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

[Jeremy Linton]

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.lin...@arm.com>
---
  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