[linux-next:master 4831/7265] drivers/fpga/zynq-fpga.c:246:14: warning: result of comparison of constant 170 with expression of type 'const char' is always false

[linux-next:master 4831/7265] drivers/fpga/zynq-fpga.c:246:14: warning: result of comparison of constant 170 with expression of type 'const char' is always false

[kernel test robot]

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
head:   f02ac5c95dfd45d2f50ecc68d79177de326c668c
commit: ada14a023a641107da1ada546e1d345ca3dc78a5 [4831/7265] fpga: zynq: Fix incorrect variable type
config: mips-randconfig-r011-20220427 (https://download.01.org/0day-ci/archive/20220427/202204272019.5oBcDYmF-lkp@intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project 1cddcfdc3c683b393df1a5c9063252eb60e52818)
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
        # install mips cross compiling tool for clang build
        # apt-get install binutils-mips-linux-gnu
        # https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?id=ada14a023a641107da1ada546e1d345ca3dc78a5
        git remote add linux-next https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
        git fetch --no-tags linux-next master
        git checkout ada14a023a641107da1ada546e1d345ca3dc78a5
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash drivers/fpga/

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

All warnings (new ones prefixed by >>):

>> drivers/fpga/zynq-fpga.c:246:14: warning: result of comparison of constant 170 with expression of type 'const char' is always false [-Wtautological-constant-out-of-range-compare]
                       buf[3] == 0xaa)
                       ~~~~~~ ^  ~~~~
   drivers/fpga/zynq-fpga.c:245:50: warning: result of comparison of constant 153 with expression of type 'const char' is always false [-Wtautological-constant-out-of-range-compare]
                   if (buf[0] == 0x66 && buf[1] == 0x55 && buf[2] == 0x99 &&
                                                           ~~~~~~ ^  ~~~~
   2 warnings generated.


vim +246 drivers/fpga/zynq-fpga.c

37784706bf9e3b Moritz Fischer     2015-10-16  237  
b496df86ac1bbe Jason Gunthorpe    2017-02-01  238  /* Sanity check the proposed bitstream. It must start with the sync word in
b496df86ac1bbe Jason Gunthorpe    2017-02-01  239   * the correct byte order, and be dword aligned. The input is a Xilinx .bin
b496df86ac1bbe Jason Gunthorpe    2017-02-01  240   * file with every 32 bit quantity swapped.
b496df86ac1bbe Jason Gunthorpe    2017-02-01  241   */
ada14a023a6411 Nava kishore Manne 2022-04-21  242  static bool zynq_fpga_has_sync(const char *buf, size_t count)
b496df86ac1bbe Jason Gunthorpe    2017-02-01  243  {
b496df86ac1bbe Jason Gunthorpe    2017-02-01  244  	for (; count >= 4; buf += 4, count -= 4)
b496df86ac1bbe Jason Gunthorpe    2017-02-01  245  		if (buf[0] == 0x66 && buf[1] == 0x55 && buf[2] == 0x99 &&
b496df86ac1bbe Jason Gunthorpe    2017-02-01 @246  		    buf[3] == 0xaa)
b496df86ac1bbe Jason Gunthorpe    2017-02-01  247  			return true;
b496df86ac1bbe Jason Gunthorpe    2017-02-01  248  	return false;
b496df86ac1bbe Jason Gunthorpe    2017-02-01  249  }
b496df86ac1bbe Jason Gunthorpe    2017-02-01  250  

:::::: The code at line 246 was first introduced by commit
:::::: b496df86ac1bbe393a55ddbfed35d46e74ef9767 fpga zynq: Check the bitstream for validity

:::::: TO: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
:::::: CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

-- 
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https://01.org/lkp