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Message-ID: <df527e53-3148-02f0-241b-fbc5e28b1618@gmx.de>
Date:   Tue, 16 May 2023 19:44:09 +0200
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Subject: Re: [PATCH v7 1/7] fbdev/hitfb: Cast I/O offset to address
Content-Language: en-US
To:     Thomas Zimmermann <tzimmermann@suse.de>, geert@linux-m68k.org,
        javierm@redhat.com, daniel@ffwll.ch, vgupta@kernel.org,
        chenhuacai@kernel.org, kernel@xen0n.name, davem@davemloft.net,
        James.Bottomley@HansenPartnership.com, arnd@arndb.de,
        sam@ravnborg.org, suijingfeng@loongson.cn
Cc:     linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org,
        linux-arch@vger.kernel.org, linux-snps-arc@lists.infradead.org,
        linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org,
        loongarch@lists.linux.dev, linux-m68k@lists.linux-m68k.org,
        sparclinux@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        linux-parisc@vger.kernel.org, kernel test robot <lkp@intel.com>,
        Artur Rojek <contact@artur-rojek.eu>
References: <20230512102444.5438-1-tzimmermann@suse.de>
 <20230512102444.5438-2-tzimmermann@suse.de>
From:   Helge Deller <deller@gmx.de>
In-Reply-To: <20230512102444.5438-2-tzimmermann@suse.de>
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Precedence: bulk

On 5/12/23 12:24, Thomas Zimmermann wrote:
> Cast I/O offsets to pointers to use them with I/O functions. The I/O
> functions expect pointers of type 'volatile void __iomem *', but the
> offsets are plain integers. Build warnings are
>
>    ../drivers/video/fbdev/hitfb.c: In function 'hitfb_accel_wait':
>    ../arch/x86/include/asm/hd64461.h:18:33: warning: passing argument 1 =
of 'fb_readw' makes pointer from integer without a cast [-Wint-conversion]
>     18 | #define HD64461_IO_OFFSET(x)    (HD64461_IOBASE + (x))
>        |                                 ^~~~~~~~~~~~~~~~~~~~~~
>        |                                 |
>        |                                 unsigned int
>    ../arch/x86/include/asm/hd64461.h:93:33: note: in expansion of macro =
'HD64461_IO_OFFSET'
>     93 | #define HD64461_GRCFGR          HD64461_IO_OFFSET(0x1044)      =
 /* Accelerator Configuration Register */
>        |                                 ^~~~~~~~~~~~~~~~~
>    ../drivers/video/fbdev/hitfb.c:47:25: note: in expansion of macro 'HD=
64461_GRCFGR'
>     47 |         while (fb_readw(HD64461_GRCFGR) & HD64461_GRCFGR_ACCSTA=
TUS) ;
>        |                         ^~~~~~~~~~~~~~
>    In file included from ../arch/x86/include/asm/fb.h:15,
>    from ../include/linux/fb.h:19,
>    from ../drivers/video/fbdev/hitfb.c:22:
>    ../include/asm-generic/fb.h:52:57: note: expected 'const volatile voi=
d *' but argument is of type 'unsigned int'
>     52 | static inline u16 fb_readw(const volatile void __iomem *addr)
>        |                            ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~
>
> This patch only fixes the build warnings. It's not clear if the I/O
> offsets can legally be passed to the I/O helpers. It was apparently
> broken in 2007 when custom inw()/outw() helpers got removed by
> commit 34a780a0afeb ("sh: hp6xx pata_platform support."). Fixing the
> driver would require setting the I/O base address.

I think your patch is the best you can do for now... So...

Acked-by: Helge Deller <deller@gmx.de>

Thanks!
