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/*
* 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 "1.10.00"
#define POLL_LOOPS 300
#define CMD_COMPLETE 0x1
#define CMD_GET_FREQ 0x0
#define CMD_SET_FREQ 0x1
#define BUF_SZ 4
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] = {0x9F, 0x2C, 0x9B, 0x63, 0x91, 0x70, 0x1f, 0x49,
0xBB, 0x4F, 0xA5, 0x98, 0x2F, 0xA1, 0xB5, 0x46};
struct pcc_cpu {
u32 input_offset;
u32 output_offset;
};
static struct pcc_cpu __percpu *pcc_cpu_info;
static int pcc_cpufreq_verify(struct cpufreq_policy *policy)
{
cpufreq_verify_within_cpu_limits(policy);
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);
pr_debug("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) {
pr_debug("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);
pr_debug("get: SUCCESS: (virtual) output_offset for cpu %d is "
"0x%p, 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) {
pr_debug("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 0;
}
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;
cpu = policy->cpu;
pcc_cpu_data = per_cpu_ptr(pcc_cpu_info, cpu);
pr_debug("target: CPU %d should go to target freq: %d "
"(virtual) input_offset is 0x%p\n",
cpu, target_freq,
(pcch_virt_addr + pcc_cpu_data->input_offset));
freqs.old = policy->cur;
freqs.new = target_freq;
cpufreq_freq_transition_begin(policy, &freqs);
spin_lock(&pcc_lock);
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);
iowrite16(0, &pcch_hdr->status);
cpufreq_freq_transition_end(policy, &freqs, status != CMD_COMPLETE);
spin_unlock(&pcc_lock);
if (status != CMD_COMPLETE) {
pr_debug("target: FAILED for cpu %d, with status: 0x%x\n",
cpu, status);
return -EINVAL;
}
pr_debug("target: was SUCCESSFUL for cpu %d\n", cpu);
return 0;
}
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
|