On Mon, 24 May 2021 09:40:05 +0200 Patrice CHOTARD <patrice.chot...@foss.st.com> wrote:
> Hi Daniil > > On 5/24/21 12:24 AM, Daniil Stas wrote: > > 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.s...@posteo.net> > > Cc: Patrick Delaunay <patrick.delau...@foss.st.com> > > Cc: Patrice Chotard <patrice.chot...@foss.st.com> > > --- > > 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 4acc9047b9..8f4aabc3d1 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; > > } > > > > Have you got a simple test to reproduce the described race condition ? > > Thanks > Patrice Hi, Patrice I found this issue on an stm32mp153 based board. To reproduce it you need to set qspi peripheral clock to a low value (for example 24 MHz). Then you can test it in the u-boot console: STM32MP> clk dump Clocks: ... - CK_PER : 24 MHz ... - QSPI(10) => parent CK_PER(30) ... STM32MP> sf probe SF: Detected w25q32jv with page size 256 Bytes, erase size 64 KiB, total 4 MiB STM32MP> sf erase 0x00300000 +1 SF: 65536 bytes @ 0x300000 Erased: OK STM32MP> sf read 0xc4100000 0x300000 10 device 0 offset 0x300000, size 0x10 SF: 16 bytes @ 0x300000 Read: OK STM32MP> md.b 0xc4100000 c4100000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ ... STM32MP> mw.b 0xc4200000 55 STM32MP> sf write 0xc4200000 0x00300000 1 device 0 offset 0x300000, size 0x1 SF: 1 bytes @ 0x300000 Written: OK STM32MP> sf read 0xc4100000 0x00300000 10 device 0 offset 0x300000, size 0x10 SF: 16 bytes @ 0x300000 Read: OK STM32MP> md.b 0xc4100000 c4100000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ................ ... With my patch applied the last command result would be: STM32MP> md.b 0xc4100000 c4100000: 55 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff U............... Thanks, Daniil