tree:   https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
head:   6794862a16ef41f753abd75c03a152836e4c8028
commit: 212836a9929f0c91214a8a1879e6e41be0e26a6f dma-mapping: remove dma_{alloc,free,mmap}_writecombine
date:   3 months ago
config: m68k-randconfig-a001-20191209 (attached as .config)
compiler: m68k-linux-gcc (GCC) 7.5.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        git checkout 212836a9929f0c91214a8a1879e6e41be0e26a6f
        # save the attached .config to linux build tree
        GCC_VERSION=7.5.0 make.cross ARCH=m68k 

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

All errors (new ones prefixed by >>):

   sound/core/pcm_native.c: In function 'snd_pcm_lib_default_mmap':
>> sound/core/pcm_native.c:3398:24: error: implicit declaration of function 'pgprot_writecombine' [-Werror=implicit-function-declaration]
      area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
                           ^~~~~~~~~~~~~~~~~~~
   sound/core/pcm_native.c:3398:22: error: incompatible types when assigning to type 'pgprot_t {aka struct <anonymous>}' from type 'int'
      area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
                         ^
   cc1: some warnings being treated as errors

vim +/pgprot_writecombine +3398 sound/core/pcm_native.c

^1da177e4c3f41 Linus Torvalds        2005-04-16  3379  
^1da177e4c3f41 Linus Torvalds        2005-04-16  3380  /*
^1da177e4c3f41 Linus Torvalds        2005-04-16  3381   * mmap the DMA buffer on RAM
^1da177e4c3f41 Linus Torvalds        2005-04-16  3382   */
30b771cf8c3120 Takashi Iwai          2014-10-30  3383  
30b771cf8c3120 Takashi Iwai          2014-10-30  3384  /**
30b771cf8c3120 Takashi Iwai          2014-10-30  3385   * snd_pcm_lib_default_mmap - Default PCM data mmap function
30b771cf8c3120 Takashi Iwai          2014-10-30  3386   * @substream: PCM substream
30b771cf8c3120 Takashi Iwai          2014-10-30  3387   * @area: VMA
30b771cf8c3120 Takashi Iwai          2014-10-30  3388   *
30b771cf8c3120 Takashi Iwai          2014-10-30  3389   * This is the default mmap handler for PCM data.  When mmap pcm_ops is NULL,
30b771cf8c3120 Takashi Iwai          2014-10-30  3390   * this function is invoked implicitly.
30b771cf8c3120 Takashi Iwai          2014-10-30  3391   */
18a2b962337047 Takashi Iwai          2011-09-28  3392  int snd_pcm_lib_default_mmap(struct snd_pcm_substream *substream,
877211f5e1b119 Takashi Iwai          2005-11-17  3393  			     struct vm_area_struct *area)
^1da177e4c3f41 Linus Torvalds        2005-04-16  3394  {
314e51b9851b4f Konstantin Khlebnikov 2012-10-08  3395  	area->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP;
a5606f85611267 Takashi Iwai          2013-10-24  3396  #ifdef CONFIG_GENERIC_ALLOCATOR
055032142c42d2 Nicolin Chen          2013-10-23  3397  	if (substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV_IRAM) {
055032142c42d2 Nicolin Chen          2013-10-23 @3398  		area->vm_page_prot = pgprot_writecombine(area->vm_page_prot);
055032142c42d2 Nicolin Chen          2013-10-23  3399  		return remap_pfn_range(area, area->vm_start,
055032142c42d2 Nicolin Chen          2013-10-23  3400  				substream->dma_buffer.addr >> PAGE_SHIFT,
055032142c42d2 Nicolin Chen          2013-10-23  3401  				area->vm_end - area->vm_start, area->vm_page_prot);
055032142c42d2 Nicolin Chen          2013-10-23  3402  	}
a5606f85611267 Takashi Iwai          2013-10-24  3403  #endif /* CONFIG_GENERIC_ALLOCATOR */
49d776ffb50f2e Takashi Iwai          2014-10-24  3404  #ifndef CONFIG_X86 /* for avoiding warnings arch/x86/mm/pat.c */
abe594c2cf55b4 Geert Uytterhoeven    2017-07-09  3405  	if (IS_ENABLED(CONFIG_HAS_DMA) && !substream->ops->page &&
657b1989dacf58 Takashi Iwai          2009-11-26  3406  	    substream->dma_buffer.dev.type == SNDRV_DMA_TYPE_DEV)
657b1989dacf58 Takashi Iwai          2009-11-26  3407  		return dma_mmap_coherent(substream->dma_buffer.dev.dev,
657b1989dacf58 Takashi Iwai          2009-11-26  3408  					 area,
657b1989dacf58 Takashi Iwai          2009-11-26  3409  					 substream->runtime->dma_area,
657b1989dacf58 Takashi Iwai          2009-11-26  3410  					 substream->runtime->dma_addr,
9066ae7ff5d89c Stefan Roese          2018-03-26  3411  					 substream->runtime->dma_bytes);
49d776ffb50f2e Takashi Iwai          2014-10-24  3412  #endif /* CONFIG_X86 */
657b1989dacf58 Takashi Iwai          2009-11-26  3413  	/* mmap with fault handler */
657b1989dacf58 Takashi Iwai          2009-11-26  3414  	area->vm_ops = &snd_pcm_vm_ops_data_fault;
^1da177e4c3f41 Linus Torvalds        2005-04-16  3415  	return 0;
^1da177e4c3f41 Linus Torvalds        2005-04-16  3416  }
18a2b962337047 Takashi Iwai          2011-09-28  3417  EXPORT_SYMBOL_GPL(snd_pcm_lib_default_mmap);
^1da177e4c3f41 Linus Torvalds        2005-04-16  3418  

:::::: The code at line 3398 was first introduced by commit
:::::: 055032142c42d2821c4aa617915292d6a08d56fc ALSA: Add SoC on-chip internal ram support for DMA buffer allocation

:::::: TO: Nicolin Chen <b42378@freescale.com>
:::::: CC: Takashi Iwai <tiwai@suse.de>

---
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