From 30554a1f0fd6a5d2e2413bdc05389995d5611736 Mon Sep 17 00:00:00 2001 From: =?utf8?q?C=C3=A9dric=20Le=20Goater?= Date: Wed, 22 Jun 2022 18:16:17 +0200 Subject: [PATCH] spi: aspeed: Fix division by zero MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When using the normal read operation for data transfers, the dummy bus width is zero. In that case, they are no dummy bytes to transfer and setting the dummy field in the controller register becomes useless. Issue was found on a custom "Bifrost" board based on the AST2500 SoC and using a MX25L51245GMI-08G SPI Flash. Reported-by: Ian Woloschin Reviewed-by: Pratyush Yadav Tested-by: Ian Woloschin Fixes: 9da06d7bdec7dad80 ("spi: aspeed: Add support for direct mapping") Signed-off-by: Cédric Le Goater Link: https://lore.kernel.org/r/20220622161617.3719096-3-clg@kaod.org Signed-off-by: Mark Brown --- drivers/spi/spi-aspeed-smc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/spi/spi-aspeed-smc.c b/drivers/spi/spi-aspeed-smc.c index ac64be289e599..3e891bf22470e 100644 --- a/drivers/spi/spi-aspeed-smc.c +++ b/drivers/spi/spi-aspeed-smc.c @@ -582,9 +582,11 @@ static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc) ctl_val = readl(chip->ctl) & ~CTRL_IO_CMD_MASK; ctl_val |= aspeed_spi_get_io_mode(op) | op->cmd.opcode << CTRL_COMMAND_SHIFT | - CTRL_IO_DUMMY_SET(op->dummy.nbytes / op->dummy.buswidth) | CTRL_IO_MODE_READ; + if (op->dummy.nbytes) + ctl_val |= CTRL_IO_DUMMY_SET(op->dummy.nbytes / op->dummy.buswidth); + /* Tune 4BYTE address mode */ if (op->addr.nbytes) { u32 addr_mode = readl(aspi->regs + CE_CTRL_REG); -- 2.30.2