/*
* pcc-cpufreq.c - Processor Clocking Control firmware cpufreq interface
*
* Copyright (C) 2009 Red Hat, Matthew Garrett <mjg@redhat.com>
* Copyright (C) 2009 Hewlett-Packard Development Company, L.P.
* Nagananda Chumbalkar <nagananda.chumbalkar@hp.com>
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*
* 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.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or NON
* INFRINGEMENT. See the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 675 Mass Ave, Cambridge, MA 02139, USA.
*
* ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <linux/sched.h>
#include <linux/cpufreq.h>
#include <linux/compiler.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/uaccess.h>
#include <acpi/processor.h>
#define PCC_VERSION "1.00.00"
#define POLL_LOOPS 300
#define CMD_COMPLETE 0x1
#define CMD_GET_FREQ 0x0
#define CMD_SET_FREQ 0x1
#define BUF_SZ 4
#define dprintk(msg...) cpufreq_debug_printk(CPUFREQ_DEBUG_DRIVER, \
"pcc-cpufreq", msg)
struct pcc_register_resource {
u8 descriptor;
u16 length;
u8 space_id;
u8 bit_width;
u8 bit_offset;
u8 access_size;
u64 address;
} __attribute__ ((packed));
struct pcc_memory_resource {
u8 descriptor;
u16 length;
u8 space_id;
u8 resource_usage;
u8 type_specific;
u64 granularity;
u64 minimum;
u64 maximum;
u64 translation_offset;
u64 address_length;
} __attribute__ ((packed));
static struct cpufreq_driver pcc_cpufreq_driver;
struct pcc_header {
u32 signature;
u16 length;
u8 major;
u8 minor;
u32 features;
u16 command;
u16 status;
u32 latency;
u32 minimum_time;
u32 maximum_time;
u32 nominal;
u32 throttled_frequency;
u32 minimum_frequency;
};
static void __iomem *pcch_virt_addr;
static struct pcc_header __iomem *pcch_hdr;
static DEFINE_SPINLOCK(pcc_lock);
static struct acpi_generic_address doorbell;
static u64 doorbell_preserve;
static u64 doorbell_write;
static u8 OSC_UUID[16] = {0x63, 0x9B, 0x2C, 0x9F, 0x70, 0x91, 0x49, 0x1f,
0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
struct pcc_cpu {
u32 input_offset;
u32 output_offset;
};
static struct pcc_cpu *pcc_cpu_info;
static int pcc_cpufreq_verify(struct cpufreq_policy *policy)
{
cpufreq_verify_within_limits(policy, policy->cpuinfo.min_freq,
policy->cpuinfo.max_freq);
return 0;
}
static inline void pcc_cmd(void)
{
u64 doorbell_value;
int i;
acpi_read(&doorbell_value, &doorbell);
acpi_write((doorbell_value & doorbell_preserve) | doorbell_write,
&doorbell);
for (i = 0; i < POLL_LOOPS; i++) {
if (ioread16(&pcch_hdr->status) & CMD_COMPLETE)
break;
}
}
static inline void pcc_clear_mapping(void)
{
if (pcch_virt_addr)
iounmap(pcch_virt_addr);
pcch_virt_addr = NULL;
}
static unsigned int pcc_get_freq(unsigned int cpu)
{
struct pcc_cpu *pcc_cpu_data;
unsigned int curr_freq;
unsigned int freq_limit;
u16 status;
u32 input_buffer;
u32 output_buffer;
spin_lock(&pcc_lock);
dprintk("get: get_freq for CPU %d\n", cpu);
pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
input_buffer = 0x1;
iowrite32(input_buffer,
(pcch_virt_addr + pcc_cpu_data->input_offset));
iowrite16(CMD_GET_FREQ, &pcch_hdr->command);
pcc_cmd();
output_buffer =
ioread32(pcch_virt_addr + pcc_cpu_data->output_offset);
/* Clear the input buffer - we are done with the current command */
memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
status = ioread16(&pcch_hdr->status);
if (status != CMD_COMPLETE) {
dprintk("get: FAILED: for CPU %d, status is %d\n",
cpu, status);
goto cmd_incomplete;
}
iowrite16(0, &pcch_hdr->status);
curr_freq = (((ioread32(&pcch_hdr->nominal) * (output_buffer & 0xff))
/ 100) * 1000);
dprintk("get: SUCCESS: (virtual) output_offset for cpu %d is "
