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

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Date:   Tue, 12 Dec 2017 02:11:06 +0100
From:   "Rafael J. Wysocki" <rjw@...ysocki.net>
To:     Jeremy Linton <jeremy.linton@....com>
Cc:     linux-acpi@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        sudeep.holla@....com, hanjun.guo@...aro.org,
        lorenzo.pieralisi@....com, will.deacon@....com,
        catalin.marinas@....com, gregkh@...uxfoundation.org,
        viresh.kumar@...aro.org, mark.rutland@....com,
        linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        jhugo@...eaurora.org, wangxiongfeng2@...wei.com,
        Jonathan.Zhang@...ium.com, ahs3@...hat.com,
        Jayachandran.Nair@...ium.com, austinwc@...eaurora.org,
        lenb@...nel.org
Subject: Re: [PATCH v5 4/9] drivers: base cacheinfo: Add support for ACPI based firmware tables

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@....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?

>  	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