On some systems the nominal_perf value retrieved via CPPC is just
a constant and fetching it doesn't require accessing any registers,
so if it is the only CPPC capability that's needed, it is wasteful
to run cppc_get_perf_caps() in order to get just that value alone,
especially when this is done for CPUs other than the one running
the code.
For this reason, introduce cppc_get_nominal_perf() allowing
nominal_perf to be obtained individually, by generalizing the
existing cppc_get_desired_perf() (and renaming it) so it can be
used to retrieve any specific CPPC capability value.
While at it, clean up the cppc_get_desired_perf() kerneldoc comment
a bit.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* acpi-misc:
ACPI: dock: fix some coding style issues
ACPI: sysfs: fix some coding style issues
ACPI: PM: add a missed blank line after declarations
ACPI: custom_method: fix a coding style issue
ACPI: CPPC: fix some coding style issues
ACPI: button: fix some coding style issues
ACPI: battery: fix some coding style issues
ACPI: acpi_pad: add a missed blank line after declarations
ACPI: LPSS: add a missed blank line after declarations
ACPI: ipmi: remove useless return statement for void function
ACPI: processor: fix some coding style issues
ACPI: APD: fix a block comment align issue
ACPI: AC: fix some coding style issues
ACPI: fix various typos in comments
All of the CPPC sysfs show functions are called via indirect call in
kobj_attr_show(), where they should be of type
ssize_t (*show)(struct kobject *kobj, struct kobj_attribute *attr, char *buf);
because that is the type of the ->show() member in
'struct kobj_attribute' but they are actually of type
ssize_t (*show)(struct kobject *kobj, struct attribute *attr, char *buf);
because of the ->show() member in 'struct cppc_attr', resulting in a
Control Flow Integrity violation [1].
$ cat /sys/devices/system/cpu/cpu0/acpi_cppc/highest_perf
3400
$ dmesg | grep "CFI failure"
[ 175.970559] CFI failure (target: show_highest_perf+0x0/0x8):
As far as I can tell, the only difference between 'struct cppc_attr'
and 'struct kobj_attribute' aside from the type of the attr parameter
is the type of the count parameter in the ->store() member (ssize_t vs.
size_t), which does not actually matter because all of these nodes are
read-only.
Eliminate 'struct cppc_attr' in favor of 'struct kobj_attribute' to fix
the violation.
[1]: https://lore.kernel.org/r/20210401233216.2540591-1-samitolvanen@google.com/
Fixes: 158c998ea4 ("ACPI / CPPC: add sysfs support to compute delivered performance")
Link: https://github.com/ClangBuiltLinux/linux/issues/1343
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fix some coding style issues reported by checkpatch.pl, including the
following types:
WARNING: Missing a blank line after declarations
WARNING: unnecessary whitespace before a quoted newline
ERROR: spaces required around that '>='
ERROR: switch and case should be at the same indent
Signed-off-by: Xiaofei Tan <tanxiaofei@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
For convenience, add empty stubs of library functions defined in
cppc_acpi.c for the CONFIG_ACPI_CPPC_LIB unset case.
Because one of them needs to return CPUFREQ_ETERNAL, include
linux/cpufreq.h into the CPPC library header file and drop the
direct inclusion of it from cppc_acpi.c.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Tested-by: Chen Yu <yu.c.chen@intel.com>
Properly initialise vaddr pointers in cpc_read() and cpc_write() to
NULL instead of 0.
This fixes the following sparse warnings:
drivers/acpi/cppc_acpi.c:937:31: warning: Using plain integer as NULL pointer
drivers/acpi/cppc_acpi.c:982:31: warning: Using plain integer as NULL pointer
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
ppc_comm_addr is a virtual address to the PCC space and it's annotated
with __iomem. Therefore, generic_comm_base which gets assigned the value of
pcc_comm_address should be annotated as well.
