110 lines
3.3 KiB
C
110 lines
3.3 KiB
C
/* Teensyduino Core Library
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* http://www.pjrc.com/teensy/
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* Copyright (c) 2013 PJRC.COM, LLC.
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*
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* Permission is hereby granted, free of charge, to any person obtaining
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* a copy of this software and associated documentation files (the
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* "Software"), to deal in the Software without restriction, including
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* without limitation the rights to use, copy, modify, merge, publish,
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* distribute, sublicense, and/or sell copies of the Software, and to
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* permit persons to whom the Software is furnished to do so, subject to
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* the following conditions:
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*
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* 1. The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* 2. If the Software is incorporated into a build system that allows
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* selection among a list of target devices, then similar target
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* devices manufactured by PJRC.COM must be included in the list of
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* target devices and selectable in the same manner.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
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* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
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* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
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* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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* SOFTWARE.
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*/
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#if F_CPU >= 20000000
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#include "mk20dx128.h"
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//#include "HardwareSerial.h"
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#include "usb_dev.h"
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#include "usb_mem.h"
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__attribute__ ((section(".usbbuffers"), used))
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unsigned char usb_buffer_memory[NUM_USB_BUFFERS * sizeof(usb_packet_t)];
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static uint32_t usb_buffer_available = 0xFFFFFFFF;
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// use bitmask and CLZ instruction to implement fast free list
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// http://www.archivum.info/gnu.gcc.help/2006-08/00148/Re-GCC-Inline-Assembly.html
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// http://gcc.gnu.org/ml/gcc/2012-06/msg00015.html
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// __builtin_clz()
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usb_packet_t * usb_malloc(void)
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{
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unsigned int n, avail;
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uint8_t *p;
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__disable_irq();
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avail = usb_buffer_available;
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n = __builtin_clz(avail); // clz = count leading zeros
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if (n >= NUM_USB_BUFFERS) {
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__enable_irq();
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return NULL;
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}
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//serial_print("malloc:");
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//serial_phex(n);
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//serial_print("\n");
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usb_buffer_available = avail & ~(0x80000000 >> n);
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__enable_irq();
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p = usb_buffer_memory + (n * sizeof(usb_packet_t));
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//serial_print("malloc:");
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//serial_phex32((int)p);
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//serial_print("\n");
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*(uint32_t *)p = 0;
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*(uint32_t *)(p + 4) = 0;
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return (usb_packet_t *)p;
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}
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// for the receive endpoints to request memory
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extern uint8_t usb_rx_memory_needed;
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extern void usb_rx_memory(usb_packet_t *packet);
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void usb_free(usb_packet_t *p)
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{
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unsigned int n, mask;
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//serial_print("free:");
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n = ((uint8_t *)p - usb_buffer_memory) / sizeof(usb_packet_t);
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if (n >= NUM_USB_BUFFERS) return;
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//serial_phex(n);
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//serial_print("\n");
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// if any endpoints are starving for memory to receive
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// packets, give this memory to them immediately!
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if (usb_rx_memory_needed && usb_configuration) {
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//serial_print("give to rx:");
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//serial_phex32((int)p);
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//serial_print("\n");
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usb_rx_memory(p);
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return;
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}
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mask = (0x80000000 >> n);
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__disable_irq();
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usb_buffer_available |= mask;
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__enable_irq();
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//serial_print("free:");
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//serial_phex32((int)p);
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//serial_print("\n");
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}
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#endif // F_CPU >= 20 MHz
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