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F3:F303/MLX90640/usb_dev.c

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+/*
+ * Copyright 2024 Edward V. Emelianov <edward.emelianoff@gmail.com>.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <string.h>
+
+#include "ringbuffer.h"
+#include "usb_descr.h"
+#include "usb_dev.h"
+
+// Class-Specific Control Requests
+#define SEND_ENCAPSULATED_COMMAND       0x00    // unused
+#define GET_ENCAPSULATED_RESPONSE       0x01    // unused
+#define SET_COMM_FEATURE                0x02    // unused
+#define GET_COMM_FEATURE                0x03    // unused
+#define CLEAR_COMM_FEATURE              0x04    // unused
+#define SET_LINE_CODING                 0x20
+#define GET_LINE_CODING                 0x21
+#define SET_CONTROL_LINE_STATE          0x22
+#define SEND_BREAK                      0x23
+
+// control line states
+#define CONTROL_DTR                     0x01
+#define CONTROL_RTS                     0x02
+
+// inbuf overflow when receiving
+static volatile uint8_t bufovrfl = 0;
+
+// receive buffer: hold data until chkin() call
+static uint8_t volatile rcvbuf[USB_RXBUFSZ];
+static uint8_t volatile rcvbuflen = 0;
+// line coding
+usb_LineCoding WEAK lineCoding = {115200, 0, 0, 8};
+// CDC configured and ready to use
+volatile uint8_t CDCready = 0;
+
+// ring buffers for incoming and outgoing data
+static uint8_t obuf[RBOUTSZ], ibuf[RBINSZ];
+static volatile ringbuffer rbout = {.data = obuf, .length = RBOUTSZ, .head = 0, .tail = 0};
+static volatile ringbuffer rbin = {.data = ibuf, .length = RBINSZ, .head = 0, .tail = 0};
+// last send data size
+static volatile int lastdsz = 0;
+
+static void chkin(){
+    if(bufovrfl) return; // allow user to know that previous buffer was overflowed and cleared
+    if(!rcvbuflen) return;
+    int w = RB_write((ringbuffer*)&rbin, (uint8_t*)rcvbuf, rcvbuflen);
+    if(w < 0){
+        return;
+    }
+    if(w != rcvbuflen) bufovrfl = 1;
+    rcvbuflen = 0;
+    uint16_t status = KEEP_DTOG(USB->EPnR[1]); // don't change DTOG
+    USB->EPnR[1] = (status & ~(USB_EPnR_STAT_TX|USB_EPnR_CTR_RX)) ^ USB_EPnR_STAT_RX; // prepare to get next data portion
+}
+
+// called from transmit EP to send next data portion or by user - when new transmission starts
+static void send_next(){
+    uint8_t usbbuff[USB_TXBUFSZ];
+    int buflen = RB_read((ringbuffer*)&rbout, (uint8_t*)usbbuff, USB_TXBUFSZ);
+    if(buflen == 0){
+        if(lastdsz == 64) EP_Write(1, NULL, 0); // send ZLP after 64 bits packet when nothing more to send
+        lastdsz = 0;
+        return;
+    }else if(buflen < 0){
+        lastdsz = 0;
+        return;
+    }
+    EP_Write(1, (uint8_t*)usbbuff, buflen);
+    lastdsz = buflen;
+}
+
+// data IN/OUT handler
+static void rxtx_handler(){
+    uint16_t epstatus = KEEP_DTOG(USB->EPnR[1]);
+    if(RX_FLAG(epstatus)){ // receive data
+        if(rcvbuflen){
+            bufovrfl = 1; // lost last data
+            rcvbuflen = 0;
+        }
+        rcvbuflen = EP_Read(1, (uint8_t*)rcvbuf);
+        USB->EPnR[1] = epstatus & ~(USB_EPnR_CTR_RX | USB_EPnR_STAT_RX | USB_EPnR_STAT_TX); // keep RX in STALL state until read data
+        chkin(); // try to write current data into RXbuf if it's not busy
+    }else{ // tx successfull
+        USB->EPnR[1] = (epstatus & ~(USB_EPnR_CTR_TX | USB_EPnR_STAT_TX)) ^ USB_EPnR_STAT_RX;
+        send_next();
+    }
+}
+
+// weak handlers: change them somewhere else if you want to setup USART
+// SET_LINE_CODING
+void WEAK linecoding_handler(usb_LineCoding *lc){
+    lineCoding = *lc;
+}
+
+// SET_CONTROL_LINE_STATE
+void WEAK clstate_handler(uint16_t val){
+    CDCready = val; // CONTROL_DTR | CONTROL_RTS -> interface connected; 0 -> disconnected
+}
+
+// SEND_BREAK
+void WEAK break_handler(){
+    CDCready = 0;
+}
+
+
