linux/drivers/acpi/cppc_acpi.c
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

1545 lines
45 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>
*
* CPPC describes a few methods for controlling CPU performance using
* information from a per CPU table called CPC. This table is described in
* the ACPI v5.0+ specification. The table consists of a list of
* registers which may be memory mapped or hardware registers and also may
* include some static integer values.
*
* CPU performance is on an abstract continuous scale as against a discretized
* P-state scale which is tied to CPU frequency only. In brief, the basic
* operation involves:
*
* - OS makes a CPU performance request. (Can provide min and max bounds)
*
* - Platform (such as BMC) is free to optimize request within requested bounds
* depending on power/thermal budgets etc.
*
* - Platform conveys its decision back to OS
*
* The communication between OS and platform occurs through another medium
* called (PCC) Platform Communication Channel. This is a generic mailbox like
* mechanism which includes doorbell semantics to indicate register updates.
* See drivers/mailbox/pcc.c for details on PCC.
*
* Finer details about the PCC and CPPC spec are available in the ACPI v5.1 and
* above specifications.
*/
#define pr_fmt(fmt) "ACPI CPPC: " fmt
#include <linux/delay.h>
#include <linux/iopoll.h>
#include <linux/ktime.h>
#include <linux/rwsem.h>
#include <linux/wait.h>
#include <linux/topology.h>
#include <acpi/cppc_acpi.h>
struct cppc_pcc_data {
struct pcc_mbox_chan *pcc_channel;
void __iomem *pcc_comm_addr;
bool pcc_channel_acquired;
unsigned int deadline_us;
unsigned int pcc_mpar, pcc_mrtt, pcc_nominal;
bool pending_pcc_write_cmd; /* Any pending/batched PCC write cmds? */
bool platform_owns_pcc; /* Ownership of PCC subspace */
unsigned int pcc_write_cnt; /* Running count of PCC write commands */
/*
* Lock to provide controlled access to the PCC channel.
*
* For performance critical usecases(currently cppc_set_perf)
* We need to take read_lock and check if channel belongs to OSPM
* before reading or writing to PCC subspace
* We need to take write_lock before transferring the channel
* ownership to the platform via a Doorbell
* This allows us to batch a number of CPPC requests if they happen
* to originate in about the same time
*
* For non-performance critical usecases(init)
* Take write_lock for all purposes which gives exclusive access
*/
struct rw_semaphore pcc_lock;
/* Wait queue for CPUs whose requests were batched */
wait_queue_head_t pcc_write_wait_q;
ktime_t last_cmd_cmpl_time;
ktime_t last_mpar_reset;
int mpar_count;
int refcount;
};
/* Array to represent the PCC channel per subspace ID */
static struct cppc_pcc_data *pcc_data[MAX_PCC_SUBSPACES];
/* The cpu_pcc_subspace_idx contains per CPU subspace ID */
static DEFINE_PER_CPU(int, cpu_pcc_subspace_idx);
/*
* The cpc_desc structure contains the ACPI register details
* as described in the per CPU _CPC tables. The details
* include the type of register (e.g. PCC, System IO, FFH etc.)
* and destination addresses which lets us READ/WRITE CPU performance
* information using the appropriate I/O methods.
*/
static DEFINE_PER_CPU(struct cpc_desc *, cpc_desc_ptr);
/* pcc mapped address + header size + offset within PCC subspace */
#define GET_PCC_VADDR(offs, pcc_ss_id) (pcc_data[pcc_ss_id]->pcc_comm_addr + \
0x8 + (offs))
/* Check if a CPC register is in PCC */
#define CPC_IN_PCC(cpc) ((cpc)->type == ACPI_TYPE_BUFFER && \
(cpc)->cpc_entry.reg.space_id == \
ACPI_ADR_SPACE_PLATFORM_COMM)
/* Check if a CPC register is in SystemMemory */
#define CPC_IN_SYSTEM_MEMORY(cpc) ((cpc)->type == ACPI_TYPE_BUFFER && \
(cpc)->cpc_entry.reg.space_id == \
ACPI_ADR_SPACE_SYSTEM_MEMORY)
/* Check if a CPC register is in SystemIo */
#define CPC_IN_SYSTEM_IO(cpc) ((cpc)->type == ACPI_TYPE_BUFFER && \
(cpc)->cpc_entry.reg.space_id == \
ACPI_ADR_SPACE_SYSTEM_IO)
/* Evaluates to True if reg is a NULL register descriptor */
#define IS_NULL_REG(reg) ((reg)->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY && \
(reg)->address == 0 && \
(reg)->bit_width == 0 && \
(reg)->bit_offset == 0 && \
(reg)->access_width == 0)
/* Evaluates to True if an optional cpc field is supported */
#define CPC_SUPPORTED(cpc) ((cpc)->type == ACPI_TYPE_INTEGER ? \
!!(cpc)->cpc_entry.int_value : \
!IS_NULL_REG(&(cpc)->cpc_entry.reg))
/*
* Arbitrary Retries in case the remote processor is slow to respond
* to PCC commands. Keeping it high enough to cover emulators where
* the processors run painfully slow.
