/*
* Copyright (C) 2002 - 2005 Benjamin Herrenschmidt <benh@kernel.crashing.org>
* and Markus Demleitner <msdemlei@cl.uni-heidelberg.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This driver adds basic cpufreq support for SMU & 970FX based G5 Macs,
* that is iMac G5 and latest single CPU desktop.
*/
#include <linux/config.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/cpufreq.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/irq.h>
#include <asm/sections.h>
#include <asm/cputable.h>
#include <asm/time.h>
#include <asm/smu.h>
#undef DEBUG
#ifdef DEBUG
#define DBG(fmt...) printk(fmt)
#else
#define DBG(fmt...)
#endif
/* see 970FX user manual */
#define SCOM_PCR 0x0aa001 /* PCR scom addr */
#define PCR_HILO_SELECT 0x80000000U /* 1 = PCR, 0 = PCRH */
#define PCR_SPEED_FULL 0x00000000U /* 1:1 speed value */
#define PCR_SPEED_HALF 0x00020000U /* 1:2 speed value */
#define PCR_SPEED_QUARTER 0x00040000U /* 1:4 speed value */
#define PCR_SPEED_MASK 0x000e0000U /* speed mask */
#define PCR_SPEED_SHIFT 17
#define PCR_FREQ_REQ_VALID 0x00010000U /* freq request valid */
#define PCR_VOLT_REQ_VALID 0x00008000U /* volt request valid */
#define PCR_TARGET_TIME_MASK 0x00006000U /* target time */
#define PCR_STATLAT_MASK 0x00001f00U /* STATLAT value */
#define PCR_SNOOPLAT_MASK 0x000000f0U /* SNOOPLAT value */
#define PCR_SNOOPACC_MASK 0x0000000fU /* SNOOPACC value */
#define SCOM_PSR 0x408001 /* PSR scom addr */
/* warning: PSR is a 64 bits register */
#define PSR_CMD_RECEIVED 0x2000000000000000U /* command received */
#define PSR_CMD_COMPLETED 0x1000000000000000U /* command completed */
#define PSR_CUR_SPEED_MASK 0x0300000000000000U /* current speed */
#define PSR_CUR_SPEED_SHIFT (56)
/*
* The G5 only supports two frequencies (Quarter speed is not supported)
*/
#define CPUFREQ_HIGH 0
#define CPUFREQ_LOW 1
static struct cpufreq_frequency_table g5_cpu_freqs[] = {
{CPUFREQ_HIGH, 0},
{CPUFREQ_LOW, 0},
{0, CPUFREQ_TABLE_END},
};
static struct freq_attr* g5_cpu_freqs_attr[] = {
&cpufreq_freq_attr_scaling_available_freqs,
NULL,
};
/* Power mode data is an array of the 32 bits PCR values to use for
* the various frequencies, retreived from the device-tree
*/
static u32 *g5_pmode_data;
static int g5_pmode_max;
static int g5_pmode_cur;
static DECLARE_MUTEX(g5_switch_mutex);
static struct smu_sdbp_fvt *g5_fvt_table; /* table of op. points */
static int g5_fvt_count; /* number of op. points */
static int g5_fvt_cur; /* current op. point */
/* ----------------- real hardware interface */
static void g5_switch_volt(int speed_mode)
{
struct smu_simple_cmd cmd;
DECLARE_COMPLETION(comp);
smu_queue_simple(&cmd, SMU_CMD_POWER_COMMAND, 8, smu_done_complete,
&comp, 'V', 'S', 'L', 'E', 'W',
0xff, g5_fvt_cur+1, speed_mode);
wait_for_completion(&comp);
}
static int g5_switch_freq(int speed_mode)
{
struct cpufreq_freqs freqs;
int to;
if (g5_pmode_cur == speed_mode)
return 0;
down(&g5_switch_mutex);
freqs.old = g5_cpu_freqs[g5_pmode_cur].frequency;
freqs.new = g5_cpu_freqs[speed_mode].frequency;
freqs.cpu = 0;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
/* If frequency is going up, first ramp up the voltage */
if (speed_mode < g5_pmode_cur)
g5_switch_volt(speed_mode);
/* Clear PCR high */
scom970_write(SCOM_PCR, 0);
/* Clear PCR low */
scom970_write(SCOM_PCR, PCR_HILO_SELECT | 0);
/* Set PCR low */
scom970_write(SCOM_PCR, PCR_HILO_SELECT |
g5_pmode_data[speed_mode]);
/* Wait for completion */
for (to = 0; to < 10; to++) {
unsigned long psr = scom970_read(SCOM_PSR);
if ((psr & PSR_CMD_RECEIVED) == 0 &&
(((psr >> PSR_CUR_SPEED_SHIFT) ^
(g5_pmode_data[speed_mode] >> PCR_SPEED_SHIFT)) & 0x3)
== 0)
break;
if (psr & PSR_CMD_COMPLETED)
break;
udelay(100);
}
/* If frequency is going down, last ramp the voltage */
if (speed_mode > g5_pmode_cur)
g5_switch_volt(speed_mode);
g5_pmode_cur = speed_mode;
ppc_proc_freq = g5_cpu_freqs[speed_mode].frequency * 1000ul;
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
