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EFM32 SPI: Change some logic that I fear could cause RX data overrun

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This commit is contained in:
Gregory Nutt 2014-10-26 12:53:26 -06:00
parent 0100d0f6c0
commit 82bf0558e1
1 changed files with 12 additions and 16 deletions
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22
arch/arm/src/efm32/efm32_spi.c
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@ -1259,12 +1259,10 @@ static void spi_exchange(struct spi_dev_s *dev, const void *txbuffer,
unsent = nwords; unsent = nwords;
while (unrecvd > 0) while (unrecvd > 0)
{ {
/* REVISIT: This might cause RX data overruns??? */ /* REVISIT: Could this cause RX data overruns??? */
/* Send data while there is space in the TX buffer. This should /* Send data if there is space in the TX buffer. */
* provide some benefit when the depth of the TC buffer is > 1
*/
while ((spi_getreg(config, EFM32_USART_STATUS_OFFSET) & USART_STATUS_TXBL) != 0 && if ((spi_getreg(config, EFM32_USART_STATUS_OFFSET) & USART_STATUS_TXBL) != 0 &&
unsent > 0) unsent > 0)
{ {
/* Get the next word to write. Is there a source buffer? */ /* Get the next word to write. Is there a source buffer? */
@ -1284,9 +1282,9 @@ static void spi_exchange(struct spi_dev_s *dev, const void *txbuffer,
unsent--; unsent--;
} }
/* Receive data where there is data available */ /* Receive data if there is data available */
while ((spi_getreg(config, EFM32_USART_STATUS_OFFSET) & USART_STATUS_RXDATAV) != 0 && if ((spi_getreg(config, EFM32_USART_STATUS_OFFSET) & USART_STATUS_RXDATAV) != 0 &&
unrecvd > 0) unrecvd > 0)
{ {
/* Receive the data */ /* Receive the data */
@ -1315,10 +1313,8 @@ static void spi_exchange(struct spi_dev_s *dev, const void *txbuffer,
unsent = nwords; unsent = nwords;
while (unrecvd > 0) while (unrecvd > 0)
{ {
/* REVISIT: This might cause RX data overruns??? */ /* REVISIT: Could this cause RX data overruns??? */
/* Send data while there is space in the TX buffer. This should /* Send data if there is space in the TX buffer. */
* provide some benefit when the depth of the TC buffer is > 1
*/
while ((spi_getreg(config, EFM32_USART_STATUS_OFFSET) & USART_STATUS_TXBL) != 0 && while ((spi_getreg(config, EFM32_USART_STATUS_OFFSET) & USART_STATUS_TXBL) != 0 &&
unsent > 0) unsent > 0)
@ -1340,9 +1336,9 @@ static void spi_exchange(struct spi_dev_s *dev, const void *txbuffer,
unsent--; unsent--;
} }
/* Receive data where there is data available */ /* Receive data if there is data available */
while ((spi_getreg(config, EFM32_USART_STATUS_OFFSET) & USART_STATUS_RXDATAV) != 0 && if ((spi_getreg(config, EFM32_USART_STATUS_OFFSET) & USART_STATUS_RXDATAV) != 0 &&
unrecvd > 0) unrecvd > 0)
{ {
/* Receive the data */ /* Receive the data */