"0x%x, contains a value of: 0x%x. Speed is: %d MHz\n",
cpu, (pcch_virt_addr + pcc_cpu_data->output_offset),
output_buffer, curr_freq);
freq_limit = (output_buffer >> 8) & 0xff;
if (freq_limit != 0xff) {
dprintk("get: frequency for cpu %d is being temporarily"
" capped at %d\n", cpu, curr_freq);
}
spin_unlock(&pcc_lock);
return curr_freq;
cmd_incomplete:
iowrite16(0, &pcch_hdr->status);
spin_unlock(&pcc_lock);
return -EINVAL;
}
static int pcc_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq,
unsigned int relation)
{
struct pcc_cpu *pcc_cpu_data;
struct cpufreq_freqs freqs;
u16 status;
u32 input_buffer;
int cpu;
spin_lock(&pcc_lock);
cpu = policy->cpu;
pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
dprintk("target: CPU %d should go to target freq: %d "
"(virtual) input_offset is 0x%x\n",
cpu, target_freq,
(pcch_virt_addr + pcc_cpu_data->input_offset));
freqs.new = target_freq;
freqs.cpu = cpu;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
input_buffer = 0x1 | (((target_freq * 100)
/ (ioread32(&pcch_hdr->nominal) * 1000)) << 8);
iowrite32(input_buffer,
(pcch_virt_addr + pcc_cpu_data->input_offset));
iowrite16(CMD_SET_FREQ, &pcch_hdr->command);
pcc_cmd();
/* Clear the input buffer - we are done with the current command */
memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
status = ioread16(&pcch_hdr->status);
if (status != CMD_COMPLETE) {
dprintk("target: FAILED for cpu %d, with status: 0x%x\n",
cpu, status);
goto cmd_incomplete;
}
iowrite16(0, &pcch_hdr->status);
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
dprintk("target: was SUCCESSFUL for cpu %d\n", cpu);
spin_unlock(&pcc_lock);
return 0;
cmd_incomplete:
iowrite16(0, &pcch_hdr->status);
spin_unlock(&pcc_lock);
return -EINVAL;
}
static int pcc_get_offset(int cpu)
{
acpi_status status;
struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
union acpi_object *pccp, *offset;
struct pcc_cpu *pcc_cpu_data;
struct acpi_processor *pr;
int ret = 0;
pr = per_cpu(processors, cpu);
pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
status = acpi_evaluate_object(pr->handle, "PCCP", NULL, &buffer);
if (ACPI_FAILURE(status))
return -ENODEV;
pccp = buffer.pointer;
if (!pccp || pccp->type != ACPI_TYPE_PACKAGE) {
ret = -ENODEV;
goto out_free;
};
offset = &(pccp->package.elements[0]);
if (!offset || offset->type != ACPI_TYPE_INTEGER) {
ret = -ENODEV;
goto out_free;
}
pcc_cpu_data->input_offset = offset->integer.value;
offset = &(pccp->package.elements[1]);
if (!offset || offset->type != ACPI_TYPE_INTEGER) {
ret = -ENODEV;
goto out_free;
}
pcc_cpu_data->output_offset = offset->integer.value;
memset_io((pcch_virt_addr + pcc_cpu_data->input_offset), 0, BUF_SZ);
memset_io((pcch_virt_addr + pcc_cpu_data->output_offset), 0, BUF_SZ);
dprintk("pcc_get_offset: for CPU %d: pcc_cpu_data "
"input_offset: 0x%x, pcc_cpu_data output_offset: 0x%x\n",
cpu, pcc_cpu_data->input_offset, pcc_cpu_data->output_offset);
out_free:
kfree(buffer.pointer);
return ret;
}
static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
{
acpi_status status;
struct acpi_object_list input;
struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
union acpi_object in_params[4];
union acpi_object *out_obj;
u32 capabilities[2];
u32 errors;
u32 supported;
int ret = 0;
input.count = 4;
input.pointer = in_params;
input.count = 4;
input.pointer = in_params;
in_params[0].type = ACPI_TYPE_BUFFER;
in_params[0].buffer.length = 16;
in_params[0].buffer.pointer = OSC_UUID;
in_params[1].type = ACPI_TYPE_INTEGER;
in_params[1].integer.value = 1;
in_params[2].type = ACPI_TYPE_INTEGER;