Helge


> Reported-by: kernel test robot <lkp@intel.com>
> Closes: https://lore.kernel.org/oe-kbuild-all/202305102136.eMjTSPwH-lkp@=
intel.com/
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> Cc: Artur Rojek <contact@artur-rojek.eu>
> ---
>   drivers/video/fbdev/hitfb.c | 122 ++++++++++++++++++++----------------
>   1 file changed, 69 insertions(+), 53 deletions(-)
>
> diff --git a/drivers/video/fbdev/hitfb.c b/drivers/video/fbdev/hitfb.c
> index 3033f5056976..7737923b7a0a 100644
> --- a/drivers/video/fbdev/hitfb.c
> +++ b/drivers/video/fbdev/hitfb.c
> @@ -42,17 +42,33 @@ static struct fb_fix_screeninfo hitfb_fix =3D {
>   	.accel		=3D FB_ACCEL_NONE,
>   };
>
> +static volatile void __iomem *hitfb_offset_to_addr(unsigned int offset)
> +{
> +	return (__force volatile void __iomem *)(uintptr_t)offset;
> +}
> +
> +static u16 hitfb_readw(unsigned int offset)
> +{
> +	return fb_readw(hitfb_offset_to_addr(offset));
> +}
> +
> +static void hitfb_writew(u16 value, unsigned int offset)
> +{
> +	fb_writew(value, hitfb_offset_to_addr(offset));
> +}
> +
>   static inline void hitfb_accel_wait(void)
>   {
> -	while (fb_readw(HD64461_GRCFGR) & HD64461_GRCFGR_ACCSTATUS) ;
> +	while (hitfb_readw(HD64461_GRCFGR) & HD64461_GRCFGR_ACCSTATUS)
> +		;
>   }
>
>   static inline void hitfb_accel_start(int truecolor)
>   {
>   	if (truecolor) {
> -		fb_writew(6, HD64461_GRCFGR);
> +		hitfb_writew(6, HD64461_GRCFGR);
>   	} else {
> -		fb_writew(7, HD64461_GRCFGR);
> +		hitfb_writew(7, HD64461_GRCFGR);
>   	}
>   }
>
> @@ -63,11 +79,11 @@ static inline void hitfb_accel_set_dest(int truecolo=
r, u16 dx, u16 dy,
>   	if (truecolor)
>   		saddr <<=3D 1;
>
> -	fb_writew(width-1, HD64461_BBTDWR);
> -	fb_writew(height-1, HD64461_BBTDHR);
> +	hitfb_writew(width-1, HD64461_BBTDWR);
> +	hitfb_writew(height-1, HD64461_BBTDHR);
>
> -	fb_writew(saddr & 0xffff, HD64461_BBTDSARL);
> -	fb_writew(saddr >> 16, HD64461_BBTDSARH);
> +	hitfb_writew(saddr & 0xffff, HD64461_BBTDSARL);
> +	hitfb_writew(saddr >> 16, HD64461_BBTDSARH);
>
>   }
>
> @@ -80,7 +96,7 @@ static inline void hitfb_accel_bitblt(int truecolor, u=
16 sx, u16 sy, u16 dx,
>
>   	height--;
>   	width--;
> -	fb_writew(rop, HD64461_BBTROPR);
> +	hitfb_writew(rop, HD64461_BBTROPR);
>   	if ((sy < dy) || ((sy =3D=3D dy) && (sx <=3D dx))) {
>   		saddr =3D WIDTH * (sy + height) + sx + width;
>   		daddr =3D WIDTH * (dy + height) + dx + width;
> @@ -91,32 +107,32 @@ static inline void hitfb_accel_bitblt(int truecolor=
, u16 sx, u16 sy, u16 dx,
>   				maddr =3D
>   				    (((width >> 4) + 1) * (height + 1) - 1) * 2;
>
> -			fb_writew((1 << 5) | 1, HD64461_BBTMDR);
> +			hitfb_writew((1 << 5) | 1, HD64461_BBTMDR);
>   		} else
> -			fb_writew(1, HD64461_BBTMDR);
> +			hitfb_writew(1, HD64461_BBTMDR);
>   	} else {
>   		saddr =3D WIDTH * sy + sx;
>   		daddr =3D WIDTH * dy + dx;
>   		if (mask_addr) {
> -			fb_writew((1 << 5), HD64461_BBTMDR);
> +			hitfb_writew((1 << 5), HD64461_BBTMDR);
