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* [PATCH] usb: renesas_usbhs: fix __le16 warnings
@ 2019-10-15 15:50 Ben Dooks (Codethink)
  2019-10-15 16:45 ` Geert Uytterhoeven
                   ` (2 more replies)
  0 siblings, 3 replies; 7+ messages in thread
From: Ben Dooks (Codethink) @ 2019-10-15 15:50 UTC (permalink / raw)
  To: linux-kernel
  Cc: Ben Dooks (Codethink),
	Greg Kroah-Hartman, Yoshihiro Shimoda, Simon Horman,
	Geert Uytterhoeven, linux-usb, linux-kernel

Fix the warnings generated by casting to/from __le16 without
using the correct functions.

Fixes the following sparse warnings:

drivers/usb/renesas_usbhs/common.c:165:25: warning: incorrect type in assignment (different base types)
drivers/usb/renesas_usbhs/common.c:165:25:    expected restricted __le16 [usertype] wValue
drivers/usb/renesas_usbhs/common.c:165:25:    got unsigned short
drivers/usb/renesas_usbhs/common.c:166:25: warning: incorrect type in assignment (different base types)
drivers/usb/renesas_usbhs/common.c:166:25:    expected restricted __le16 [usertype] wIndex
drivers/usb/renesas_usbhs/common.c:166:25:    got unsigned short
drivers/usb/renesas_usbhs/common.c:167:25: warning: incorrect type in assignment (different base types)
drivers/usb/renesas_usbhs/common.c:167:25:    expected restricted __le16 [usertype] wLength
drivers/usb/renesas_usbhs/common.c:167:25:    got unsigned short
drivers/usb/renesas_usbhs/common.c:173:39: warning: incorrect type in argument 3 (different base types)
drivers/usb/renesas_usbhs/common.c:173:39:    expected unsigned short [usertype] data
drivers/usb/renesas_usbhs/common.c:173:39:    got restricted __le16 [usertype] wValue
drivers/usb/renesas_usbhs/common.c:174:39: warning: incorrect type in argument 3 (different base types)
drivers/usb/renesas_usbhs/common.c:174:39:    expected unsigned short [usertype] data
drivers/usb/renesas_usbhs/common.c:174:39:    got restricted __le16 [usertype] wIndex
drivers/usb/renesas_usbhs/common.c:175:39: warning: incorrect type in argument 3 (different base types)
drivers/usb/renesas_usbhs/common.c:175:39:    expected unsigned short [usertype] data

Note. I belive this to be correct, and should be a no-op on arm.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
---
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Simon Horman <horms+renesas@verge.net.au>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: linux-usb@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
---
 drivers/usb/renesas_usbhs/common.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/renesas_usbhs/common.c b/drivers/usb/renesas_usbhs/common.c
index 4c3de777ef6c..a3c30b609433 100644
--- a/drivers/usb/renesas_usbhs/common.c
+++ b/drivers/usb/renesas_usbhs/common.c
@@ -162,17 +162,17 @@ void usbhs_usbreq_get_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
 	req->bRequest		= (val >> 8) & 0xFF;
 	req->bRequestType	= (val >> 0) & 0xFF;
 
-	req->wValue	= usbhs_read(priv, USBVAL);
-	req->wIndex	= usbhs_read(priv, USBINDX);
-	req->wLength	= usbhs_read(priv, USBLENG);
+	req->wValue	= cpu_to_le16(usbhs_read(priv, USBVAL));
+	req->wIndex	= cpu_to_le16(usbhs_read(priv, USBINDX));
+	req->wLength	= cpu_to_le16(usbhs_read(priv, USBLENG));
 }
 
 void usbhs_usbreq_set_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
 {
 	usbhs_write(priv, USBREQ,  (req->bRequest << 8) | req->bRequestType);
-	usbhs_write(priv, USBVAL,  req->wValue);
-	usbhs_write(priv, USBINDX, req->wIndex);
-	usbhs_write(priv, USBLENG, req->wLength);
+	usbhs_write(priv, USBVAL,  le16_to_cpu(req->wValue));
+	usbhs_write(priv, USBINDX, le16_to_cpu(req->wIndex));
+	usbhs_write(priv, USBLENG, le16_to_cpu(req->wLength));
 
