ca36645410
The USB IRQ may fire once USBD_HID_ClearNAK() is called and then change the last_read_len value.
107 lines
3.7 KiB
C
107 lines
3.7 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_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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uint8_t *usbd_hid_init(usbd_hid_itf_t *hid, usbd_cdc_msc_hid_state_t *usbd) {
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hid->usbd = usbd;
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hid->current_read_buffer = 0;
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hid->last_read_len = 0;
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hid->current_write_buffer = 0;
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// Return the buffer to place the first USB OUT packet
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return hid->buffer[hid->current_write_buffer];
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}
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// Data received over USB OUT endpoint is processed here.
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// len: number of bytes received into the buffer we passed to USBD_HID_ReceivePacket
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// Returns USBD_OK if all operations are OK else USBD_FAIL
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int8_t usbd_hid_receive(usbd_hid_itf_t *hid, size_t len) {
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hid->current_write_buffer = !hid->current_write_buffer;
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hid->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_ReceivePacket(hid->usbd, hid->buffer[hid->current_write_buffer]);
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// Set NAK to indicate we need to process read buffer
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USBD_HID_SetNAK(hid->usbd);
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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_rx_num(usbd_hid_itf_t *hid) {
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return hid->current_read_buffer != hid->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(usbd_hid_itf_t *hid, size_t len, uint8_t *buf, 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 (hid->current_read_buffer == hid->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 < hid->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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int read_len = hid->last_read_len;
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memcpy(buf, hid->buffer[hid->current_read_buffer], read_len);
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hid->current_read_buffer = !hid->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(hid->usbd);
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// Success, return number of bytes read
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return read_len;
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}
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