Re: [RESEND PATCH v2 9/9] ath5k: Constify ioreadX() iomem argument (as in generic implementation)

From: Jiri Slaby <jirislaby@gmail.com>
To: Krzysztof Kozlowski <krzk@kernel.org>,
	Richard Henderson <rth@twiddle.net>,
	Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
	Matt Turner <mattst88@gmail.com>,
	Alexey Brodkin <abrodkin@synopsys.com>,
	Vineet Gupta <vgupta@synopsys.com>,
	"James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
	Helge Deller <deller@gmx.de>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Yoshinori Sato <ysato@users.sourceforge.jp>,
	Rich Felker <dalias@libc.org>, Dave Airlie <airlied@redhat.com>,
	David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
	Ben Skeggs <bskeggs@redhat.com>,
	Mauro Carvalho Chehab <mchehab@kernel.org>,
	Nick Kossifidis <mickflemm@gmail.com>,
	Lui
Subject: Re: [RESEND PATCH v2 9/9] ath5k: Constify ioreadX() iomem argument (as in generic implementation)
Date: Thu, 20 Feb 2020 10:48:33 +0100	[thread overview]
Message-ID: <518a9023-f802-17b3-fca5-582400bc34ae__42884.5047064655$1582192127$gmane$org@gmail.com> (raw)
In-Reply-To: <20200219175007.13627-10-krzk@kernel.org>

On 19. 02. 20, 18:50, Krzysztof Kozlowski wrote:
> The ioreadX() helpers have inconsistent interface.  On some architectures
> void *__iomem address argument is a pointer to const, on some not.
> 
> Implementations of ioreadX() do not modify the memory under the address
> so they can be converted to a "const" version for const-safety and
> consistency among architectures.
> 
> Signed-off-by: Krzysztof Kozlowski <krzk@kernel.org>
> Acked-by: Kalle Valo <kvalo@codeaurora.org>
> ---
>  drivers/net/wireless/ath/ath5k/ahb.c | 10 +++++-----
>  1 file changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/wireless/ath/ath5k/ahb.c b/drivers/net/wireless/ath/ath5k/ahb.c
> index 2c9cec8b53d9..8bd01df369fb 100644
> --- a/drivers/net/wireless/ath/ath5k/ahb.c
> +++ b/drivers/net/wireless/ath/ath5k/ahb.c
> @@ -138,18 +138,18 @@ static int ath_ahb_probe(struct platform_device *pdev)
>  
>  	if (bcfg->devid >= AR5K_SREV_AR2315_R6) {
>  		/* Enable WMAC AHB arbitration */
> -		reg = ioread32((void __iomem *) AR5K_AR2315_AHB_ARB_CTL);
> +		reg = ioread32((const void __iomem *) AR5K_AR2315_AHB_ARB_CTL);

While I understand why the parameter of ioread32 should be const, I
don't see a reason for these casts on the users' side. What does it
bring except longer code to read?

thanks,
-- 
js