 	usbhs_bset(priv, DCPCTR, SUREQ, SUREQ);
 }
-- 
2.23.0


^ permalink raw reply related	[flat|nested] 7+ messages in thread
* Re: [PATCH] usb: renesas_usbhs: fix __le16 warnings
  2019-10-15 15:50 [PATCH] usb: renesas_usbhs: fix __le16 warnings Ben Dooks (Codethink)
@ 2019-10-15 16:45 ` Geert Uytterhoeven
  2019-10-16  2:35 ` Yoshihiro Shimoda
  2019-10-16 12:26 ` Simon Horman
  2 siblings, 0 replies; 7+ messages in thread
From: Geert Uytterhoeven @ 2019-10-15 16:45 UTC (permalink / raw)
  To: Ben Dooks (Codethink)
  Cc: linux-kernel, Greg Kroah-Hartman, Yoshihiro Shimoda,
	Simon Horman, Geert Uytterhoeven, USB list,
	Linux Kernel Mailing List

On Tue, Oct 15, 2019 at 5:50 PM Ben Dooks (Codethink)
<ben.dooks@codethink.co.uk> wrote:
> Fix the warnings generated by casting to/from __le16 without
> using the correct functions.
>
> Fixes the following sparse warnings:
>
> drivers/usb/renesas_usbhs/common.c:165:25: warning: incorrect type in assignment (different base types)
> drivers/usb/renesas_usbhs/common.c:165:25:    expected restricted __le16 [usertype] wValue
> drivers/usb/renesas_usbhs/common.c:165:25:    got unsigned short
> drivers/usb/renesas_usbhs/common.c:166:25: warning: incorrect type in assignment (different base types)
> drivers/usb/renesas_usbhs/common.c:166:25:    expected restricted __le16 [usertype] wIndex
> drivers/usb/renesas_usbhs/common.c:166:25:    got unsigned short
> drivers/usb/renesas_usbhs/common.c:167:25: warning: incorrect type in assignment (different base types)
> drivers/usb/renesas_usbhs/common.c:167:25:    expected restricted __le16 [usertype] wLength
> drivers/usb/renesas_usbhs/common.c:167:25:    got unsigned short
> drivers/usb/renesas_usbhs/common.c:173:39: warning: incorrect type in argument 3 (different base types)
> drivers/usb/renesas_usbhs/common.c:173:39:    expected unsigned short [usertype] data
> drivers/usb/renesas_usbhs/common.c:173:39:    got restricted __le16 [usertype] wValue
> drivers/usb/renesas_usbhs/common.c:174:39: warning: incorrect type in argument 3 (different base types)
> drivers/usb/renesas_usbhs/common.c:174:39:    expected unsigned short [usertype] data
> drivers/usb/renesas_usbhs/common.c:174:39:    got restricted __le16 [usertype] wIndex
> drivers/usb/renesas_usbhs/common.c:175:39: warning: incorrect type in argument 3 (different base types)
> drivers/usb/renesas_usbhs/common.c:175:39:    expected unsigned short [usertype] data
>
> Note. I belive this to be correct, and should be a no-op on arm.

Yep, the affected platforms are little-endian.

> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

^ permalink raw reply	[flat|nested] 7+ messages in thread
* RE: [PATCH] usb: renesas_usbhs: fix __le16 warnings
  2019-10-15 15:50 [PATCH] usb: renesas_usbhs: fix __le16 warnings Ben Dooks (Codethink)
  2019-10-15 16:45 ` Geert Uytterhoeven
@ 2019-10-16  2:35 ` Yoshihiro Shimoda
  2019-10-16 12:26 ` Simon Horman
  2 siblings, 0 replies; 7+ messages in thread
From: Yoshihiro Shimoda @ 2019-10-16  2:35 UTC (permalink / raw)
  To: Ben Dooks (Codethink), linux-kernel
  Cc: Greg Kroah-Hartman, Simon Horman, Geert Uytterhoeven, linux-usb,
	linux-kernel

