[mingo-tip:sched/headers 2357/2384] drivers/usb/chipidea/ci.h:427:32: error: implicit declaration of function '__ffs'

[kernel test robot]

tree:   git://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git sched/headers
head:   4c707c1c0de83967079b4e385012fa5b00e2cd11
commit: 61ea5a6fab5c8fae043a02a100970041dc6a877e [2357/2384] headers/deps: delay: Optimize <linux/delay.h> dependencies, remove <linux/sched.h> inclusion
config: mips-randconfig-m031-20220124 (https://download.01.org/0day-ci/archive/20220125/202201251220.wdEh9zG4-lkp@xxxxxxxxx/config)
compiler: mips64-linux-gcc (GCC) 11.2.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git/commit/?id=61ea5a6fab5c8fae043a02a100970041dc6a877e
        git remote add mingo-tip git://git.kernel.org/pub/scm/linux/kernel/git/mingo/tip.git
        git fetch --no-tags mingo-tip sched/headers
        git checkout 61ea5a6fab5c8fae043a02a100970041dc6a877e
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-11.2.0 make.cross O=build_dir ARCH=mips SHELL=/bin/bash drivers/usb/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@xxxxxxxxx>

All errors (new ones prefixed by >>):

   In file included from drivers/usb/chipidea/otg.c:23:
   drivers/usb/chipidea/ci.h: In function 'hw_test_and_write':
>> drivers/usb/chipidea/ci.h:427:32: error: implicit declaration of function '__ffs' [-Werror=implicit-function-declaration]
     427 |         return (val & mask) >> __ffs(mask);
         |                                ^~~~~
   cc1: some warnings being treated as errors


vim +/__ffs +427 drivers/usb/chipidea/ci.h

e443b333629f82 Alexander Shishkin 2012-05-11  411  
e443b333629f82 Alexander Shishkin 2012-05-11  412  /**
e443b333629f82 Alexander Shishkin 2012-05-11  413   * hw_test_and_write: tests & writes a hw register
19353881b4afc9 Peter Chen         2014-09-22  414   * @ci: the controller
e443b333629f82 Alexander Shishkin 2012-05-11  415   * @reg:  register index
e443b333629f82 Alexander Shishkin 2012-05-11  416   * @mask: bitfield mask
e443b333629f82 Alexander Shishkin 2012-05-11  417   * @data: new value
e443b333629f82 Alexander Shishkin 2012-05-11  418   *
e443b333629f82 Alexander Shishkin 2012-05-11  419   * This function returns register contents
e443b333629f82 Alexander Shishkin 2012-05-11  420   */
8e22978c57087a Alexander Shishkin 2013-06-24  421  static inline u32 hw_test_and_write(struct ci_hdrc *ci, enum ci_hw_regs reg,
e443b333629f82 Alexander Shishkin 2012-05-11  422  				    u32 mask, u32 data)
e443b333629f82 Alexander Shishkin 2012-05-11  423  {
26c696c678c4ce Richard Zhao       2012-07-07  424  	u32 val = hw_read(ci, reg, ~0);
e443b333629f82 Alexander Shishkin 2012-05-11  425  
26c696c678c4ce Richard Zhao       2012-07-07  426  	hw_write(ci, reg, mask, data);
727b4ddb48dcd8 Felipe Balbi       2013-03-30 @427  	return (val & mask) >> __ffs(mask);
e443b333629f82 Alexander Shishkin 2012-05-11  428  }
e443b333629f82 Alexander Shishkin 2012-05-11  429  

:::::: The code at line 427 was first introduced by commit
:::::: 727b4ddb48dcd8c9ca81b58ca58191233bdf75aa usb: chipidea: don't redefine __ffs()

:::::: TO: Felipe Balbi <balbi@xxxxxx>
:::::: CC: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@xxxxxxxxxxxx