This already happens in check_pcc_chan(), but not in send_pcc_cmd(), which
results in the following sparse warnings:
drivers/acpi/cppc_acpi.c:237:18: warning: cast removes address space '__iomem' of expression
drivers/acpi/cppc_acpi.c:299:9: warning: incorrect type in argument 2 (different address spaces)
drivers/acpi/cppc_acpi.c:299:9: expected void volatile [noderef] __iomem *addr
drivers/acpi/cppc_acpi.c:299:9: got unsigned short *
drivers/acpi/cppc_acpi.c:302:9: warning: incorrect type in argument 2 (different address spaces)
drivers/acpi/cppc_acpi.c:302:9: expected void volatile [noderef] __iomem *addr
drivers/acpi/cppc_acpi.c:302:9: got unsigned short *
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
* pm-cpufreq:
cpufreq: intel_pstate: Use most recent guaranteed performance values
cpufreq: intel_pstate: Implement the ->adjust_perf() callback
cpufreq: Add special-purpose fast-switching callback for drivers
cpufreq: schedutil: Add util to struct sg_cpu
cppc_cpufreq: replace per-cpu data array with a list
cppc_cpufreq: expose information on frequency domains
cppc_cpufreq: clarify support for coordination types
cppc_cpufreq: use policy->cpu as driver of frequency setting
ACPI: processor: fix NONE coordination for domain mapping failure
ACPI: processor: Drop duplicate setting of shared_cpu_map
The cppc_cpudata per-cpu storage was inefficient (1) additional to causing
functional issues (2) when CPUs are hotplugged out, due to per-cpu data
being improperly initialised.
(1) The amount of information needed for CPPC performance control in its
cpufreq driver depends on the domain (PSD) coordination type:
ANY: One set of CPPC control and capability data (e.g desired
performance, highest/lowest performance, etc) applies to all
CPUs in the domain.
ALL: Same as ANY. To be noted that this type is not currently
supported. When supported, information about which CPUs
belong to a domain is needed in order for frequency change
requests to be sent to each of them.
HW: It's necessary to store CPPC control and capability
information for all the CPUs. HW will then coordinate the
performance state based on their limitations and requests.
NONE: Same as HW. No HW coordination is expected.
Despite this, the previous initialisation code would indiscriminately
allocate memory for all CPUs (all_cpu_data) and unnecessarily
duplicate performance capabilities and the domain sharing mask and type
for each possible CPU.
(2) With the current per-cpu structure, when having ANY coordination,
the cppc_cpudata cpu information is not initialised (will remain 0)
for all CPUs in a policy, other than policy->cpu. When policy->cpu is
hotplugged out, the driver will incorrectly use the uninitialised (0)
value of the other CPUs when making frequency changes. Additionally,
the previous values stored in the perf_ctrls.desired_perf will be
lost when policy->cpu changes.
Therefore replace the array of per cpu data with a list. The memory for
each structure is allocated at policy init, where a single structure
can be allocated per policy, not per cpu. In order to accommodate the
struct list_head node in the cppc_cpudata structure, the now unused cpu
and cur_policy variables are removed.
For example, on a arm64 Juno platform with 6 CPUs: (0, 1, 2, 3) in PSD1,
(4, 5) in PSD2 - ANY coordination, the memory allocation comparison shows:
Before patch:
- ANY coordination:
total slack req alloc/free caller
0 0 0 0/1 _kernel_size_le_hi32+0x0xffff800008ff7810
0 0 0 0/6 _kernel_size_le_hi32+0x0xffff800008ff7808
128 80 48 1/0 _kernel_size_le_hi32+0x0xffff800008ffc070
768 0 768 6/0 _kernel_size_le_hi32+0x0xffff800008ffc0e4
After patch:
- ANY coordination:
total slack req alloc/free caller
256 0 256 2/0 _kernel_size_le_hi32+0x0xffff800008fed410
0 0 0 0/2 _kernel_size_le_hi32+0x0xffff800008fed274
Additional notes:
- A pointer to the policy's cppc_cpudata is stored in policy->driver_data
- Driver registration is skipped if _CPC entries are not present.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Tested-by: Mian Yousaf Kaukab <ykaukab@suse.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
For errors parsing the _PSD domains, a separate domain is returned for
each CPU in the failed _PSD domain with no coordination (as per previous
comment). But contrary to the intention, the code was setting
CPUFREQ_SHARED_TYPE_ALL as coordination type.
Change shared_type to CPUFREQ_SHARED_TYPE_NONE in case of errors parsing
the domain information. The function still returns the error and the caller
is free to bail out the domain initialisation altogether in that case.
