From 88f7ca03b4a2dca45c33ae360c99f6dbe3fe394d Mon Sep 17 00:00:00 2001 From: Daniil Stas Date: Sun, 23 May 2021 22:24:49 +0000 Subject: [PATCH] spi: stm32_qspi: Fix short data write operation 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 Cc: Patrick Delaunay Cc: Patrice Chotard Reviewed-by: Patrice Chotard Reviewed-by: Patrick Delaunay --- drivers/spi/stm32_qspi.c | 29 +++++++++++++++-------------- 1 file changed, 15 insertions(+), 14 deletions(-) diff --git a/drivers/spi/stm32_qspi.c b/drivers/spi/stm32_qspi.c index 4acc904..8f4aabc 100644 --- a/drivers/spi/stm32_qspi.c +++ b/drivers/spi/stm32_qspi.c @@ -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; - - if (!op->data.nbytes) - return _stm32_qspi_wait_for_not_busy(priv); + int ret = 0; - 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; } -- 2.7.4