Hi Ben,

> From: Ben Dooks (Codethink), Sent: Wednesday, October 16, 2019 12:51 AM
> 
> Fix the warnings generated by casting to/from __le16 without
> using the correct functions.
> 
> Fixes the following sparse warnings:
> 
> drivers/usb/renesas_usbhs/common.c:165:25: warning: incorrect type in assignment (different base types)
> drivers/usb/renesas_usbhs/common.c:165:25:    expected restricted __le16 [usertype] wValue
> drivers/usb/renesas_usbhs/common.c:165:25:    got unsigned short
> drivers/usb/renesas_usbhs/common.c:166:25: warning: incorrect type in assignment (different base types)
> drivers/usb/renesas_usbhs/common.c:166:25:    expected restricted __le16 [usertype] wIndex
> drivers/usb/renesas_usbhs/common.c:166:25:    got unsigned short
> drivers/usb/renesas_usbhs/common.c:167:25: warning: incorrect type in assignment (different base types)
> drivers/usb/renesas_usbhs/common.c:167:25:    expected restricted __le16 [usertype] wLength
> drivers/usb/renesas_usbhs/common.c:167:25:    got unsigned short
> drivers/usb/renesas_usbhs/common.c:173:39: warning: incorrect type in argument 3 (different base types)
> drivers/usb/renesas_usbhs/common.c:173:39:    expected unsigned short [usertype] data
> drivers/usb/renesas_usbhs/common.c:173:39:    got restricted __le16 [usertype] wValue
> drivers/usb/renesas_usbhs/common.c:174:39: warning: incorrect type in argument 3 (different base types)
> drivers/usb/renesas_usbhs/common.c:174:39:    expected unsigned short [usertype] data
> drivers/usb/renesas_usbhs/common.c:174:39:    got restricted __le16 [usertype] wIndex
> drivers/usb/renesas_usbhs/common.c:175:39: warning: incorrect type in argument 3 (different base types)
> drivers/usb/renesas_usbhs/common.c:175:39:    expected unsigned short [usertype] data
> 
> Note. I belive this to be correct, and should be a no-op on arm.
> 
> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>

Thank you for the patch!

Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

Best regards,
Yoshihiro Shimoda


^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] usb: renesas_usbhs: fix __le16 warnings
  2019-10-15 15:50 [PATCH] usb: renesas_usbhs: fix __le16 warnings Ben Dooks (Codethink)
  2019-10-15 16:45 ` Geert Uytterhoeven
  2019-10-16  2:35 ` Yoshihiro Shimoda
@ 2019-10-16 12:26 ` Simon Horman
  2019-10-17  2:18   ` Yoshihiro Shimoda
  2 siblings, 1 reply; 7+ messages in thread
From: Simon Horman @ 2019-10-16 12:26 UTC (permalink / raw)
  To: Ben Dooks (Codethink)
  Cc: linux-kernel, Greg Kroah-Hartman, Yoshihiro Shimoda,
	Geert Uytterhoeven, linux-usb, linux-kernel

On Tue, Oct 15, 2019 at 04:50:44PM +0100, Ben Dooks (Codethink) wrote:
> Fix the warnings generated by casting to/from __le16 without
> using the correct functions.
> 
> Fixes the following sparse warnings:
> 
> drivers/usb/renesas_usbhs/common.c:165:25: warning: incorrect type in assignment (different base types)
> drivers/usb/renesas_usbhs/common.c:165:25:    expected restricted __le16 [usertype] wValue
> drivers/usb/renesas_usbhs/common.c:165:25:    got unsigned short
> drivers/usb/renesas_usbhs/common.c:166:25: warning: incorrect type in assignment (different base types)
> drivers/usb/renesas_usbhs/common.c:166:25:    expected restricted __le16 [usertype] wIndex
> drivers/usb/renesas_usbhs/common.c:166:25:    got unsigned short
> drivers/usb/renesas_usbhs/common.c:167:25: warning: incorrect type in assignment (different base types)
> drivers/usb/renesas_usbhs/common.c:167:25:    expected restricted __le16 [usertype] wLength
> drivers/usb/renesas_usbhs/common.c:167:25:    got unsigned short
> drivers/usb/renesas_usbhs/common.c:173:39: warning: incorrect type in argument 3 (different base types)
> drivers/usb/renesas_usbhs/common.c:173:39:    expected unsigned short [usertype] data
> drivers/usb/renesas_usbhs/common.c:173:39:    got restricted __le16 [usertype] wValue
> drivers/usb/renesas_usbhs/common.c:174:39: warning: incorrect type in argument 3 (different base types)
> drivers/usb/renesas_usbhs/common.c:174:39:    expected unsigned short [usertype] data
> drivers/usb/renesas_usbhs/common.c:174:39:    got restricted __le16 [usertype] wIndex
> drivers/usb/renesas_usbhs/common.c:175:39: warning: incorrect type in argument 3 (different base types)
> drivers/usb/renesas_usbhs/common.c:175:39:    expected unsigned short [usertype] data
> 
> Note. I belive this to be correct, and should be a no-op on arm.
> 
> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> ---
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
> Cc: Simon Horman <horms+renesas@verge.net.au>
> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> Cc: linux-usb@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> ---
>  drivers/usb/renesas_usbhs/common.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/usb/renesas_usbhs/common.c b/drivers/usb/renesas_usbhs/common.c
> index 4c3de777ef6c..a3c30b609433 100644
> --- a/drivers/usb/renesas_usbhs/common.c
> +++ b/drivers/usb/renesas_usbhs/common.c
> @@ -162,17 +162,17 @@ void usbhs_usbreq_get_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
>  	req->bRequest		= (val >> 8) & 0xFF;
>  	req->bRequestType	= (val >> 0) & 0xFF;
>  
> -	req->wValue	= usbhs_read(priv, USBVAL);
> -	req->wIndex	= usbhs_read(priv, USBINDX);
> -	req->wLength	= usbhs_read(priv, USBLENG);
> +	req->wValue	= cpu_to_le16(usbhs_read(priv, USBVAL));
> +	req->wIndex	= cpu_to_le16(usbhs_read(priv, USBINDX));
> +	req->wLength	= cpu_to_le16(usbhs_read(priv, USBLENG));

