/*
* Copyright (C) 2007 PA Semi, Inc
*
* Authors: Egor Martovetsky <egor@pasemi.com>
* Olof Johansson <olof@lixom.net>
*
* Maintained by: Olof Johansson <olof@lixom.net>
*
* Based on arch/powerpc/platforms/cell/cbe_cpufreq.c:
* (C) Copyright IBM Deutschland Entwicklung GmbH 2005
*
* 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; either version 2, or (at your option)
* any later version.
*
* 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. 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/cpufreq.h>
#include <linux/timer.h>
#include <linux/module.h>
#include <linux/of_address.h>
#include <asm/hw_irq.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/time.h>
#include <asm/smp.h>
#define SDCASR_REG 0x0100
#define SDCASR_REG_STRIDE 0x1000
#define SDCPWR_CFGA0_REG 0x0100
#define SDCPWR_PWST0_REG 0x0000
#define SDCPWR_GIZTIME_REG 0x0440
/* SDCPWR_GIZTIME_REG fields */
#define SDCPWR_GIZTIME_GR 0x80000000
#define SDCPWR_GIZTIME_LONGLOCK 0x000000ff
/* Offset of ASR registers from SDC base */
#define SDCASR_OFFSET 0x120000
static void __iomem *sdcpwr_mapbase;
static void __iomem *sdcasr_mapbase;
/* Current astate, is used when waking up from power savings on
* one core, in case the other core has switched states during
* the idle time.
*/
static int current_astate;
/* We support 5(A0-A4) power states excluding turbo(A5-A6) modes */
static struct cpufreq_frequency_table pas_freqs[] = {
{0, 0, 0},
{0, 1, 0},
{0, 2, 0},
{0, 3, 0},
{0, 4, 0},
{0, 0, CPUFREQ_TABLE_END},
};
/*
* hardware specific functions
*/
static int get_astate_freq(int astate)
{
u32 ret;
ret = in_le32(sdcpwr_mapbase + SDCPWR_CFGA0_REG + (astate * 0x10));
return ret & 0x3f;
}
static int get_cur_astate(int cpu)
{
u32 ret;
ret = in_le32(sdcpwr_mapbase + SDCPWR_PWST0_REG);
ret = (ret >> (cpu * 4)) & 0x7;
return ret;
}
static int get_gizmo_latency(void)
{
u32 giztime, ret;
giztime = in_le32(sdcpwr_mapbase + SDCPWR_GIZTIME_REG);
/* just provide the upper bound */
if (giztime & SDCPWR_GIZTIME_GR)
ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 128000;
else
ret = (giztime & SDCPWR_GIZTIME_LONGLOCK) * 1000;
return ret;
}
static void set_astate(int cpu, unsigned int astate)
{
unsigned long flags;
/* Return if called before init has run */
if (unlikely(!sdcasr_mapbase))
return;
local_irq_save(flags);
out_le32(sdcasr_mapbase + SDCASR_REG + SDCASR_REG_STRIDE*cpu, astate);
local_irq_restore(flags);
}
int check_astate(void)
{
return get_cur_astate(hard_smp_processor_id());
}
void restore_astate(int cpu)
{
set_astate(cpu, current_astate);
}
/*
* cpufreq functions
*/
static int pas_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
struct cpufreq_frequency_table *pos;
const u32 *max_freqp;
u32 max_freq;
int cur_astate;
struct resource res;
struct device_node *cpu, *dn;
int err = -ENODEV;
cpu = of_get_cpu_node(policy->cpu, NULL);
if (!cpu)
goto out;
dn = of_find_compatible_node(NULL, NULL, "1682m-sdc");
if (!dn)
dn = of_find_compatible_node(NULL, NULL,
"pasemi,pwrficient-sdc");
