linux/drivers/cpufreq/cppc_cpufreq.c, branch v6.7

cpufreq: cppc: Set fie_disabled to FIE_DISABLED if fails to create kworker_fie

2023-08-17T08:54:58Z

The function cppc_freq_invariance_init() may failed to create kworker_fie, make it more robust by setting fie_disabled to FIE_DISBALED to prevent an invalid pointer dereference in kthread_destroy_worker(), which called from cppc_freq_invariance_exit(). Signed-off-by: Liao Chang Signed-off-by: Viresh Kumar

cpufreq: cppc: cppc_cpufreq_get_rate() returns zero in all error cases.

2023-08-17T08:42:11Z

The cpufreq framework used to use the zero of return value to reflect the cppc_cpufreq_get_rate() had failed to get current frequecy and treat all positive integer to be succeed. Since cppc_get_perf_ctrs() returns a negative integer in error case, so it is better to convert the value to zero as the return value of cppc_cpufreq_get_rate(). Signed-off-by: Liao Chang Signed-off-by: Viresh Kumar

cpufreq: CPPC: Add u64 casts to avoid overflowing

2022-12-27T02:57:14Z

The fields of the _CPC object are unsigned 32-bits values. To avoid overflows while using _CPC's values, add 'u64' casts. Signed-off-by: Pierre Gondois Signed-off-by: Viresh Kumar

ACPI: CPPC: Disable FIE if registers in PCC regions

2022-09-24T16:43:46Z

PCC regions utilize a mailbox to set/retrieve register values used by the CPPC code. This is fine as long as the operations are infrequent. With the FIE code enabled though the overhead can range from 2-11% of system CPU overhead (ex: as measured by top) on Arm based machines. So, before enabling FIE assure none of the registers used by cppc_get_perf_ctrs() are in the PCC region. Finally, add a module parameter which can override the PCC region detection at boot or module reload. Signed-off-by: Jeremy Linton Acked-by: Viresh Kumar Reviewed-by: Ionela Voinescu Signed-off-by: Rafael J. Wysocki

ACPI: CPPC: Add ACPI disabled check to acpi_cpc_valid()

2022-08-25T11:55:17Z

Make acpi_cpc_valid() check if ACPI is disabled, so that its callers don't need to check that separately. This will also cause the AMD pstate driver to refuse to load right away when ACPI is disabled. Also update the warning message in amd_pstate_init() to mention the ACPI disabled case for completeness. Signed-off-by: Perry Yuan [ rjw: Subject edits, new changelog ] Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Fix unused-function warning

2022-05-30T13:33:42Z

Building the cppc_cpufreq driver with for arm64 with CONFIG_ENERGY_MODEL=n triggers the following warnings: drivers/cpufreq/cppc_cpufreq.c:550:12: error: ‘cppc_get_cpu_cost’ defined but not used [-Werror=unused-function] 550 | static int cppc_get_cpu_cost(struct device *cpu_dev, unsigned long KHz, | ^~~~~~~~~~~~~~~~~ drivers/cpufreq/cppc_cpufreq.c:481:12: error: ‘cppc_get_cpu_power’ defined but not used [-Werror=unused-function] 481 | static int cppc_get_cpu_power(struct device *cpu_dev, | ^~~~~~~~~~~~~~~~~~ Move the Energy Model related functions into specific guards. This allows to fix the warning and prevent doing extra work when the Energy Model is not present. Fixes: 740fcdc2c20e ("cpufreq: CPPC: Register EM based on efficiency class information") Reported-by: Shaokun Zhang Signed-off-by: Pierre Gondois Tested-by: Shaokun Zhang Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Fix build error without CONFIG_ACPI_CPPC_CPUFREQ_FIE

2022-05-30T13:31:28Z

If CONFIG_ACPI_CPPC_CPUFREQ_FIE is not set, building fails: drivers/cpufreq/cppc_cpufreq.c: In function ‘populate_efficiency_class’: drivers/cpufreq/cppc_cpufreq.c:584:2: error: ‘cppc_cpufreq_driver’ undeclared (first use in this function); did you mean ‘cpufreq_driver’? cppc_cpufreq_driver.register_em = cppc_cpufreq_register_em; ^~~~~~~~~~~~~~~~~~~ cpufreq_driver Make declare of cppc_cpufreq_driver out of CONFIG_ACPI_CPPC_CPUFREQ_FIE to fix this. Fixes: 740fcdc2c20e ("cpufreq: CPPC: Register EM based on efficiency class information") Signed-off-by: Zheng Bin Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Enable dvfs_possible_from_any_cpu

2022-05-19T17:45:34Z

The communication mean of the _CPC desired performance can be PCC, System Memory, System IO, or Functional Fixed Hardware (FFH). PCC, SystemMemory and SystemIo address spaces are available from any CPU. Thus, dvfs_possible_from_any_cpu should be enabled in such case. For FFH, let the FFH implementation do smp_call_function_*() calls. Signed-off-by: Pierre Gondois Reviewed-by: Sudeep Holla Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Enable fast_switch

2022-05-19T17:45:34Z

The communication mean of the _CPC desired performance can be PCC, System Memory, System IO, or Functional Fixed Hardware. commit b7898fda5bc7 ("cpufreq: Support for fast frequency switching") fast_switching is 'for switching CPU frequencies from interrupt context'. Writes to SystemMemory and SystemIo are fast and suitable this. This is not the case for PCC and might not be the case for FFH. Enable fast_switching for the cppc_cpufreq driver in above cases. Add cppc_allow_fast_switch() to check the desired performance register address space and set fast_switching accordingly. Signed-off-by: Pierre Gondois Reviewed-by: Sudeep Holla Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki

cpufreq: CPPC: Register EM based on efficiency class information

2022-05-06T19:01:17Z

Performance states and energy consumption values are not advertised in ACPI. In the GicC structure of the MADT table, the "Processor Power Efficiency Class field" (called efficiency class from now) allows to describe the relative energy efficiency of CPUs. To leverage the EM and EAS, the CPPC driver creates a set of artificial performance states and registers them in the Energy Model (EM), such as: - Every 20 capacity unit, a performance state is created. - The energy cost of each performance state gradually increases. No power value is generated as only the cost is used in the EM. During task placement, a task can raise the frequency of its whole pd. This can make EAS place a task on a pd with CPUs that are individually less energy efficient. As cost values are artificial, and to place tasks on CPUs with the lower efficiency class, a gap in cost values is generated for adjacent efficiency classes. E.g.: - efficiency class = 0, capacity is in [0-1024], so cost values are in [0: 51] (one performance state every 20 capacity unit) - efficiency class = 1, capacity is in [0-1024], cost values are in [1*gap+0: 1*gap+51]. The value of the cost gap is chosen to absorb a the energy of 4 CPUs at their maximum capacity. This means that between: 1- a pd of 4 CPUs, each of them being used at almost their full capacity. Their efficiency class is N. 2- a CPU using almost none of its capacity. Its efficiency class is N+1 EAS will choose the first option. This patch also populates the (struct cpufreq_driver).register_em callback if the valid efficiency_class ACPI values are provided. Signed-off-by: Pierre Gondois Acked-by: Viresh Kumar Signed-off-by: Rafael J. Wysocki