Hi Stephen,
On 18 October 2016 at 12:58, Stephen Warren swarren@wwwdotorg.org wrote:
On 10/18/2016 10:23 AM, Simon Glass wrote:
Hi Stephen,
On 17 October 2016 at 15:35, Stephen Warren swarren@wwwdotorg.org wrote:
From: Stephen Warren swarren@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 swarren@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.
Regards, Simon