Given that both functions return domains with a single CPU, this change
does not affect the functionality, but clarifies the intention.
Signed-off-by: Ionela Voinescu <ionela.voinescu@arm.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
[ rjw: Subject edit ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This is the first pass in creating the ability to calculate the
frequency invariance on AMD systems. This approach uses the CPPC
highest performance and nominal performance values that range from
0 - 255 instead of a high and base frquency. This is because we do
not have the ability on AMD to get a highest frequency value.
On AMD systems the highest performance and nominal performance
vaues do correspond to the highest and base frequencies for the system
so using them should produce an appropriate ratio but some tweaking
is likely necessary.
Due to CPPC being initialized later in boot than when the frequency
invariant calculation is currently made, I had to create a callback
from the CPPC init code to do the calculation after we have CPPC
data.
Special thanks to "kernel test robot <lkp@intel.com>" for reporting that
compilation of drivers/acpi/cppc_acpi.c is conditional to
CONFIG_ACPI_CPPC_LIB, not just CONFIG_ACPI.
[ ggherdovich@suse.cz: made safe under CPU hotplug, edited changelog. ]
Signed-off-by: Nathan Fontenot <nathan.fontenot@amd.com>
Signed-off-by: Giovanni Gherdovich <ggherdovich@suse.cz>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lkml.kernel.org/r/20201112182614.10700-2-ggherdovich@suse.cz
kobject_init_and_add() takes reference even when it fails.
If this function returns an error, kobject_put() must be called to
properly clean up the memory associated with the object. Previous
commit "b8eb718348b8" fixed a similar problem.
Fixes: 158c998ea4 ("ACPI / CPPC: add sysfs support to compute delivered performance")
Signed-off-by: Qiushi Wu <wu000273@umn.edu>
Cc: 4.10+ <stable@vger.kernel.org> # 4.10+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fix the following sparse warnings:
drivers/acpi/cppc_acpi.c:353:20: warning: symbol 'cppc_mbox_cl' was not declared. Should it be static?
drivers/acpi/cppc_acpi.c:600:5: warning: symbol 'pcc_data_alloc' was not declared. Should it be static?
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zou Wei <zou_wei@huawei.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
In acpi_get_psd_map() variable all_cpu_data[] can't be NULL and variable
match_cpc_ptr has been checked before, no need check again at the end of
the funchtion.
Some additional optimizations can be made on top of that.
Signed-off-by: Liguang Zhang <zhangliguang@linux.alibaba.com>
[ rjw: Subject & changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
According to the ACPI 6.3 specification, the _PSD method is optional
when using CPPC. The underlying assumption is that each CPU can change
frequency independently from all other CPUs; _PSD is provided to tell
the OS that some processors can NOT do that.
However, the acpi_get_psd() function returns ENODEV if there is no _PSD
method present, or an ACPI error status if an error occurs when evaluating
_PSD, if present. This makes _PSD mandatory when using CPPC, in violation
of the specification, and only on Linux.
This has forced some firmware writers to provide a dummy _PSD, even though
it is irrelevant, but only because Linux requires it; other OSPMs follow
the spec. We really do not want to have OS specific ACPI tables, though.
So, correct acpi_get_psd() so that it does not return an error if there
is no _PSD method present, but does return a failure when the method can
not be executed properly. This allows _PSD to be optional as it should
be.
Signed-off-by: Al Stone <ahs3@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Based on 1 normalized pattern(s):
this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation version 2 of the license
extracted by the scancode license scanner the SPDX license identifier
GPL-2.0-only
has been chosen to replace the boilerplate/reference in 315 file(s).
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Armijn Hemel <armijn@tjaldur.nl>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190531190115.503150771@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Fix some misspellings in comments. No functional change intended.
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
As per the ACPI specification, "Guaranteed Performance Register" is
a "Buffer" field and it cannot be "Integer", so treat the "Integer"
type for "Guaranteed Performance Register" field as invalid and
ignore its value in that case.
Also save one cpc_read() call when "Guaranteed Performance Register"
is not present, which means a register defined as:
"Register(SystemMemory, 0, 0, 0, 0)".