usbhs_read is backed by readl which performs
a le->cpu conversion. Rather than have a double conversion
perhaps it would be nicer to introduce usbhs_read_le.
Likewise for write.

>  }
>  
>  void usbhs_usbreq_set_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
>  {
>  	usbhs_write(priv, USBREQ,  (req->bRequest << 8) | req->bRequestType);
> -	usbhs_write(priv, USBVAL,  req->wValue);
> -	usbhs_write(priv, USBINDX, req->wIndex);
> -	usbhs_write(priv, USBLENG, req->wLength);
> +	usbhs_write(priv, USBVAL,  le16_to_cpu(req->wValue));
> +	usbhs_write(priv, USBINDX, le16_to_cpu(req->wIndex));
> +	usbhs_write(priv, USBLENG, le16_to_cpu(req->wLength));
>  
>  	usbhs_bset(priv, DCPCTR, SUREQ, SUREQ);
>  }
> -- 
> 2.23.0
> 

^ permalink raw reply	[flat|nested] 7+ messages in thread
* RE: [PATCH] usb: renesas_usbhs: fix __le16 warnings
  2019-10-16 12:26 ` Simon Horman
@ 2019-10-17  2:18   ` Yoshihiro Shimoda
  2019-10-17  6:57     ` Geert Uytterhoeven
  0 siblings, 1 reply; 7+ messages in thread
From: Yoshihiro Shimoda @ 2019-10-17  2:18 UTC (permalink / raw)
  To: Simon Horman
  Cc: linux-kernel, Greg Kroah-Hartman, Geert Uytterhoeven, linux-usb,
	linux-kernel, Ben Dooks (Codethink)

Hi Simon-san,

> From: Simon Horman, Sent: Wednesday, October 16, 2019 9:27 PM
<snip>
> > diff --git a/drivers/usb/renesas_usbhs/common.c b/drivers/usb/renesas_usbhs/common.c
> > index 4c3de777ef6c..a3c30b609433 100644
> > --- a/drivers/usb/renesas_usbhs/common.c
> > +++ b/drivers/usb/renesas_usbhs/common.c
> > @@ -162,17 +162,17 @@ void usbhs_usbreq_get_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
> >  	req->bRequest		= (val >> 8) & 0xFF;
> >  	req->bRequestType	= (val >> 0) & 0xFF;
> >
> > -	req->wValue	= usbhs_read(priv, USBVAL);
> > -	req->wIndex	= usbhs_read(priv, USBINDX);
> > -	req->wLength	= usbhs_read(priv, USBLENG);
> > +	req->wValue	= cpu_to_le16(usbhs_read(priv, USBVAL));
> > +	req->wIndex	= cpu_to_le16(usbhs_read(priv, USBINDX));
> > +	req->wLength	= cpu_to_le16(usbhs_read(priv, USBLENG));
> 
> usbhs_read is backed by readl which performs
> a le->cpu conversion. Rather than have a double conversion
> perhaps it would be nicer to introduce usbhs_read_le.
> Likewise for write.

I'm afraid but, I could not understand these comments.
At the moment, the usbhs_{read,write}() call io{read,write}16(),
not {read,write}l().

