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| author | Geert Uytterhoeven <geert+renesas@glider.be> | 2016-08-05 11:17:52 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-10-07 16:23:42 +0300 |
| commit | 0d5b1752c87c52d25484fea7ce7c24afadd8cd1c (patch) | |
| tree | 1751c0a513b0e5e68b482f79a16be6a6a870ed7b /drivers/spi/spi-sh-msiof.c | |
| parent | 1229b0840b6a846d326630a6aaa5deaf04d10120 (diff) | |
| download | linux-0d5b1752c87c52d25484fea7ce7c24afadd8cd1c.tar.xz | |
spi: sh-msiof: Avoid invalid clock generator parameters
commit c3ccf357c3d75bd2924e049b6a991f7c0c111068 upstream.
The conversion from a look-up table to a calculation for clock generator
parameters forgot to take into account that BRDV x 1/1 is valid only if
BRPS is x 1/1 or x 1/2, leading to undefined behavior (e.g. arbitrary
clock rates).
This limitation is documented for the MSIOF module in all supported
SH/R-Mobile and R-Car Gen2/Gen3 ARM SoCs.
Tested on r8a7791/koelsch and r8a7795/salvator-x.
Fixes: 65d5665bb260b034 ("spi: sh-msiof: Update calculation of frequency dividing")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/spi/spi-sh-msiof.c')
| -rw-r--r-- | drivers/spi/spi-sh-msiof.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/spi/spi-sh-msiof.c b/drivers/spi/spi-sh-msiof.c index a7934ab00b96..d22de4c8c399 100644 --- a/drivers/spi/spi-sh-msiof.c +++ b/drivers/spi/spi-sh-msiof.c @@ -263,6 +263,9 @@ static void sh_msiof_spi_set_clk_regs(struct sh_msiof_spi_priv *p, for (k = 0; k < ARRAY_SIZE(sh_msiof_spi_div_table); k++) { brps = DIV_ROUND_UP(div, sh_msiof_spi_div_table[k].div); + /* SCR_BRDV_DIV_1 is valid only if BRPS is x 1/1 or x 1/2 */ + if (sh_msiof_spi_div_table[k].div == 1 && brps > 2) + continue; if (brps <= 32) /* max of brdv is 32 */ break; } |