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

Jeremy Linton
2017-12-12T17:03:33Z

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@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
>