*/
#define NUM_RETRIES 500ULL
#define OVER_16BTS_MASK ~0xFFFFULL
#define define_one_cppc_ro(_name) \
static struct kobj_attribute _name = \
__ATTR(_name, 0444, show_##_name, NULL)
#define to_cpc_desc(a) container_of(a, struct cpc_desc, kobj)
#define show_cppc_data(access_fn, struct_name, member_name) \
static ssize_t show_##member_name(struct kobject *kobj, \
struct kobj_attribute *attr, char *buf) \
{ \
struct cpc_desc *cpc_ptr = to_cpc_desc(kobj); \
struct struct_name st_name = {0}; \
int ret; \
\
ret = access_fn(cpc_ptr->cpu_id, &st_name); \
if (ret) \
return ret; \
\
return scnprintf(buf, PAGE_SIZE, "%llu\n", \
(u64)st_name.member_name); \
} \
define_one_cppc_ro(member_name)
show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, highest_perf);
show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_perf);
show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_perf);
show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_nonlinear_perf);
show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, lowest_freq);
show_cppc_data(cppc_get_perf_caps, cppc_perf_caps, nominal_freq);
show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, reference_perf);
show_cppc_data(cppc_get_perf_ctrs, cppc_perf_fb_ctrs, wraparound_time);
static ssize_t show_feedback_ctrs(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
struct cpc_desc *cpc_ptr = to_cpc_desc(kobj);
struct cppc_perf_fb_ctrs fb_ctrs = {0};
int ret;
ret = cppc_get_perf_ctrs(cpc_ptr->cpu_id, &fb_ctrs);
if (ret)
return ret;
return scnprintf(buf, PAGE_SIZE, "ref:%llu del:%llu\n",
fb_ctrs.reference, fb_ctrs.delivered);
}
define_one_cppc_ro(feedback_ctrs);
static struct attribute *cppc_attrs[] = {
&feedback_ctrs.attr,
&reference_perf.attr,
&wraparound_time.attr,
&highest_perf.attr,
&lowest_perf.attr,
&lowest_nonlinear_perf.attr,
&nominal_perf.attr,
&nominal_freq.attr,
&lowest_freq.attr,
NULL
};
ATTRIBUTE_GROUPS(cppc);
static struct kobj_type cppc_ktype = {
.sysfs_ops = &kobj_sysfs_ops,
.default_groups = cppc_groups,
};
static int check_pcc_chan(int pcc_ss_id, bool chk_err_bit)
{
int ret, status;
struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
struct acpi_pcct_shared_memory __iomem *generic_comm_base =
pcc_ss_data->pcc_comm_addr;
if (!pcc_ss_data->platform_owns_pcc)
return 0;
/*
* Poll PCC status register every 3us(delay_us) for maximum of
* deadline_us(timeout_us) until PCC command complete bit is set(cond)
*/
ret = readw_relaxed_poll_timeout(&generic_comm_base->status, status,
status & PCC_CMD_COMPLETE_MASK, 3,
pcc_ss_data->deadline_us);
if (likely(!ret)) {
pcc_ss_data->platform_owns_pcc = false;
if (chk_err_bit && (status & PCC_ERROR_MASK))
ret = -EIO;
}
if (unlikely(ret))
pr_err("PCC check channel failed for ss: %d. ret=%d\n",
pcc_ss_id, ret);
return ret;
}
/*
* This function transfers the ownership of the PCC to the platform
* So it must be called while holding write_lock(pcc_lock)
*/
static int send_pcc_cmd(int pcc_ss_id, u16 cmd)
{
int ret = -EIO, i;
struct cppc_pcc_data *pcc_ss_data = pcc_data[pcc_ss_id];
struct acpi_pcct_shared_memory __iomem *generic_comm_base =
pcc_ss_data->pcc_comm_addr;
unsigned int time_delta;
/*
* For CMD_WRITE we know for a fact the caller should have checked
* the channel before writing to PCC space
*/
if (cmd == CMD_READ) {
/*
* If there are pending cpc_writes, then we stole the channel
* before write completion, so first send a WRITE command to
* platform
*/
if (pcc_ss_data->pending_pcc_write_cmd)
send_pcc_cmd(pcc_ss_id, CMD_WRITE);
ret = check_pcc_chan(pcc_ss_id, false);
if (ret)
goto end;
} else /* CMD_WRITE */
pcc_ss_data->pending_pcc_write_cmd = FALSE;
/*
* Handle the Minimum Request Turnaround Time(MRTT)
* "The minimum amount of time that OSPM must wait after the completion
* of a command before issuing the next command, in microseconds"
*/
if (pcc_ss_data->pcc_mrtt) {
time_delta = ktime_us_delta(ktime_get(),
pcc_ss_data->last_cmd_cmpl_time);
if (pcc_ss_data->pcc_mrtt > time_delta)
udelay(pcc_ss_data->pcc_mrtt - time_delta);
}
/*
* Handle the non-zero Maximum Periodic Access Rate(MPAR)
* "The maximum number of periodic requests that the subspace channel can
* support, reported in commands per minute. 0 indicates no limitation."
*
* This parameter should be ideally zero or large enough so that it can
* handle maximum number of requests that all the cores in the system can
* collectively generate. If it is not, we will follow the spec and just
* not send the request to the platform after hitting the MPAR limit in
* any 60s window
*/
if (pcc_ss_data->pcc_mpar) {
if (pcc_ss_data->mpar_count == 0) {
time_delta = ktime_ms_delta(ktime_get(),
pcc_ss_data->last_mpar_reset);
if ((time_delta < 60 * MSEC_PER_SEC) && pcc_ss_data->last_mpar_reset) {
pr_debug("PCC cmd for subspace %d not sent due to MPAR limit",
pcc_ss_id);
ret = -EIO;
goto end;
}
pcc_ss_data->last_mpar_reset = ktime_get();
pcc_ss_data->mpar_count = pcc_ss_data->pcc_mpar;
}
pcc_ss_data->mpar_count--;
}
/* Write to the shared comm region. */
writew_relaxed(cmd, &generic_comm_base->command);
/* Flip CMD COMPLETE bit */
writew_relaxed(0, &generic_comm_base->status);
pcc_ss_data->platform_owns_pcc = true;
/* Ring doorbell */
ret = mbox_send_message(pcc_ss_data->pcc_channel->mchan, &cmd);
if (ret < 0) {
pr_err("Err sending PCC mbox message. ss: %d cmd:%d, ret:%d\n",
pcc_ss_id, cmd, ret);
goto end;
}
/* wait for completion and check for PCC error bit */
ret = check_pcc_chan(pcc_ss_id, true);
if (pcc_ss_data->pcc_mrtt)
pcc_ss_data->last_cmd_cmpl_time = ktime_get();
if (pcc_ss_data->pcc_channel->mchan->mbox->txdone_irq)
mbox_chan_txdone(pcc_ss_data->pcc_channel->mchan, ret);
else
mbox_client_txdone(pcc_ss_data->pcc_channel->mchan, ret);
end:
if (cmd == CMD_WRITE) {
if (unlikely(ret)) {
for_each_possible_cpu(i) {
