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Message-ID: <20171019152012.GB18883@red-moon>
Date: Thu, 19 Oct 2017 16:20:12 +0100
From: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
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, rjw@...ysocki.net,
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
Subject: Re: [PATCH v3 3/7] drivers: base: cacheinfo: arm64: Add support for
ACPI based firmware tables
On Thu, Oct 12, 2017 at 02:48:52PM -0500, Jeremy Linton wrote:
> The /sys cache entries should support ACPI/PPTT generated cache
> topology information. Lets detect ACPI systems and call
> an arch specific cache_setup_acpi() routine to update the hardware
> probed cache topology.
>
> For arm64, if ACPI is enabled, determine the max number of cache
> levels and populate them using a PPTT table if one is available.
>
> Signed-off-by: Jeremy Linton <jeremy.linton@....com>
> ---
> arch/arm64/kernel/cacheinfo.c | 23 ++++++++++++++++++-----
> drivers/acpi/pptt.c | 1 +
> drivers/base/cacheinfo.c | 17 +++++++++++------
> include/linux/cacheinfo.h | 11 +++++++++--
> 4 files changed, 39 insertions(+), 13 deletions(-)
>
> diff --git a/arch/arm64/kernel/cacheinfo.c b/arch/arm64/kernel/cacheinfo.c
> index 380f2e2fbed5..2e2cf0d312ba 100644
> --- a/arch/arm64/kernel/cacheinfo.c
> +++ b/arch/arm64/kernel/cacheinfo.c
> @@ -17,6 +17,7 @@
> * along with this program. If not, see <http://www.gnu.org/licenses/>.
> */
>
> +#include <linux/acpi.h>
> #include <linux/cacheinfo.h>
> #include <linux/of.h>
>
> @@ -44,9 +45,17 @@ static void ci_leaf_init(struct cacheinfo *this_leaf,
> this_leaf->type = type;
> }
>
> +#ifndef CONFIG_ACPI
> +int acpi_find_last_cache_level(unsigned int cpu)
> +{
> + /*ACPI kernels should be built with PPTT support*/
> + return 0;
> +}
> +#endif
> +
> static int __init_cache_level(unsigned int cpu)
> {
> - unsigned int ctype, level, leaves, of_level;
> + unsigned int ctype, level, leaves, fw_level;
> struct cpu_cacheinfo *this_cpu_ci = get_cpu_cacheinfo(cpu);
>
> for (level = 1, leaves = 0; level <= MAX_CACHE_LEVEL; level++) {
> @@ -59,15 +68,19 @@ static int __init_cache_level(unsigned int cpu)
> leaves += (ctype == CACHE_TYPE_SEPARATE) ? 2 : 1;
> }
>
> - of_level = of_find_last_cache_level(cpu);
> - if (level < of_level) {
> + if (acpi_disabled)
> + fw_level = of_find_last_cache_level(cpu);
> + else
> + fw_level = acpi_find_last_cache_level(cpu);
> +
> + if (level < fw_level) {
> /*
> * some external caches not specified in CLIDR_EL1
> * the information may be available in the device tree
> * only unified external caches are considered here
> */
> - leaves += (of_level - level);
> - level = of_level;
> + leaves += (fw_level - level);
> + level = fw_level;
> }
>
> this_cpu_ci->num_levels = level;
> diff --git a/drivers/acpi/pptt.c b/drivers/acpi/pptt.c
> index c86715fed4a7..b5c6de37e328 100644
> --- a/drivers/acpi/pptt.c
> +++ b/drivers/acpi/pptt.c
> @@ -355,6 +355,7 @@ static void update_cache_properties(struct cacheinfo *this_leaf,
> struct acpi_pptt_cache *found_cache,
> struct acpi_pptt_processor *cpu_node)
> {
> + this_leaf->firmware_node = cpu_node;
This pointer comes from an ACPI static table mapping that happens
to be permanent so it should be safe given that the mapping is carried
out at device_initcall (ie cache_setup_acpi()) but it is not that
obvious. More to it below.
> if (found_cache->flags & ACPI_PPTT_SIZE_PROPERTY_VALID)
> this_leaf->size = found_cache->size;
> if (found_cache->flags & ACPI_PPTT_LINE_SIZE_VALID)
> diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
> index eb3af2739537..8eca279e50d1 100644
> --- a/drivers/base/cacheinfo.c
> +++ b/drivers/base/cacheinfo.c
> @@ -86,7 +86,7 @@ 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;
> + return sib_leaf->firmware_node == this_leaf->firmware_node;
> }
>
> /* OF properties to query for a given cache type */
> @@ -215,6 +215,11 @@ 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 +230,11 @@ 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 +291,7 @@ 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 6a524bf6a06d..d1e9b8e01981 100644
> --- a/include/linux/cacheinfo.h
> +++ b/include/linux/cacheinfo.h
> @@ -36,6 +36,9 @@ 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: Shared with of_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
> @@ -64,8 +67,10 @@ struct cacheinfo {
> #define CACHE_ALLOCATE_POLICY_MASK \
> (CACHE_READ_ALLOCATE | CACHE_WRITE_ALLOCATE)
> #define CACHE_ID BIT(4)
> -
> - struct device_node *of_node;
> + union {
> + struct device_node *of_node;
> + void *firmware_node;
> + };
How about turning of_node into a struct fwnode_handle* (and allocate
one for each PPTT cache node - acpi_static_fwnode - to have the
ACPI counterpart) ?
It will make more churn given that that pointer is just used to
carry out a pointer comparison but it's also a bit more elegant.
Lorenzo
> bool disable_sysfs;
> void *priv;
> };
> @@ -98,6 +103,8 @@ 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);
>
> const struct attribute_group *cache_get_priv_group(struct cacheinfo *this_leaf);
>
> --
> 2.13.5
>
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