From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: stable@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	patches@lists.linux.dev,
	Larisa Grigore <larisa.grigore@nxp.com>,
	James Clark <james.clark@linaro.org>,
	Mark Brown <broonie@kernel.org>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 6.1 537/609] spi: spi-fsl-dspi: Avoid setup_accel logic for DMA transfers
Date: Mon, 17 Aug 2026 15:33:53 +0200
Message-ID: <20260817132601.738397741@linuxfoundation.org>
In-Reply-To: <20260817132543.039278408@linuxfoundation.org>
References: <20260817132543.039278408@linuxfoundation.org>
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6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Larisa Grigore <larisa.grigore@nxp.com>

[ Upstream commit cac7e5054115fcc41b1cb050af8e8971f7c9b22b ]

Repacking multiple smaller words into larger ones to make use of the
full FIFO doesn't save anything in DMA mode, so don't bother doing it.

Signed-off-by: Larisa Grigore <larisa.grigore@nxp.com>
Signed-off-by: James Clark <james.clark@linaro.org>
Link: https://patch.msgid.link/20250522-james-nxp-spi-v2-8-bea884630cfb@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-fsl-dspi.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 3a33156f52740..840b97ae6ec30 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -751,8 +751,12 @@ static void dspi_setup_accel(struct fsl_dspi *dspi)
 	struct spi_transfer *xfer = dspi->cur_transfer;
 	bool odd = !!(dspi->len & 1);
 
-	/* No accel for frames not multiple of 8 bits at the moment */
-	if (xfer->bits_per_word % 8)
+	/*
+	 * No accel for DMA transfers or frames not multiples of 8 bits at the
+	 * moment.
+	 */
+	if (dspi->devtype_data->trans_mode == DSPI_DMA_MODE ||
+	    xfer->bits_per_word % 8)
 		goto no_accel;
 
 	if (!odd && dspi->len <= dspi->devtype_data->fifo_size * 2) {
@@ -761,10 +765,7 @@ static void dspi_setup_accel(struct fsl_dspi *dspi)
 		dspi->oper_bits_per_word = 8;
 	} else {
 		/* Start off with maximum supported by hardware */
-		if (dspi->devtype_data->trans_mode == DSPI_XSPI_MODE)
-			dspi->oper_bits_per_word = 32;
-		else
-			dspi->oper_bits_per_word = 16;
+		dspi->oper_bits_per_word = 32;
 
 		/*
 		 * And go down only if the buffer can't be sent with
-- 
2.53.0