struct cpc_desc *desc = per_cpu(cpc_desc_ptr, i);
if (!desc)
continue;
if (desc->write_cmd_id == pcc_ss_data->pcc_write_cnt)
desc->write_cmd_status = ret;
}
}
pcc_ss_data->pcc_write_cnt++;
wake_up_all(&pcc_ss_data->pcc_write_wait_q);
}
return ret;
}
static void cppc_chan_tx_done(struct mbox_client *cl, void *msg, int ret)
{
if (ret < 0)
pr_debug("TX did not complete: CMD sent:%x, ret:%d\n",
*(u16 *)msg, ret);
else
pr_debug("TX completed. CMD sent:%x, ret:%d\n",
*(u16 *)msg, ret);
}
static struct mbox_client cppc_mbox_cl = {
.tx_done = cppc_chan_tx_done,
.knows_txdone = true,
};
static int acpi_get_psd(struct cpc_desc *cpc_ptr, acpi_handle handle)
{
int result = -EFAULT;
acpi_status status = AE_OK;
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
struct acpi_buffer format = {sizeof("NNNNN"), "NNNNN"};
struct acpi_buffer state = {0, NULL};
union acpi_object *psd = NULL;
struct acpi_psd_package *pdomain;
status = acpi_evaluate_object_typed(handle, "_PSD", NULL,
&buffer, ACPI_TYPE_PACKAGE);
if (status == AE_NOT_FOUND) /* _PSD is optional */
return 0;
if (ACPI_FAILURE(status))
return -ENODEV;
psd = buffer.pointer;
if (!psd || psd->package.count != 1) {
pr_debug("Invalid _PSD data\n");
goto end;
}
pdomain = &(cpc_ptr->domain_info);
state.length = sizeof(struct acpi_psd_package);
state.pointer = pdomain;
status = acpi_extract_package(&(psd->package.elements[0]),
&format, &state);
if (ACPI_FAILURE(status)) {
pr_debug("Invalid _PSD data for CPU:%d\n", cpc_ptr->cpu_id);
goto end;
}
if (pdomain->num_entries != ACPI_PSD_REV0_ENTRIES) {
pr_debug("Unknown _PSD:num_entries for CPU:%d\n", cpc_ptr->cpu_id);
goto end;
}
if (pdomain->revision != ACPI_PSD_REV0_REVISION) {
pr_debug("Unknown _PSD:revision for CPU: %d\n", cpc_ptr->cpu_id);
goto end;
}
if (pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ALL &&
pdomain->coord_type != DOMAIN_COORD_TYPE_SW_ANY &&
pdomain->coord_type != DOMAIN_COORD_TYPE_HW_ALL) {
pr_debug("Invalid _PSD:coord_type for CPU:%d\n", cpc_ptr->cpu_id);
goto end;
}
result = 0;
end:
kfree(buffer.pointer);
return result;
}
bool acpi_cpc_valid(void)
{
struct cpc_desc *cpc_ptr;
int cpu;
for_each_present_cpu(cpu) {
cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
if (!cpc_ptr)
return false;
}
return true;
}
EXPORT_SYMBOL_GPL(acpi_cpc_valid);
bool cppc_allow_fast_switch(void)
{
struct cpc_register_resource *desired_reg;
struct cpc_desc *cpc_ptr;
int cpu;
for_each_possible_cpu(cpu) {
cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
desired_reg = &cpc_ptr->cpc_regs[DESIRED_PERF];
if (!CPC_IN_SYSTEM_MEMORY(desired_reg) &&
!CPC_IN_SYSTEM_IO(desired_reg))
return false;
}
return true;
}
EXPORT_SYMBOL_GPL(cppc_allow_fast_switch);
/**
* acpi_get_psd_map - Map the CPUs in the freq domain of a given cpu
* @cpu: Find all CPUs that share a domain with cpu.
* @cpu_data: Pointer to CPU specific CPPC data including PSD info.
*
* Return: 0 for success or negative value for err.
*/
int acpi_get_psd_map(unsigned int cpu, struct cppc_cpudata *cpu_data)
{
struct cpc_desc *cpc_ptr, *match_cpc_ptr;
struct acpi_psd_package *match_pdomain;
struct acpi_psd_package *pdomain;
int count_target, i;
/*
* Now that we have _PSD data from all CPUs, let's setup P-state
* domain info.
*/
cpc_ptr = per_cpu(cpc_desc_ptr, cpu);
if (!cpc_ptr)
return -EFAULT;
pdomain = &(cpc_ptr->domain_info);
cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
if (pdomain->num_processors <= 1)
return 0;
/* Validate the Domain info */
count_target = pdomain->num_processors;
if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ALL;
else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
cpu_data->shared_type = CPUFREQ_SHARED_TYPE_HW;
else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
cpu_data->shared_type = CPUFREQ_SHARED_TYPE_ANY;
for_each_possible_cpu(i) {
if (i == cpu)
continue;
match_cpc_ptr = per_cpu(cpc_desc_ptr, i);
if (!match_cpc_ptr)
goto err_fault;
match_pdomain = &(match_cpc_ptr->domain_info);
if (match_pdomain->domain != pdomain->domain)
continue;
/* Here i and cpu are in the same domain */
if (match_pdomain->num_processors != count_target)
goto err_fault;
if (pdomain->coord_type != match_pdomain->coord_type)
goto err_fault;
cpumask_set_cpu(i, cpu_data->shared_cpu_map);
}
return 0;
err_fault:
/* Assume no coordination on any error parsing domain info */
cpumask_clear(cpu_data->shared_cpu_map);
cpumask_set_cpu(cpu, cpu_data->shared_cpu_map);
cpu_data->shared_type = CPUFREQ_SHARED_TYPE_NONE;
return -EFAULT;
}
EXPORT_SYMBOL_GPL(acpi_get_psd_map);
static int register_pcc_channel(int pcc_ss_idx)
{
struct pcc_mbox_chan *pcc_chan;
u64 usecs_lat;
if (pcc_ss_idx >= 0) {
pcc_chan = pcc_mbox_request_channel(&cppc_mbox_cl, pcc_ss_idx);
if (IS_ERR(pcc_chan)) {
pr_err("Failed to find PCC channel for subspace %d\n",
pcc_ss_idx);
return -ENODEV;
}
pcc_data[pcc_ss_idx]->pcc_channel = pcc_chan;
/*
* cppc_ss->latency is just a Nominal value. In reality
* the remote processor could be much slower to reply.
* So add an arbitrary amount of wait on top of Nominal.
*/
usecs_lat = NUM_RETRIES * pcc_chan->latency;
pcc_data[pcc_ss_idx]->deadline_us = usecs_lat;
pcc_data[pcc_ss_idx]->pcc_mrtt = pcc_chan->min_turnaround_time;
pcc_data[pcc_ss_idx]->pcc_mpar = pcc_chan->max_access_rate;
pcc_data[pcc_ss_idx]->pcc_nominal = pcc_chan->latency;
pcc_data[pcc_ss_idx]->pcc_comm_addr =
acpi_os_ioremap(pcc_chan->shmem_base_addr,
pcc_chan->shmem_size);
if (!pcc_data[pcc_ss_idx]->pcc_comm_addr) {
pr_err("Failed to ioremap PCC comm region mem for %d\n",
pcc_ss_idx);
return -ENOMEM;
}
/* Set flag so that we don't come here for each CPU. */
pcc_data[pcc_ss_idx]->pcc_channel_acquired = true;
}
return 0;
}
/**
* cpc_ffh_supported() - check if FFH reading supported
*
* Check if the architecture has support for functional fixed hardware
* read/write capability.
