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arch/arm/src/imxrt/imxrt_lpspi.c: Fixed race on register setting. The ouput frequency was not being initialized correctly. The value of LPSPI_TCR_PRESCALE was getting set to 7. Making the setting atomic fixed the race. I suppose a DSB() could have also fixed it.

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David Sidrane 2019-12-12 08:31:24 -06:00 committed by Gregory Nutt
parent 587dcaa6e6
commit 42dfd18d7c
1 changed files with 7 additions and 13 deletions
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20
arch/arm/src/imxrt/imxrt_lpspi.c
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@ -901,7 +901,6 @@ static uint32_t imxrt_lpspi_setfrequency(FAR struct spi_dev_s *dev,
FAR struct imxrt_lpspidev_s *priv = (FAR struct imxrt_lpspidev_s *)dev;
uint32_t men;
uint32_t regval;
uint32_t pll_freq;
uint32_t pll3_div;
uint32_t src_freq = 0;
@ -986,14 +985,12 @@ static uint32_t imxrt_lpspi_setfrequency(FAR struct spi_dev_s *dev,
/* Write the best values in the CCR register */
regval = imxrt_lpspi_getreg32(priv, IMXRT_LPSPI_CCR_OFFSET);
regval &= ~LPSPI_CCR_SCKDIV_MASK;
regval |= LPSPI_CCR_SCKDIV(best_scaler);
imxrt_lpspi_putreg32(priv, IMXRT_LPSPI_CCR_OFFSET, regval);
imxrt_lpspi_modifyreg32(priv, IMXRT_LPSPI_CCR_OFFSET,
LPSPI_CCR_SCKDIV_MASK,
LPSPI_CCR_SCKDIV(best_scaler));
imxrt_lpspi_modifyreg32(priv, IMXRT_LPSPI_TCR_OFFSET,
LPSPI_TCR_PRESCALE_MASK, 0);
imxrt_lpspi_modifyreg32(priv, IMXRT_LPSPI_TCR_OFFSET, 0,
LPSPI_TCR_PRESCALE_MASK,
LPSPI_TCR_PRESCALE(best_prescaler));
priv->frequency = frequency;
@ -1120,7 +1117,6 @@ static void imxrt_lpspi_setmode(FAR struct spi_dev_s *dev, enum spi_mode_e mode)
static void imxrt_lpspi_setbits(FAR struct spi_dev_s *dev, int nbits)
{
FAR struct imxrt_lpspidev_s *priv = (FAR struct imxrt_lpspidev_s *)dev;
uint32_t regval;
uint32_t men;
int savbits = nbits;
@ -1144,11 +1140,9 @@ static void imxrt_lpspi_setbits(FAR struct spi_dev_s *dev, int nbits)
imxrt_lpspi_modifyreg32(priv, IMXRT_LPSPI_CR_OFFSET, LPSPI_CR_MEN, 0);
}
regval = imxrt_lpspi_getreg32(priv, IMXRT_LPSPI_TCR_OFFSET);
regval &= ~LPSPI_TCR_FRAMESZ_MASK;
regval |= LPSPI_TCR_FRAMESZ(nbits - 1);
imxrt_lpspi_putreg32(priv, IMXRT_LPSPI_TCR_OFFSET, regval);
imxrt_lpspi_modifyreg32(priv, IMXRT_LPSPI_TCR_OFFSET,
LPSPI_TCR_FRAMESZ_MASK,
LPSPI_TCR_FRAMESZ(nbits - 1));
/* Save the selection so the subsequence re-configurations will be faster */