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From: <patrice.chotard@foss.st.com>
To: Mark Brown <broonie@kernel.org>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: <linux-spi@vger.kernel.org>,
	<linux-stm32@st-md-mailman.stormreply.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <christophe.kerello@foss.st.com>,
	<patrice.chotard@foss.st.com>
Subject: spi: stm32-qspi: Always wait BUSY bit to be cleared in stm32_qspi_wait_cmd()
Date: Thu, 3 Jun 2021 09:34:21 +0200	[thread overview]
Message-ID: <20210603073421.8441-1-patrice.chotard@foss.st.com> (raw)

From: Patrice Chotard <patrice.chotard@foss.st.com>

In U-boot side, an issue has been encountered when QSPI source clock is
running at low frequency (24 MHz for example), waiting for TCF bit to be
set didn't ensure that all data has been send out the FIFO, we should also
wait that BUSY bit is cleared.

To prevent similar issue in kernel driver, we implement similar behavior
by always waiting BUSY bit to be cleared.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
---
 drivers/spi/spi-stm32-qspi.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
index 7e640ccc7e77..594f64136208 100644
--- a/drivers/spi/spi-stm32-qspi.c
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -294,7 +294,7 @@ static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi,
 	int err = 0;
 
 	if (!op->data.nbytes)
-		return stm32_qspi_wait_nobusy(qspi);
+		goto wait_nobusy;
 
 	if (readl_relaxed(qspi->io_base + QSPI_SR) & SR_TCF)
 		goto out;
@@ -315,6 +315,9 @@ static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi,
 out:
 	/* clear flags */
 	writel_relaxed(FCR_CTCF | FCR_CTEF, qspi->io_base + QSPI_FCR);
+wait_nobusy:
+	if (!err)
+		err = stm32_qspi_wait_nobusy(qspi);
 
 	return err;
 }
-- 
2.17.1


WARNING: multiple messages have this Message-ID (diff)
From: <patrice.chotard@foss.st.com>
To: Mark Brown <broonie@kernel.org>,
	Alexandre Torgue <alexandre.torgue@foss.st.com>
Cc: <linux-spi@vger.kernel.org>,
	<linux-stm32@st-md-mailman.stormreply.com>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, <christophe.kerello@foss.st.com>,
	<patrice.chotard@foss.st.com>
Subject: spi: stm32-qspi: Always wait BUSY bit to be cleared in stm32_qspi_wait_cmd()
Date: Thu, 3 Jun 2021 09:34:21 +0200	[thread overview]
Message-ID: <20210603073421.8441-1-patrice.chotard@foss.st.com> (raw)

From: Patrice Chotard <patrice.chotard@foss.st.com>

In U-boot side, an issue has been encountered when QSPI source clock is
running at low frequency (24 MHz for example), waiting for TCF bit to be
set didn't ensure that all data has been send out the FIFO, we should also
wait that BUSY bit is cleared.

To prevent similar issue in kernel driver, we implement similar behavior
by always waiting BUSY bit to be cleared.

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
---
 drivers/spi/spi-stm32-qspi.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
index 7e640ccc7e77..594f64136208 100644
--- a/drivers/spi/spi-stm32-qspi.c
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -294,7 +294,7 @@ static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi,
 	int err = 0;
 
 	if (!op->data.nbytes)
-		return stm32_qspi_wait_nobusy(qspi);
+		goto wait_nobusy;
 
 	if (readl_relaxed(qspi->io_base + QSPI_SR) & SR_TCF)
 		goto out;
@@ -315,6 +315,9 @@ static int stm32_qspi_wait_cmd(struct stm32_qspi *qspi,
 out:
 	/* clear flags */
 	writel_relaxed(FCR_CTCF | FCR_CTEF, qspi->io_base + QSPI_FCR);
+wait_nobusy:
+	if (!err)
+		err = stm32_qspi_wait_nobusy(qspi);
 
 	return err;
 }
-- 
2.17.1


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             reply	other threads:[~2021-06-03  7:34 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-03  7:34 patrice.chotard [this message]
2021-06-03  7:34 ` spi: stm32-qspi: Always wait BUSY bit to be cleared in stm32_qspi_wait_cmd() patrice.chotard
2021-06-03 11:56 ` Mark Brown
2021-06-03 11:56   ` Mark Brown
2021-06-03 18:41 ` Mark Brown
2021-06-03 18:41   ` Mark Brown

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