*
* Return: true for supported, false for not supported
*/
bool __weak cpc_ffh_supported(void)
{
return false;
}
/**
* cpc_supported_by_cpu() - check if CPPC is supported by CPU
*
* Check if the architectural support for CPPC is present even
* if the _OSC hasn't prescribed it
*
* Return: true for supported, false for not supported
*/
bool __weak cpc_supported_by_cpu(void)
{
return false;
}
/**
* pcc_data_alloc() - Allocate the pcc_data memory for pcc subspace
*
* Check and allocate the cppc_pcc_data memory.
* In some processor configurations it is possible that same subspace
* is shared between multiple CPUs. This is seen especially in CPUs
* with hardware multi-threading support.
*
* Return: 0 for success, errno for failure
*/
static int pcc_data_alloc(int pcc_ss_id)
{
if (pcc_ss_id < 0 || pcc_ss_id >= MAX_PCC_SUBSPACES)
return -EINVAL;
if (pcc_data[pcc_ss_id]) {
pcc_data[pcc_ss_id]->refcount++;
} else {
pcc_data[pcc_ss_id] = kzalloc(sizeof(struct cppc_pcc_data),
GFP_KERNEL);
if (!pcc_data[pcc_ss_id])
return -ENOMEM;
pcc_data[pcc_ss_id]->refcount++;
}
return 0;
}
/*
* An example CPC table looks like the following.
*
* Name (_CPC, Package() {
* 17, // NumEntries
* 1, // Revision
* ResourceTemplate() {Register(PCC, 32, 0, 0x120, 2)}, // Highest Performance
* ResourceTemplate() {Register(PCC, 32, 0, 0x124, 2)}, // Nominal Performance
* ResourceTemplate() {Register(PCC, 32, 0, 0x128, 2)}, // Lowest Nonlinear Performance
* ResourceTemplate() {Register(PCC, 32, 0, 0x12C, 2)}, // Lowest Performance
* ResourceTemplate() {Register(PCC, 32, 0, 0x130, 2)}, // Guaranteed Performance Register
* ResourceTemplate() {Register(PCC, 32, 0, 0x110, 2)}, // Desired Performance Register
* ResourceTemplate() {Register(SystemMemory, 0, 0, 0, 0)},
* ...
* ...
* ...
* }
* Each Register() encodes how to access that specific register.
* e.g. a sample PCC entry has the following encoding:
*
* Register (
* PCC, // AddressSpaceKeyword
* 8, // RegisterBitWidth
* 8, // RegisterBitOffset
* 0x30, // RegisterAddress
* 9, // AccessSize (subspace ID)
* )
*/
#ifndef arch_init_invariance_cppc
static inline void arch_init_invariance_cppc(void) { }
#endif
/**
* acpi_cppc_processor_probe - Search for per CPU _CPC objects.
* @pr: Ptr to acpi_processor containing this CPU's logical ID.
*
* Return: 0 for success or negative value for err.
*/
int acpi_cppc_processor_probe(struct acpi_processor *pr)
{
struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
union acpi_object *out_obj, *cpc_obj;
struct cpc_desc *cpc_ptr;
struct cpc_reg *gas_t;
struct device *cpu_dev;
acpi_handle handle = pr->handle;
unsigned int num_ent, i, cpc_rev;
int pcc_subspace_id = -1;
acpi_status status;
int ret = -ENODATA;
if (!osc_sb_cppc2_support_acked) {
pr_debug("CPPC v2 _OSC not acked\n");
if (!cpc_supported_by_cpu())
return -ENODEV;
}
/* Parse the ACPI _CPC table for this CPU. */
status = acpi_evaluate_object_typed(handle, "_CPC", NULL, &output,
ACPI_TYPE_PACKAGE);
if (ACPI_FAILURE(status)) {
ret = -ENODEV;
goto out_buf_free;
}
out_obj = (union acpi_object *) output.pointer;
cpc_ptr = kzalloc(sizeof(struct cpc_desc), GFP_KERNEL);
if (!cpc_ptr) {
ret = -ENOMEM;
goto out_buf_free;
}
/* First entry is NumEntries. */
cpc_obj = &out_obj->package.elements[0];
if (cpc_obj->type == ACPI_TYPE_INTEGER) {
num_ent = cpc_obj->integer.value;
if (num_ent <= 1) {
pr_debug("Unexpected _CPC NumEntries value (%d) for CPU:%d\n",
num_ent, pr->id);
goto out_free;
}
} else {
pr_debug("Unexpected _CPC NumEntries entry type (%d) for CPU:%d\n",
cpc_obj->type, pr->id);
goto out_free;
}
/* Second entry should be revision. */
cpc_obj = &out_obj->package.elements[1];
if (cpc_obj->type == ACPI_TYPE_INTEGER) {
cpc_rev = cpc_obj->integer.value;
} else {
pr_debug("Unexpected _CPC Revision entry type (%d) for CPU:%d\n",
cpc_obj->type, pr->id);
goto out_free;
}
if (cpc_rev < CPPC_V2_REV) {
pr_debug("Unsupported _CPC Revision (%d) for CPU:%d\n", cpc_rev,
pr->id);
goto out_free;
}
/*
* Disregard _CPC if the number of entries in the return pachage is not
* as expected, but support future revisions being proper supersets of
* the v3 and only causing more entries to be returned by _CPC.
*/
if ((cpc_rev == CPPC_V2_REV && num_ent != CPPC_V2_NUM_ENT) ||
(cpc_rev == CPPC_V3_REV && num_ent != CPPC_V3_NUM_ENT) ||
(cpc_rev > CPPC_V3_REV && num_ent <= CPPC_V3_NUM_ENT)) {
pr_debug("Unexpected number of _CPC return package entries (%d) for CPU:%d\n",
num_ent, pr->id);
goto out_free;
}
if (cpc_rev > CPPC_V3_REV) {
num_ent = CPPC_V3_NUM_ENT;
cpc_rev = CPPC_V3_REV;
}
cpc_ptr->num_entries = num_ent;
cpc_ptr->version = cpc_rev;
/* Iterate through remaining entries in _CPC */
for (i = 2; i < num_ent; i++) {
cpc_obj = &out_obj->package.elements[i];
if (cpc_obj->type == ACPI_TYPE_INTEGER) {
cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_INTEGER;
cpc_ptr->cpc_regs[i-2].cpc_entry.int_value = cpc_obj->integer.value;
} else if (cpc_obj->type == ACPI_TYPE_BUFFER) {
gas_t = (struct cpc_reg *)
cpc_obj->buffer.pointer;
/*
* The PCC Subspace index is encoded inside
* the CPC table entries. The same PCC index
* will be used for all the PCC entries,
* so extract it only once.
