/*
* Copyright (C) 2016 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <string.h>
#include <nanohub/crc.h>
#include <seos.h>
#include <plat/inc/pwr.h>
struct StmCrcRegs {
volatile uint32_t DR;
volatile uint32_t IDR;
volatile uint32_t CR;
};
#define STM_CRC_CR_RESET 1
static uint32_t mRevCrcTab[] =
{
0x00000000, 0xB2B4BCB6, 0x61A864DB, 0xD31CD86D,
0xC350C9B6, 0x71E47500, 0xA2F8AD6D, 0x104C11DB,
0x82608EDB, 0x30D4326D, 0xE3C8EA00 ,0x517C56B6,
0x4130476D, 0xF384FBDB, 0x209823B6, 0x922C9F00
};
static uint32_t revCrc32Word(uint32_t crc, uint32_t data, uint32_t cnt)
{
uint32_t i;
for (i = 0; i < cnt; i++)
crc = (crc >> 4) ^ mRevCrcTab[crc & 0x0F];
return crc ^ data;
}
static struct StmCrcRegs *mCrcRegs = (struct StmCrcRegs *)CRC_BASE;
uint32_t crc32(const void *buf, size_t size, uint32_t crc)
{
const uint32_t *words = (const uint32_t *)buf;
size_t numWords = size / 4;
unsigned int leftoverBytes = size % 4;
size_t i;
pwrUnitClock(PERIPH_BUS_AHB1, PERIPH_AHB1_CRC, true);
if (mCrcRegs->DR == crc)
;
else if (crc == CRC_INIT)
mCrcRegs->CR = STM_CRC_CR_RESET;
else
mCrcRegs->DR = revCrc32Word(crc, mCrcRegs->DR, 8);
for (i = 0; i < numWords; i++)
mCrcRegs->DR = words[i];
if (leftoverBytes) {
uint32_t word = 0;
memcpy(&word, words + numWords, leftoverBytes);
/* n.b.: no shifting is needed, since the CRC block looks at the
* lowest byte first (i.e., we need the padding in the upper bytes)
*/
mCrcRegs->DR = word;
}
crc = mCrcRegs->DR;
pwrUnitClock(PERIPH_BUS_AHB1, PERIPH_AHB1_CRC, false);
return crc;
}