linux-sg2042/drivers/cpufreq/maple-cpufreq.c

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/*
* Copyright (C) 2011 Dmitry Eremin-Solenikov
* 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.
*/
#undef DEBUG
#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/cpufreq.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/mutex.h>
#include <linux/time.h>
#include <linux/of_device.h>
#define DBG(fmt...) pr_debug(fmt)
/* 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 maple_cpu_freqs[] = {
{CPUFREQ_HIGH, 0},
{CPUFREQ_LOW, 0},
{0, CPUFREQ_TABLE_END},
};
/* Power mode data is an array of the 32 bits PCR values to use for
* the various frequencies, retrieved from the device-tree
*/
static int maple_pmode_cur;
static const u32 *maple_pmode_data;
static int maple_pmode_max;
/*
* SCOM based frequency switching for 970FX rev3
*/
static int maple_scom_switch_freq(int speed_mode)
{
unsigned long flags;
int to;
local_irq_save(flags);
/* 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 |
maple_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) ^
(maple_pmode_data[speed_mode] >> PCR_SPEED_SHIFT)) & 0x3)
== 0)
break;
if (psr & PSR_CMD_COMPLETED)
break;
udelay(100);
}
local_irq_restore(flags);
maple_pmode_cur = speed_mode;
ppc_proc_freq = maple_cpu_freqs[speed_mode].frequency * 1000ul;
return 0;
}
static int maple_scom_query_freq(void)
{
unsigned long psr = scom970_read(SCOM_PSR);
int i;
for (i = 0; i <= maple_pmode_max; i++)
if ((((psr >> PSR_CUR_SPEED_SHIFT) ^
(maple_pmode_data[i] >> PCR_SPEED_SHIFT)) & 0x3) == 0)
break;
return i;
}
/*
* Common interface to the cpufreq core
*/
static int maple_cpufreq_target(struct cpufreq_policy *policy,
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:15:48 +08:00
unsigned int index)
{
return maple_scom_switch_freq(index);
}
static unsigned int maple_cpufreq_get_speed(unsigned int cpu)
{
return maple_cpu_freqs[maple_pmode_cur].frequency;
}
static int maple_cpufreq_cpu_init(struct cpufreq_policy *policy)
{
return cpufreq_generic_init(policy, maple_cpu_freqs, 12000);
}
static struct cpufreq_driver maple_cpufreq_driver = {
.name = "maple",
.flags = CPUFREQ_CONST_LOOPS,
.init = maple_cpufreq_cpu_init,
.verify = cpufreq_generic_frequency_table_verify,
cpufreq: Implement light weight ->target_index() routine Currently, the prototype of cpufreq_drivers target routines is: int target(struct cpufreq_policy *policy, unsigned int target_freq, unsigned int relation); And most of the drivers call cpufreq_frequency_table_target() to get a valid index of their frequency table which is closest to the target_freq. And they don't use target_freq and relation after that. So, it makes sense to just do this work in cpufreq core before calling cpufreq_frequency_table_target() and simply pass index instead. But this can be done only with drivers which expose their frequency table with cpufreq core. For others we need to stick with the old prototype of target() until those drivers are converted to expose frequency tables. This patch implements the new light weight prototype for target_index() routine. It looks like this: int target_index(struct cpufreq_policy *policy, unsigned int index); CPUFreq core will call cpufreq_frequency_table_target() before calling this routine and pass index to it. Because CPUFreq core now requires to call routines present in freq_table.c CONFIG_CPU_FREQ_TABLE must be enabled all the time. This also marks target() interface as deprecated. So, that new drivers avoid using it. And Documentation is updated accordingly. It also converts existing .target() to newly defined light weight .target_index() routine for many driver. Acked-by: Hans-Christian Egtvedt <egtvedt@samfundet.no> Acked-by: Jesper Nilsson <jesper.nilsson@axis.com> Acked-by: Linus Walleij <linus.walleij@linaro.org> Acked-by: Russell King <linux@arm.linux.org.uk> Acked-by: David S. Miller <davem@davemloft.net> Tested-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rjw@rjwysocki.net>
2013-10-25 22:15:48 +08:00
.target_index = maple_cpufreq_target,
.get = maple_cpufreq_get_speed,
.attr = cpufreq_generic_attr,
};
static int __init maple_cpufreq_init(void)
{
struct device_node *cpunode;
unsigned int psize;
unsigned long max_freq;
const u32 *valp;
u32 pvr_hi;
int rc = -ENODEV;
/*
* Behave here like powermac driver which checks machine compatibility
* to ease merging of two drivers in future.
*/
if (!of_machine_is_compatible("Momentum,Maple") &&
!of_machine_is_compatible("Momentum,Apache"))
return 0;
/* Get first CPU node */
cpunode = of_cpu_device_node_get(0);
if (cpunode == NULL) {
printk(KERN_ERR "cpufreq: Can't find any CPU 0 node\n");
goto bail_noprops;
}
/* Check 970FX for now */
/* we actually don't care on which CPU to access PVR */
pvr_hi = PVR_VER(mfspr(SPRN_PVR));
if (pvr_hi != 0x3c && pvr_hi != 0x44) {
printk(KERN_ERR "cpufreq: Unsupported CPU version (%x)\n",
pvr_hi);
goto bail_noprops;
}
/* Look for the powertune data in the device-tree */
/*
* On Maple this property is provided by PIBS in dual-processor config,
* not provided by PIBS in CPU0 config and also not provided by SLOF,
* so YMMV
*/
maple_pmode_data = of_get_property(cpunode, "power-mode-data", &psize);
if (!maple_pmode_data) {
DBG("No power-mode-data !\n");
goto bail_noprops;
}
maple_pmode_max = psize / sizeof(u32) - 1;
/*
* 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 = of_get_property(cpunode, "clock-frequency", NULL);
if (!valp)
return -ENODEV;
max_freq = (*valp)/1000;
maple_cpu_freqs[0].frequency = max_freq;
maple_cpu_freqs[1].frequency = max_freq/2;
/* Force apply current frequency to make sure everything is in
* sync (voltage is right for example). Firmware may leave us with
* a strange setting ...
*/
msleep(10);
maple_pmode_cur = -1;
maple_scom_switch_freq(maple_scom_query_freq());
printk(KERN_INFO "Registering Maple CPU frequency driver\n");
printk(KERN_INFO "Low: %d Mhz, High: %d Mhz, Cur: %d MHz\n",
maple_cpu_freqs[1].frequency/1000,
maple_cpu_freqs[0].frequency/1000,
maple_cpu_freqs[maple_pmode_cur].frequency/1000);
rc = cpufreq_register_driver(&maple_cpufreq_driver);
of_node_put(cpunode);
return rc;
bail_noprops:
of_node_put(cpunode);
return rc;
}
module_init(maple_cpufreq_init);
MODULE_LICENSE("GPL");