*/
if (gas_t->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
if (pcc_subspace_id < 0) {
pcc_subspace_id = gas_t->access_width;
if (pcc_data_alloc(pcc_subspace_id))
goto out_free;
} else if (pcc_subspace_id != gas_t->access_width) {
pr_debug("Mismatched PCC ids in _CPC for CPU:%d\n",
pr->id);
goto out_free;
}
} else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
if (gas_t->address) {
void __iomem *addr;
if (!osc_cpc_flexible_adr_space_confirmed) {
pr_debug("Flexible address space capability not supported\n");
if (!cpc_supported_by_cpu())
goto out_free;
}
addr = ioremap(gas_t->address, gas_t->bit_width/8);
if (!addr)
goto out_free;
cpc_ptr->cpc_regs[i-2].sys_mem_vaddr = addr;
}
} else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
if (gas_t->access_width < 1 || gas_t->access_width > 3) {
/*
* 1 = 8-bit, 2 = 16-bit, and 3 = 32-bit.
* SystemIO doesn't implement 64-bit
* registers.
*/
pr_debug("Invalid access width %d for SystemIO register in _CPC\n",
gas_t->access_width);
goto out_free;
}
if (gas_t->address & OVER_16BTS_MASK) {
/* SystemIO registers use 16-bit integer addresses */
pr_debug("Invalid IO port %llu for SystemIO register in _CPC\n",
gas_t->address);
goto out_free;
}
if (!osc_cpc_flexible_adr_space_confirmed) {
pr_debug("Flexible address space capability not supported\n");
if (!cpc_supported_by_cpu())
goto out_free;
}
} else {
if (gas_t->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE || !cpc_ffh_supported()) {
/* Support only PCC, SystemMemory, SystemIO, and FFH type regs. */
pr_debug("Unsupported register type (%d) in _CPC\n",
gas_t->space_id);
goto out_free;
}
}
cpc_ptr->cpc_regs[i-2].type = ACPI_TYPE_BUFFER;
memcpy(&cpc_ptr->cpc_regs[i-2].cpc_entry.reg, gas_t, sizeof(*gas_t));
} else {
pr_debug("Invalid entry type (%d) in _CPC for CPU:%d\n",
i, pr->id);
goto out_free;
}
}
per_cpu(cpu_pcc_subspace_idx, pr->id) = pcc_subspace_id;
/*
* Initialize the remaining cpc_regs as unsupported.
* Example: In case FW exposes CPPC v2, the below loop will initialize
* LOWEST_FREQ and NOMINAL_FREQ regs as unsupported
*/
for (i = num_ent - 2; i < MAX_CPC_REG_ENT; i++) {
cpc_ptr->cpc_regs[i].type = ACPI_TYPE_INTEGER;
cpc_ptr->cpc_regs[i].cpc_entry.int_value = 0;
}
/* Store CPU Logical ID */
cpc_ptr->cpu_id = pr->id;
/* Parse PSD data for this CPU */
ret = acpi_get_psd(cpc_ptr, handle);
if (ret)
goto out_free;
/* Register PCC channel once for all PCC subspace ID. */
if (pcc_subspace_id >= 0 && !pcc_data[pcc_subspace_id]->pcc_channel_acquired) {
ret = register_pcc_channel(pcc_subspace_id);
if (ret)
goto out_free;
init_rwsem(&pcc_data[pcc_subspace_id]->pcc_lock);
init_waitqueue_head(&pcc_data[pcc_subspace_id]->pcc_write_wait_q);
}
/* Everything looks okay */
pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);
/* Add per logical CPU nodes for reading its feedback counters. */
cpu_dev = get_cpu_device(pr->id);
if (!cpu_dev) {
ret = -EINVAL;
goto out_free;
}
/* Plug PSD data into this CPU's CPC descriptor. */
per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
ret = kobject_init_and_add(&cpc_ptr->kobj, &cppc_ktype, &cpu_dev->kobj,
"acpi_cppc");
if (ret) {
per_cpu(cpc_desc_ptr, pr->id) = NULL;
kobject_put(&cpc_ptr->kobj);
goto out_free;
}
arch_init_invariance_cppc();
kfree(output.pointer);
return 0;
out_free:
/* Free all the mapped sys mem areas for this CPU */
for (i = 2; i < cpc_ptr->num_entries; i++) {
void __iomem *addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
if (addr)
iounmap(addr);
}
kfree(cpc_ptr);
out_buf_free:
kfree(output.pointer);
return ret;
}
EXPORT_SYMBOL_GPL(acpi_cppc_processor_probe);
/**
* acpi_cppc_processor_exit - Cleanup CPC structs.
* @pr: Ptr to acpi_processor containing this CPU's logical ID.
*
* Return: Void
*/
void acpi_cppc_processor_exit(struct acpi_processor *pr)
{
struct cpc_desc *cpc_ptr;
unsigned int i;
void __iomem *addr;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, pr->id);
if (pcc_ss_id >= 0 && pcc_data[pcc_ss_id]) {
if (pcc_data[pcc_ss_id]->pcc_channel_acquired) {
pcc_data[pcc_ss_id]->refcount--;
if (!pcc_data[pcc_ss_id]->refcount) {
pcc_mbox_free_channel(pcc_data[pcc_ss_id]->pcc_channel);
kfree(pcc_data[pcc_ss_id]);
pcc_data[pcc_ss_id] = NULL;
}
}
}
cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
if (!cpc_ptr)
return;
/* Free all the mapped sys mem areas for this CPU */
for (i = 2; i < cpc_ptr->num_entries; i++) {
addr = cpc_ptr->cpc_regs[i-2].sys_mem_vaddr;
if (addr)
iounmap(addr);
}
kobject_put(&cpc_ptr->kobj);
kfree(cpc_ptr);
}
EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
/**
* cpc_read_ffh() - Read FFH register
* @cpunum: CPU number to read
* @reg: cppc register information
* @val: place holder for return value
*
* Read bit_width bits from a specified address and bit_offset
*
* Return: 0 for success and error code
*/
int __weak cpc_read_ffh(int cpunum, struct cpc_reg *reg, u64 *val)
{
return -ENOTSUPP;
}
/**
* cpc_write_ffh() - Write FFH register
* @cpunum: CPU number to write
* @reg: cppc register information
* @val: value to write
*
* Write value of bit_width bits to a specified address and bit_offset
*
* Return: 0 for success and error code
*/
int __weak cpc_write_ffh(int cpunum, struct cpc_reg *reg, u64 val)
{
return -ENOTSUPP;
}
/*
* Since cpc_read and cpc_write are called while holding pcc_lock, it should be
* as fast as possible. We have already mapped the PCC subspace during init, so
* we can directly write to it.
