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[CPUFREQ] Longhaul - Hook into ACPI C states.
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Minimal change necessary for hardware support.

Changes in longhaul.c:
- most important - now C3 state is causing transition,
- code responsible for clearing "bus master" bit removed,
- protect bcr2 transition in the same way as longhaul.

Signed-off-by: Rafa³ Bilski <rafalbilski@interia.pl>
Signed-off-by: Dave Jones <davej@redhat.com>
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Rafa³ Bilski authored and Dave Jones committed Jul 31, 2006
1 parent 9c9a43e commit dadb49d
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Showing 2 changed files with 109 additions and 87 deletions.
2 changes: 1 addition & 1 deletion arch/i386/kernel/cpu/cpufreq/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -202,7 +202,7 @@ config X86_LONGRUN
config X86_LONGHAUL
tristate "VIA Cyrix III Longhaul"
select CPU_FREQ_TABLE
depends on BROKEN
depends on ACPI_PROCESSOR
help
This adds the CPUFreq driver for VIA Samuel/CyrixIII,
VIA Cyrix Samuel/C3, VIA Cyrix Ezra and VIA Cyrix Ezra-T
Expand Down
194 changes: 108 additions & 86 deletions arch/i386/kernel/cpu/cpufreq/longhaul.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -29,11 +29,13 @@
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/pci.h>

#include <asm/msr.h>
#include <asm/timex.h>
#include <asm/io.h>
#include <asm/acpi.h>
#include <linux/acpi.h>
#include <acpi/processor.h>

#include "longhaul.h"

Expand All @@ -56,6 +58,8 @@ static int minvid, maxvid;
static unsigned int minmult, maxmult;
static int can_scale_voltage;
static int vrmrev;
static struct acpi_processor *pr = NULL;
static struct acpi_processor_cx *cx = NULL;

/* Module parameters */
static int dont_scale_voltage;
Expand Down Expand Up @@ -118,84 +122,64 @@ static int longhaul_get_cpu_mult(void)
return eblcr_table[invalue];
}

/* For processor with BCR2 MSR */

static void do_powersaver(union msr_longhaul *longhaul,
unsigned int clock_ratio_index)
static void do_longhaul1(int cx_address, unsigned int clock_ratio_index)
{
struct pci_dev *dev;
unsigned long flags;
unsigned int tmp_mask;
int version;
int i;
u16 pci_cmd;
u16 cmd_state[64];
union msr_bcr2 bcr2;
u32 t;

switch (cpu_model) {
case CPU_EZRA_T:
version = 3;
break;
case CPU_NEHEMIAH:
version = 0xf;
break;
default:
return;
}
rdmsrl(MSR_VIA_BCR2, bcr2.val);
/* Enable software clock multiplier */
bcr2.bits.ESOFTBF = 1;
bcr2.bits.CLOCKMUL = clock_ratio_index;

rdmsrl(MSR_VIA_LONGHAUL, longhaul->val);
longhaul->bits.SoftBusRatio = clock_ratio_index & 0xf;
longhaul->bits.SoftBusRatio4 = (clock_ratio_index & 0x10) >> 4;
longhaul->bits.EnableSoftBusRatio = 1;
longhaul->bits.RevisionKey = 0;
/* Sync to timer tick */
safe_halt();
ACPI_FLUSH_CPU_CACHE();
/* Change frequency on next halt or sleep */
wrmsrl(MSR_VIA_BCR2, bcr2.val);
/* Invoke C3 */
inb(cx_address);
/* Dummy op - must do something useless after P_LVL3 read */
t = inl(acpi_fadt.xpm_tmr_blk.address);

/* Disable software clock multiplier */
local_irq_disable();
rdmsrl(MSR_VIA_BCR2, bcr2.val);
bcr2.bits.ESOFTBF = 0;
wrmsrl(MSR_VIA_BCR2, bcr2.val);
}

preempt_disable();
local_irq_save(flags);
/* For processor with Longhaul MSR */

/*
* get current pci bus master state for all devices
* and clear bus master bit
*/
dev = NULL;
i = 0;
do {
dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
if (dev != NULL) {
pci_read_config_word(dev, PCI_COMMAND, &pci_cmd);
cmd_state[i++] = pci_cmd;
pci_cmd &= ~PCI_COMMAND_MASTER;
pci_write_config_word(dev, PCI_COMMAND, pci_cmd);
}
} while (dev != NULL);
static void do_powersaver(int cx_address, unsigned int clock_ratio_index)
{
union msr_longhaul longhaul;
u32 t;

tmp_mask=inb(0x21); /* works on C3. save mask. */
outb(0xFE,0x21); /* TMR0 only */
outb(0xFF,0x80); /* delay */
rdmsrl(MSR_VIA_LONGHAUL, longhaul.val);
longhaul.bits.RevisionKey = longhaul.bits.RevisionID;
longhaul.bits.SoftBusRatio = clock_ratio_index & 0xf;
longhaul.bits.SoftBusRatio4 = (clock_ratio_index & 0x10) >> 4;

/* Sync to timer tick */
safe_halt();
wrmsrl(MSR_VIA_LONGHAUL, longhaul->val);
halt();

ACPI_FLUSH_CPU_CACHE();
/* Change frequency on next halt or sleep */
wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
/* Invoke C3 */
inb(cx_address);
/* Dummy op - must do something useless after P_LVL3 read */
t = inl(acpi_fadt.xpm_tmr_blk.address);

