From e1b799dd32210d447c00b082950b730f49c4e405 Mon Sep 17 00:00:00 2001 From: Stefan Wahren Date: Wed, 12 Mar 2025 22:51:00 +0900 Subject: [PATCH] spi: spi-fsl-lpspi: Adjust type of scldiv BugLink: https://bugs.launchpad.net/bugs/2102118 [ Upstream commit fa8ecda9876ac1e7b29257aa82af1fd0695496e2 ] The target value of scldiv is just a byte, but its calculation in fsl_lpspi_set_bitrate could be negative. So use an adequate type to store the result and avoid overflows. After that this needs range check adjustments, but this should make the code less opaque. Signed-off-by: Stefan Wahren Reviewed-by: Frank Li Link: https://patch.msgid.link/20240930093056.93418-2-wahrenst@gmx.net Signed-off-by: Mark Brown Signed-off-by: Sasha Levin Signed-off-by: Koichiro Den Signed-off-by: Stefan Bader --- drivers/spi/spi-fsl-lpspi.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/drivers/spi/spi-fsl-lpspi.c b/drivers/spi/spi-fsl-lpspi.c index 514a2c5c8422..9e2541dee56e 100644 --- a/drivers/spi/spi-fsl-lpspi.c +++ b/drivers/spi/spi-fsl-lpspi.c @@ -315,9 +315,10 @@ static void fsl_lpspi_set_watermark(struct fsl_lpspi_data *fsl_lpspi) static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi) { struct lpspi_config config = fsl_lpspi->config; - unsigned int perclk_rate, scldiv, div; + unsigned int perclk_rate, div; u8 prescale_max; u8 prescale; + int scldiv; perclk_rate = clk_get_rate(fsl_lpspi->clk_per); prescale_max = fsl_lpspi->devtype_data->prescale_max; @@ -338,13 +339,13 @@ static int fsl_lpspi_set_bitrate(struct fsl_lpspi_data *fsl_lpspi) for (prescale = 0; prescale <= prescale_max; prescale++) { scldiv = div / (1 << prescale) - 2; - if (scldiv < 256) { + if (scldiv >= 0 && scldiv < 256) { fsl_lpspi->config.prescale = prescale; break; } } - if (scldiv >= 256) + if (scldiv < 0 || scldiv >= 256) return -EINVAL; writel(scldiv | (scldiv << 8) | ((scldiv >> 1) << 16),