diff mbox series

[06/11] spi: cadence-quadspi: unconditionally disable auto status register reads

Message ID 20240411223709.573-7-greg.malysa@timesys.com
State Deferred
Delegated to: Tom Rini
Headers show
Series cadence-qspi: Add DTR support including PHY mode calibration | expand

Commit Message

Greg Malysa April 11, 2024, 10:36 p.m. UTC 
From: Ian Roberts <ian.roberts@timesys.com>

In addition to the given reason for the conditional disable
of this feature for DTR:

Theoretically, some flashes have their WIP bit in different
bit positions or have a different bit polarity. spi-nor
currently does not have an interface in place to dictate
this information to this driver for proper configuration.

The default of the controller hardware has this status register
auto polling without expiration. This means that if there is any
controller misconfiguration or communication failure, it will
completely lock up the controller.

Thus, unconditionally disable this feature for now.

Co-developed-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
Signed-off-by: Nathan Barrett-Morrison <nathan.morrison@timesys.com>
Signed-off-by: Greg Malysa <greg.malysa@timesys.com>
Signed-off-by: Ian Roberts <ian.roberts@timesys.com>
---

 drivers/spi/cadence_qspi_apb.c | 46 ++++++++++++++++++----------------
 1 file changed, 24 insertions(+), 22 deletions(-)
diff mbox series

Patch

diff --git a/drivers/spi/cadence_qspi_apb.c b/drivers/spi/cadence_qspi_apb.c
index 176cff5338..d347cb8d47 100644
--- a/drivers/spi/cadence_qspi_apb.c
+++ b/drivers/spi/cadence_qspi_apb.c
@@ -853,19 +853,29 @@  int cadence_qspi_apb_write_setup(struct cadence_spi_priv *priv,
 
 	writel(op->addr.val, priv->regbase + CQSPI_REG_INDIRECTWRSTARTADDR);
 
-	if (priv->dtr) {
-		/*
-		 * Some flashes like the cypress Semper flash expect a 4-byte
-		 * dummy address with the Read SR command in DTR mode, but this
-		 * controller does not support sending address with the Read SR
-		 * command. So, disable write completion polling on the
-		 * controller's side. spi-nor will take care of polling the
-		 * status register.
-		 */
-		reg = readl(priv->regbase + CQSPI_REG_WR_COMPLETION_CTRL);
-		reg |= CQSPI_REG_WR_DISABLE_AUTO_POLL;
-		writel(reg, priv->regbase + CQSPI_REG_WR_COMPLETION_CTRL);
-	}
+	/*
+	 * Some flashes like the cypress Semper flash expect a 4-byte
+	 * dummy address with the Read SR command in DTR mode, but this
+	 * controller does not support sending address with the Read SR
+	 * command. So, disable write completion polling on the
+	 * controller's side. spi-nor will take care of polling the
+	 * status register.
+	 *
+	 * Theoretically, some flashes have their WIP bit in different
+	 * bit positions or have a different bit polarity. spi-nor
+	 * currently does not have an interface in place to dictate
+	 * this information to this driver for proper configuration.
+	 *
+	 * The default of the controller hardware has this status register
+	 * auto polling without expiration. This means that if there is any
+	 * controller misconfiguration or communication failure, it will
+	 * completely lock up the controller.
+	 *
+	 * Thus, unconditionally disable this feature for now.
+	 */
+	reg = readl(priv->regbase + CQSPI_REG_WR_COMPLETION_CTRL);
+	reg |= CQSPI_REG_WR_DISABLE_AUTO_POLL;
+	writel(reg, priv->regbase + CQSPI_REG_WR_COMPLETION_CTRL);
 
 	reg = readl(priv->regbase + CQSPI_REG_SIZE);
 	reg &= ~CQSPI_REG_SIZE_ADDRESS_MASK;
@@ -970,16 +980,8 @@  int cadence_qspi_apb_write_execute(struct cadence_spi_priv *priv,
 	const void *buf = op->data.buf.out;
 	size_t len = op->data.nbytes;
 
-	/*
-	 * Some flashes like the Cypress Semper flash expect a dummy 4-byte
-	 * address (all 0s) with the read status register command in DTR mode.
-	 * But this controller does not support sending dummy address bytes to
-	 * the flash when it is polling the write completion register in DTR
-	 * mode. So, we can not use direct mode when in DTR mode for writing
-	 * data.
-	 */
 	cadence_qspi_apb_enable_linear_mode(true);
-	if (!priv->dtr && priv->use_dac_mode && (to + len < priv->ahbsize)) {
+	if (priv->use_dac_mode && (to + len < priv->ahbsize)) {
 		memcpy_toio(priv->ahbbase + to, buf, len);
 		if (!cadence_qspi_wait_idle(priv->regbase))
 			return -EIO;