From 10b4640833e95eeacaef8060bc1b35e636df3218 Mon Sep 17 00:00:00 2001 From: Vladimir Zapolskiy Date: Fri, 13 Apr 2018 15:44:16 +0300 Subject: [PATCH] spi: sh-msiof: Fix bit field overflow writes to TSCR/RSCR The change fixes a bit field overflow which allows to write to higher bits while calculating SPI transfer clock and setting BRPS and BRDV bit fields, the problem is reproduced if 'parent_rate' to 'spi_hz' ratio is greater than 1024, for instance p->min_div = 2, MSO rate = 33333333, SPI device rate = 10000 results in k = 5, i.e. BRDV = 0b100 or 1/32 prescaler output, BRPS = 105, TSCR value = 0x6804, thus MSSEL and MSIMM bit fields are non-zero. Fixes: 65d5665bb260 ("spi: sh-msiof: Update calculation of frequency dividing") Signed-off-by: Vladimir Zapolskiy Signed-off-by: Mark Brown --- drivers/spi/spi-sh-msiof.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c index ae086aab57d5..8171eedbfc90 100644 --- a/drivers/spi/spi-sh-msiof.c +++ b/drivers/spi/spi-sh-msiof.c @@ -283,6 +283,7 @@ static void sh_msiof_spi_set_clk_regs(struct sh_msiof_spi_priv *p, } k = min_t(int, k, ARRAY_SIZE(sh_msiof_spi_div_table) - 1); + brps = min_t(int, brps, 32); scr = sh_msiof_spi_div_table[k].brdv | SCR_BRPS(brps); sh_msiof_write(p, TSCR, scr); -- 2.20.1