Re: [PATCH v2] scsi: ufs: exclude UECxx from SFR dump list

[Adrian Hunter <adrian.hunter@intel.com>]

On 8.3.2022 10.11, Kiwoong Kim wrote:
> v1 -> v2: does skipping only for zero offset
> 
> These are ROC type things that means their values
> are cleared when the SFRs are read.
> They are usually read in ISR when an UIC error occur.
> Thus, their values would be zero at many cases. And
> there might be a little bit risky when they are read to
> be cleared before the ISR reads them, e.g. the case that
> a command is timed-out, ufshcd_dump_regs is called in
> ufshcd_abort and an UIC error occurs at the nearly
> same time. In this case, ISR will be called but UFS error handler
> will not be scheduled.
> This patch is to make UFS driver not read those SFRs in the
> dump function, i.e. ufshcd_dump_regs.

This is essentially a fix, so perhaps a fixes tag?

Wouldn't hurt to wrap the commit description more nicely.

> 
> Signed-off-by: Kiwoong Kim <kwmad.kim@samsung.com>
> ---
>  drivers/scsi/ufs/ufshcd.c | 7 ++++++-
>  1 file changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
> index 460d2b4..7f2a1ed 100644
> --- a/drivers/scsi/ufs/ufshcd.c
> +++ b/drivers/scsi/ufs/ufshcd.c
> @@ -115,8 +115,13 @@ int ufshcd_dump_regs(struct ufs_hba *hba, size_t offset, size_t len,
>  	if (!regs)
>  		return -ENOMEM;
>  
> -	for (pos = 0; pos < len; pos += 4)
> +	for (pos = 0; pos < len; pos += 4) {
> +		if (offset == 0 &&

So it will still read them if the offset is not zero.  That seems unexpectedly inconsistent.

> +		    pos >= REG_UIC_ERROR_CODE_PHY_ADAPTER_LAYER &&
> +		    pos <= REG_UIC_ERROR_CODE_DME)
> +			continue;
>  		regs[pos / 4] = ufshcd_readl(hba, offset + pos);
> +	}
>  
>  	ufshcd_hex_dump(prefix, regs, len);
>  	kfree(regs);