freebsd-dev/sys/powerpc/cpufreq/pcr.c
Nathan Whitehorn 1016f143f0 Add cpufreq support on the PowerPC G5, along with a skeleton SMU driver
in order to slew CPU voltage during frequency changes. The OpenBSD SMU
driver was an extremely helpful reference for this.
2009-06-23 04:28:32 +00:00

334 lines
7.2 KiB
C

/*-
* Copyright (c) 2009 Nathan Whitehorn
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/bus.h>
#include <sys/cpu.h>
#include <sys/kernel.h>
#include <sys/module.h>
#include <dev/ofw/ofw_bus.h>
#include "cpufreq_if.h"
struct pcr_softc {
device_t dev;
uint32_t pcr_vals[3];
int nmodes;
};
static void pcr_identify(driver_t *driver, device_t parent);
static int pcr_probe(device_t dev);
static int pcr_attach(device_t dev);
static int pcr_settings(device_t dev, struct cf_setting *sets, int *count);
static int pcr_set(device_t dev, const struct cf_setting *set);
static int pcr_get(device_t dev, struct cf_setting *set);
static int pcr_type(device_t dev, int *type);
static device_method_t pcr_methods[] = {
/* Device interface */
DEVMETHOD(device_identify, pcr_identify),
DEVMETHOD(device_probe, pcr_probe),
DEVMETHOD(device_attach, pcr_attach),
/* cpufreq interface */
DEVMETHOD(cpufreq_drv_set, pcr_set),
DEVMETHOD(cpufreq_drv_get, pcr_get),
DEVMETHOD(cpufreq_drv_type, pcr_type),
DEVMETHOD(cpufreq_drv_settings, pcr_settings),
{0, 0}
};
static driver_t pcr_driver = {
"pcr",
pcr_methods,
sizeof(struct pcr_softc)
};
static devclass_t pcr_devclass;
DRIVER_MODULE(pcr, cpu, pcr_driver, pcr_devclass, 0, 0);
/*
* States
*/
#define PCR_TO_FREQ(a) ((a >> 17) & 3)
#define PCR_FULL 0
#define PCR_HALF 1
#define PCR_QUARTER 2 /* Only on 970MP */
#define PSR_RECEIVED (1ULL << 61)
#define PSR_COMPLETED (1ULL << 61)
/*
* SCOM addresses
*/
#define SCOM_PCR 0x0aa00100 /* Power Control Register */
#define SCOM_PCR_BIT 0x80000000 /* Data bit for PCR */
#define SCOM_PSR 0x40800100 /* Power Status Register */
/*
* SCOM Glue
*/
#define SCOMC_READ 0x00008000
#define SCOMC_WRITE 0x00000000
static void
write_scom(register_t address, uint64_t value)
{
register_t msr;
register_t hi, lo, scratch;
hi = (value >> 32) & 0xffffffff;
lo = value & 0xffffffff;
msr = mfmsr();
mtmsr(msr & ~PSL_EE); isync();
mtspr64(SPR_SCOMD, hi, lo, scratch);
isync();
mtspr(SPR_SCOMC, address | SCOMC_WRITE);
isync();
mtmsr(msr); isync();
}
static uint64_t
read_scom(register_t address)
{
register_t msr;
uint64_t ret;
msr = mfmsr();
mtmsr(msr & ~PSL_EE); isync();
mtspr(SPR_SCOMC, address | SCOMC_READ);
isync();
__asm __volatile ("mfspr %0,%1;"
" mr %0+1, %0; srdi %0,%0,32" : "=r" (ret) : "K" (SPR_SCOMD));
(void)mfspr(SPR_SCOMC); /* Complete transcation */
mtmsr(msr); isync();
return (ret);
}
static void
pcr_identify(driver_t *driver, device_t parent)
{
uint16_t vers;
vers = mfpvr() >> 16;
/* Check for an IBM 970-class CPU */
switch (vers) {
case IBM970FX:
case IBM970GX:
case IBM970MP:
break;
default:
return;
}
/* Make sure we're not being doubly invoked. */
if (device_find_child(parent, "pcr", -1) != NULL)
return;
/*
* We attach a child for every CPU since settings need to
* be performed on every CPU in the SMP case.
