diff options
Diffstat (limited to 'drivers/acpi/cppc_acpi.c')
| -rw-r--r-- | drivers/acpi/cppc_acpi.c | 1385 |
1 files changed, 1385 insertions, 0 deletions
diff --git a/drivers/acpi/cppc_acpi.c b/drivers/acpi/cppc_acpi.c new file mode 100644 index 000000000..f68a4ffd3 --- /dev/null +++ b/drivers/acpi/cppc_acpi.c @@ -0,0 +1,1385 @@ +/* + * 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/iopoll.h> +#include <linux/ktime.h> +#include <linux/rwsem.h> +#include <linux/wait.h> + +#include <acpi/cppc_acpi.h> + +struct cppc_pcc_data { + struct 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 containsper 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) + +/* Evalutes 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) + +/* Evalutes 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 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 +}; + +static struct kobj_type cppc_ktype = { + .sysfs_ops = &kobj_sysfs_ops, + .default_attrs = cppc_attrs, +}; + +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 *generic_comm_base = + (struct acpi_pcct_shared_memory *)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, &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 errro 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->mbox->txdone_irq) + mbox_chan_txdone(pcc_ss_data->pcc_channel, ret); + else + mbox_client_txdone(pcc_ss_data->pcc_channel, 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); +} + +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; +} + +/** + * 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 cppc_cpudata **all_cpu_data) +{ + int count_target; + int retval = 0; + unsigned int i, j; + cpumask_var_t covered_cpus; + struct cppc_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) { + retval = -EFAULT; + goto err_ret; + } + + 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) { + retval = -EFAULT; + goto err_ret; + } + + 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) { + retval = -EFAULT; + goto err_ret; + } + + 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_ss_idx) +{ + struct acpi_pcct_hw_reduced *cppc_ss; + u64 usecs_lat; + + if (pcc_ss_idx >= 0) { + pcc_data[pcc_ss_idx]->pcc_channel = + pcc_mbox_request_channel(&cppc_mbox_cl, pcc_ss_idx); + + if (IS_ERR(pcc_data[pcc_ss_idx]->pcc_channel)) { + pr_err("Failed to find PCC channel for subspace %d\n", + pcc_ss_idx); + 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_data[pcc_ss_idx]->pcc_channel)->con_priv; + + if (!cppc_ss) { + pr_err("No PCC subspace found for %d CPPC\n", + pcc_ss_idx); + return -ENODEV; + } + + /* + * 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; + pcc_data[pcc_ss_idx]->deadline_us = usecs_lat; + pcc_data[pcc_ss_idx]->pcc_mrtt = cppc_ss->min_turnaround_time; + pcc_data[pcc_ss_idx]->pcc_mpar = cppc_ss->max_access_rate; + pcc_data[pcc_ss_idx]->pcc_nominal = cppc_ss->latency; + + pcc_data[pcc_ss_idx]->pcc_comm_addr = + acpi_os_ioremap(cppc_ss->base_address, cppc_ss->length); + 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 dont 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; +} + +/** + * 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 CPU's. This is seen especially in CPU's + * with hardware multi-threading support. + * + * Return: 0 for success, errno for failure + */ +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; +} + +/* Check if CPPC revision + num_ent combination is supported */ +static bool is_cppc_supported(int revision, int num_ent) +{ + int expected_num_ent; + + switch (revision) { + case CPPC_V2_REV: + expected_num_ent = CPPC_V2_NUM_ENT; + break; + case CPPC_V3_REV: + expected_num_ent = CPPC_V3_NUM_ENT; + break; + default: + pr_debug("Firmware exports unsupported CPPC revision: %d\n", + revision); + return false; + } + + if (expected_num_ent != num_ent) { + pr_debug("Firmware exports %d entries. Expected: %d for CPPC rev:%d\n", + num_ent, expected_num_ent, revision); + return false; + } + + return true; +} + +/* + * 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; + 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 = -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; + 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 entry type(%d) for NumEntries\n", + cpc_obj->type); + goto out_free; + } + cpc_ptr->num_entries = num_ent; + + /* 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; + } + cpc_ptr->version = cpc_rev; + + if (!is_cppc_supported(cpc_rev, num_ent)) + 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_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.\n"); + goto out_free; + } + } else if (gas_t->space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { + if (gas_t->address) { + void __iomem *addr; + + 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_FIXED_HARDWARE || !cpc_ffh_supported()) { + /* Support only PCC ,SYS MEM and FFH 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; + } + } + 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 CPUs 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; + } + + 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 CPUs 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) +{ + int ret_val = 0; + void __iomem *vaddr = 0; + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu); + struct cpc_reg *reg = ®_res->cpc_entry.reg; + + if (reg_res->type == ACPI_TYPE_INTEGER) { + *val = reg_res->cpc_entry.int_value; + return ret_val; + } + + *val = 0; + 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); + ret_val = -EFAULT; + } + + return ret_val; +} + +static int cpc_write(int cpu, struct cpc_register_resource *reg_res, u64 val) +{ + int ret_val = 0; + void __iomem *vaddr = 0; + int pcc_ss_id = per_cpu(cpu_pcc_subspace_idx, cpu); + struct cpc_reg *reg = ®_res->cpc_entry.reg; + + 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; +} + +/** + * 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, + *lowest_non_linear_reg, *nominal_reg, + *low_freq_reg = NULL, *nom_freq_reg = NULL; + u64 high, low, 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]; + + /* 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; + + 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 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, + *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 refernce 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_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 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. pcc_send_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 specifiy how a platform can specify the + * transition latency for perfromance 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. + */ +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_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); |