Re: [PATCH v2] clk: imx: Use div64_ul instead of do_div

From: Abel Vesa
Date: Mon Nov 22 2021 - 08:28:17 EST


On 21-11-18 08:06:34, cgel.zte@xxxxxxxxx wrote:
> From: Changcheng Deng <deng.changcheng@xxxxxxxxxx>
>
> do_div() does a 64-by-32 division. Here the divisor is an unsigned long
> which on some platforms is 64 bit wide. So use div64_ul instead of do_div
> to avoid a possible truncation.
>
> Reported-by: Zeal Robot <zealci@xxxxxxxxxx>
> Signed-off-by: Changcheng Deng <deng.changcheng@xxxxxxxxxx>

Reviewed-by: Abel Vesa <abel.vesa@xxxxxxx>

> ---
> drivers/clk/imx/clk-pllv3.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/clk/imx/clk-pllv3.c b/drivers/clk/imx/clk-pllv3.c
> index 20ee9611ba6e..55497e0585a6 100644
> --- a/drivers/clk/imx/clk-pllv3.c
> +++ b/drivers/clk/imx/clk-pllv3.c
> @@ -247,7 +247,7 @@ static long clk_pllv3_av_round_rate(struct clk_hw *hw, unsigned long rate,
> div = rate / parent_rate;
> temp64 = (u64) (rate - div * parent_rate);
> temp64 *= mfd;
> - do_div(temp64, parent_rate);
> + temp64 = div64_ul(temp64, parent_rate);
> mfn = temp64;
>
> temp64 = (u64)parent_rate;
> @@ -277,7 +277,7 @@ static int clk_pllv3_av_set_rate(struct clk_hw *hw, unsigned long rate,
> div = rate / parent_rate;
> temp64 = (u64) (rate - div * parent_rate);
> temp64 *= mfd;
> - do_div(temp64, parent_rate);
> + temp64 = div64_ul(temp64, parent_rate);
> mfn = temp64;
>
> val = readl_relaxed(pll->base);
> @@ -334,7 +334,7 @@ static struct clk_pllv3_vf610_mf clk_pllv3_vf610_rate_to_mf(
> /* rate = parent_rate * (mfi + mfn/mfd) */
> temp64 = rate - parent_rate * mf.mfi;
> temp64 *= mf.mfd;
> - do_div(temp64, parent_rate);
> + temp64 = div64_ul(temp64, parent_rate);
> mf.mfn = temp64;
> }
>
> --
> 2.25.1
>