linux/drivers/acpi/cppc_acpi.c

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/*
* CPPC (Collaborative Processor Performance Control) methods used by CPUfreq drivers.
*
* (C) Copyright 2014, 2015 Linaro Ltd.
* Author: Ashwin Chaugule <ashwin.chaugule@linaro.org>
*
* 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.
*
* 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/cpufreq.h>
#include <linux/delay.h>
#include <linux/ktime.h>
#include <acpi/cppc_acpi.h>
/*
* Lock to provide mutually exclusive access to the PCC
* channel. e.g. When the remote updates the shared region
* with new data, the reader needs to be protected from
* other CPUs activity on the same channel.
*/
static DEFINE_SPINLOCK(pcc_lock);
/*
* 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);
/* This layer handles all the PCC specifics for CPPC. */
static struct mbox_chan *pcc_channel;
static void __iomem *pcc_comm_addr;
static u64 comm_base_addr;
static int pcc_subspace_idx = -1;
static bool pcc_channel_acquired;
static ktime_t deadline;
static unsigned int pcc_mpar, pcc_mrtt;
/* pcc mapped address + header size + offset within PCC subspace */
#define GET_PCC_VADDR(offs) (pcc_comm_addr + 0x8 + (offs))
/*
* 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 500
static int check_pcc_chan(void)
{
int ret = -EIO;
struct acpi_pcct_shared_memory __iomem *generic_comm_base = pcc_comm_addr;
ktime_t next_deadline = ktime_add(ktime_get(), deadline);
/* Retry in case the remote processor was too slow to catch up. */
while (!ktime_after(ktime_get(), next_deadline)) {
/*
* Per spec, prior to boot the PCC space wil be initialized by
* platform and should have set the command completion bit when
* PCC can be used by OSPM
*/
if (readw_relaxed(&generic_comm_base->status) & PCC_CMD_COMPLETE) {
ret = 0;
break;
}
/*
* Reducing the bus traffic in case this loop takes longer than
* a few retries.
*/
udelay(3);
}
return ret;
}
static int send_pcc_cmd(u16 cmd)
{
int ret = -EIO;
struct acpi_pcct_shared_memory *generic_comm_base =
(struct acpi_pcct_shared_memory *) pcc_comm_addr;
static ktime_t last_cmd_cmpl_time, last_mpar_reset;
static int mpar_count;
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) {
ret = check_pcc_chan();
if (ret)
return ret;
}
/*
* 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_mrtt) {
time_delta = ktime_us_delta(ktime_get(), last_cmd_cmpl_time);
if (pcc_mrtt > time_delta)
udelay(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_mpar) {
if (mpar_count == 0) {
time_delta = ktime_ms_delta(ktime_get(), last_mpar_reset);
if (time_delta < 60 * MSEC_PER_SEC) {
pr_debug("PCC cmd not sent due to MPAR limit");
return -EIO;
}
last_mpar_reset = ktime_get();
mpar_count = pcc_mpar;
}
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);
/* Ring doorbell */
ret = mbox_send_message(pcc_channel, &cmd);
if (ret < 0) {
pr_err("Err sending PCC mbox message. cmd:%d, ret:%d\n",
cmd, ret);
return ret;
}
/*
* For READs we need to ensure the cmd completed to ensure
* the ensuing read()s can proceed. For WRITEs we dont care
* because the actual write()s are done before coming here
* and the next READ or WRITE will check if the channel
* is busy/free at the entry of this call.
*
* If Minimum Request Turnaround Time is non-zero, we need
* to record the completion time of both READ and WRITE
* command for proper handling of MRTT, so we need to check
* for pcc_mrtt in addition to CMD_READ
*/
if (cmd == CMD_READ || pcc_mrtt) {
ret = check_pcc_chan();
if (pcc_mrtt)
last_cmd_cmpl_time = ktime_get();
}
mbox_client_txdone(pcc_channel, ret);
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);
}
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 (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;
}
/**
* acpi_get_psd_map - Map the CPUs in a common freq domain.