*/
static int cpc_read(int cpu, struct cpc_register_resource *reg_res, u64 *val)
{
void __iomem *vaddr = NULL;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
struct cpc_reg *reg = &reg_res->cpc_entry.reg;
if (reg_res->type == ACPI_TYPE_INTEGER) {
*val = reg_res->cpc_entry.int_value;
return 0;
}
*val = 0;
if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
u32 width = 8 << (reg->access_width - 1);
u32 val_u32;
acpi_status status;
status = acpi_os_read_port((acpi_io_address)reg->address,
&val_u32, width);
if (ACPI_FAILURE(status)) {
pr_debug("Error: Failed to read SystemIO port %llx\n",
reg->address);
return -EFAULT;
}
*val = val_u32;
return 0;
} else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
vaddr = reg_res->sys_mem_vaddr;
else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
return cpc_read_ffh(cpu, reg, val);
else
return acpi_os_read_memory((acpi_physical_address)reg->address,
val, reg->bit_width);
switch (reg->bit_width) {
case 8:
*val = readb_relaxed(vaddr);
break;
case 16:
*val = readw_relaxed(vaddr);
break;
case 32:
*val = readl_relaxed(vaddr);
break;
case 64:
*val = readq_relaxed(vaddr);
break;
default:
pr_debug("Error: Cannot read %u bit width from PCC for ss: %d\n",
reg->bit_width, pcc_ss_id);
return -EFAULT;
}
return 0;
}
static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val)
{
int ret_val = 0;
void __iomem *vaddr = NULL;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
struct cpc_reg *reg = &reg_res->cpc_entry.reg;
if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_IO) {
u32 width = 8 << (reg->access_width - 1);
acpi_status status;
status = acpi_os_write_port((acpi_io_address)reg->address,
(u32)val, width);
if (ACPI_FAILURE(status)) {
pr_debug("Error: Failed to write SystemIO port %llx\n",
reg->address);
return -EFAULT;
}
return 0;
} else if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM && pcc_ss_id >= 0)
vaddr = GET_PCC_VADDR(reg->address, pcc_ss_id);
else if (reg->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY)
vaddr = reg_res->sys_mem_vaddr;
else if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE)
return cpc_write_ffh(cpu, reg, val);
else
return acpi_os_write_memory((acpi_physical_address)reg->address,
val, reg->bit_width);
switch (reg->bit_width) {
case 8:
writeb_relaxed(val, vaddr);
break;
case 16:
writew_relaxed(val, vaddr);
break;
case 32:
writel_relaxed(val, vaddr);
break;
case 64:
writeq_relaxed(val, vaddr);
break;
default:
pr_debug("Error: Cannot write %u bit width to PCC for ss: %d\n",
reg->bit_width, pcc_ss_id);
ret_val = -EFAULT;
break;
}
return ret_val;
}
static int cppc_get_perf(int cpunum, enum cppc_regs reg_idx, u64 *perf)
{
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
struct cpc_register_resource *reg;
if (!cpc_desc) {
pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
return -ENODEV;
}
reg = &cpc_desc->cpc_regs[reg_idx];
if (CPC_IN_PCC(reg)) {
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
struct cppc_pcc_data *pcc_ss_data = NULL;
int ret = 0;
if (pcc_ss_id < 0)
return -EIO;
pcc_ss_data = pcc_data[pcc_ss_id];
down_write(&pcc_ss_data->pcc_lock);
if (send_pcc_cmd(pcc_ss_id, CMD_READ) >= 0)
cpc_read(cpunum, reg, perf);
else
ret = -EIO;
up_write(&pcc_ss_data->pcc_lock);
return ret;
}
cpc_read(cpunum, reg, perf);
return 0;
}
/**
* cppc_get_desired_perf - Get the desired performance register value.
* @cpunum: CPU from which to get desired performance.
* @desired_perf: Return address.
*
* Return: 0 for success, -EIO otherwise.
*/
int cppc_get_desired_perf(int cpunum, u64 *desired_perf)
{
return cppc_get_perf(cpunum, DESIRED_PERF, desired_perf);
}
EXPORT_SYMBOL_GPL(cppc_get_desired_perf);
/**
* cppc_get_nominal_perf - Get the nominal performance register value.
* @cpunum: CPU from which to get nominal performance.
* @nominal_perf: Return address.
*
* Return: 0 for success, -EIO otherwise.
*/
int cppc_get_nominal_perf(int cpunum, u64 *nominal_perf)
{
return cppc_get_perf(cpunum, NOMINAL_PERF, nominal_perf);
}
/**
* cppc_get_perf_caps - Get a CPU's performance capabilities.
* @cpunum: CPU from which to get capabilities info.
* @perf_caps: ptr to cppc_perf_caps. See cppc_acpi.h
*
* Return: 0 for success with perf_caps populated else -ERRNO.
*/
int cppc_get_perf_caps(int cpunum, struct cppc_perf_caps *perf_caps)
{
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
struct cpc_register_resource *highest_reg, *lowest_reg,
*lowest_non_linear_reg, *nominal_reg, *guaranteed_reg,
*low_freq_reg = NULL, *nom_freq_reg = NULL;
u64 high, low, guaranteed, nom, min_nonlinear, low_f = 0, nom_f = 0;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
struct cppc_pcc_data *pcc_ss_data = NULL;
int ret = 0, regs_in_pcc = 0;
if (!cpc_desc) {
pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
return -ENODEV;
}
highest_reg = &cpc_desc->cpc_regs[HIGHEST_PERF];
lowest_reg = &cpc_desc->cpc_regs[LOWEST_PERF];
lowest_non_linear_reg = &cpc_desc->cpc_regs[LOW_NON_LINEAR_PERF];
nominal_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
low_freq_reg = &cpc_desc->cpc_regs[LOWEST_FREQ];
nom_freq_reg = &cpc_desc->cpc_regs[NOMINAL_FREQ];
guaranteed_reg = &cpc_desc->cpc_regs[GUARANTEED_PERF];
/* Are any of the regs PCC ?*/
if (CPC_IN_PCC(highest_reg) || CPC_IN_PCC(lowest_reg) ||
CPC_IN_PCC(lowest_non_linear_reg) || CPC_IN_PCC(nominal_reg) ||
CPC_IN_PCC(low_freq_reg) || CPC_IN_PCC(nom_freq_reg)) {
if (pcc_ss_id < 0) {
pr_debug("Invalid pcc_ss_id\n");
return -ENODEV;
}
pcc_ss_data = pcc_data[pcc_ss_id];
regs_in_pcc = 1;
down_write(&pcc_ss_data->pcc_lock);
/* Ring doorbell once to update PCC subspace */
if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
ret = -EIO;
goto out_err;
}
}
cpc_read(cpunum, highest_reg, &high);
perf_caps->highest_perf = high;
cpc_read(cpunum, lowest_reg, &low);
perf_caps->lowest_perf = low;
cpc_read(cpunum, nominal_reg, &nom);
perf_caps->nominal_perf = nom;
if (guaranteed_reg->type != ACPI_TYPE_BUFFER ||
IS_NULL_REG(&guaranteed_reg->cpc_entry.reg)) {
perf_caps->guaranteed_perf = 0;
} else {
cpc_read(cpunum, guaranteed_reg, &guaranteed);
perf_caps->guaranteed_perf = guaranteed;
}
cpc_read(cpunum, lowest_non_linear_reg, &min_nonlinear);
perf_caps->lowest_nonlinear_perf = min_nonlinear;
if (!high || !low || !nom || !min_nonlinear)
ret = -EFAULT;
/* Read optional lowest and nominal frequencies if present */
if (CPC_SUPPORTED(low_freq_reg))
cpc_read(cpunum, low_freq_reg, &low_f);
if (CPC_SUPPORTED(nom_freq_reg))
cpc_read(cpunum, nom_freq_reg, &nom_f);
perf_caps->lowest_freq = low_f;
perf_caps->nominal_freq = nom_f;
out_err:
if (regs_in_pcc)
up_write(&pcc_ss_data->pcc_lock);
return ret;
}
EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
/**
* cppc_get_perf_ctrs - Read a CPU's performance feedback counters.
