Re: [PATCH v5 4/9] drivers: base cacheinfo: Add support for ACPI based firmware tables

From: Jeremy Linton
Date: Tue Dec 12 2017 - 12:03:36 EST


Hi,

On 12/11/2017 07:11 PM, Rafael J. Wysocki wrote:
On Friday, December 1, 2017 11:23:25 PM CET Jeremy Linton wrote:
Add a entry to to struct cacheinfo to maintain a reference to the PPTT
node which can be used to match identical caches across cores. Also
stub out cache_setup_acpi() so that individual architectures can
enable ACPI topology parsing.

Signed-off-by: Jeremy Linton <jeremy.linton@xxxxxxx>
---
drivers/acpi/pptt.c | 1 +
drivers/base/cacheinfo.c | 20 ++++++++++++++------
include/linux/cacheinfo.h | 13 ++++++++++++-
3 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
index 0f8a1631af33..a35e457cefb7 100644
--- a/drivers/acpi/pptt.c
+++ b/drivers/acpi/pptt.c
@@ -329,6 +329,7 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
{
int valid_flags = 0;
+ this_leaf->firmware_node = cpu_node;
if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID) {
this_leaf->size = found_cache->size;
valid_flags++;
diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index eb3af2739537..ba89f9310e6f 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -86,7 +86,10 @@ static int cache_setup_of_node(unsigned int cpu)
static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
struct cacheinfo *sib_leaf)
{
- return sib_leaf->of_node == this_leaf->of_node;
+ if (acpi_disabled)
+ return sib_leaf->of_node == this_leaf->of_node;
+ else
+ return sib_leaf->firmware_node == this_leaf->firmware_node;
}
/* OF properties to query for a given cache type */
@@ -215,6 +218,11 @@ static inline bool cache_leaves_are_shared(struct cacheinfo *this_leaf,
}
#endif
+int __weak cache_setup_acpi(unsigned int cpu)
+{
+ return -ENOTSUPP;
+}
+
static int cache_shared_cpu_map_setup(unsigned int cpu)
{
struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
@@ -225,11 +233,11 @@ static int cache_shared_cpu_map_setup(unsigned int cpu)
if (this_cpu_ci->cpu_map_populated)
return 0;
- if (of_have_populated_dt())
+ if (!acpi_disabled)
+ ret = cache_setup_acpi(cpu);
+ else if (of_have_populated_dt())
ret = cache_setup_of_node(cpu);
- else if (!acpi_disabled)
- /* No cache property/hierarchy support yet in ACPI */
- ret = -ENOTSUPP;
+
if (ret)
return ret;
@@ -286,7 +294,7 @@ static void cache_shared_cpu_map_remove(unsigned int cpu)
static void cache_override_properties(unsigned int cpu)
{
- if (of_have_populated_dt())
+ if (acpi_disabled && of_have_populated_dt())
return cache_of_override_properties(cpu);
}
diff --git a/include/linux/cacheinfo.h b/include/linux/cacheinfo.h
index 3d9805297cda..7ebff157ae6c 100644
--- a/include/linux/cacheinfo.h
+++ b/include/linux/cacheinfo.h
@@ -37,6 +37,8 @@ enum cache_type {
* @of_node: if devicetree is used, this represents either the cpu node in
* case there's no explicit cache node or the cache node itself in the
* device tree
+ * @firmware_node: When not using DT, this may contain pointers to other
+ * firmware based values. Particularly ACPI/PPTT unique values.
* @disable_sysfs: indicates whether this node is visible to the user via
* sysfs or not
* @priv: pointer to any private data structure specific to particular
@@ -65,8 +67,8 @@ struct cacheinfo {
#define CACHE_ALLOCATE_POLICY_MASK \
(CACHE_READ_ALLOCATE | CACHE_WRITE_ALLOCATE)
#define CACHE_ID BIT(4)
-
struct device_node *of_node;
+ void *firmware_node;

What about converting this to using struct fwnode instead of adding
fields to it?

I didn't really want to add another field here, but I've also pointed out how I thought converting it to a fwnode wasn't a good choice.

https://lkml.org/lkml/2017/11/20/502

Mostly because IMHO its even more misleading (lacking any fwnode_operations) than misusing the of_node as a void *.

Given that I'm in the minority thinking this, how far down the fwnode path on the ACPI side do we want to go? Is simply treating it as a void pointer sufficient for the ACPI side, considering all the PPTT code needs is a unique token?



bool disable_sysfs;
void *priv;
};
@@ -99,6 +101,15 @@ int func(unsigned int cpu) \
struct cpu_cacheinfo *get_cpu_cacheinfo(unsigned int cpu);
int init_cache_level(unsigned int cpu);
int populate_cache_leaves(unsigned int cpu);
+int cache_setup_acpi(unsigned int cpu);
+int acpi_find_last_cache_level(unsigned int cpu);
+#ifndef CONFIG_ACPI
+int acpi_find_last_cache_level(unsigned int cpu)
+{
+ /*ACPI kernels should be built with PPTT support*/
+ return 0;
+}
+#endif
const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf);


Thanks,
Rafael