* @all_cpu_data: Ptrs to CPU specific CPPC data including PSD info.
*
* Return: 0 for success or negative value for err.
*/
int acpi_get_psd_map(struct cpudata **all_cpu_data)
{
int count_target;
int retval = 0;
unsigned int i, j;
cpumask_var_t covered_cpus;
struct cpudata *pr, *match_pr;
struct acpi_psd_package *pdomain;
struct acpi_psd_package *match_pdomain;
struct cpc_desc *cpc_ptr, *match_cpc_ptr;
if (!zalloc_cpumask_var(&covered_cpus, GFP_KERNEL))
return -ENOMEM;
/*
* Now that we have _PSD data from all CPUs, lets setup P-state
* domain info.
*/
for_each_possible_cpu(i) {
pr = all_cpu_data[i];
if (!pr)
continue;
if (cpumask_test_cpu(i, covered_cpus))
continue;
cpc_ptr = per_cpu(cpc_desc_ptr, i);
if (!cpc_ptr)
continue;
pdomain = &(cpc_ptr->domain_info);
cpumask_set_cpu(i, pr->shared_cpu_map);
cpumask_set_cpu(i, covered_cpus);
if (pdomain->num_processors <= 1)
continue;
/* Validate the Domain info */
count_target = pdomain->num_processors;
if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ALL)
pr->shared_type = CPUFREQ_SHARED_TYPE_ALL;
else if (pdomain->coord_type == DOMAIN_COORD_TYPE_HW_ALL)
pr->shared_type = CPUFREQ_SHARED_TYPE_HW;
else if (pdomain->coord_type == DOMAIN_COORD_TYPE_SW_ANY)
pr->shared_type = CPUFREQ_SHARED_TYPE_ANY;
for_each_possible_cpu(j) {
if (i == j)
continue;
match_cpc_ptr = per_cpu(cpc_desc_ptr, j);
if (!match_cpc_ptr)
continue;
match_pdomain = &(match_cpc_ptr->domain_info);
if (match_pdomain->domain != pdomain->domain)
continue;
/* Here i and j are in the same domain */
if (match_pdomain->num_processors != count_target) {
retval = -EFAULT;
goto err_ret;
}
if (pdomain->coord_type != match_pdomain->coord_type) {
retval = -EFAULT;
goto err_ret;
}
cpumask_set_cpu(j, covered_cpus);
cpumask_set_cpu(j, pr->shared_cpu_map);
}
for_each_possible_cpu(j) {
if (i == j)
continue;
match_pr = all_cpu_data[j];
if (!match_pr)
continue;
match_cpc_ptr = per_cpu(cpc_desc_ptr, j);
if (!match_cpc_ptr)
continue;
match_pdomain = &(match_cpc_ptr->domain_info);
if (match_pdomain->domain != pdomain->domain)
continue;
match_pr->shared_type = pr->shared_type;
cpumask_copy(match_pr->shared_cpu_map,
pr->shared_cpu_map);
}
}
err_ret:
for_each_possible_cpu(i) {
pr = all_cpu_data[i];
if (!pr)
continue;
/* Assume no coordination on any error parsing domain info */
if (retval) {
cpumask_clear(pr->shared_cpu_map);
cpumask_set_cpu(i, pr->shared_cpu_map);
pr->shared_type = CPUFREQ_SHARED_TYPE_ALL;
}
}
free_cpumask_var(covered_cpus);
return retval;
}
EXPORT_SYMBOL_GPL(acpi_get_psd_map);
static int register_pcc_channel(int pcc_subspace_idx)
{
struct acpi_pcct_hw_reduced *cppc_ss;
unsigned int len;
u64 usecs_lat;
if (pcc_subspace_idx >= 0) {
pcc_channel = pcc_mbox_request_channel(&cppc_mbox_cl,
pcc_subspace_idx);
if (IS_ERR(pcc_channel)) {
pr_err("Failed to find PCC communication channel\n");
return -ENODEV;
}
/*
* The PCC mailbox controller driver should
* have parsed the PCCT (global table of all
* PCC channels) and stored pointers to the
* subspace communication region in con_priv.