* @cpunum: CPU from which to read counters.
* @perf_fb_ctrs: ptr to cppc_perf_fb_ctrs. See cppc_acpi.h
*
* Return: 0 for success with perf_fb_ctrs populated else -ERRNO.
*/
int cppc_get_perf_ctrs(int cpunum, struct cppc_perf_fb_ctrs *perf_fb_ctrs)
{
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpunum);
struct cpc_register_resource *delivered_reg, *reference_reg,
*ref_perf_reg, *ctr_wrap_reg;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpunum);
struct cppc_pcc_data *pcc_ss_data = NULL;
u64 delivered, reference, ref_perf, ctr_wrap_time;
int ret = 0, regs_in_pcc = 0;
if (!cpc_desc) {
pr_debug("No CPC descriptor for CPU:%d\n", cpunum);
return -ENODEV;
}
delivered_reg = &cpc_desc->cpc_regs[DELIVERED_CTR];
reference_reg = &cpc_desc->cpc_regs[REFERENCE_CTR];
ref_perf_reg = &cpc_desc->cpc_regs[REFERENCE_PERF];
ctr_wrap_reg = &cpc_desc->cpc_regs[CTR_WRAP_TIME];
/*
* If reference perf register is not supported then we should
* use the nominal perf value
*/
if (!CPC_SUPPORTED(ref_perf_reg))
ref_perf_reg = &cpc_desc->cpc_regs[NOMINAL_PERF];
/* Are any of the regs PCC ?*/
if (CPC_IN_PCC(delivered_reg) || CPC_IN_PCC(reference_reg) ||
CPC_IN_PCC(ctr_wrap_reg) || CPC_IN_PCC(ref_perf_reg)) {
if (pcc_ss_id < 0) {
pr_debug("Invalid pcc_ss_id\n");
return -ENODEV;
}
pcc_ss_data = pcc_data[pcc_ss_id];
down_write(&pcc_ss_data->pcc_lock);
regs_in_pcc = 1;
/* Ring doorbell once to update PCC subspace */
if (send_pcc_cmd(pcc_ss_id, CMD_READ) < 0) {
ret = -EIO;
goto out_err;
}
}
cpc_read(cpunum, delivered_reg, &delivered);
cpc_read(cpunum, reference_reg, &reference);
cpc_read(cpunum, ref_perf_reg, &ref_perf);
/*
* Per spec, if ctr_wrap_time optional register is unsupported, then the
* performance counters are assumed to never wrap during the lifetime of
* platform
*/
ctr_wrap_time = (u64)(~((u64)0));
if (CPC_SUPPORTED(ctr_wrap_reg))
cpc_read(cpunum, ctr_wrap_reg, &ctr_wrap_time);
if (!delivered || !reference || !ref_perf) {
ret = -EFAULT;
goto out_err;
}
perf_fb_ctrs->delivered = delivered;
perf_fb_ctrs->reference = reference;
perf_fb_ctrs->reference_perf = ref_perf;
perf_fb_ctrs->wraparound_time = ctr_wrap_time;
out_err:
if (regs_in_pcc)
up_write(&pcc_ss_data->pcc_lock);
return ret;
}
EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
/**
* cppc_set_enable - Set to enable CPPC on the processor by writing the
* Continuous Performance Control package EnableRegister field.
* @cpu: CPU for which to enable CPPC register.
* @enable: 0 - disable, 1 - enable CPPC feature on the processor.
*
* Return: 0 for success, -ERRNO or -EIO otherwise.
*/
int cppc_set_enable(int cpu, bool enable)
{
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
struct cpc_register_resource *enable_reg;
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
struct cppc_pcc_data *pcc_ss_data = NULL;
int ret = -EINVAL;
if (!cpc_desc) {
pr_debug("No CPC descriptor for CPU:%d\n", cpu);
return -EINVAL;
}
enable_reg = &cpc_desc->cpc_regs[ENABLE];
if (CPC_IN_PCC(enable_reg)) {
if (pcc_ss_id < 0)
return -EIO;
ret = cpc_write(cpu, enable_reg, enable);
if (ret)
return ret;
pcc_ss_data = pcc_data[pcc_ss_id];
down_write(&pcc_ss_data->pcc_lock);
/* after writing CPC, transfer the ownership of PCC to platfrom */
ret = send_pcc_cmd(pcc_ss_id, CMD_WRITE);
up_write(&pcc_ss_data->pcc_lock);
return ret;
}
return cpc_write(cpu, enable_reg, enable);
}
EXPORT_SYMBOL_GPL(cppc_set_enable);
/**
* cppc_set_perf - Set a CPU's performance controls.
* @cpu: CPU for which to set performance controls.
* @perf_ctrls: ptr to cppc_perf_ctrls. See cppc_acpi.h
*
* Return: 0 for success, -ERRNO otherwise.