Fixes: 29523f0953 ("ACPI / CPPC: Add support for guaranteed performance")
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: 4.20+ <stable@vger.kernel.org> # 4.20+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This patch add a helper to get the value of desired performance
register.
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
[ rjw: More white space ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The Continuous Performance Control package may contain an optional
guaranteed performance field.
Add support to read guaranteed performance from _CPC.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Replace the faulty PCC status register polling code with a iopoll.h
macro to fix incorrect reporting of PCC check errors ("PCC check
channel failed").
There were potential codepaths where we could incorrectly return
PCC channel status as busy even without checking the PCC status
register once or not checking the status register before breaking
out of the polling loop. For example, if the thread polling PCC
status register was preempted and scheduled back after we have
crossed the deadline then we can report that the channel is busy
even without checking the status register.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Changes the behavior where we return error if there are no valid PCC
subspace for a given performance domain.
The ACPI spec does not mandate the use PCC, so it is possible to have
platforms where a PCC subspace may not be present, so we need to check
for a valid PCC subspace ID only if the register is a PCC register.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CPPC V3 introduces two new entries to make it easier to convert between
abstract processor performance and frequency. The two new entries are
lowest frequency and nominal frequency. These are the frequencies
corresponding to lowest and nominal abstract performance.
Add support to read the new entries and populate them as part of the
CPPC performance capabilities which can be used by cpufreq drivers
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CPPC dirver is aware of multiple PCC subspace IDs. Enhance the debug
and error messages in the driver to print the subspace id. In case of
error it will be helpful to find which particular subspace is failing.
Signed-off-by: George Cherian <george.cherian@cavium.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Add suffix ULL to constant 500 in order to give the compiler complete
information about the proper arithmetic to use. Notice that this
constant is used in a context that expects an expression of type
u64 (64 bits, unsigned).
The expression NUM_RETRIES * cppc_ss->latency at line 578, which at
preprocessing time translates to 500 * cppc_ss->latency is currently
being evaluated using 32-bit arithmetic.
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The initialization of pcc_ss_data from pcc_data[pcc_ss_id] before
pcc_ss_id is being range checked could lead to an out-of-bounds array
read. This very same initialization is also being performed after
the range check on pcc_ss_id, so we can just remove this problematic
and also redundant assignment to fix the issue.
Detected by cppcheck:
warning: Value stored to 'pcc_ss_data' during its initialization is never
read
Fixes: 85b1407bf6 (ACPI / CPPC: Make CPPC ACPI driver aware of PCC subspace IDs)
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Based on ACPI 6.2 Section 8.4.7.1.9 If the PCC register space is used,
all PCC registers, for all processors in the same performance domain
(as defined by _PSD), must be defined to be in the same subspace.
Based on Section 14.1 of ACPI specification, it is possible to have a
maximum of 256 PCC subspace IDs. Add support of multiple PCC subspace
ID instead of using a single global pcc_data structure.
While at that, fix the time_delta check in send_pcc_cmd() so that
last_mpar_reset and mpar_count are initialized properly.
Signed-off-by: George Cherian <george.cherian@cavium.com>
Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This typo is quite common. Fix it and add it to the spelling file so
that checkpatch catches it earlier.
Link: http://lkml.kernel.org/r/20170317011131.6881-2-sboyd@codeaurora.org
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Computed delivered performance using CPPC feedback counters are in the
CPPC abstract scale, whereas cppc_cpufreq driver operates in KHz scale.
Exposing the CPPC performance capabilities (highest,lowest, nominal,
lowest non-linear) will allow userspace to figure out the conversion
factor from CPPC abstract scale to KHz.
Also rename ctr_wrap_time to wraparound_time so that show_cppc_data()
macro will work with it.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Read lowest non linear perf in cppc_get_perf_caps so that it can be exposed
via sysfs to the usespace. Lowest non linear perf is the lowest performance
level at which nonlinear power savings are achieved.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Fix a possible use-after-free scenario in acpi_cppc_processor_probe()
that can happen if the function returns without cleaning up the
per-CPU pointer set by it previously.
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We should return -EINVAL (instead of 0) if get_cpu_device() fails.
Fixes: 158c998ea4 (ACPI / CPPC: add sysfs support to compute delivered performance)
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
For PCC mailbox with interrupt flag, CPPC should call mbox_chan_txdone()
function to notify the mailbox framework about TX completion.
