On Mon, 29 Dec 2025 16:59:19 +0800
Shengjiu Wang <[email protected]> wrote:
> Fix below cocci warnings, the real width of val1 is 32bit, so use force
> cast to avoid warning.
I just looked at the uses of 'frac_bits' in that file.
Some of the related code looks very dubious.
The 200 has:
val = (u64)in_rate << frac_bits;
do_div(val, out_rate);
r = (uint32_t *)&val;
followed by uses of r[0] and r[1] - that probably isn't going to DTRT big endian
and will generate worse code LE than using val and val >> 32.
Line 2063 has:
val <<= (frac_bits - 31);
regmap_write(easrc->regmap, REG_EASRC_RUC(pair->index),
EASRC_RSUC_RS_RM(val));
where EASRC_RSUC_RS_RM(v) is (v) << 32
That is a lot of shift lefts on an 'int'.
The code in question can shift 'val1' right and convert to 32 bits
before ctx_priv->ratio_mod is added in.
David
>
> cocci warnings: (new ones prefixed by >>)
> >> sound/soc/fsl/fsl_easrc.c:1999:2-8: WARNING: do_div() does a 64-by-32
> >> division, please consider using div64_u64 instead.
>
> Fixes: 27147695aaf7 ("ASoC: fsl_easrc: define functions for memory to memory
> usage")
> Reported-by: kernel test robot <[email protected]>
> Closes:
> https://lore.kernel.org/oe-kbuild-all/[email protected]/
> Signed-off-by: Shengjiu Wang <[email protected]>
> ---
> sound/soc/fsl/fsl_easrc.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/sound/soc/fsl/fsl_easrc.c b/sound/soc/fsl/fsl_easrc.c
> index f404a39009e1..16a45a7146e8 100644
> --- a/sound/soc/fsl/fsl_easrc.c
> +++ b/sound/soc/fsl/fsl_easrc.c
> @@ -1996,7 +1996,7 @@ static int fsl_easrc_m2m_calc_out_len(struct
> fsl_asrc_pair *pair, int input_buff
> /* right shift 12 bit to make ratio in 32bit space */
> val2 = (u64)in_samples << (frac_bits - 12);
> val1 = val1 >> 12;
> - do_div(val2, val1);
> + do_div(val2, (u32)val1);
> out_samples = val2;
>
> out_length = out_samples * out_width * channels;
