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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>© 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 <stdint.h>
#include "usbd_cdc_msc_hid.h"
#include "usbd_hid_interface.h"
#include "py/obj.h"
#include "irq.h"
#include "usb.h"
/* Private variables ---------------------------------------------------------*/
static uint8_t buffer[2][HID_DATA_FS_MAX_PACKET_SIZE]; // pair of buffers to read individual packets into
static int8_t current_read_buffer = 0; // which buffer to read from
static uint32_t last_read_len = 0; // length of last read
static int8_t current_write_buffer = 0; // which buffer to write to
/* Private function prototypes -----------------------------------------------*/
static int8_t HID_Itf_Init (void);
static int8_t HID_Itf_Receive (uint8_t* pbuf, uint32_t Len);
const USBD_HID_ItfTypeDef USBD_HID_fops = {
HID_Itf_Init,
HID_Itf_Receive
};
/**
* @brief HID_Itf_Init
* Initializes the HID media low layer
* @param None
* @retval Result of the opeartion: USBD_OK if all operations are OK else USBD_FAIL
*/
static int8_t HID_Itf_Init(void)
{
current_read_buffer = 0;
last_read_len = 0;
current_write_buffer = 0;
USBD_HID_SetRxBuffer(&hUSBDDevice, buffer[current_write_buffer]);
return USBD_OK;
}
/**
* @brief HID_Itf_Receive
* Data received over USB OUT endpoint is processed here.
* @param Buf: Buffer of data received
* @param Len: Number of data received (in bytes)
* @retval Result of the opeartion: USBD_OK if all operations are OK else USBD_FAIL
* @note The buffer we are passed here is just UserRxBuffer, so we are
* free to modify it.
*/
static int8_t HID_Itf_Receive(uint8_t* Buf, uint32_t Len) {
current_write_buffer = !current_write_buffer;
last_read_len = Len;
// initiate next USB packet transfer, to append to existing data in buffer
USBD_HID_SetRxBuffer(&hUSBDDevice, buffer[current_write_buffer]);
USBD_HID_ReceivePacket(&hUSBDDevice);
// Set NAK to indicate we need to process read buffer
USBD_HID_SetNAK(&hUSBDDevice);
return USBD_OK;
}
// Returns number of ready rx buffers.
int USBD_HID_RxNum(void) {
return (current_read_buffer != current_write_buffer);
}
// timout in milliseconds.
// Returns number of bytes read from the device.
int USBD_HID_Rx(uint8_t *buf, uint32_t len, uint32_t timeout) {
// Wait until we have buffer to read
uint32_t start = HAL_GetTick();
while (current_read_buffer == current_write_buffer) {
// Wraparound of tick is taken care of by 2's complement arithmetic.
if (HAL_GetTick() - start >= timeout) {
// timeout
return 0;
}
if (query_irq() == IRQ_STATE_DISABLED) {
// IRQs disabled so buffer will never be filled; return immediately
return 0;
}
__WFI(); // enter sleep mode, waiting for interrupt
}
// There is not enough space in buffer
if (len < last_read_len) {
return 0;
}
// Copy bytes from device to user buffer
memcpy(buf, buffer[current_read_buffer], last_read_len);
current_read_buffer = !current_read_buffer;
// Clear NAK to indicate we are ready to read more data
USBD_HID_ClearNAK(&hUSBDDevice);
// Success, return number of bytes read
return last_read_len;
}
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