1 /*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <string.h>
18
19 #include <nanohub/crc.h>
20 #include <seos.h>
21
22 #include <plat/pwr.h>
23
24 struct StmCrcRegs {
25 volatile uint32_t DR;
26 volatile uint32_t IDR;
27 volatile uint32_t CR;
28 };
29
30 #define STM_CRC_CR_RESET 1
31
32 static uint32_t mRevCrcTab[] =
33 {
34 0x00000000, 0xB2B4BCB6, 0x61A864DB, 0xD31CD86D,
35 0xC350C9B6, 0x71E47500, 0xA2F8AD6D, 0x104C11DB,
36 0x82608EDB, 0x30D4326D, 0xE3C8EA00 ,0x517C56B6,
37 0x4130476D, 0xF384FBDB, 0x209823B6, 0x922C9F00
38 };
39
revCrc32Word(uint32_t crc,uint32_t data,uint32_t cnt)40 static uint32_t revCrc32Word(uint32_t crc, uint32_t data, uint32_t cnt)
41 {
42 uint32_t i;
43
44 for (i = 0; i < cnt; i++)
45 crc = (crc >> 4) ^ mRevCrcTab[crc & 0x0F];
46
47 return crc ^ data;
48 }
49
50 static struct StmCrcRegs *mCrcRegs = (struct StmCrcRegs *)CRC_BASE;
51
crc32(const void * buf,size_t size,uint32_t crc)52 uint32_t crc32(const void *buf, size_t size, uint32_t crc)
53 {
54 const uint32_t *words = (const uint32_t *)buf;
55 size_t numWords = size / 4;
56 unsigned int leftoverBytes = size % 4;
57 size_t i;
58
59 pwrUnitClock(PERIPH_BUS_AHB1, PERIPH_AHB1_CRC, true);
60
61 if (mCrcRegs->DR == crc)
62 ;
63 else if (crc == CRC_INIT)
64 mCrcRegs->CR = STM_CRC_CR_RESET;
65 else
66 mCrcRegs->DR = revCrc32Word(crc, mCrcRegs->DR, 8);
67
68 for (i = 0; i < numWords; i++)
69 mCrcRegs->DR = words[i];
70
71 if (leftoverBytes) {
72 uint32_t word = 0;
73 memcpy(&word, words + numWords, leftoverBytes);
74 /* n.b.: no shifting is needed, since the CRC block looks at the
75 * lowest byte first (i.e., we need the padding in the upper bytes)
76 */
77 mCrcRegs->DR = word;
78 }
79
80 crc = mCrcRegs->DR;
81 pwrUnitClock(PERIPH_BUS_AHB1, PERIPH_AHB1_CRC, false);
82 return crc;
83 }
84