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/renesas_usbhs/common.c?h=v5.4-rc3#n62

Best regards,
Yoshihiro Shimoda

> 
> >  }
> >
> >  void usbhs_usbreq_set_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
> >  {
> >  	usbhs_write(priv, USBREQ,  (req->bRequest << 8) | req->bRequestType);
> > -	usbhs_write(priv, USBVAL,  req->wValue);
> > -	usbhs_write(priv, USBINDX, req->wIndex);
> > -	usbhs_write(priv, USBLENG, req->wLength);
> > +	usbhs_write(priv, USBVAL,  le16_to_cpu(req->wValue));
> > +	usbhs_write(priv, USBINDX, le16_to_cpu(req->wIndex));
> > +	usbhs_write(priv, USBLENG, le16_to_cpu(req->wLength));
> >
> >  	usbhs_bset(priv, DCPCTR, SUREQ, SUREQ);
> >  }
> > --
> > 2.23.0
> >

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] usb: renesas_usbhs: fix __le16 warnings
  2019-10-17  2:18   ` Yoshihiro Shimoda
@ 2019-10-17  6:57     ` Geert Uytterhoeven
  2019-10-17 10:00       ` Simon Horman
  0 siblings, 1 reply; 7+ messages in thread
From: Geert Uytterhoeven @ 2019-10-17  6:57 UTC (permalink / raw)
  To: Yoshihiro Shimoda, Simon Horman
  Cc: linux-kernel, Greg Kroah-Hartman, Geert Uytterhoeven, linux-usb,
	linux-kernel, Ben Dooks (Codethink)

Hi Shimoda-san, Simon,

On Thu, Oct 17, 2019 at 4:18 AM Yoshihiro Shimoda
<yoshihiro.shimoda.uh@renesas.com> wrote:
> > From: Simon Horman, Sent: Wednesday, October 16, 2019 9:27 PM
> <snip>
> > > diff --git a/drivers/usb/renesas_usbhs/common.c b/drivers/usb/renesas_usbhs/common.c
> > > index 4c3de777ef6c..a3c30b609433 100644
> > > --- a/drivers/usb/renesas_usbhs/common.c
> > > +++ b/drivers/usb/renesas_usbhs/common.c
> > > @@ -162,17 +162,17 @@ void usbhs_usbreq_get_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
> > >     req->bRequest           = (val >> 8) & 0xFF;
> > >     req->bRequestType       = (val >> 0) & 0xFF;
> > >
> > > -   req->wValue     = usbhs_read(priv, USBVAL);
> > > -   req->wIndex     = usbhs_read(priv, USBINDX);
> > > -   req->wLength    = usbhs_read(priv, USBLENG);
> > > +   req->wValue     = cpu_to_le16(usbhs_read(priv, USBVAL));
> > > +   req->wIndex     = cpu_to_le16(usbhs_read(priv, USBINDX));
> > > +   req->wLength    = cpu_to_le16(usbhs_read(priv, USBLENG));
> >
> > usbhs_read is backed by readl which performs
> > a le->cpu conversion. Rather than have a double conversion
> > perhaps it would be nicer to introduce usbhs_read_le.
> > Likewise for write.
>
> I'm afraid but, I could not understand these comments.
> At the moment, the usbhs_{read,write}() call io{read,write}16(),
> not {read,write}l().
>
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/renesas_usbhs/common.c?h=v5.4-rc3#n62

ioread16() and readw() don't do byteswapping on ARM, as ARM is
little-endian. Likewise, cpu_to_le16() is a no-op on ARM.

Double swapping would matter only on a big-endian platform, and could
indeed be avoided by introducing usbhs_read_le*() functions that are
just wrappers around __raw_read16() on big-endian.
However, until the Renesas USBHS IP core ends up on a big-endian
platform, it's not worth doing that, IMHO.

> > >  }
> > >
> > >  void usbhs_usbreq_set_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
> > >  {
> > >     usbhs_write(priv, USBREQ,  (req->bRequest << 8) | req->bRequestType);
> > > -   usbhs_write(priv, USBVAL,  req->wValue);
> > > -   usbhs_write(priv, USBINDX, req->wIndex);
> > > -   usbhs_write(priv, USBLENG, req->wLength);
> > > +   usbhs_write(priv, USBVAL,  le16_to_cpu(req->wValue));
> > > +   usbhs_write(priv, USBINDX, le16_to_cpu(req->wIndex));
> > > +   usbhs_write(priv, USBLENG, le16_to_cpu(req->wLength));
> > >
> > >     usbhs_bset(priv, DCPCTR, SUREQ, SUREQ);
> > >  }

