cdc->rx_packet_buf);
return;
}
}
enable_irq(irq_state);
}
// Data received over USB OUT endpoint is processed here.
// len: number of bytes received into the buffer we passed to USBD_CDC_ReceivePacket
// Returns USBD_OK if all operations are OK else USBD_FAIL
int8_t usbd_cdc_receive(usbd_cdc_state_t *cdc_in, size_t len) {
usbd_cdc_itf_t *cdc = (usbd_cdc_itf_t *)cdc_in;
// copy the incoming data into the circular buffer
for (const uint8_t *src = cdc->rx_packet_buf, *top = cdc->rx_packet_buf + len; src < top; ++src) {
if (cdc->attached_to_repl && *src == mp_interrupt_char) {
pendsv_kbd_intr();
} else {
uint16_t next_put = (cdc->rx_buf_put + 1) & (USBD_CDC_RX_DATA_SIZE - 1);
if (next_put == cdc->rx_buf_get) {
// overflow, we just discard the rest of the chars
break;
}
cdc->rx_user_buf[cdc->rx_buf_put] = *src;
cdc->rx_buf_put = next_put;
}
}
if ((cdc->flow & USBD_CDC_FLOWCONTROL_RTS) && (usbd_cdc_rx_buffer_full(cdc))) {
cdc->rx_buf_full = true;
return USBD_BUSY;
} else {
// initiate next USB packet transfer
cdc->rx_buf_full = false;
return USBD_CDC_ReceivePacket(&cdc->base, cdc->rx_packet_buf);
}
}
int usbd_cdc_tx_half_empty(usbd_cdc_itf_t *cdc) {
int32_t tx_waiting = (int32_t)cdc->tx_buf_ptr_in - (int32_t)cdc->tx_buf_ptr_out;
if (tx_waiting < 0) {
tx_waiting += USBD_CDC_TX_DATA_SIZE;
}
return tx_waiting <= USBD_CDC_TX_DATA_SIZE / 2;
}
// Writes only the data that fits if flow & CTS, else writes all data
// Returns number of bytes actually written to the device
int usbd_cdc_tx_flow(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len) {
if (cdc->flow & USBD_CDC_FLOWCONTROL_CTS) {
// Only write as much as can fit in tx buffer
return usbd_cdc_tx(cdc, buf, len, 0);
} else {
// Never block, keep most recent data in rolling buffer
usbd_cdc_tx_always(cdc, buf, len);
return len;
}
}
// timout in milliseconds.
// Returns number of bytes written to the device.
int usbd_cdc_tx(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len, uint32_t timeout) {
for (uint32_t i = 0; i < len; i++) {
// Wait until the device is connected and the buffer has space, with a given timeout
uint32_t start = HAL_GetTick();
while (cdc->connect_state == USBD_CDC_CONNECT_STATE_DISCONNECTED
|| ((cdc->tx_buf_ptr_in + 1) & (USBD_CDC_TX_DATA_SIZE - 1)) == cdc->tx_buf_ptr_out) {
usbd_cdc_try_tx(cdc);
// Wraparound of tick is taken care of by 2's complement arithmetic.
if (HAL_GetTick() - start >= timeout) {
// timeout
return i;
}
if (query_irq() == IRQ_STATE_DISABLED) {
// IRQs disabled so buffer will never be drained; return immediately
return i;
}
__WFI(); // enter sleep mode, waiting for interrupt
}
// Write data to device buffer
cdc->tx_buf[cdc->tx_buf_ptr_in] = buf[i];
cdc->tx_buf_ptr_in = (cdc->tx_buf_ptr_in + 1) & (USBD_CDC_TX_DATA_SIZE - 1);
}
usbd_cdc_try_tx(cdc);
// Success, return number of bytes read
return len;
}
// Always write all of the data to the device tx buffer, even if the
// device is not connected, or if the buffer is full. Has a small timeout
// to wait for the buffer to be drained, in the case the device is connected.
void usbd_cdc_tx_always(usbd_cdc_itf_t *cdc, const uint8_t *buf, uint32_t len) {
for (int i = 0; i < len; i++) {
// If the CDC device is not connected to the host then we don't have anyone to receive our data.
// The device may become connected in the future, so we should at least try to fill the buffer
// and hope that it doesn't overflow by the time the device connects.
// If the device is not connected then we should go ahead and fill the buffer straight away,
// ignoring overflow. Otherwise, we should make sure that we have enough room in the buffer.
if (cdc->connect_state != USBD_CDC_CONNECT_STATE_DISCONNECTED) {
// If the buffer is full, wait until it gets drained, with a timeout of 500ms
// (wraparound of tick is taken care of by 2's complement arithmetic).
uint32_t start = HAL_GetTick();
while (((cdc->tx_buf_ptr_in + 1) & (USBD_CDC_TX_DATA_SIZE - 1)) == cdc->tx_buf_ptr_out && HAL_GetTick() - start <= 500) {
usbd_cdc_try_tx(cdc);
if (query_irq() == IRQ_STATE_DISABLED) {
// IRQs disabled so buffer will never be drained; exit loop
break;
}
__WFI(); // enter sleep mode, waiting for interrupt
}
}
cdc->tx_buf[cdc->tx_buf_ptr_in] = buf[i];
cdc->tx_buf_ptr_in = (cdc->tx_buf_ptr_in + 1) & (USBD_CDC_TX_DATA_SIZE - 1);
}
usbd_cdc_try_tx(cdc);
}
// Returns number of bytes in the rx buffer.
int usbd_cdc_rx_num(usbd_cdc_itf_t *cdc) {
int32_t rx_waiting = (int32_t)cdc->rx_buf_put - (int32_t)cdc->rx_buf_get;
if (rx_waiting < 0) {
rx_waiting += USBD_CDC_RX_DATA_SIZE;
}
usbd_cdc_rx_check_resume(cdc);
return rx_waiting;
}
// timout in milliseconds.
// Returns number of bytes read from the device.
int usbd_cdc_rx(usbd_cdc_itf_t *cdc, uint8_t *buf, uint32_t len, uint32_t timeout) {
// loop to read bytes
for (uint32_t i = 0; i < len; i++) {
// Wait until we have at least 1 byte to read
uint32_t start = HAL_GetTick();
while (cdc->rx_buf_put == cdc->rx_buf_get) {
// Wraparound of tick is taken care of by 2's complement arithmetic.
if (HAL_GetTick() - start >= timeout) {
// timeout
return i;
}
if (query_irq() == IRQ_STATE_DISABLED) {
// IRQs disabled so buffer will never be filled; return immediately
return i;
}
usbd_cdc_rx_check_resume(cdc);
__WFI(); // enter sleep mode, waiting for interrupt
}
// Copy byte from device to user buffer
buf[i] = cdc->rx_user_buf[cdc->rx_buf_get];
cdc->rx_buf_get = (cdc->rx_buf_get + 1) & (USBD_CDC_RX_DATA_SIZE - 1);
}
usbd_cdc_rx_check_resume(cdc);
// Success, return number of bytes read
return len;
}
#endif
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