linux-stable/include/acpi/cppc_acpi.h
Rafael J. Wysocki 4f4179fcf4 ACPI: CPPC: Do not prevent CPPC from working in the future
There is a problem with the current revision checks in
is_cppc_supported() that they essentially prevent the CPPC support
from working if a new _CPC package format revision being a proper
superset of the v3 and only causing _CPC to return a package with more
entries (while retaining the types and meaning of the entries defined by
the v3) is introduced in the future and used by the platform firmware.

In that case, as long as the number of entries in the _CPC return
package is at least CPPC_V3_NUM_ENT, it should be perfectly fine to
use the v3 support code and disregard the additional package entries
added by the new package format revision.

For this reason, drop is_cppc_supported() altogether, put the revision
checks directly into acpi_cppc_processor_probe() so they are easier to
follow and rework them to take the case mentioned above into account.

Fixes: 4773e77cdc ("ACPI / CPPC: Add support for CPPC v3")
Cc: 4.18+ <stable@vger.kernel.org> # 4.18+
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2022-07-26 20:56:49 +02:00

202 lines
4.5 KiB
C

/* SPDX-License-Identifier: GPL-2.0-only */
/*
* CPPC (Collaborative Processor Performance Control) methods used
* by CPUfreq drivers.
*
* (C) Copyright 2014, 2015 Linaro Ltd.
* Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
*/
#ifndef _CPPC_ACPI_H
#define _CPPC_ACPI_H
#include <linux/acpi.h>
#include <linux/cpufreq.h>
#include <linux/types.h>
#include <acpi/pcc.h>
#include <acpi/processor.h>
/* CPPCv2 and CPPCv3 support */
#define CPPC_V2_REV 2
#define CPPC_V3_REV 3
#define CPPC_V2_NUM_ENT 21
#define CPPC_V3_NUM_ENT 23
#define PCC_CMD_COMPLETE_MASK (1 << 0)
#define PCC_ERROR_MASK (1 << 2)
#define MAX_CPC_REG_ENT 21
/* CPPC specific PCC commands. */
#define CMD_READ 0
#define CMD_WRITE 1
/* Each register has the folowing format. */
struct cpc_reg {
u8 descriptor;
u16 length;
u8 space_id;
u8 bit_width;
u8 bit_offset;
u8 access_width;
u64 address;
} __packed;
/*
* Each entry in the CPC table is either
* of type ACPI_TYPE_BUFFER or
* ACPI_TYPE_INTEGER.
*/
struct cpc_register_resource {
acpi_object_type type;
u64 __iomem *sys_mem_vaddr;
union {
struct cpc_reg reg;
u64 int_value;
} cpc_entry;
};
/* Container to hold the CPC details for each CPU */
struct cpc_desc {
int num_entries;
int version;
int cpu_id;
int write_cmd_status;
int write_cmd_id;
struct cpc_register_resource cpc_regs[MAX_CPC_REG_ENT];
struct acpi_psd_package domain_info;
struct kobject kobj;
};
/* These are indexes into the per-cpu cpc_regs[]. Order is important. */
enum cppc_regs {
HIGHEST_PERF,
NOMINAL_PERF,
LOW_NON_LINEAR_PERF,
LOWEST_PERF,
GUARANTEED_PERF,
DESIRED_PERF,
MIN_PERF,
MAX_PERF,
PERF_REDUC_TOLERANCE,
TIME_WINDOW,
CTR_WRAP_TIME,
REFERENCE_CTR,
DELIVERED_CTR,
PERF_LIMITED,
ENABLE,
AUTO_SEL_ENABLE,
AUTO_ACT_WINDOW,
ENERGY_PERF,
REFERENCE_PERF,
LOWEST_FREQ,
NOMINAL_FREQ,
};
/*
* Categorization of registers as described
* in the ACPI v.5.1 spec.
* XXX: Only filling up ones which are used by governors
* today.
*/
struct cppc_perf_caps {
u32 guaranteed_perf;
u32 highest_perf;
u32 nominal_perf;
u32 lowest_perf;
u32 lowest_nonlinear_perf;
u32 lowest_freq;
u32 nominal_freq;
};
struct cppc_perf_ctrls {
u32 max_perf;
u32 min_perf;
u32 desired_perf;
};
struct cppc_perf_fb_ctrs {
u64 reference;
u64 delivered;
u64 reference_perf;
u64 wraparound_time;
};
/* Per CPU container for runtime CPPC management. */
struct cppc_cpudata {
struct list_head node;
struct cppc_perf_caps perf_caps;
struct cppc_perf_ctrls perf_ctrls;
struct cppc_perf_fb_ctrs perf_fb_ctrs;
unsigned int shared_type;
cpumask_var_t shared_cpu_map;
};
#ifdef CONFIG_ACPI_CPPC_LIB
extern int cppc_get_desired_perf(int cpunum, u64 *desired_perf);
extern int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf);
extern int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs);
extern int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls);
extern int cppc_set_enable(int cpu, bool enable);
extern int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps);
extern bool acpi_cpc_valid(void);
extern bool cppc_allow_fast_switch(void);
extern int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data);
extern unsigned int cppc_get_transition_latency(int cpu);
extern bool cpc_ffh_supported(void);
extern bool cpc_supported_by_cpu(void);
extern int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val);
extern int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val);
#else /* !CONFIG_ACPI_CPPC_LIB */
static inline int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
{
return -ENOTSUPP;
}
static inline int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
{
return -ENOTSUPP;
}
static inline int cppc_get_perf_ctrs(int cpu, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
{
return -ENOTSUPP;
}
static inline int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
{
return -ENOTSUPP;
}
static inline int cppc_set_enable(int cpu, bool enable)
{
return -ENOTSUPP;
}
static inline int cppc_get_perf_caps(int cpu, struct cppc_perf_caps *caps)
{
return -ENOTSUPP;
}
static inline bool acpi_cpc_valid(void)
{
return false;
}
static inline bool cppc_allow_fast_switch(void)
{
return false;
}
static inline unsigned int cppc_get_transition_latency(int cpu)
{
return CPUFREQ_ETERNAL;
}
static inline bool cpc_ffh_supported(void)
{
return false;
}
static inline int cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
{
return -ENOTSUPP;
}
static inline int cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
{
return -ENOTSUPP;
}
#endif /* !CONFIG_ACPI_CPPC_LIB */
#endif /* _CPPC_ACPI_H*/