in_params[2].integer.value = 2;
in_params[3].type = ACPI_TYPE_BUFFER;
in_params[3].buffer.length = 8;
in_params[3].buffer.pointer = (u8 *)&capabilities;
capabilities[0] = OSC_QUERY_ENABLE;
capabilities[1] = 0x1;
status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
if (ACPI_FAILURE(status))
return -ENODEV;
if (!output.length)
return -ENODEV;
out_obj = output.pointer;
if (out_obj->type != ACPI_TYPE_BUFFER) {
ret = -ENODEV;
goto out_free;
}
errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
if (errors) {
ret = -ENODEV;
goto out_free;
}
supported = *((u32 *)(out_obj->buffer.pointer + 4));
if (!(supported & 0x1)) {
ret = -ENODEV;
goto out_free;
}
kfree(output.pointer);
capabilities[0] = 0x0;
capabilities[1] = 0x1;
status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
if (ACPI_FAILURE(status))
return -ENODEV;
if (!output.length)
return -ENODEV;
out_obj = output.pointer;
if (out_obj->type != ACPI_TYPE_BUFFER) {
ret = -ENODEV;
goto out_free;
}
errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
if (errors) {
ret = -ENODEV;
goto out_free;
}
supported = *((u32 *)(out_obj->buffer.pointer + 4));
if (!(supported & 0x1)) {
ret = -ENODEV;
goto out_free;
}
out_free:
kfree(output.pointer);
return ret;
}
static int __init pcc_cpufreq_probe(void)
{
acpi_status status;
struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
struct pcc_memory_resource *mem_resource;
struct pcc_register_resource *reg_resource;
union acpi_object *out_obj, *member;
acpi_handle handle, osc_handle, pcch_handle;
int ret = 0;
status = acpi_get_handle(NULL, "\\_SB", &handle);
if (ACPI_FAILURE(status))
return -ENODEV;
status = acpi_get_handle(handle, "PCCH", &pcch_handle);
if (ACPI_FAILURE(status))
return -ENODEV;
status = acpi_get_handle(handle, "_OSC", &osc_handle);
if (ACPI_SUCCESS(status)) {
ret = pcc_cpufreq_do_osc(&osc_handle);
if (ret)
dprintk("probe: _OSC evaluation did not succeed\n");
/* Firmware's use of _OSC is optional */
ret = 0;
}
status = acpi_evaluate_object(handle, "PCCH", NULL, &output);
if (ACPI_FAILURE(status))
return -ENODEV;
out_obj = output.pointer;
if (out_obj->type != ACPI_TYPE_PACKAGE) {
ret = -ENODEV;
goto out_free;
}
member = &out_obj->package.elements[0];
if (member->type != ACPI_TYPE_BUFFER) {
ret = -ENODEV;
goto out_free;
}
mem_resource = (struct pcc_memory_resource *)member->buffer.pointer;
dprintk("probe: mem_resource descriptor: 0x%x,"
" length: %d, space_id: %d, resource_usage: %d,"
" type_specific: %d, granularity: 0x%llx,"
" minimum: 0x%llx, maximum: 0x%llx,"
" translation_offset: 0x%llx, address_length: 0x%llx\n",
mem_resource->descriptor, mem_resource->length,
mem_resource->space_id, mem_resource->resource_usage,
mem_resource->type_specific, mem_resource->granularity,
mem_resource->minimum, mem_resource->maximum,
mem_resource->translation_offset,
mem_resource->address_length);
if (mem_resource->space_id != ACPI_ADR_SPACE_SYSTEM_MEMORY) {
ret = -ENODEV;
goto out_free;
}
pcch_virt_addr = ioremap_nocache(mem_resource->minimum,
mem_resource->address_length);
if (pcch_virt_addr == NULL) {
dprintk("probe: could not map shared mem region\n");
goto out_free;
}
pcch_hdr = pcch_virt_addr;
dprintk("probe: PCCH header (virtual) addr: 0x%p\n", pcch_hdr);
dprintk("probe: PCCH header is at physical address: 0x%llx,"
" signature: 0x%x, length: %d bytes, major: %d, minor: %d,"
" supported features: 0x%x, command field: 0x%x,"
" status field: 0x%x, nominal latency: %d us\n",
mem_resource->minimum, ioread32(&pcch_hdr->signature),
ioread16(&pcch_hdr->length), ioread8(&pcch_hdr->major),
