Re: [soc:broadcom/drivers 2/4] drivers/soc/bcm/bcm63xx/bcm-pmb.c:103:45: sparse: sparse: cast to restricted __le32

On 10.02.2021 22:48, kernel test robot wrote:

tree:   https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git broadcom/drivers
head:   8b8f095b9076ca61107c0910c9273afd1dfa1f04
commit: 8bcac4011ebe0dbdd46fd55b036ee855c95702d3 [2/4] soc: bcm: add PM driver for Broadcom's PMB
config: i386-randconfig-s002-20210211 (attached as .config)
compiler: gcc-9 (Debian 9.3.0-15) 9.3.0
reproduce:
         # apt-get install sparse
         # sparse version: v0.6.3-215-g0fb77bb6-dirty
         # https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git/commit/?id=8bcac4011ebe0dbdd46fd55b036ee855c95702d3
         git remote add soc https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git
         git fetch --no-tags soc broadcom/drivers
         git checkout 8bcac4011ebe0dbdd46fd55b036ee855c95702d3
         # save the attached .config to linux build tree
         make W=1 C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' ARCH=i386

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


"sparse warnings: (new ones prefixed by >>)"
    drivers/soc/bcm/bcm63xx/bcm-pmb.c:103:65: sparse: sparse: cast to restricted __be32
    drivers/soc/bcm/bcm63xx/bcm-pmb.c:103:65: sparse: sparse: cast to restricted __be32
    drivers/soc/bcm/bcm63xx/bcm-pmb.c:103:65: sparse: sparse: cast to restricted __be32
    drivers/soc/bcm/bcm63xx/bcm-pmb.c:103:65: sparse: sparse: cast to restricted __be32
    drivers/soc/bcm/bcm63xx/bcm-pmb.c:103:65: sparse: sparse: cast to restricted __be32
    drivers/soc/bcm/bcm63xx/bcm-pmb.c:103:65: sparse: sparse: cast to restricted __be32

quoted

quoted

drivers/soc/bcm/bcm63xx/bcm-pmb.c:103:45: sparse: sparse: cast to restricted __le32
drivers/soc/bcm/bcm63xx/bcm-pmb.c:115:36: sparse: sparse: restricted __le32 degrades to integer

    drivers/soc/bcm/bcm63xx/bcm-pmb.c:115:55: sparse: sparse: restricted __be32 degrades to integer

vim +103 drivers/soc/bcm/bcm63xx/bcm-pmb.c

     90	
     91	static int bcm_pmb_bpcm_read(struct bcm_pmb *pmb, int bus, u8 device,
     92				     int offset, u32 *val)
     93	{
     94		void __iomem *base = pmb->base + bus * 0x20;
     95		unsigned long flags;
     96		int err;
     97	
     98		spin_lock_irqsave(&pmb->lock, flags);
     99		err = bpcm_rd(base, device, offset, val);
    100		spin_unlock_irqrestore(&pmb->lock, flags);
    101	
    102		if (!err)
  > 103			*val = pmb->little_endian ? le32_to_cpu(*val) : be32_to_cpu(*val);
    104	
    105		return err;
    106	}
    107	
    108	static int bcm_pmb_bpcm_write(struct bcm_pmb *pmb, int bus, u8 device,
    109				      int offset, u32 val)
    110	{
    111		void __iomem *base = pmb->base + bus * 0x20;
    112		unsigned long flags;
    113		int err;
    114	
  > 115		val = pmb->little_endian ? cpu_to_le32(val) : cpu_to_be32(val);
    116	
    117		spin_lock_irqsave(&pmb->lock, flags);
    118		err = bpcm_wr(base, device, offset, val);
    119		spin_unlock_irqrestore(&pmb->lock, flags);
    120	
    121		return err;
    122	}
    123	

Florian: can you review above code & verify my logic is correct there?
That I need to use le32_to_cpu() / be32_to_cpu() on the readl() value?

Assuming my logic is correct, above code doesn't use __le32 / __be32 as
that would require extra variables and code paths. Current code is quite
simple & clear.

Is there any way of avoiding those sparse warnings?

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