linux-kernel - [PATCH 5.15 344/917] spi: Fixed division by zero warning

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Message-Id: <20211115165440.410904383@linuxfoundation.org>
Date:   Mon, 15 Nov 2021 17:57:19 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Yoshitaka Ikeda <ikeda@...int.co.jp>,
        Pratyush Yadav <p.yadav@...com>,
        Mark Brown <broonie@...nel.org>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.15 344/917] spi: Fixed division by zero warning

From: Yoshitaka Ikeda <ikeda@...int.co.jp>

[ Upstream commit 09134c5322df9f105d9ed324051872d5d0e162aa ]

The reason for dividing by zero is because the dummy bus width is zero,
but if the dummy n bytes is zero, it indicates that there is no data transfer,
so there is no need for calculation.

Fixes: 7512eaf54190 ("spi: cadence-quadspi: Fix dummy cycle calculation when buswidth > 1")
Signed-off-by: Yoshitaka Ikeda <ikeda@...int.co.jp>
Acked-by: Pratyush Yadav <p.yadav@...com>
Link: https://lore.kernel.org/r/OSZPR01MB70049C8F56ED8902852DF97B8BD49@OSZPR01MB7004.jpnprd01.prod.outlook.com
Signed-off-by: Mark Brown <broonie@...nel.org>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 drivers/spi/atmel-quadspi.c  | 2 +-
 drivers/spi/spi-bcm-qspi.c   | 3 ++-
 drivers/spi/spi-mtk-nor.c    | 2 +-
 drivers/spi/spi-stm32-qspi.c | 2 +-
 4 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/atmel-quadspi.c b/drivers/spi/atmel-quadspi.c
index 95d4fa32c2995..92d9610df1fd8 100644
--- a/drivers/spi/atmel-quadspi.c
+++ b/drivers/spi/atmel-quadspi.c
@@ -310,7 +310,7 @@ static int atmel_qspi_set_cfg(struct atmel_qspi *aq,
 		return mode;
 	ifr |= atmel_qspi_modes[mode].config;
 
-	if (op->dummy.buswidth && op->dummy.nbytes)
+	if (op->dummy.nbytes)
 		dummy_cycles = op->dummy.nbytes * 8 / op->dummy.buswidth;
 
 	/*
diff --git a/drivers/spi/spi-bcm-qspi.c b/drivers/spi/spi-bcm-qspi.c
index ea1865c08fc22..151e154284bde 100644
--- a/drivers/spi/spi-bcm-qspi.c
+++ b/drivers/spi/spi-bcm-qspi.c
@@ -395,7 +395,8 @@ static int bcm_qspi_bspi_set_flex_mode(struct bcm_qspi *qspi,
 	if (addrlen == BSPI_ADDRLEN_4BYTES)
 		bpp = BSPI_BPP_ADDR_SELECT_MASK;
 
-	bpp |= (op->dummy.nbytes * 8) / op->dummy.buswidth;
+	if (op->dummy.nbytes)
+		bpp |= (op->dummy.nbytes * 8) / op->dummy.buswidth;
 
 	switch (width) {
 	case SPI_NBITS_SINGLE:
diff --git a/drivers/spi/spi-mtk-nor.c b/drivers/spi/spi-mtk-nor.c
index 41e7b341d2616..5c93730615f8d 100644
--- a/drivers/spi/spi-mtk-nor.c
+++ b/drivers/spi/spi-mtk-nor.c
@@ -160,7 +160,7 @@ static bool mtk_nor_match_read(const struct spi_mem_op *op)
 {
 	int dummy = 0;
 
-	if (op->dummy.buswidth)
+	if (op->dummy.nbytes)
 		dummy = op->dummy.nbytes * BITS_PER_BYTE / op->dummy.buswidth;
 
 	if ((op->data.buswidth == 2) || (op->data.buswidth == 4)) {
diff --git a/drivers/spi/spi-stm32-qspi.c b/drivers/spi/spi-stm32-qspi.c
index 27f35aa2d746d..514337c86d2c3 100644
--- a/drivers/spi/spi-stm32-qspi.c
+++ b/drivers/spi/spi-stm32-qspi.c
@@ -397,7 +397,7 @@ static int stm32_qspi_send(struct spi_mem *mem, const struct spi_mem_op *op)
 		ccr |= FIELD_PREP(CCR_ADSIZE_MASK, op->addr.nbytes - 1);
 	}
 
-	if (op->dummy.buswidth && op->dummy.nbytes)
+	if (op->dummy.nbytes)
 		ccr |= FIELD_PREP(CCR_DCYC_MASK,
 				  op->dummy.nbytes * 8 / op->dummy.buswidth);
 
-- 
2.33.0