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| author | Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com> | 2018-04-13 15:44:16 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-06-20 22:02:41 +0300 |
| commit | 3ca7dddaa13f8e7f4e618bf54dad2d18e9efc251 (patch) | |
| tree | 5357859e49db9c6715b17ece20c47d6e0edc15d4 | |
| parent | b3ccb8a77ed11c366fe8d3c3d64a71b5ddf44a75 (diff) | |
| download | linux-3ca7dddaa13f8e7f4e618bf54dad2d18e9efc251.tar.xz | |
spi: sh-msiof: Fix bit field overflow writes to TSCR/RSCR
[ Upstream commit 10b4640833e95eeacaef8060bc1b35e636df3218 ]
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 <vladimir_zapolskiy@mentor.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/spi/spi-sh-msiof.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c index 2770fbd4ce49..52056535f54e 100644 --- a/drivers/spi/spi-sh-msiof.c +++ b/drivers/spi/spi-sh-msiof.c @@ -277,6 +277,7 @@ 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); |