Re: [PATCH v12 2/5] clk: imx: add fractional PLL output clock

From: Stephen Boyd
Date: Fri Nov 09 2018 - 12:25:31 EST


Quoting kbuild test robot (2018-11-09 02:18:24)
> Hi Lucas,
>
> I love your patch! Yet something to improve:
>
> [auto build test ERROR on shawnguo/for-next]
> [also build test ERROR on v4.20-rc1 next-20181109]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
>
> url: https://github.com/0day-ci/linux/commits/Abel-Vesa/Add-i-MX8MQ-clock-driver/20181109-063930
> base: https://git.kernel.org/pub/scm/linux/kernel/git/shawnguo/linux.git for-next
> config: arm-multi_v5_defconfig (attached as .config)
> compiler: arm-linux-gnueabi-gcc (Debian 7.2.0-11) 7.2.0
> reproduce:
> wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # save the attached .config to linux build tree
> GCC_VERSION=7.2.0 make.cross ARCH=arm
>
> All errors (new ones prefixed by >>):
>
> drivers/clk/imx/clk-frac-pll.o: In function `clk_pll_recalc_rate':
> >> clk-frac-pll.c:(.text+0x74): undefined reference to `__aeabi_uldivmod'
> drivers/clk/imx/clk-frac-pll.o: In function `clk_pll_round_rate':
> clk-frac-pll.c:(.text+0xbc): undefined reference to `__aeabi_uldivmod'
>

Why does the code do essentially:

u64 val;

do_div(val, div);
val /= div2;

That should be using do_div() twice it seems.