From: Daniil Stas <daniil.stas@posteo.net>
To: Patrice CHOTARD <patrice.chotard@foss.st.com>
Cc: <u-boot@lists.denx.de>, Patrick Delaunay <patrick.delaunay@foss.st.com>
Subject: Re: [PATCH] spi: stm32_qspi: Fix short data write operation
Date: Mon, 24 May 2021 12:53:30 +0000 [thread overview]
Message-ID: <20210524155330.47e8d96c@ux550ve> (raw)
In-Reply-To: <4e531f04-4228-05e6-6bdb-32c29becb38f@foss.st.com>
On Mon, 24 May 2021 09:40:05 +0200
Patrice CHOTARD <patrice.chotard@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.stas@posteo.net>
> > Cc: Patrick Delaunay <patrick.delaunay@foss.st.com>
> > Cc: Patrice Chotard <patrice.chotard@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
next prev parent reply other threads:[~2021-05-24 12:54 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-23 22:24 [PATCH] net: dwc_eth_qos: Fix needless phy auto-negotiation restarts Daniil Stas
2021-05-23 22:24 ` [PATCH] spi: stm32_qspi: Fix short data write operation Daniil Stas
2021-05-24 7:40 ` Patrice CHOTARD
2021-05-24 12:53 ` Daniil Stas [this message]
2021-05-25 16:02 ` Patrice CHOTARD
2021-06-18 8:01 ` Patrice CHOTARD
2021-06-01 15:31 ` Patrick DELAUNAY
2021-05-24 8:30 ` [PATCH] net: dwc_eth_qos: Fix needless phy auto-negotiation restarts Patrice CHOTARD
2021-05-25 6:53 ` Ramon Fried
2021-06-01 15:26 ` Patrick DELAUNAY
2021-06-12 18:36 ` Ramon Fried
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210524155330.47e8d96c@ux550ve \
--to=daniil.stas@posteo.net \
--cc=patrice.chotard@foss.st.com \
--cc=patrick.delaunay@foss.st.com \
--cc=u-boot@lists.denx.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.