linux-kernel - Re: [RFC PATCH] mtd: lpddr: Fix bad logic in print_drs

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Date:   Mon, 27 Apr 2020 15:29:13 +0200
From:   Miquel Raynal <miquel.raynal@...tlin.com>
To:     Joe Perches <joe@...ches.com>
Cc:     Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        linux-mtd@...ts.infradead.org,
        linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: [RFC PATCH] mtd: lpddr: Fix bad logic in print_drs_error

Hi Joe,

Joe Perches <joe@...ches.com> wrote on Mon, 30 Mar 2020 12:56:59 -0700:

> Update logic for broken test.
> Use a more common logging style.
> 
> Miscellanea:
> 
> o Coalesce formats
> 
> Signed-off-by: Joe Perches <joe@...ches.com>
> ---
> 
> Found by inspection of include files using printk.
> 
> It appears the logic in this function is broken for the
> consecutive tests of
> 
> 	if (prog_status & 0x3)
> 		...
> 	else if (prog_status & 0x2)
> 		...
> 	else (prog_status & 0x1)
> 		...
> 
> Likely the first test should be
> 
> 	if ((prog_status & 0x3) == 0x3)

I had a hard time understanding the patch just with the commit log, I
think the above text is as important.

In fact, would you mind doing the printk->pr_notice in a first patch,
and fix the wrong condition in a separate change?

> 
> And this function is only used in drivers/mtd/lpddr/lpddr_cmds.c
> perhaps it should be moved there.

Agreed, do not hesitate to move the function as suggested in a third
patch.

> 
>  include/linux/mtd/pfow.h | 31 ++++++++++++++-----------------
>  1 file changed, 14 insertions(+), 17 deletions(-)
> 
> diff --git a/include/linux/mtd/pfow.h b/include/linux/mtd/pfow.h
> index 122f343..1c08e75 100644
> --- a/include/linux/mtd/pfow.h
> +++ b/include/linux/mtd/pfow.h
> @@ -127,31 +127,28 @@ static inline void print_drs_error(unsigned dsr)
>  	int prog_status = (dsr & DSR_RPS) >> 8;
>  
>  	if (!(dsr & DSR_AVAILABLE))
> -		printk(KERN_NOTICE"DSR.15: (0) Device not Available\n");
> -	if (prog_status & 0x03)
> -		printk(KERN_NOTICE"DSR.9,8: (11) Attempt to program invalid "
> -						"half with 41h command\n");
> +		pr_notice("DSR.15: (0) Device not Available\n");
> +
> +	if ((prog_status & 0x03) == 0x03)
> +		pr_notice("DSR.9,8: (11) Attempt to program invalid half with 41h command\n");
>  	else if (prog_status & 0x02)
> -		printk(KERN_NOTICE"DSR.9,8: (10) Object Mode Program attempt "
> -					"in region with Control Mode data\n");
> +		pr_notice("DSR.9,8: (10) Object Mode Program attempt in region with Control Mode data\n");
>  	else if (prog_status &  0x01)
> -		printk(KERN_NOTICE"DSR.9,8: (01) Program attempt in region "
> -						"with Object Mode data\n");
> +		pr_notice("DSR.9,8: (01) Program attempt in region with Object Mode data\n");
> +
>  	if (!(dsr & DSR_READY_STATUS))
> -		printk(KERN_NOTICE"DSR.7: (0) Device is Busy\n");
> +		pr_notice("DSR.7: (0) Device is Busy\n");
>  	if (dsr & DSR_ESS)
> -		printk(KERN_NOTICE"DSR.6: (1) Erase Suspended\n");
> +		pr_notice("DSR.6: (1) Erase Suspended\n");
>  	if (dsr & DSR_ERASE_STATUS)
> -		printk(KERN_NOTICE"DSR.5: (1) Erase/Blank check error\n");
> +		pr_notice("DSR.5: (1) Erase/Blank check error\n");
>  	if (dsr & DSR_PROGRAM_STATUS)
> -		printk(KERN_NOTICE"DSR.4: (1) Program Error\n");
> +		pr_notice("DSR.4: (1) Program Error\n");
>  	if (dsr & DSR_VPPS)
> -		printk(KERN_NOTICE"DSR.3: (1) Vpp low detect, operation "
> -					"aborted\n");
> +		pr_notice("DSR.3: (1) Vpp low detect, operation aborted\n");
>  	if (dsr & DSR_PSS)
> -		printk(KERN_NOTICE"DSR.2: (1) Program suspended\n");
> +		pr_notice("DSR.2: (1) Program suspended\n");
>  	if (dsr & DSR_DPS)
> -		printk(KERN_NOTICE"DSR.1: (1) Aborted Erase/Program attempt "
> -					"on locked block\n");
> +		pr_notice("DSR.1: (1) Aborted Erase/Program attempt on locked block\n");
>  }
>  #endif /* __LINUX_MTD_PFOW_H */
> 
> 

Thanks,
Miquèl