Signed-off-by: Hoan Tran <hotran@apm.com>
Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Since struct cpudata is defined in a header file, add prefix cppc_ to
make it not a generic name. Otherwise it causes compile issue in locally
define structure with the same name.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The CPPC registers can also be accessed via functional fixed hardware
addresse(FFH) in X86. Add support by modifying cpc_read and cpc_write to
be able to read/write MSRs on x86 platform on per cpu basis.
Also with this change, acpi_cppc_processor_probe doesn't bail out if
address space id is not equal to PCC or memory address space and FFH
is supported on the system.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
PCC status field exposes an error bit(2) to indicate any errors during
the execution of last comamnd. This patch checks the error bit before
notifying success/failure to the cpufreq driver.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
There are several global variables in cppc driver that are related
to PCC channel used for CPPC. This patch collects all such
information into a single consolidated structure(cppc_pcc_data).
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The CPPC tables contain entries for per CPU feedback counters which
allows us to compute the delivered performance over a given interval
of time.
The math for delivered performance per the CPPCv5.0+ spec is:
reference perf * delta(delivered perf ctr)/delta(ref perf ctr)
Maintaining deltas of the counters in the kernel is messy, as it
depends on when the reads are triggered. (e.g. via the cpufreq
->get() interface). Also the ->get() interace only returns one
value, so cant return raw values. So instead, leave it to userspace
to keep track of raw values and do its math for CPUs it cares about.
delivered and reference perf counters are exposed via the same
sysfs file to avoid the potential "skid", if these values are read
individually from userspace.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Compute the expected transition latency for frequency transitions
using the values from the PCCT tables when the desired perf
register is in PCC.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Reviewed-by: Alexey Klimov <alexey.klimov@arm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CPPC defined in section 8.4.7 of ACPI 6.0 specification suggests
"To amortize the cost of PCC transactions, OSPM should read or write
all PCC registers via a single read or write command when possible"
This patch enables opportunistic batching of frequency transition
requests whenever the request happen to overlap in time.
Currently the access to pcc is serialized by a spin lock which does
not scale well as we increase the number of cores in the system. This
patch improves the scalability by allowing the differnt CPU cores to
update PCC subspace in parallel and by batching requests which will
reduce the certain types of operation(checking command completion bit,
ringing doorbell) by a significant margin.
Profiling shows significant improvement in the overall effeciency
to service freq. transition requests. With this patch we observe close
to 30% of the frequency transition requests being batched with other
requests while running apache bench on a ARM platform with 6
independent domains(or sets of related cpus).
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
We need to acquire pcc_lock only when we are accessing registers
that are in the PCC subspsace.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
For cases where sys mapped CPC registers need to be accessed
frequently, it helps immensly to pre-map them rather than map
and unmap for each operation. e.g. case where feedback counters
are sys mem map registers.
Restructure cpc_read/write and the cpc_regs structure to allow
pre-mapping the system addresses and unmap them when the CPU exits.
Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
When CPPC fails to request a PCC channel, the CPC data is freed
and cpc_desc_ptr points to the invalid data.
Avoid this issue by moving the cpc_desc_ptr assignment after the PCC
channel request.
Signed-off-by: Hoan Tran <hotran@apm.com>
Acked-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Based on 8.4.7.1 section of ACPI 6.1 specification, if the platform
supports CPPC, the _CPC object must exist under all processor objects.
If cpc_desc_ptr pointer is invalid on any CPUs, acpi_get_psd_map()
should return error and CPPC cpufreq driver can not be registered.
Signed-off-by: Hoan Tran <hotran@apm.com>
Reviewed-by: Prashanth Prakash <pprakash@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
The ACPI spec defines Minimum Request Turnaround Time(MRTT) and
Maximum Periodic Access Rate(MPAR) to prevent the OSPM from sending
too many requests than the platform can handle. For further details
on these parameters please refer to section 14.1.3 of ACPI 6.0 spec.
This patch includes MRTT/MPAR in deciding if or when a CPPC request
can be sent to the platform to make sure CPPC implementation is
compliant to the spec.
Signed-off-by: Prashanth Prakash <pprakash@codeaurora.org>
Acked-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Rafael J. Wysocki