*/
if (BUS_ADD_CHILD(parent, 10, "pcr", -1) == NULL)
device_printf(parent, "add pcr child failed\n");
}
static int
pcr_probe(device_t dev)
{
if (resource_disabled("pcr", 0))
return (ENXIO);
device_set_desc(dev, "PPC 970 Power Control Register");
return (0);
}
static int
pcr_attach(device_t dev)
{
struct pcr_softc *sc;
phandle_t cpu;
uint32_t modes[3];
int i;
sc = device_get_softc(dev);
sc->dev = dev;
cpu = ofw_bus_get_node(device_get_parent(dev));
if (cpu <= 0) {
device_printf(dev,"No CPU device tree node!\n");
return (ENXIO);
}
/*
* Collect the PCR values for each mode from the device tree.
* These include bus timing information, and so cannot be
* directly computed.
*/
sc->nmodes = OF_getproplen(cpu, "power-mode-data");
if (sc->nmodes <= 0 || sc->nmodes > sizeof(sc->pcr_vals)) {
device_printf(dev,"No power mode data in device tree!\n");
return (ENXIO);
}
OF_getprop(cpu, "power-mode-data", modes, sc->nmodes);
sc->nmodes /= sizeof(modes[0]);
/* Sort the modes */
for (i = 0; i < sc->nmodes; i++)
sc->pcr_vals[PCR_TO_FREQ(modes[i])] = modes[i];
cpufreq_register(dev);
return (0);
}
static int
pcr_settings(device_t dev, struct cf_setting *sets, int *count)
{
struct pcr_softc *sc;
sc = device_get_softc(dev);
if (sets == NULL || count == NULL)
return (EINVAL);
if (*count < sc->nmodes)
return (E2BIG);
/* Return a list of valid settings for this driver. */
memset(sets, CPUFREQ_VAL_UNKNOWN, sizeof(*sets) * sc->nmodes);
sets[0].freq = 10000; sets[0].dev = dev;
sets[1].freq = 5000; sets[1].dev = dev;
if (sc->nmodes > 2)
sets[2].freq = 2500; sets[2].dev = dev;
*count = sc->nmodes;
return (0);
}
static int
pcr_set(device_t dev, const struct cf_setting *set)
{
struct pcr_softc *sc;
register_t pcr, msr;
uint64_t psr;
if (set == NULL)
return (EINVAL);
sc = device_get_softc(dev);
/* Construct the new PCR */
pcr = SCOM_PCR_BIT;
if (set->freq == 10000)
pcr |= sc->pcr_vals[0];
else if (set->freq == 5000)
pcr |= sc->pcr_vals[1];
else if (set->freq == 2500)
pcr |= sc->pcr_vals[2];
msr = mfmsr();
mtmsr(msr & ~PSL_EE); isync();
/* 970MP requires PCR and PCRH to be cleared first */
write_scom(SCOM_PCR,0); /* Clear PCRH */
write_scom(SCOM_PCR,SCOM_PCR_BIT); /* Clear PCR */
/* Set PCR */
write_scom(SCOM_PCR, pcr);
/* Wait for completion */
do {
DELAY(100);
psr = read_scom(SCOM_PSR);
} while ((psr & PSR_RECEIVED) && !(psr & PSR_COMPLETED));
mtmsr(msr); isync();
return (0);
}
static int
pcr_get(device_t dev, struct cf_setting *set)
{
struct pcr_softc *sc;
uint64_t psr;
if (set == NULL)
return (EINVAL);
sc = device_get_softc(dev);
memset(set, CPUFREQ_VAL_UNKNOWN, sizeof(*set));
psr = read_scom(SCOM_PSR);
/* We want bits 6 and 7 */
psr = (psr >> 56) & 3;
set->freq = 10000;
if (psr == PCR_HALF)
set->freq = 5000;
else if (psr == PCR_QUARTER)
set->freq = 2500;
set->dev = dev;
return (0);
}
static int
pcr_type(device_t dev, int *type)
{
if (type == NULL)
return (EINVAL);
*type = CPUFREQ_TYPE_RELATIVE;
return (0);
}