*/
cppc_ss = pcc_channel->con_priv;
if (!cppc_ss) {
pr_err("No PCC subspace found for CPPC\n");
return -ENODEV;
}
/*
* This is the shared communication region
* for the OS and Platform to communicate over.
*/
comm_base_addr = cppc_ss->base_address;
len = cppc_ss->length;
/*
* 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 * cppc_ss->latency;
deadline = ns_to_ktime(usecs_lat * NSEC_PER_USEC);
pcc_mrtt = cppc_ss->min_turnaround_time;
pcc_mpar = cppc_ss->max_access_rate;
pcc_comm_addr = acpi_os_ioremap(comm_base_addr, len);
if (!pcc_comm_addr) {
pr_err("Failed to ioremap PCC comm region mem\n");
return -ENOMEM;
}
/* Set flag so that we dont come here for each CPU. */
pcc_channel_acquired = true;
}
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)
* 0
* )
* }
*/
/**
* acpi_cppc_processor_probe - Search for per CPU _CPC objects.
* @pr: Ptr to acpi_processor containing this CPUs 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;
acpi_handle handle = pr->handle;
unsigned int num_ent, i, cpc_rev;
acpi_status status;
int ret = -EFAULT;
/* 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;
} else {
pr_debug("Unexpected entry type(%d) for NumEntries\n",
cpc_obj->type);
goto out_free;
}
/* Only support CPPCv2. Bail otherwise. */
if (num_ent != CPPC_NUM_ENT) {
pr_debug("Firmware exports %d entries. Expected: %d\n",
num_ent, CPPC_NUM_ENT);
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 entry type(%d) for Revision\n",
cpc_obj->type);
goto out_free;
}
if (cpc_rev != CPPC_REV) {
pr_debug("Firmware exports revision:%d. Expected:%d\n",
cpc_rev, CPPC_REV);
goto out_free;
}
/* 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_idx < 0)
pcc_subspace_idx = gas_t->access_width;
else if (pcc_subspace_idx != gas_t->access_width) {
pr_debug("Mismatched PCC ids.\n");
goto out_free;
}
} else if (gas_t->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
/* Support only PCC and SYS MEM type regs */
pr_debug("Unsupported register type: %d\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("Err in entry:%d in CPC table of CPU:%d \n", i, pr->id);
goto out_free;
}
}
/* Store CPU Logical ID */
cpc_ptr->cpu_id = pr->id;
/* Plug it into this CPUs CPC descriptor. */
per_cpu(cpc_desc_ptr, pr->id) = cpc_ptr;
/* Parse PSD data for this CPU */
ret = acpi_get_psd(cpc_ptr, handle);
if (ret)
goto out_free;
/* Register PCC channel once for all CPUs. */
if (!pcc_channel_acquired) {
ret = register_pcc_channel(pcc_subspace_idx);
if (ret)
goto out_free;
}
/* Everything looks okay */
pr_debug("Parsed CPC struct for CPU: %d\n", pr->id);
kfree(output.pointer);
return 0;
out_free:
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 CPUs logical Id.