*/
int cppc_set_perf(int cpu, struct cppc_perf_ctrls *perf_ctrls)
{
struct cpc_desc *cpc_desc = per_cpu(cpc_desc_ptr, cpu);
struct cpc_register_resource *desired_reg;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu);
struct cppc_pcc_data *pcc_ss_data = NULL;
int ret = 0;
if (!cpc_desc) {
pr_debug("No CPC descriptor for CPU:%d\n", cpu);
return -ENODEV;
}
desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
/*
* This is Phase-I where we want to write to CPC registers
* -> We want all CPUs to be able to execute this phase in parallel
*
* Since read_lock can be acquired by multiple CPUs simultaneously we
* achieve that goal here
*/
if (CPC_IN_PCC(desired_reg)) {
if (pcc_ss_id < 0) {
pr_debug("Invalid pcc_ss_id\n");
return -ENODEV;
}
pcc_ss_data = pcc_data[pcc_ss_id];
down_read(&pcc_ss_data->pcc_lock); /* BEGIN Phase-I */
if (pcc_ss_data->platform_owns_pcc) {
ret = check_pcc_chan(pcc_ss_id, false);
if (ret) {
up_read(&pcc_ss_data->pcc_lock);
return ret;
}
}
/*
* Update the pending_write to make sure a PCC CMD_READ will not
* arrive and steal the channel during the switch to write lock
*/
pcc_ss_data->pending_pcc_write_cmd = true;
cpc_desc->write_cmd_id = pcc_ss_data->pcc_write_cnt;
cpc_desc->write_cmd_status = 0;
}
/*
* Skip writing MIN/MAX until Linux knows how to come up with
* useful values.
*/
cpc_write(cpu, desired_reg, perf_ctrls->desired_perf);
if (CPC_IN_PCC(desired_reg))
up_read(&pcc_ss_data->pcc_lock); /* END Phase-I */
/*
* This is Phase-II where we transfer the ownership of PCC to Platform
*
* Short Summary: Basically if we think of a group of cppc_set_perf
* requests that happened in short overlapping interval. The last CPU to
* come out of Phase-I will enter Phase-II and ring the doorbell.
*
* We have the following requirements for Phase-II:
* 1. We want to execute Phase-II only when there are no CPUs
* currently executing in Phase-I
* 2. Once we start Phase-II we want to avoid all other CPUs from
* entering Phase-I.
* 3. We want only one CPU among all those who went through Phase-I
* to run phase-II
*
* If write_trylock fails to get the lock and doesn't transfer the
* PCC ownership to the platform, then one of the following will be TRUE
* 1. There is at-least one CPU in Phase-I which will later execute
* write_trylock, so the CPUs in Phase-I will be responsible for
* executing the Phase-II.
* 2. Some other CPU has beaten this CPU to successfully execute the
* write_trylock and has already acquired the write_lock. We know for a
* fact it (other CPU acquiring the write_lock) couldn't have happened
* before this CPU's Phase-I as we held the read_lock.
* 3. Some other CPU executing pcc CMD_READ has stolen the
* down_write, in which case, send_pcc_cmd will check for pending
* CMD_WRITE commands by checking the pending_pcc_write_cmd.
* So this CPU can be certain that its request will be delivered
* So in all cases, this CPU knows that its request will be delivered
* by another CPU and can return
*
* After getting the down_write we still need to check for
* pending_pcc_write_cmd to take care of the following scenario
* The thread running this code could be scheduled out between
* Phase-I and Phase-II. Before it is scheduled back on, another CPU
* could have delivered the request to Platform by triggering the
* doorbell and transferred the ownership of PCC to platform. So this
* avoids triggering an unnecessary doorbell and more importantly before
* triggering the doorbell it makes sure that the PCC channel ownership
* is still with OSPM.
* pending_pcc_write_cmd can also be cleared by a different CPU, if
* there was a pcc CMD_READ waiting on down_write and it steals the lock
* before the pcc CMD_WRITE is completed. send_pcc_cmd checks for this
* case during a CMD_READ and if there are pending writes it delivers
* the write command before servicing the read command
*/
if (CPC_IN_PCC(desired_reg)) {
if (down_write_trylock(&pcc_ss_data->pcc_lock)) {/* BEGIN Phase-II */
/* Update only if there are pending write commands */
if (pcc_ss_data->pending_pcc_write_cmd)
send_pcc_cmd(pcc_ss_id, CMD_WRITE);
up_write(&pcc_ss_data->pcc_lock); /* END Phase-II */
} else
/* Wait until pcc_write_cnt is updated by send_pcc_cmd */
wait_event(pcc_ss_data->pcc_write_wait_q,
cpc_desc->write_cmd_id != pcc_ss_data->pcc_write_cnt);
/* send_pcc_cmd updates the status in case of failure */
ret = cpc_desc->write_cmd_status;
}
return ret;
}
EXPORT_SYMBOL_GPL(cppc_set_perf);
/**
* cppc_get_transition_latency - returns frequency transition latency in ns
*
* ACPI CPPC does not explicitly specify how a platform can specify the
* transition latency for performance change requests. The closest we have
* is the timing information from the PCCT tables which provides the info
* on the number and frequency of PCC commands the platform can handle.
*
* If desired_reg is in the SystemMemory or SystemIo ACPI address space,
* then assume there is no latency.
*/
unsigned int cppc_get_transition_latency(int cpu_num)
{
/*
* Expected transition latency is based on the PCCT timing values
* Below are definition from ACPI spec:
* pcc_nominal- Expected latency to process a command, in microseconds
* pcc_mpar - The maximum number of periodic requests that the subspace
* channel can support, reported in commands per minute. 0
* indicates no limitation.
* pcc_mrtt - The minimum amount of time that OSPM must wait after the
* completion of a command before issuing the next command,
* in microseconds.
*/
unsigned int latency_ns = 0;
struct cpc_desc *cpc_desc;
struct cpc_register_resource *desired_reg;
int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu_num);
struct cppc_pcc_data *pcc_ss_data;
cpc_desc = per_cpu(cpc_desc_ptr, cpu_num);
if (!cpc_desc)
return CPUFREQ_ETERNAL;
desired_reg = &cpc_desc->cpc_regs[DESIRED_PERF];
if (CPC_IN_SYSTEM_MEMORY(desired_reg) || CPC_IN_SYSTEM_IO(desired_reg))
return 0;
else if (!CPC_IN_PCC(desired_reg))
return CPUFREQ_ETERNAL;
if (pcc_ss_id < 0)
return CPUFREQ_ETERNAL;
pcc_ss_data = pcc_data[pcc_ss_id];
if (pcc_ss_data->pcc_mpar)
latency_ns = 60 * (1000 * 1000 * 1000 / pcc_ss_data->pcc_mpar);
latency_ns = max(latency_ns, pcc_ss_data->pcc_nominal * 1000);
latency_ns = max(latency_ns, pcc_ss_data->pcc_mrtt * 1000);
return latency_ns;
}
EXPORT_SYMBOL_GPL(cppc_get_transition_latency);