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From: Marek Vasut <marex@denx.de>
To: u-boot@lists.denx.de
Subject: [U-Boot] [PATCH 1/3] Create API to map between CPU physical and bus addresses
Date: Wed, 25 Mar 2015 15:57:01 +0100	[thread overview]
Message-ID: <201503251557.01193.marex@denx.de> (raw)
In-Reply-To: <5512C8DC.6000208@wwwdotorg.org>

On Wednesday, March 25, 2015 at 03:40:28 PM, Stephen Warren wrote:
> On 03/25/2015 05:55 AM, Marek Vasut wrote:
> > On Wednesday, March 25, 2015 at 03:07:33 AM, Stephen Warren wrote:
> >> On some SoCs, DMA-capable peripherals see a different address space to
> >> the CPU's physical address space. Create an API to allow
> >> platform-agnostic drivers to convert between the two address spaces
> >> when programming DMA operations.
> >> 
> >> This API will exist on all platforms, but will have a dummy
> >> implementation when this feature is not required. Other platforms will
> >> enable
> >> CONFIG_PHYS_TO_BUS and provide the required implementation.
> >> 
> >> Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>
> > 
> > Applied to -next, thanks!
> > 
> > btw. can't you use __weak here instead of a new ifdef macro (which is not
> > documented btw)?
> 
> __weak wont' work with inlines, which I used to ensure zero code
> overhead in the case the functions aren't needed. If we were OK with
> calling a no-op function in all cases, we could indeed provide a weak
> default implementation and get rid of the ifdef.

OK, makes sense.

> The new option is documented in the Kconfig file. I assume we don't need
> to document options in multiple places (both Kconfig and README), since
> if we do, the documentation is bound to become inconsistent in those two
> places. Hopefully README goes away once everything is in Kconfig.

Yup, agreed.

Thanks for clearing this up :)

Best regards,
Marek Vasut

      reply	other threads:[~2015-03-25 14:57 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-25  2:07 [U-Boot] [PATCH 1/3] Create API to map between CPU physical and bus addresses Stephen Warren
2015-03-25  2:07 ` [U-Boot] [PATCH 2/3] ARM: bcm2835: implement phys_to_bus/bus_to_phys Stephen Warren
2015-03-25 11:53   ` Marek Vasut
2015-03-25  2:07 ` [U-Boot] [PATCH 3/3] usb: dwc2: use phys_to_bus/bus_to_phys Stephen Warren
2015-03-25 11:55   ` Marek Vasut
2015-03-25 11:55 ` [U-Boot] [PATCH 1/3] Create API to map between CPU physical and bus addresses Marek Vasut
2015-03-25 14:40   ` Stephen Warren
2015-03-25 14:57     ` Marek Vasut [this message]

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