On 10/18/2016 01:03 PM, Simon Glass wrote:
Hi Stephen,
On 18 October 2016 at 12:58, Stephen Warren <swar...@wwwdotorg.org> wrote:
On 10/18/2016 10:23 AM, Simon Glass wrote:
Hi Stephen,
On 17 October 2016 at 15:35, Stephen Warren <swar...@wwwdotorg.org> wrote:
From: Stephen Warren <swar...@nvidia.com>
SoC-specific logic may be required for all forms of cache-wide
operations; invalidate and flush of both dcache and icache (note that
only 3 of the 4 possible combinations make sense, since the icache never
contains dirty lines). This patch adds an optional hook for all
implemented cache-wide operations, and renames the one existing hook to
better represent exactly which operation it is implementing. A dummy
no-op implementation of each hook is provided. These dummy
implementations are moved into C code, since there's no need to
implement them in assembly.
Signed-off-by: Stephen Warren <swar...@nvidia.com>
---
arch/arm/cpu/armv8/cache.S | 6 ------
arch/arm/cpu/armv8/cache_v8.c | 23
++++++++++++++++++++---
arch/arm/cpu/armv8/fsl-layerscape/lowlevel.S | 4 ++--
arch/arm/include/asm/system.h | 5 ++++-
arch/arm/mach-tegra/tegra186/cache.c | 2 +-
5 files changed, 27 insertions(+), 13 deletions(-)
I think we should have a proper interface for this stuff rather than
weak functions. Maybe we need a linker-list approach, or a cache
uclass?
What's improper about this interface? Presumably we could argue that no
function in the entire of U-Boot be called by symbol name, which doesn't
seem useful.
I'm not sure exactly what you envisage by a linker-list approach. Can you
provide some background? I understand how the linker can construct list of
objects/implementations/..., but that doesn't seem useful here since there's
a known-ahead-of-time single implementation of these functions in a single
build of U-Boot.
Your own commit messages says that this is SoC-specific. I'm
suggesting that we define an interface (which I think you have already
done with your header file additions), and allow SoCs to implement it
via a linker list.
IMO the cache code in U-Boot is starting to get a bit creaky.
A cache uclass seems like /massive/ overkill, especially since I'd expect
these very low-level functions to be required well before any higher level
code like DM/classes/... to be available.
DM is available very early. But it's not clear from your patch when
this code is actually called.
I believe that weak functions are a perfectly acceptable approach here.
Yes, the implementation of these functions is SoC-specific. The
Makefiles will pull in the appropriate implementation for that SoC
whenever U-Boot is built, just like every other board- or SoC-specific
function in the entire of U-Boot.
There's no need for linker lists since there is only ever one
implementation.
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
