linux-kernel - Re: [PATCH v2 02/19] ARM: at91/at91x40: remove use of at91_sys

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Message-ID: <20120223060151.GD20176@game.jcrosoft.org>
Date:	Thu, 23 Feb 2012 07:01:51 +0100
From:	Jean-Christophe PLAGNIOL-VILLARD <plagnioj@...osoft.com>
To:	Ryan Mallon <rmallon@...il.com>
Cc:	Nicolas Ferre <nicolas.ferre@...el.com>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux@....linux.org.uk
Subject: Re: [PATCH v2 02/19] ARM: at91/at91x40: remove use of
 at91_sys_read/write

On 14:59 Thu 23 Feb     , Ryan Mallon wrote:
> On 23/02/12 14:25, Jean-Christophe PLAGNIOL-VILLARD wrote:
> 
> > On 09:22 Thu 23 Feb     , Ryan Mallon wrote:
> >> On 22/02/12 20:39, Nicolas Ferre wrote:
> >>
> >>> From: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@...osoft.com>
> >>>
> >>> Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@...osoft.com>
> >>> Acked-by: Nicolas Ferre <nicolas.ferre@...el.com>
> >>> ---
> >>>  arch/arm/mach-at91/at91x40.c              |    2 +-
> >>>  arch/arm/mach-at91/at91x40_time.c         |   28 +++++++++++++++++-----------
> >>>  arch/arm/mach-at91/include/mach/at91x40.h |   18 +++++++++---------
> >>>  3 files changed, 27 insertions(+), 21 deletions(-)
> >>>
> >>> diff --git a/arch/arm/mach-at91/at91x40.c b/arch/arm/mach-at91/at91x40.c
> >>> index 0154b7f..5400a1d 100644
> >>> --- a/arch/arm/mach-at91/at91x40.c
> >>> +++ b/arch/arm/mach-at91/at91x40.c
> >>> @@ -44,7 +44,7 @@ static void at91x40_idle(void)
> >>>  	 * Disable the processor clock.  The processor will be automatically
> >>>  	 * re-enabled by an interrupt or by a reset.
> >>>  	 */
> >>> -	at91_sys_write(AT91_PS_CR, AT91_PS_CR_CPU);
> >>> +	__raw_writel(AT91_PS_CR_CPU, AT91_PS_CR);
> >>
> >>
> >> This doesn't seem to be equivalent, at91_sys_write does:
> >>
> >>   void __iomem *addr = (void __iomem *)AT91_VA_BASE_SYS;
> >>   __raw_writel(value, addr + reg_offset);
> >>
> >> and this patch doesn't redefine AT91_PS_CR. Was it broken before this
> >> patch? What am I missing?
> > this is right
> > #define AT91_PS_CR      (AT91_PS + 0)   /* PS Control register */
> 
> 
> That doesn't answer my question.
> 
> The old, at91_sys_write, version was writing to (using __raw_writel):
> 
>   AT91_VA_BASE_SYS + AT91_PS_CR
> 
> The new version is writing, also using __raw_writel, to:
> 
>   AT91_PS_CR
> 
> The value of AT91_PS_CR is not changed in this patch. Assuming that
> AT91_VA_BASE_SYS for at91x40 (which at a quick glance it is not), then
> the old and the new version of the code are not writing to the same
> address.
> 
> Was it previously incorrect, or is it incorrect now?
it's as we update

+#define AT91_PS		0xffff4000	/* Power Save */

Best Regards,
J.
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