ioread8(&pcch_hdr->minor), ioread32(&pcch_hdr->features),
ioread16(&pcch_hdr->command), ioread16(&pcch_hdr->status),
ioread32(&pcch_hdr->latency));
dprintk("probe: min time between commands: %d us,"
" max time between commands: %d us,"
" nominal CPU frequency: %d MHz,"
" minimum CPU frequency: %d MHz,"
" minimum CPU frequency without throttling: %d MHz\n",
ioread32(&pcch_hdr->minimum_time),
ioread32(&pcch_hdr->maximum_time),
ioread32(&pcch_hdr->nominal),
ioread32(&pcch_hdr->throttled_frequency),
ioread32(&pcch_hdr->minimum_frequency));
member = &out_obj->package.elements[1];
if (member->type != ACPI_TYPE_BUFFER) {
ret = -ENODEV;
goto pcch_free;
}
reg_resource = (struct pcc_register_resource *)member->buffer.pointer;
doorbell.space_id = reg_resource->space_id;
doorbell.bit_width = reg_resource->bit_width;
doorbell.bit_offset = reg_resource->bit_offset;
doorbell.access_width = 64;
doorbell.address = reg_resource->address;
dprintk("probe: doorbell: space_id is %d, bit_width is %d, "
"bit_offset is %d, access_width is %d, address is 0x%llx\n",
doorbell.space_id, doorbell.bit_width, doorbell.bit_offset,
doorbell.access_width, reg_resource->address);
member = &out_obj->package.elements[2];
if (member->type != ACPI_TYPE_INTEGER) {
ret = -ENODEV;
goto pcch_free;
}
doorbell_preserve = member->integer.value;
member = &out_obj->package.elements[3];
if (member->type != ACPI_TYPE_INTEGER) {
ret = -ENODEV;
goto pcch_free;
}
doorbell_write = member->integer.value;
dprintk("probe: doorbell_preserve: 0x%llx,"
" doorbell_write: 0x%llx\n",
doorbell_preserve, doorbell_write);
pcc_cpu_info = alloc_percpu(struct pcc_cpu);
if (!pcc_cpu_info) {
ret = -ENOMEM;
goto pcch_free;
}
printk(KERN_DEBUG "pcc-cpufreq: (v%s) driver loaded with frequency"
" limits: %d MHz, %d MHz\n", PCC_VERSION,
ioread32(&pcch_hdr->minimum_frequency),
ioread32(&pcch_hdr->nominal));
kfree(output.pointer);
return ret;
pcch_free:
pcc_clear_mapping();
out_free:
kfree(output.pointer);
return ret;
}
static int pcc_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
unsigned int cpu = policy->cpu;
unsigned int result = 0;
if (!pcch_virt_addr) {
result = -1;
goto pcch_null;
}
result = pcc_get_offset(cpu);
if (result) {
dprintk("init: PCCP evaluation failed\n");
goto free;
}
policy->max = policy->cpuinfo.max_freq =
ioread32(&pcch_hdr->nominal) * 1000;
policy->min = policy->cpuinfo.min_freq =
ioread32(&pcch_hdr->minimum_frequency) * 1000;
policy->cur = pcc_get_freq(cpu);
dprintk("init: policy->max is %d, policy->min is %d\n",
policy->max, policy->min);
return 0;
free:
pcc_clear_mapping();
free_percpu(pcc_cpu_info);
pcch_null:
return result;
}
static int pcc_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
return 0;
}
static struct cpufreq_driver pcc_cpufreq_driver = {
.flags = CPUFREQ_CONST_LOOPS,
.get = pcc_get_freq,
.verify = pcc_cpufreq_verify,
.target = pcc_cpufreq_target,
.init = pcc_cpufreq_cpu_init,
.exit = pcc_cpufreq_cpu_exit,
.name = "pcc-cpufreq",
.owner = THIS_MODULE,
};
static int __init pcc_cpufreq_init(void)
{
int ret;
if (acpi_disabled)
return 0;
ret = pcc_cpufreq_probe();
if (ret) {
dprintk("pcc_cpufreq_init: PCCH evaluation failed\n");
return ret;
}
ret = cpufreq_register_driver(&pcc_cpufreq_driver);
return ret;
}
static void __exit pcc_cpufreq_exit(void)
{
cpufreq_unregister_driver(&pcc_cpufreq_driver);
pcc_clear_mapping();
free_percpu(pcc_cpu_info);
}
MODULE_AUTHOR("Matthew Garrett, Naga Chumbalkar");
MODULE_VERSION(PCC_VERSION);
MODULE_DESCRIPTION("Processor Clocking Control interface driver");
MODULE_LICENSE("GPL");
late_initcall(pcc_cpufreq_init);
module_exit(pcc_cpufreq_exit);