up(&g5_switch_mutex);
return 0;
}
static int g5_query_freq(void)
{
unsigned long psr = scom970_read(SCOM_PSR);
int i;
for (i = 0; i <= g5_pmode_max; i++)
if ((((psr >> PSR_CUR_SPEED_SHIFT) ^
(g5_pmode_data[i] >> PCR_SPEED_SHIFT)) & 0x3) == 0)
break;
return i;
}
/* ----------------- cpufreq bookkeeping */
static int g5_cpufreq_verify(struct cpufreq_policy *policy)
{
return cpufreq_frequency_table_verify(policy, g5_cpu_freqs);
}
static int g5_cpufreq_target(struct cpufreq_policy *policy,
unsigned int target_freq, unsigned int relation)
{
unsigned int newstate = 0;
if (cpufreq_frequency_table_target(policy, g5_cpu_freqs,
target_freq, relation, &newstate))
return -EINVAL;
return g5_switch_freq(newstate);
}
static unsigned int g5_cpufreq_get_speed(unsigned int cpu)
{
return g5_cpu_freqs[g5_pmode_cur].frequency;
}
static int g5_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
if (policy->cpu != 0)
return -ENODEV;
policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
policy->cur = g5_cpu_freqs[g5_query_freq()].frequency;
cpufreq_frequency_table_get_attr(g5_cpu_freqs, policy->cpu);
return cpufreq_frequency_table_cpuinfo(policy,
g5_cpu_freqs);
}
static struct cpufreq_driver g5_cpufreq_driver = {
.name = "powermac",
.owner = THIS_MODULE,
.flags = CPUFREQ_CONST_LOOPS,
.init = g5_cpufreq_cpu_init,
.verify = g5_cpufreq_verify,
.target = g5_cpufreq_target,
.get = g5_cpufreq_get_speed,
.attr = g5_cpu_freqs_attr,
};
static int __init g5_cpufreq_init(void)
{
struct device_node *cpunode;
unsigned int psize, ssize;
struct smu_sdbp_header *shdr;
unsigned long max_freq;
u32 *valp;
int rc = -ENODEV;
/* Look for CPU and SMU nodes */
cpunode = of_find_node_by_type(NULL, "cpu");
if (!cpunode) {
DBG("No CPU node !\n");
return -ENODEV;
}
/* Check 970FX for now */
valp = (u32 *)get_property(cpunode, "cpu-version", NULL);
if (!valp) {
DBG("No cpu-version property !\n");
goto bail_noprops;
}
if (((*valp) >> 16) != 0x3c) {
DBG("Wrong CPU version: %08x\n", *valp);
goto bail_noprops;
}
/* Look for the powertune data in the device-tree */
g5_pmode_data = (u32 *)get_property(cpunode, "power-mode-data",&psize);
if (!g5_pmode_data) {
DBG("No power-mode-data !\n");
goto bail_noprops;
}
g5_pmode_max = psize / sizeof(u32) - 1;
/* Look for the FVT table */
shdr = smu_get_sdb_partition(SMU_SDB_FVT_ID, NULL);
if (!shdr)
goto bail_noprops;
g5_fvt_table = (struct smu_sdbp_fvt *)&shdr[1];
ssize = (shdr->len * sizeof(u32)) - sizeof(struct smu_sdbp_header);
g5_fvt_count = ssize / sizeof(struct smu_sdbp_fvt);
g5_fvt_cur = 0;
/* Sanity checking */
if (g5_fvt_count < 1 || g5_pmode_max < 1)
goto bail_noprops;
/*
* From what I see, clock-frequency is always the maximal frequency.
* The current driver can not slew sysclk yet, so we really only deal
* with powertune steps for now. We also only implement full freq and
* half freq in this version. So far, I haven't yet seen a machine
* supporting anything else.
*/
valp = (u32 *)get_property(cpunode, "clock-frequency", NULL);
if (!valp)
return -ENODEV;
max_freq = (*valp)/1000;
g5_cpu_freqs[0].frequency = max_freq;
g5_cpu_freqs[1].frequency = max_freq/2;
/* Check current frequency */
g5_pmode_cur = g5_query_freq();
if (g5_pmode_cur > 1)
/* We don't support anything but 1:1 and 1:2, fixup ... */
g5_pmode_cur = 1;
/* Force apply current frequency to make sure everything is in
* sync (voltage is right for example). Firmware may leave us with
* a strange setting ...
*/
g5_switch_freq(g5_pmode_cur);
printk(KERN_INFO "Registering G5 CPU frequency driver\n");
printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
g5_cpu_freqs[1].frequency/1000,
g5_cpu_freqs[0].frequency/1000,
g5_cpu_freqs[g5_pmode_cur].frequency/1000);
rc = cpufreq_register_driver(&g5_cpufreq_driver);
/* We keep the CPU node on hold... hopefully, Apple G5 don't have
* hotplug CPU with a dynamic device-tree ...
*/
return rc;
bail_noprops:
of_node_put(cpunode);
return rc;
}
module_init(g5_cpufreq_init);
MODULE_LICENSE("GPL");
