F439的HASH模块DMA传输计算问题

kokoro 提问时间：2019-5-16 08:37 /

问答
是否解决:

本帖最后由 kokoromi 于 2019-5-16 08:38 编辑

项目中需要使用439的的HASH模块计算文件的MD5值，使用的DMA方式，为了提高CPU效率，让其他任务在DMA传输数据、硬件计算MD5期间可以得到运行，DMA的数据来自FMC外扩的SDRAM。

现在的问题是，经过多次调试发现，启动DMA传输后 CPU貌似没运行代码，而是等DMA传输和计算都完成了之后才运行后面的代码，我使用时间戳功能测量了函数 HAL_HASH_MD5_Start_DMA 的运行时间，得到的时间就是DMA传入数据和MD5计算的时间，也就是说，这个函数里面启动了DMA传输后程序就停了，等整个MD5都计算完了才从这个函数中出来，很是费解，我看了下总线矩阵，也没冲突的地方啊，为什么会出现这个情况...有人知道吗？

下面的是HAL的程序，我在里面加入了测量时间功能，86-89行是我指出的有问题的地方：

HAL_StatusTypeDef HASH_Start_DMA(HASH_HandleTypeDef *hhash, uint8_t *pInBuffer, uint32_t Size, uint32_t Algorithm)
{
uint32_t inputaddr;
uint32_t inputSize;
HAL_StatusTypeDef status ;
HAL_HASH_StateTypeDef State_tmp = hhash->State;
#if defined (HASH_CR_MDMAT)
/* Make sure the input buffer size (in bytes) is a multiple of 4 when MDMAT bit is set
(case of multi-buffer HASH processing) */
assert_param(IS_HASH_DMA_MULTIBUFFER_SIZE(Size));
#endif /* MDMA defined*/
/* If State is ready or suspended, start or resume polling-based HASH processing */
if((State_tmp == HAL_HASH_STATE_READY) || (State_tmp == HAL_HASH_STATE_SUSPENDED))
{
/* Check input parameters */
if ( (pInBuffer == NULL ) || (Size == 0U) ||
/* Check phase coherency. Phase must be
either READY (fresh start)
or PROCESS (multi-buffer HASH management) */
((hhash->Phase != HAL_HASH_PHASE_READY) && (!(IS_HASH_PROCESSING(hhash)))))
{
hhash->State = HAL_HASH_STATE_READY;
return HAL_ERROR;
}
/* Process Locked */
__HAL_LOCK(hhash);
/* If not a resumption case */
if (hhash->State == HAL_HASH_STATE_READY)
{
/* Change the HASH state */
hhash->State = HAL_HASH_STATE_BUSY;
/* Check if initialization phase has already been performed.
If Phase is already set to HAL_HASH_PHASE_PROCESS, this means the
API is processing a new input data message in case of multi-buffer HASH
computation. */
if(hhash->Phase == HAL_HASH_PHASE_READY)
{
/* Select the HASH algorithm, clear HMAC mode and long key selection bit, reset the HASH processor core */
MODIFY_REG(HASH->CR, HASH_CR_LKEY|HASH_CR_ALGO|HASH_CR_MODE|HASH_CR_INIT, Algorithm | HASH_CR_INIT);
/* Set the phase */
hhash->Phase = HAL_HASH_PHASE_PROCESS;
}
/* Configure the Number of valid bits in last word of the message */
__HAL_HASH_SET_NBVALIDBITS(Size);
inputaddr = (uint32_t)pInBuffer; /* DMA transfer start address */
inputSize = Size; /* DMA transfer size (in bytes) */
/* In case of suspension request, save the starting parameters */
hhash->pHashInBuffPtr = pInBuffer; /* DMA transfer start address */
hhash->HashInCount = Size; /* DMA transfer size (in bytes) */
}
/* If resumption case */
else
{
/* Change the HASH state */
hhash->State = HAL_HASH_STATE_BUSY;
/* Resumption case, inputaddr and inputSize are not set to the API input parameters
but to those saved beforehand by HAL_HASH_DMAFeed_ProcessSuspend() when the
processing was suspended */
inputaddr = (uint32_t)hhash->pHashInBuffPtr; /* DMA transfer start address */
inputSize = hhash->HashInCount; /* DMA transfer size (in bytes) */
}
/* Set the HASH DMA transfert complete callback */
hhash->hdmain->XferCpltCallback = HASH_DMAXferCplt;
/* Set the DMA error callback */
hhash->hdmain->XferErrorCallback = HASH_DMAError;
/* Store number of words already pushed to manage proper DMA processing suspension */
hhash->NbWordsAlreadyPushed = HASH_NBW_PUSHED();
/* Enable the DMA In DMA Stream */
status = HAL_DMA_Start_IT(hhash->hdmain, inputaddr, (uint32_t)&HASH->DIN, (((inputSize %4U)!=0U) ? ((inputSize+(4U-(inputSize %4U)))/4U):(inputSize/4U)));
sts = OS_TS_GET(); //获取时间戳；
/* Enable DMA requests */
SET_BIT(HASH->CR, HASH_CR_DMAE); //就是这一句，执行完这一句按理说程序应该继续往下执行，但是实际上经过时间戳的测量，执行完这句耗费了约 4ms，这个时间正好是DMA传输数据+MD5的计算时间。
ets = OS_TS_GET() - sts; //计算耗费的时间
/* Process Unlock */
__HAL_UNLOCK(hhash);
/* Return function status */
if (status != HAL_OK)
{
/* Update HASH state machine to error */
hhash->State = HAL_HASH_STATE_ERROR;
}
else
{
/* Change HASH state */
hhash->State = HAL_HASH_STATE_READY;
}
return status;
}
else
{
return HAL_BUSY;
}
}