/* Disable bus ratio bit */
local_irq_disable();

outb(tmp_mask,0x21); /* restore mask */

/* restore pci bus master state for all devices */
dev = NULL;
i = 0;
do {
dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
if (dev != NULL) {
pci_cmd = cmd_state[i++];
pci_write_config_byte(dev, PCI_COMMAND, pci_cmd);
}
} while (dev != NULL);
local_irq_restore(flags);
preempt_enable();

/* disable bus ratio bit */
rdmsrl(MSR_VIA_LONGHAUL, longhaul->val);
longhaul->bits.EnableSoftBusRatio = 0;
longhaul->bits.RevisionKey = version;
wrmsrl(MSR_VIA_LONGHAUL, longhaul->val);
longhaul.bits.RevisionKey = longhaul.bits.RevisionID;
longhaul.bits.EnableSoftBusRatio = 0;
longhaul.bits.EnableSoftBSEL = 0;
longhaul.bits.EnableSoftVID = 0;
wrmsrl(MSR_VIA_LONGHAUL, longhaul.val);
}

/**
Expand All @@ -209,9 +193,9 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
{
int speed, mult;
struct cpufreq_freqs freqs;
union msr_longhaul longhaul;
union msr_bcr2 bcr2;
static unsigned int old_ratio=-1;
unsigned long flags;
unsigned int pic1_mask, pic2_mask;

if (old_ratio == clock_ratio_index)
return;
Expand All @@ -234,6 +218,20 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
dprintk ("Setting to FSB:%dMHz Mult:%d.%dx (%s)\n",
fsb, mult/10, mult%10, print_speed(speed/1000));

preempt_disable();
local_irq_save(flags);

pic2_mask = inb(0xA1);
pic1_mask = inb(0x21); /* works on C3. save mask. */
outb(0xFF,0xA1); /* Overkill */
outb(0xFE,0x21); /* TMR0 only */

/* Disable bus master arbitration */
if (pr->flags.bm_check) {
acpi_set_register(ACPI_BITREG_ARB_DISABLE, 1,
ACPI_MTX_DO_NOT_LOCK);
}

switch (longhaul_version) {

/*
Expand All @@ -245,20 +243,7 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
*/
case TYPE_LONGHAUL_V1:
case TYPE_LONGHAUL_V2:
rdmsrl (MSR_VIA_BCR2, bcr2.val);
/* Enable software clock multiplier */
bcr2.bits.ESOFTBF = 1;
bcr2.bits.CLOCKMUL = clock_ratio_index;
local_irq_disable();
wrmsrl (MSR_VIA_BCR2, bcr2.val);
safe_halt();

/* Disable software clock multiplier */
rdmsrl (MSR_VIA_BCR2, bcr2.val);
bcr2.bits.ESOFTBF = 0;
local_irq_disable();
wrmsrl (MSR_VIA_BCR2, bcr2.val);
local_irq_enable();
do_longhaul1(cx->address, clock_ratio_index);
break;

/*
Expand All @@ -273,10 +258,22 @@ static void longhaul_setstate(unsigned int clock_ratio_index)
* to work in practice.
*/
case TYPE_POWERSAVER:
do_powersaver(&longhaul, clock_ratio_index);
do_powersaver(cx->address, clock_ratio_index);
break;
}

/* Enable bus master arbitration */
if (pr->flags.bm_check) {
acpi_set_register(ACPI_BITREG_ARB_DISABLE, 0,
ACPI_MTX_DO_NOT_LOCK);
}

outb(pic2_mask,0xA1); /* restore mask */
outb(pic1_mask,0x21);

local_irq_restore(flags);
preempt_enable();

cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}

Expand Down Expand Up @@ -527,13 +524,34 @@ static unsigned int longhaul_get(unsigned int cpu)
return calc_speed(longhaul_get_cpu_mult());
}

acpi_status longhaul_walk_callback(acpi_handle obj_handle,
u32 nesting_level,
void *context, void **return_value)
{
struct acpi_device *d;

if ( acpi_bus_get_device(obj_handle, &d) ) {
return 0;
}
*return_value = (void *)acpi_driver_data(d);
return 1;
}

static int __init longhaul_cpu_init(struct cpufreq_policy *policy)
{
struct cpuinfo_x86 *c = cpu_data;
char *cpuname=NULL;
int ret;

/* Check ACPI support for C3 state */
acpi_walk_namespace(ACPI_TYPE_PROCESSOR, ACPI_ROOT_OBJECT, ACPI_UINT32_MAX,
&longhaul_walk_callback, NULL, (void *)&pr);
if (pr == NULL) goto err_acpi;

cx = &pr->power.states[ACPI_STATE_C3];
if (cx == NULL || cx->latency > 1000) goto err_acpi;

/* Now check what we have on this motherboard */
switch (c->x86_model) {
case 6:
cpu_model = CPU_SAMUEL;
Expand Down Expand Up @@ -634,6 +652,10 @@ static int __init longhaul_cpu_init(struct cpufreq_policy *policy)
cpufreq_frequency_table_get_attr(longhaul_table, policy->cpu);

return 0;

err_acpi:
printk(KERN_ERR PFX "No ACPI support for CPU frequency changes.\n");
return -ENODEV;
}

static int __devexit longhaul_cpu_exit(struct cpufreq_policy *policy)
Expand Down

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