>   		} else {
> -			fb_writew(0, HD64461_BBTMDR);
> +			hitfb_writew(0, HD64461_BBTMDR);
>   		}
>   	}
>   	if (truecolor) {
>   		saddr <<=3D 1;
>   		daddr <<=3D 1;
>   	}
> -	fb_writew(width, HD64461_BBTDWR);
> -	fb_writew(height, HD64461_BBTDHR);
> -	fb_writew(saddr & 0xffff, HD64461_BBTSSARL);
> -	fb_writew(saddr >> 16, HD64461_BBTSSARH);
> -	fb_writew(daddr & 0xffff, HD64461_BBTDSARL);
> -	fb_writew(daddr >> 16, HD64461_BBTDSARH);
> +	hitfb_writew(width, HD64461_BBTDWR);
> +	hitfb_writew(height, HD64461_BBTDHR);
> +	hitfb_writew(saddr & 0xffff, HD64461_BBTSSARL);
> +	hitfb_writew(saddr >> 16, HD64461_BBTSSARH);
> +	hitfb_writew(daddr & 0xffff, HD64461_BBTDSARL);
> +	hitfb_writew(daddr >> 16, HD64461_BBTDSARH);
>   	if (mask_addr) {
>   		maddr +=3D mask_addr;
> -		fb_writew(maddr & 0xffff, HD64461_BBTMARL);
> -		fb_writew(maddr >> 16, HD64461_BBTMARH);
> +		hitfb_writew(maddr & 0xffff, HD64461_BBTMARL);
> +		hitfb_writew(maddr >> 16, HD64461_BBTMARH);
>   	}
>   	hitfb_accel_start(truecolor);
>   }
> @@ -127,17 +143,17 @@ static void hitfb_fillrect(struct fb_info *p, cons=
t struct fb_fillrect *rect)
>   		cfb_fillrect(p, rect);
>   	else {
>   		hitfb_accel_wait();
> -		fb_writew(0x00f0, HD64461_BBTROPR);
> -		fb_writew(16, HD64461_BBTMDR);
> +		hitfb_writew(0x00f0, HD64461_BBTROPR);
> +		hitfb_writew(16, HD64461_BBTMDR);
>
>   		if (p->var.bits_per_pixel =3D=3D 16) {
> -			fb_writew(((u32 *) (p->pseudo_palette))[rect->color],
> +			hitfb_writew(((u32 *) (p->pseudo_palette))[rect->color],
>   				  HD64461_GRSCR);
>   			hitfb_accel_set_dest(1, rect->dx, rect->dy, rect->width,
>   					     rect->height);
>   			hitfb_accel_start(1);
>   		} else {
> -			fb_writew(rect->color, HD64461_GRSCR);
> +			hitfb_writew(rect->color, HD64461_GRSCR);
>   			hitfb_accel_set_dest(0, rect->dx, rect->dy, rect->width,
>   					     rect->height);
>   			hitfb_accel_start(0);
> @@ -162,7 +178,7 @@ static int hitfb_pan_display(struct fb_var_screeninf=
o *var,
>   	if (xoffset !=3D 0)
>   		return -EINVAL;
>
> -	fb_writew((yoffset*info->fix.line_length)>>10, HD64461_LCDCBAR);
> +	hitfb_writew((yoffset*info->fix.line_length)>>10, HD64461_LCDCBAR);
>
>   	return 0;
>   }
> @@ -172,33 +188,33 @@ int hitfb_blank(int blank_mode, struct fb_info *in=
fo)
>   	unsigned short v;
>
>   	if (blank_mode) {
> -		v =3D fb_readw(HD64461_LDR1);
> +		v =3D hitfb_readw(HD64461_LDR1);
>   		v &=3D ~HD64461_LDR1_DON;
> -		fb_writew(v, HD64461_LDR1);
> +		hitfb_writew(v, HD64461_LDR1);
>
> -		v =3D fb_readw(HD64461_LCDCCR);
> +		v =3D hitfb_readw(HD64461_LCDCCR);
>   		v |=3D HD64461_LCDCCR_MOFF;
> -		fb_writew(v, HD64461_LCDCCR);
> +		hitfb_writew(v, HD64461_LCDCCR);
>
> -		v =3D fb_readw(HD64461_STBCR);
> +		v =3D hitfb_readw(HD64461_STBCR);
>   		v |=3D HD64461_STBCR_SLCDST;
> -		fb_writew(v, HD64461_STBCR);
> +		hitfb_writew(v, HD64461_STBCR);
>   	} else {
> -		v =3D fb_readw(HD64461_STBCR);
