135 lines
4.5 KiB
C
135 lines
4.5 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* Taken from ST Cube library and heavily modified. See below for original
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* copyright header.
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*/
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/**
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******************************************************************************
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* @file USB_Device/CDC_Standalone/Src/usbd_cdc_interface.c
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* @author MCD Application Team
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* @version V1.0.1
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* @date 26-February-2014
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* @brief Source file for USBD CDC interface
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******************************************************************************
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* @attention
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*
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* <h2><center>© COPYRIGHT(c) 2014 STMicroelectronics</center></h2>
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*
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* Licensed under MCD-ST Liberty SW License Agreement V2, (the "License");
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* You may not use this file except in compliance with the License.
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* You may obtain a copy of the License at:
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*
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* http://www.st.com/software_license_agreement_liberty_v2
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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******************************************************************************
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*/
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/* Includes ------------------------------------------------------------------*/
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#include <stdint.h>
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#include "usbd_cdc_msc_hid.h"
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#include "usbd_hid_interface.h"
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#include "py/obj.h"
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#include "irq.h"
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#include "usb.h"
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/* Private variables ---------------------------------------------------------*/
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static uint8_t buffer[2][HID_DATA_FS_MAX_PACKET_SIZE]; // pair of buffers to read individual packets into
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static int8_t current_read_buffer = 0; // which buffer to read from
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static uint32_t last_read_len = 0; // length of last read
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static int8_t current_write_buffer = 0; // which buffer to write to
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/* Private function prototypes -----------------------------------------------*/
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static int8_t HID_Itf_Init (void);
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static int8_t HID_Itf_Receive (uint8_t* pbuf, uint32_t Len);
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const USBD_HID_ItfTypeDef USBD_HID_fops = {
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HID_Itf_Init,
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HID_Itf_Receive
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};
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/**
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* @brief HID_Itf_Init
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* Initializes the HID media low layer
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* @param None
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* @retval Result of the opeartion: USBD_OK if all operations are OK else USBD_FAIL
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*/
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static int8_t HID_Itf_Init(void)
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{
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current_read_buffer = 0;
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last_read_len = 0;
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current_write_buffer = 0;
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USBD_HID_SetRxBuffer(&hUSBDDevice, buffer[current_write_buffer]);
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return USBD_OK;
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}
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/**
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* @brief HID_Itf_Receive
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* Data received over USB OUT endpoint is processed here.
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* @param Buf: Buffer of data received
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* @param Len: Number of data received (in bytes)
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* @retval Result of the opeartion: USBD_OK if all operations are OK else USBD_FAIL
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* @note The buffer we are passed here is just UserRxBuffer, so we are
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* free to modify it.
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*/
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static int8_t HID_Itf_Receive(uint8_t* Buf, uint32_t Len) {
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current_write_buffer = !current_write_buffer;
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last_read_len = Len;
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// initiate next USB packet transfer, to append to existing data in buffer
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USBD_HID_SetRxBuffer(&hUSBDDevice, buffer[current_write_buffer]);
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USBD_HID_ReceivePacket(&hUSBDDevice);
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// Set NAK to indicate we need to process read buffer
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USBD_HID_SetNAK(&hUSBDDevice);
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return USBD_OK;
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}
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// Returns number of ready rx buffers.
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int USBD_HID_RxNum(void) {
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return (current_read_buffer != current_write_buffer);
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}
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// timout in milliseconds.
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// Returns number of bytes read from the device.
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int USBD_HID_Rx(uint8_t *buf, uint32_t len, uint32_t timeout) {
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// Wait until we have buffer to read
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uint32_t start = HAL_GetTick();
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while (current_read_buffer == current_write_buffer) {
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// Wraparound of tick is taken care of by 2's complement arithmetic.
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if (HAL_GetTick() - start >= timeout) {
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// timeout
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return 0;
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}
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if (query_irq() == IRQ_STATE_DISABLED) {
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// IRQs disabled so buffer will never be filled; return immediately
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return 0;
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}
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__WFI(); // enter sleep mode, waiting for interrupt
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}
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// There is not enough space in buffer
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if (len < last_read_len) {
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return 0;
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}
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// Copy bytes from device to user buffer
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memcpy(buf, buffer[current_read_buffer], last_read_len);
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current_read_buffer = !current_read_buffer;
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// Clear NAK to indicate we are ready to read more data
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USBD_HID_ClearNAK(&hUSBDDevice);
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// Success, return number of bytes read
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return last_read_len;
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}
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