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.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