Re: [PATCH 02/12] bcm2835-dma: Add proper 40-bit DMA support

[kernel test robot <lkp@intel.com>]

Hi Andrea,

kernel test robot noticed the following build warnings:

[auto build test WARNING on vkoul-dmaengine/next]
[also build test WARNING on linus/master v6.8-rc3 next-20240202]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Andrea-della-Porta/bcm2835-dma-Add-support-for-per-channel-flags/20240204-150430
base:   https://git.kernel.org/pub/scm/linux/kernel/git/vkoul/dmaengine.git next
patch link:    https://lore.kernel.org/r/eeb94204c30c2182f5ffd3ec083c04399ecdee32.1706948717.git.andrea.porta%40suse.com
patch subject: [PATCH 02/12] bcm2835-dma: Add proper 40-bit DMA support
config: arm-defconfig (https://download.01.org/0day-ci/archive/20240205/202402050701.GXVPwpd1-lkp@intel.com/config)
compiler: clang version 14.0.6 (https://github.com/llvm/llvm-project.git f28c006a5895fc0e329fe15fead81e37457cb1d1)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240205/202402050701.GXVPwpd1-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202402050701.GXVPwpd1-lkp@intel.com/

All warnings (new ones prefixed by >>):

>> drivers/dma/bcm2835-dma.c:1175:5: warning: no previous prototype for function 'bcm2711_dma40_memcpy_init' [-Wmissing-prototypes]
   int bcm2711_dma40_memcpy_init(void)
       ^
   drivers/dma/bcm2835-dma.c:1175:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   int bcm2711_dma40_memcpy_init(void)
   ^
   static 
>> drivers/dma/bcm2835-dma.c:1190:6: warning: no previous prototype for function 'bcm2711_dma40_memcpy' [-Wmissing-prototypes]
   void bcm2711_dma40_memcpy(dma_addr_t dst, dma_addr_t src, size_t size)
        ^
   drivers/dma/bcm2835-dma.c:1190:1: note: declare 'static' if the function is not intended to be used outside of this translation unit
   void bcm2711_dma40_memcpy(dma_addr_t dst, dma_addr_t src, size_t size)
   ^
   static 
   2 warnings generated.
--
>> drivers/dma/bcm2835-dma.c:57: warning: Function parameter or struct member 'cfg_data' not described in 'bcm2835_dmadev'


vim +/bcm2711_dma40_memcpy_init +1175 drivers/dma/bcm2835-dma.c

  1174	
> 1175	int bcm2711_dma40_memcpy_init(void)
  1176	{
  1177		if (!memcpy_parent)
  1178			return -EPROBE_DEFER;
  1179	
  1180		if (!memcpy_chan)
  1181			return -EINVAL;
  1182	
  1183		if (!memcpy_scb)
  1184			return -ENOMEM;
  1185	
  1186		return 0;
  1187	}
  1188	EXPORT_SYMBOL(bcm2711_dma40_memcpy_init);
  1189	
> 1190	void bcm2711_dma40_memcpy(dma_addr_t dst, dma_addr_t src, size_t size)
  1191	{
  1192		struct bcm2711_dma40_scb *scb = memcpy_scb;
  1193		unsigned long flags;
  1194	
  1195		if (!scb) {
  1196			pr_err("%s not initialised!\n", __func__);
  1197			return;
  1198		}
  1199	
  1200		spin_lock_irqsave(&memcpy_lock, flags);
  1201	
  1202		scb->ti = 0;
  1203		scb->src = lower_32_bits(src);
  1204		scb->srci = upper_32_bits(src) | BCM2711_DMA40_MEMCPY_XFER_INFO;
  1205		scb->dst = lower_32_bits(dst);
  1206		scb->dsti = upper_32_bits(dst) | BCM2711_DMA40_MEMCPY_XFER_INFO;
  1207		scb->len = size;
  1208		scb->next_cb = 0;
  1209	
  1210		writel((u32)(memcpy_scb_dma >> 5), memcpy_chan + BCM2711_DMA40_CB);
  1211		writel(BCM2711_DMA40_MEMCPY_FLAGS + BCM2711_DMA40_ACTIVE,
  1212		       memcpy_chan + BCM2711_DMA40_CS);
  1213	
  1214		/* Poll for completion */
  1215		while (!(readl(memcpy_chan + BCM2711_DMA40_CS) & BCM2711_DMA40_END))
  1216			cpu_relax();
  1217	
  1218		writel(BCM2711_DMA40_END, memcpy_chan + BCM2711_DMA40_CS);
  1219	
  1220		spin_unlock_irqrestore(&memcpy_lock, flags);
  1221	}
  1222	EXPORT_SYMBOL(bcm2711_dma40_memcpy);
  1223	

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