Re: [PATCH v6 02/12] drivers: base: cacheinfo: setup DT cache properties early
From: Jeremy Linton
Date: Tue Jan 16 2018 - 16:26:47 EST
Hi,
On 01/15/2018 10:07 AM, Palmer Dabbelt wrote:
On Mon, 15 Jan 2018 04:33:38 PST (-0800), sudeep.holla@xxxxxxx wrote:
On Fri, Jan 12, 2018 at 06:59:10PM -0600, Jeremy Linton wrote:
The original intent in cacheinfo was that an architecture
specific populate_cache_leaves() would probe the hardware
and then cache_shared_cpu_map_setup() and
cache_override_properties() would provide firmware help to
extend/expand upon what was probed. Arm64 was really
the only architecture that was working this way, and
with the removal of most of the hardware probing logic it
became clear that it was possible to simplify the logic a bit.
This patch combines the walk of the DT nodes with the
code updating the cache size/line_size and nr_sets.
cache_override_properties() (which was DT specific) is
then removed. The result is that cacheinfo.of_node is
no longer used as a temporary place to hold DT references
for future calls that update cache properties. That change
helps to clarify its one remaining use (matching
cacheinfo nodes that represent shared caches) which
will be used by the ACPI/PPTT code in the following patches.
Cc: Palmer Dabbelt <palmer@xxxxxxxxxx>
Cc: Albert Ou <albert@xxxxxxxxxx>
Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
---
Âarch/riscv/kernel/cacheinfo.c |Â 1 +
Âdrivers/base/cacheinfo.cÂÂÂÂÂ | 65
+++++++++++++++++++------------------------
Âinclude/linux/cacheinfo.hÂÂÂÂ |Â 1 +
Â3 files changed, 31 insertions(+), 36 deletions(-)
diff --git a/arch/riscv/kernel/cacheinfo.c
b/arch/riscv/kernel/cacheinfo.c
index 10ed2749e246..6f4500233cf8 100644
--- a/arch/riscv/kernel/cacheinfo.c
+++ b/arch/riscv/kernel/cacheinfo.c
@@ -30,6 +30,7 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
ÂÂÂÂÂÂÂÂ CACHE_WRITE_BACK
ÂÂÂÂÂÂÂÂ | CACHE_READ_ALLOCATE
ÂÂÂÂÂÂÂÂ | CACHE_WRITE_ALLOCATE;
+ÂÂÂ cache_of_set_props(this_leaf, node);
This may be necessary but can it be done as later patch ? So far nothing
is added that may break riscv IIUC.
Palmer, Albert,
Can you confirm ? Also, as I see we can thin down arch specific
implementation on riscv if it's just using DT like ARM64. Sorry if
I am missing to see something, so thought of checking.
[...]
Sorry, I guess I'm a bit confused as to what's going on here. RISC-V
uses device tree on all Linux systems.
If I'm understanding the context correctly:
The first part of this patch set just straightens out the DT setup order
so it happens in a single pass (rather that doing one pass to find the
DT nodes, then another later on to update the cacheinfo from DT). This
clarifies/simplifies how the firmware_unique (firmware_token?) field in
cacheinfo is actually being used.
riscv is a bit odd because its actually doing some DT manipulation in
its arch setup (populate_cache_leaves()). I think the thought process is
that it might be nicer if the common DT code handled whatever required
that bit of logic to be added to riscv. If that were changed, then it
might be possible to drop most of the DT cache setup code from the
riscv/arch tree.
diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
index 3d9805297cda..d35299a590a4 100644
--- a/include/linux/cacheinfo.h
+++ b/include/linux/cacheinfo.h
@@ -99,6 +99,7 @@ int func(unsigned int cpu)ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ \
Âstruct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu);
Âint init_cache_level(unsigned int cpu);
Âint populate_cache_leaves(unsigned int cpu);
+void cache_of_set_props(struct cacheinfo *this_leaf, struct
device_node *np);
IIUC riscv is the only user for this outside of cacheinfo.c, right ?
Hopefully we can get rid of it.
Other than that, it looks OK. I will wait for response from riscv team
do that these riscv related changes can be dropped or move to later
patch if really needed.