if (!dn)
goto out;
err = of_address_to_resource(dn, 0, &res);
of_node_put(dn);
if (err)
goto out;
sdcasr_mapbase = ioremap(res.start + SDCASR_OFFSET, 0x2000);
if (!sdcasr_mapbase) {
err = -EINVAL;
goto out;
}
dn = of_find_compatible_node(NULL, NULL, "1682m-gizmo");
if (!dn)
dn = of_find_compatible_node(NULL, NULL,
"pasemi,pwrficient-gizmo");
if (!dn) {
err = -ENODEV;
goto out_unmap_sdcasr;
}
err = of_address_to_resource(dn, 0, &res);
of_node_put(dn);
if (err)
goto out_unmap_sdcasr;
sdcpwr_mapbase = ioremap(res.start, 0x1000);
if (!sdcpwr_mapbase) {
err = -EINVAL;
goto out_unmap_sdcasr;
}
pr_debug("init cpufreq on CPU %d\n", policy->cpu);
max_freqp = of_get_property(cpu, "clock-frequency", NULL);
if (!max_freqp) {
err = -EINVAL;
goto out_unmap_sdcpwr;
}
/* we need the freq in kHz */
max_freq = *max_freqp / 1000;
pr_debug("max clock-frequency is at %u kHz\n", max_freq);
pr_debug("initializing frequency table\n");
/* initialize frequency table */
cpufreq_for_each_entry(pos, pas_freqs) {
pos->frequency = get_astate_freq(pos->driver_data) * 100000;
pr_debug("%d: %d\n", (int)(pos - pas_freqs), pos->frequency);
}
cur_astate = get_cur_astate(policy->cpu);
pr_debug("current astate is at %d\n",cur_astate);
policy->cur = pas_freqs[cur_astate].frequency;
ppc_proc_freq = policy->cur * 1000ul;
return cpufreq_generic_init(policy, pas_freqs, get_gizmo_latency());
out_unmap_sdcpwr:
iounmap(sdcpwr_mapbase);
out_unmap_sdcasr:
iounmap(sdcasr_mapbase);
out:
return err;
}
static int pas_cpufreq_cpu_exit(struct cpufreq_policy *policy)
{
/*
* We don't support CPU hotplug. Don't unmap after the system
* has already made it to a running state.
*/
if (system_state != SYSTEM_BOOTING)
return 0;
if (sdcasr_mapbase)
iounmap(sdcasr_mapbase);
if (sdcpwr_mapbase)
iounmap(sdcpwr_mapbase);
return 0;
}
static int pas_cpufreq_target(struct cpufreq_policy *policy,
unsigned int pas_astate_new)
{
int i;
pr_debug("setting frequency for cpu %d to %d kHz, 1/%d of max frequency\n",
policy->cpu,
pas_freqs[pas_astate_new].frequency,
pas_freqs[pas_astate_new].driver_data);
current_astate = pas_astate_new;
for_each_online_cpu(i)
set_astate(i, pas_astate_new);
ppc_proc_freq = pas_freqs[pas_astate_new].frequency * 1000ul;
return 0;
}
static struct cpufreq_driver pas_cpufreq_driver = {
.name = "pas-cpufreq",
.flags = CPUFREQ_CONST_LOOPS,
.init = pas_cpufreq_cpu_init,
.exit = pas_cpufreq_cpu_exit,
.verify = cpufreq_generic_frequency_table_verify,
.target_index = pas_cpufreq_target,
.attr = cpufreq_generic_attr,
};
/*
* module init and destoy
*/
static int __init pas_cpufreq_init(void)
{
if (!of_machine_is_compatible("PA6T-1682M") &&
!of_machine_is_compatible("pasemi,pwrficient"))
return -ENODEV;
return cpufreq_register_driver(&pas_cpufreq_driver);
}
static void __exit pas_cpufreq_exit(void)
{
cpufreq_unregister_driver(&pas_cpufreq_driver);
}
module_init(pas_cpufreq_init);
module_exit(pas_cpufreq_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>, Olof Johansson <olof@lixom.net>");
