From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Warren Date: Tue, 18 Oct 2016 12:58:02 -0600 Subject: [U-Boot] [PATCH 1/2] armv8: add hooks for all cache-wide operations In-Reply-To: References: <20161017213540.5984-1-swarren@wwwdotorg.org> Message-ID: <2eb98062-bf22-2a49-ea13-701f3dd65c4e@wwwdotorg.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 10/18/2016 10:23 AM, Simon Glass wrote: > Hi Stephen, > > On 17 October 2016 at 15:35, Stephen Warren wrote: >> From: Stephen Warren >> >> 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 >> --- >> 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. 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.