35f00b6c |
1 | /* Teensyduino Core Library |
2 | * http://www.pjrc.com/teensy/ |
3 | * Copyright (c) 2013 PJRC.COM, LLC. |
4 | * |
5 | * Permission is hereby granted, free of charge, to any person obtaining |
6 | * a copy of this software and associated documentation files (the |
7 | * "Software"), to deal in the Software without restriction, including |
8 | * without limitation the rights to use, copy, modify, merge, publish, |
9 | * distribute, sublicense, and/or sell copies of the Software, and to |
10 | * permit persons to whom the Software is furnished to do so, subject to |
11 | * the following conditions: |
12 | * |
13 | * 1. The above copyright notice and this permission notice shall be |
14 | * included in all copies or substantial portions of the Software. |
15 | * |
16 | * 2. If the Software is incorporated into a build system that allows |
17 | * selection among a list of target devices, then similar target |
18 | * devices manufactured by PJRC.COM must be included in the list of |
19 | * target devices and selectable in the same manner. |
20 | * |
21 | * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
22 | * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
23 | * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
24 | * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
25 | * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
26 | * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
27 | * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
28 | * SOFTWARE. |
29 | */ |
30 | |
31 | #include "mk20dx128.h" |
32 | //#include "HardwareSerial.h" |
33 | #include "usb_dev.h" |
34 | #include "usb_mem.h" |
35 | |
36 | __attribute__ ((section(".usbbuffers"), used)) |
37 | unsigned char usb_buffer_memory[NUM_USB_BUFFERS * sizeof(usb_packet_t)]; |
38 | |
39 | static uint32_t usb_buffer_available = 0xFFFFFFFF; |
40 | |
41 | // use bitmask and CLZ instruction to implement fast free list |
42 | // http://www.archivum.info/gnu.gcc.help/2006-08/00148/Re-GCC-Inline-Assembly.html |
43 | // http://gcc.gnu.org/ml/gcc/2012-06/msg00015.html |
44 | // __builtin_clz() |
45 | |
46 | usb_packet_t * usb_malloc(void) |
47 | { |
48 | unsigned int n, avail; |
49 | uint8_t *p; |
50 | |
51 | __disable_irq(); |
52 | avail = usb_buffer_available; |
53 | n = __builtin_clz(avail); // clz = count leading zeros |
54 | if (n >= NUM_USB_BUFFERS) { |
55 | __enable_irq(); |
56 | return NULL; |
57 | } |
58 | //serial_print("malloc:"); |
59 | //serial_phex(n); |
60 | //serial_print("\n"); |
61 | |
62 | usb_buffer_available = avail & ~(0x80000000 >> n); |
63 | __enable_irq(); |
64 | p = usb_buffer_memory + (n * sizeof(usb_packet_t)); |
65 | //serial_print("malloc:"); |
66 | //serial_phex32((int)p); |
67 | //serial_print("\n"); |
68 | *(uint32_t *)p = 0; |
69 | *(uint32_t *)(p + 4) = 0; |
70 | return (usb_packet_t *)p; |
71 | } |
72 | |
73 | // for the receive endpoints to request memory |
74 | extern uint8_t usb_rx_memory_needed; |
75 | extern void usb_rx_memory(usb_packet_t *packet); |
76 | |
77 | void usb_free(usb_packet_t *p) |
78 | { |
79 | unsigned int n, mask; |
80 | |
81 | //serial_print("free:"); |
82 | n = ((uint8_t *)p - usb_buffer_memory) / sizeof(usb_packet_t); |
83 | if (n >= NUM_USB_BUFFERS) return; |
84 | //serial_phex(n); |
85 | //serial_print("\n"); |
86 | |
87 | // if any endpoints are starving for memory to receive |
88 | // packets, give this memory to them immediately! |
89 | if (usb_rx_memory_needed && usb_configuration) { |
90 | //serial_print("give to rx:"); |
91 | //serial_phex32((int)p); |
92 | //serial_print("\n"); |
93 | usb_rx_memory(p); |
94 | return; |
95 | } |
96 | |
97 | mask = (0x80000000 >> n); |
98 | __disable_irq(); |
99 | usb_buffer_available |= mask; |
100 | __enable_irq(); |
101 | |
102 | //serial_print("free:"); |
103 | //serial_phex32((int)p); |
104 | //serial_print("\n"); |
105 | } |
106 | |