*
* Return: Void
*/
void acpi_cppc_processor_exit(struct acpi_processor *pr)
{
struct cpc_desc *cpc_ptr;
cpc_ptr = per_cpu(cpc_desc_ptr, pr->id);
kfree(cpc_ptr);
}
EXPORT_SYMBOL_GPL(acpi_cppc_processor_exit);
/*
* 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(struct cpc_reg *reg, u64 *val)
{
int ret_val = 0;
*val = 0;
if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
void __iomem *vaddr = GET_PCC_VADDR(reg->address);
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\n",
reg->bit_width);
ret_val = -EFAULT;
}
} else
ret_val = acpi_os_read_memory((acpi_physical_address)reg->address,
val, reg->bit_width);
return ret_val;
}
static int cpc_write(struct cpc_reg *reg, u64 val)
{
int ret_val = 0;
if (reg->space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
void __iomem *vaddr = GET_PCC_VADDR(reg->address);
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\n",
reg->bit_width);
ret_val = -EFAULT;
break;
}
} else
ret_val = acpi_os_write_memory((acpi_physical_address)reg->address,
val, reg->bit_width);
return ret_val;
}
/**
* cppc_get_perf_caps - Get a CPUs 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, *ref_perf,
*nom_perf;
u64 high, low, ref, nom;
int ret = 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];
ref_perf = &cpc_desc->cpc_regs[REFERENCE_PERF];
nom_perf = &cpc_desc->cpc_regs[NOMINAL_PERF];
spin_lock(&pcc_lock);
/* Are any of the regs PCC ?*/
if ((highest_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
(lowest_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
(ref_perf->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
(nom_perf->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM)) {
/* Ring doorbell once to update PCC subspace */
if (send_pcc_cmd(CMD_READ) < 0) {
ret = -EIO;
goto out_err;
}
}
cpc_read(&highest_reg->cpc_entry.reg, &high);
perf_caps->highest_perf = high;
cpc_read(&lowest_reg->cpc_entry.reg, &low);
perf_caps->lowest_perf = low;
cpc_read(&ref_perf->cpc_entry.reg, &ref);
perf_caps->reference_perf = ref;
cpc_read(&nom_perf->cpc_entry.reg, &nom);
perf_caps->nominal_perf = nom;
if (!ref)
perf_caps->reference_perf = perf_caps->nominal_perf;
if (!high || !low || !nom)
ret = -EFAULT;
out_err:
spin_unlock(&pcc_lock);
return ret;
}
EXPORT_SYMBOL_GPL(cppc_get_perf_caps);
/**
* cppc_get_perf_ctrs - Read a CPUs 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;
u64 delivered, reference;
int ret = 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];
spin_lock(&pcc_lock);
/* Are any of the regs PCC ?*/
if ((delivered_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) ||
(reference_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM)) {
/* Ring doorbell once to update PCC subspace */
if (send_pcc_cmd(CMD_READ) < 0) {
ret = -EIO;
goto out_err;
}
}
cpc_read(&delivered_reg->cpc_entry.reg, &delivered);
cpc_read(&reference_reg->cpc_entry.reg, &reference);
if (!delivered || !reference) {
ret = -EFAULT;
goto out_err;
}
perf_fb_ctrs->delivered = delivered;
perf_fb_ctrs->reference = reference;
perf_fb_ctrs->delivered -= perf_fb_ctrs->prev_delivered;
perf_fb_ctrs->reference -= perf_fb_ctrs->prev_reference;
perf_fb_ctrs->prev_delivered = delivered;
perf_fb_ctrs->prev_reference = reference;
out_err:
spin_unlock(&pcc_lock);
return ret;
}
EXPORT_SYMBOL_GPL(cppc_get_perf_ctrs);
/**
* cppc_set_perf - Set a CPUs 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 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];
spin_lock(&pcc_lock);
/* If this is PCC reg, check if channel is free before writing */
if (desired_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
ret = check_pcc_chan();
if (ret)
goto busy_channel;
}
/*
* Skip writing MIN/MAX until Linux knows how to come up with
* useful values.
*/
cpc_write(&desired_reg->cpc_entry.reg, perf_ctrls->desired_perf);
/* Is this a PCC reg ?*/
if (desired_reg->cpc_entry.reg.space_id == ACPI_ADR_SPACE_PLATFORM_COMM) {
/* Ring doorbell so Remote can get our perf request. */
if (send_pcc_cmd(CMD_WRITE) < 0)
ret = -EIO;
}
busy_channel:
spin_unlock(&pcc_lock);
return ret;
}
EXPORT_SYMBOL_GPL(cppc_set_perf);