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Message-ID: <0d4872d9-580b-091d-82cf-671f40cea02a@arm.com>
Date: Thu, 19 Oct 2017 10:52:32 -0500
From: Jeremy Linton <jeremy.linton@....com>
To: Lorenzo Pieralisi <lorenzo.pieralisi@....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
Hi,
On 10/19/2017 10:20 AM, Lorenzo Pieralisi wrote:
> 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) ?
As pointed out internally (with a patch), I converted this whole module
into fwnode, but the ACPI side is still a mess because it doesn't map
cleanly to what ends up being an relative acpi pointer, mostly because
fwnode is really designed more for parsing DT and the ACPI DSDT/etc. So
you end up with fwnode routines that simply don't have mappings to PPTT,
with IMHO is going to just create far more confusion than any assumed
cleanliness that might result.
>
> 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.
Except for the huge api surface that takes a fwnode which won't work.
>
> 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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