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spi: stm32_qspi: Fix short data write operation

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TCF flag only means that all data was sent to FIFO. To check if the
data was sent out of FIFO we should also wait for the BUSY flag to be
cleared. Otherwise there is a race condition which can lead to
inability to write short (one byte long) data.

Signed-off-by: Daniil Stas <daniil.stas@posteo.net>
Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
Cc: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
This commit is contained in:
Daniil Stas 2021-05-23 22:24:49 +00:00 committed by Patrice Chotard
parent 95a34eb42e
commit 88f7ca03b4
1 changed files with 15 additions and 14 deletions
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29
drivers/spi/stm32_qspi.c
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@ -148,23 +148,24 @@ static int _stm32_qspi_wait_cmd(struct stm32_qspi_priv *priv,
const struct spi_mem_op *op)
{
u32 sr;
int ret;
int ret = 0;
if (!op->data.nbytes)
return _stm32_qspi_wait_for_not_busy(priv);
ret = readl_poll_timeout(&priv->regs->sr, sr,
sr & STM32_QSPI_SR_TCF,
STM32_QSPI_CMD_TIMEOUT_US);
if (ret) {
log_err("cmd timeout (stat:%#x)\n", sr);
} else if (readl(&priv->regs->sr) & STM32_QSPI_SR_TEF) {
log_err("transfer error (stat:%#x)\n", sr);
ret = -EIO;
if (op->data.nbytes) {
ret = readl_poll_timeout(&priv->regs->sr, sr,
sr & STM32_QSPI_SR_TCF,
STM32_QSPI_CMD_TIMEOUT_US);
if (ret) {
log_err("cmd timeout (stat:%#x)\n", sr);
} else if (readl(&priv->regs->sr) & STM32_QSPI_SR_TEF) {
log_err("transfer error (stat:%#x)\n", sr);
ret = -EIO;
}
/* clear flags */
writel(STM32_QSPI_FCR_CTCF | STM32_QSPI_FCR_CTEF, &priv->regs->fcr);
}
/* clear flags */
writel(STM32_QSPI_FCR_CTCF | STM32_QSPI_FCR_CTEF, &priv->regs->fcr);
if (!ret)
ret = _stm32_qspi_wait_for_not_busy(priv);
return ret;
}