> +		v =3D hitfb_readw(HD64461_STBCR);
>   		v &=3D ~HD64461_STBCR_SLCDST;
> -		fb_writew(v, HD64461_STBCR);
> +		hitfb_writew(v, HD64461_STBCR);
>
> -		v =3D fb_readw(HD64461_LCDCCR);
> +		v =3D hitfb_readw(HD64461_LCDCCR);
>   		v &=3D ~(HD64461_LCDCCR_MOFF | HD64461_LCDCCR_STREQ);
> -		fb_writew(v, HD64461_LCDCCR);
> +		hitfb_writew(v, HD64461_LCDCCR);
>
>   		do {
> -		    v =3D fb_readw(HD64461_LCDCCR);
> +		    v =3D hitfb_readw(HD64461_LCDCCR);
>   		} while(v&HD64461_LCDCCR_STBACK);
>
> -		v =3D fb_readw(HD64461_LDR1);
> +		v =3D hitfb_readw(HD64461_LDR1);
>   		v |=3D HD64461_LDR1_DON;
> -		fb_writew(v, HD64461_LDR1);
> +		hitfb_writew(v, HD64461_LDR1);
>   	}
>   	return 0;
>   }
> @@ -211,10 +227,10 @@ static int hitfb_setcolreg(unsigned regno, unsigne=
d red, unsigned green,
>
>   	switch (info->var.bits_per_pixel) {
>   	case 8:
> -		fb_writew(regno << 8, HD64461_CPTWAR);
> -		fb_writew(red >> 10, HD64461_CPTWDR);
> -		fb_writew(green >> 10, HD64461_CPTWDR);
> -		fb_writew(blue >> 10, HD64461_CPTWDR);
> +		hitfb_writew(regno << 8, HD64461_CPTWAR);
> +		hitfb_writew(red >> 10, HD64461_CPTWDR);
> +		hitfb_writew(green >> 10, HD64461_CPTWDR);
> +		hitfb_writew(blue >> 10, HD64461_CPTWDR);
>   		break;
>   	case 16:
>   		if (regno >=3D 16)
> @@ -302,11 +318,11 @@ static int hitfb_set_par(struct fb_info *info)
>   		break;
>   	}
>
> -	fb_writew(info->fix.line_length, HD64461_LCDCLOR);
> -	ldr3 =3D fb_readw(HD64461_LDR3);
> +	hitfb_writew(info->fix.line_length, HD64461_LCDCLOR);
> +	ldr3 =3D hitfb_readw(HD64461_LDR3);
>   	ldr3 &=3D ~15;
>   	ldr3 |=3D (info->var.bits_per_pixel =3D=3D 8) ? 4 : 8;
> -	fb_writew(ldr3, HD64461_LDR3);
> +	hitfb_writew(ldr3, HD64461_LDR3);
>   	return 0;
>   }
>
> @@ -337,9 +353,9 @@ static int hitfb_probe(struct platform_device *dev)
>   	hitfb_fix.smem_start =3D HD64461_IO_OFFSET(0x02000000);
>   	hitfb_fix.smem_len =3D 512 * 1024;
>
> -	lcdclor =3D fb_readw(HD64461_LCDCLOR);
> -	ldvndr =3D fb_readw(HD64461_LDVNDR);
> -	ldr3 =3D fb_readw(HD64461_LDR3);
> +	lcdclor =3D hitfb_readw(HD64461_LCDCLOR);
> +	ldvndr =3D hitfb_readw(HD64461_LDVNDR);
> +	ldr3 =3D hitfb_readw(HD64461_LDR3);
>
>   	switch (ldr3 & 15) {
>   	default:
> @@ -429,9 +445,9 @@ static int hitfb_suspend(struct device *dev)
>   	u16 v;
>
>   	hitfb_blank(1,0);
> -	v =3D fb_readw(HD64461_STBCR);
> +	v =3D hitfb_readw(HD64461_STBCR);
>   	v |=3D HD64461_STBCR_SLCKE_IST;
> -	fb_writew(v, HD64461_STBCR);
> +	hitfb_writew(v, HD64461_STBCR);
>
>   	return 0;
>   }
> @@ -440,12 +456,12 @@ static int hitfb_resume(struct device *dev)
>   {
>   	u16 v;
>
> -	v =3D fb_readw(HD64461_STBCR);
> +	v =3D hitfb_readw(HD64461_STBCR);
>   	v &=3D ~HD64461_STBCR_SLCKE_OST;
>   	msleep(100);
> -	v =3D fb_readw(HD64461_STBCR);
> +	v =3D hitfb_readw(HD64461_STBCR);
>   	v &=3D ~HD64461_STBCR_SLCKE_IST;
> -	fb_writew(v, HD64461_STBCR);
> +	hitfb_writew(v, HD64461_STBCR);
>   	hitfb_blank(0,0);
>
>   	return 0;