+// USB is configured: setup endpoints
+void set_configuration(){
+    EP_Init(1, EP_TYPE_BULK, USB_TXBUFSZ, USB_RXBUFSZ, rxtx_handler); // IN1 and OUT1
+}
+
+// PL2303 CLASS request
+void usb_class_request(config_pack_t *req, uint8_t *data, uint16_t datalen){
+    uint8_t recipient = REQUEST_RECIPIENT(req->bmRequestType);
+    uint8_t dev2host = (req->bmRequestType & 0x80) ? 1 : 0;
+    switch(recipient){
+        case REQ_RECIPIENT_INTERFACE:
+            switch(req->bRequest){
+                case SET_LINE_CODING:
+                    if(!data || !datalen) break; // wait for data
+                    if(datalen == sizeof(usb_LineCoding))
+                        linecoding_handler((usb_LineCoding*)data);
+                break;
+                case GET_LINE_CODING:
+                    EP_WriteIRQ(0, (uint8_t*)&lineCoding, sizeof(lineCoding));
+                break;
+                case SET_CONTROL_LINE_STATE:
+                    clstate_handler(req->wValue);
+                break;
+                case SEND_BREAK:
+                    break_handler();
+                break;
+                default:
+                    break;
+            }
+        break;
+        default:
+            if(dev2host) EP_WriteIRQ(0, NULL, 0);
+    }
+    if(!dev2host) EP_WriteIRQ(0, NULL, 0);
+}
+
+// blocking send full content of ring buffer
+int USB_sendall(){
+    while(lastdsz > 0){
+        if(!CDCready) return FALSE;
+    }
+    return TRUE;
+}
+
+// put `buf` into queue to send
+int USB_send(const uint8_t *buf, int len){
+    if(!buf || !CDCready || !len) return FALSE;
+    while(len){
+        int a = RB_write((ringbuffer*)&rbout, buf, len);
+        if(a > 0){
+            len -= a;
+            buf += a;
+        } else if (a < 0) continue; // do nothing if buffer is in reading state
+        if(lastdsz == 0) send_next(); // need to run manually - all data sent, so no IRQ on IN
+    }
+    return TRUE;
+}
+
+int USB_putbyte(uint8_t byte){
+    if(!CDCready) return FALSE;
+    int l = 0;
+    while((l = RB_write((ringbuffer*)&rbout, &byte, 1)) != 1){
+        if(l < 0) continue;
+    }
+    if(lastdsz == 0) send_next(); // need to run manually - all data sent, so no IRQ on IN
+    return TRUE;
+}
+
+int USB_sendstr(const char *string){
+    if(!string || !CDCready) return FALSE;
+    int len = 0;
+    const char *b = string;
+    while(*b++) ++len;
+    if(!len) return FALSE;
+    return USB_send((const uint8_t*)string, len);
+}
+
+/**
+ * @brief USB_receive - get binary data from receiving ring-buffer
+ * @param buf (i) - buffer for received data
+ * @param len - length of `buf`
+ * @return amount of received bytes (negative, if overfull happened)
+ */
+int USB_receive(uint8_t *buf, int len){
+    chkin();
+    if(bufovrfl){
+        while(1 != RB_clearbuf((ringbuffer*)&rbin));
+        bufovrfl = 0;
+        return -1;
+    }
+    int sz = RB_read((ringbuffer*)&rbin, buf, len);
+    if(sz < 0) return 0; // buffer in writting state
+    return sz;
+}
+
+/**
+ * @brief USB_receivestr - get string up to '\n' and replace '\n' with 0
+ * @param buf - receiving buffer
+ * @param len - its length
+ * @return strlen or negative value indicating overflow (if so, string won't be ends with 0 and buffer should be cleared)
+ */
+int USB_receivestr(char *buf, int len){
+    chkin();
+    if(bufovrfl){
+        while(1 != RB_clearbuf((ringbuffer*)&rbin));
+        bufovrfl = 0;
+        return -1;
+    }
+    int l = RB_readto((ringbuffer*)&rbin, '\n', (uint8_t*)buf, len);
+    if(l < 1){
+        if(rbin.length == RB_datalen((ringbuffer*)&rbin)){ // buffer is full but no '\n' found
+            while(1 != RB_clearbuf((ringbuffer*)&rbin));
+            return -1;
+        }
+        return 0;
+    }
+    if(l == 0) return 0;
+    buf[l-1] = 0; // replace '\n' with strend
+    return l;
+}
+