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

^ permalink raw reply	[flat|nested] 7+ messages in thread
* Re: [PATCH] usb: renesas_usbhs: fix __le16 warnings
  2019-10-17  6:57     ` Geert Uytterhoeven
@ 2019-10-17 10:00       ` Simon Horman
  0 siblings, 0 replies; 7+ messages in thread
From: Simon Horman @ 2019-10-17 10:00 UTC (permalink / raw)
  To: Geert Uytterhoeven
  Cc: Yoshihiro Shimoda, linux-kernel, Greg Kroah-Hartman,
	Geert Uytterhoeven, linux-usb, linux-kernel,
	Ben Dooks (Codethink)

On Thu, Oct 17, 2019 at 08:57:26AM +0200, Geert Uytterhoeven wrote:
> Hi Shimoda-san, Simon,
> 
> On Thu, Oct 17, 2019 at 4:18 AM Yoshihiro Shimoda
> <yoshihiro.shimoda.uh@renesas.com> wrote:
> > > From: Simon Horman, Sent: Wednesday, October 16, 2019 9:27 PM
> > <snip>
> > > > diff --git a/drivers/usb/renesas_usbhs/common.c b/drivers/usb/renesas_usbhs/common.c
> > > > index 4c3de777ef6c..a3c30b609433 100644
> > > > --- a/drivers/usb/renesas_usbhs/common.c
> > > > +++ b/drivers/usb/renesas_usbhs/common.c
> > > > @@ -162,17 +162,17 @@ void usbhs_usbreq_get_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
> > > >     req->bRequest           = (val >> 8) & 0xFF;
> > > >     req->bRequestType       = (val >> 0) & 0xFF;
> > > >
> > > > -   req->wValue     = usbhs_read(priv, USBVAL);
> > > > -   req->wIndex     = usbhs_read(priv, USBINDX);
> > > > -   req->wLength    = usbhs_read(priv, USBLENG);
> > > > +   req->wValue     = cpu_to_le16(usbhs_read(priv, USBVAL));
> > > > +   req->wIndex     = cpu_to_le16(usbhs_read(priv, USBINDX));
> > > > +   req->wLength    = cpu_to_le16(usbhs_read(priv, USBLENG));
> > >
> > > usbhs_read is backed by readl which performs
> > > a le->cpu conversion. Rather than have a double conversion
> > > perhaps it would be nicer to introduce usbhs_read_le.
> > > Likewise for write.
> >
> > I'm afraid but, I could not understand these comments.
> > At the moment, the usbhs_{read,write}() call io{read,write}16(),
> > not {read,write}l().
> >
> > https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/usb/renesas_usbhs/common.c?h=v5.4-rc3#n62
> 
> ioread16() and readw() don't do byteswapping on ARM, as ARM is
> little-endian. Likewise, cpu_to_le16() is a no-op on ARM.
> 
> Double swapping would matter only on a big-endian platform, and could
> indeed be avoided by introducing usbhs_read_le*() functions that are
> just wrappers around __raw_read16() on big-endian.
> However, until the Renesas USBHS IP core ends up on a big-endian
> platform, it's not worth doing that, IMHO.

Yes, that is all true.
I'm fine with this patch as it is.

> 
> > > >  }
> > > >
> > > >  void usbhs_usbreq_set_val(struct usbhs_priv *priv, struct usb_ctrlrequest *req)
> > > >  {
> > > >     usbhs_write(priv, USBREQ,  (req->bRequest << 8) | req->bRequestType);
> > > > -   usbhs_write(priv, USBVAL,  req->wValue);
> > > > -   usbhs_write(priv, USBINDX, req->wIndex);
> > > > -   usbhs_write(priv, USBLENG, req->wLength);
> > > > +   usbhs_write(priv, USBVAL,  le16_to_cpu(req->wValue));
> > > > +   usbhs_write(priv, USBINDX, le16_to_cpu(req->wIndex));
> > > > +   usbhs_write(priv, USBLENG, le16_to_cpu(req->wLength));
> > > >
> > > >     usbhs_bset(priv, DCPCTR, SUREQ, SUREQ);
> > > >  }
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
> 
> -- 
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds
> 

^ permalink raw reply	[flat|nested] 7+ messages in thread
end of thread, other threads:[~2019-10-17 10:00 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-10-15 15:50 [PATCH] usb: renesas_usbhs: fix __le16 warnings Ben Dooks (Codethink)
2019-10-15 16:45 ` Geert Uytterhoeven
2019-10-16  2:35 ` Yoshihiro Shimoda
2019-10-16 12:26 ` Simon Horman
2019-10-17  2:18   ` Yoshihiro Shimoda
2019-10-17  6:57     ` Geert Uytterhoeven
2019-10-17 10:00       ` Simon Horman

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