[PATCH 2/2] amd76x_pm: C2 powersaving for AMD K7
From: Joerg Sommrey
Date: Fri Nov 04 2005 - 15:16:06 EST
This patch adds some experimental features to amd76x_pm, namely C3, NTH
and POS support. These features are not enabled by default and are
intended for kernel hackers only.
This patch can also be found at
http://www.sommrey.de/amd76x_pm/amd76x_pm-2.6.14-1-extra.patch
Signed-off-by: Joerg Sommrey <jo@xxxxxxxxxx>
--- linux-2.6.14-jo/drivers/acpi/amd76x_pm.c.orig 2005-11-04 20:36:19.000000000 +0100
+++ linux-2.6.14-jo/drivers/acpi/amd76x_pm.c 2005-11-04 20:41:47.000000000 +0100
@@ -59,12 +59,17 @@
#include <linux/amd76x_pm.h>
-#define VERSION "20050906"
+#define VERSION "20050906-extra"
+// #define AMD76X_NTH 1
+// #define AMD76X_POS 1
+// #define AMD76X_C3 1
// #define AMD76X_LOG_C1 1
extern void default_idle(void);
+#ifndef AMD76X_NTH
static void amd76x_smp_idle(void);
+#endif
static int amd76x_pm_main(void);
static unsigned long lazy_idle = 0;
@@ -72,8 +77,10 @@
static unsigned long watch_int = 0;
static unsigned long min_C1 = AMD76X_MIN_C1;
+#ifndef AMD76X_NTH
static int show_watch_irqs(char *, struct kernel_param *);
static int set_watch_irqs(const char *, struct kernel_param *);
+#endif
module_param(lazy_idle, long, S_IRUGO | S_IWUSR);
@@ -84,6 +91,7 @@
MODULE_PARM_DESC(spin_idle,
"\tnumber of spin cycles to wait for other CPUs to become idle");
+#ifndef AMD76X_NTH
module_param(watch_int, long, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(watch_int,
"\twatch interval (in milliseconds) for interrupts");
@@ -94,6 +102,7 @@
"\tlist of irqs (and optional their limit per second) that "
"cause fallback to C1 mode. "
"Syntax: irq0[:limit0],irq1[:limit1],...");
+#endif
module_param(min_C1, long, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(min_C1,
@@ -110,6 +119,12 @@
struct PM_cfg {
unsigned int status_reg;
unsigned int C2_reg;
+#ifdef AMD76X_C3
+ unsigned int C3_reg;
+#endif
+#ifdef AMD76X_NTH
+ unsigned int NTH_reg;
+#endif
unsigned int slp_reg;
unsigned int resume_reg;
void (*orig_idle) (void);
@@ -118,21 +133,34 @@
static struct PM_cfg amd76x_pm_cfg __cacheline_aligned_in_smp;
+#ifndef AMD76X_NTH
struct idle_stat {
atomic_t num_idle;
+#ifdef AMD76X_C3
+ atomic_t num_C2;
+#endif
};
static struct idle_stat amd76x_stat __cacheline_aligned_in_smp = {
.num_idle = ATOMIC_INIT(0),
+#ifdef AMD76X_C3
+ .num_C2 = ATOMIC_INIT(0)
+#endif
};
struct cpu_stat {
int idle_count;
int C2_cnt;
+#ifdef AMD76X_C3
+ int C3_cnt;
+ int C2_active;
+#else
int _fill[2];
+#endif
};
static struct cpu_stat prs[NR_CPUS] __cacheline_aligned_in_smp;
+#endif
struct watch_item {
int irq;
@@ -216,7 +244,13 @@
regdword &= 0xff80;
amd76x_pm_cfg.status_reg = (regdword + 0x00);
amd76x_pm_cfg.slp_reg = (regdword + 0x04);
+#ifdef AMD76X_NTH
+ amd76x_pm_cfg.NTH_reg = (regdword + 0x10);
+#endif
amd76x_pm_cfg.C2_reg = (regdword + 0x14);
+#ifdef AMD76X_C3
+ amd76x_pm_cfg.C3_reg = (regdword + 0x15);
+#endif
amd76x_pm_cfg.resume_reg = (regdword + 0x16); /* N/A for 768 */
}
@@ -261,6 +295,52 @@
regdword &= ~((STPCLK_EN | CPUSLP_EN) << C2_REGS);
pci_write_config_dword(pdev_sb, 0x50, regdword);
}
+#ifdef AMD76X_C3
+/*
+ * Untested C3 idle support for AMD-766.
+ */
+static void
+config_amd766_C3(int enable)
+{
+ unsigned int regdword;
+
+ /* Set C3 options in C3A50, page 63 in AMD-766 doc */
+ pci_read_config_dword(pdev_sb, 0x50, ®dword);
+ if(enable) {
+ regdword &= ~((DCSTOP_EN | PCISTP_EN | SUSPND_EN | CPURST_EN)
+ << C3_REGS);
+ regdword |= (STPCLK_EN /* ~ 20 Watt savings max */
+ | CPUSLP_EN /* Additional ~ 70 Watts max! */
+ | CPUSTP_EN) /* yet more savings! */
+ << C3_REGS;
+ }
+ else
+ regdword &= ~((STPCLK_EN | CPUSLP_EN | CPUSTP_EN) << C3_REGS);
+ pci_write_config_dword(pdev_sb, 0x50, regdword);
+}
+#endif
+
+
+#ifdef AMD76X_POS
+static void
+config_amd766_POS(int enable)
+{
+ unsigned int regdword;
+
+ /* Set C3 options in C3A50, page 63 in AMD-766 doc */
+ pci_read_config_dword(pdev_sb, 0x50, ®dword);
+ if(enable) {
+ regdword &= ~((ZZ_CACHE_EN | CPURST_EN) << POS_REGS);
+ regdword |= ((DCSTOP_EN | STPCLK_EN | CPUSTP_EN | PCISTP_EN |
+ CPUSLP_EN | SUSPND_EN) << POS_REGS);
+ }
+ else
+ regdword ^= (0xff << POS_REGS);
+ pci_write_config_dword(pdev_sb, 0x50, regdword);
+}
+#endif
+
+
/*
* Configures the 765 & 766 southbridges.
@@ -271,6 +351,13 @@
amd76x_get_PM();
config_PMIO_amd76x(1, 1);
config_amd766_C2(enable);
+#ifdef AMD76X_C3
+ config_amd766_C3(enable);
+#endif
+
+#ifdef AMD76X_POS
+ config_amd766_POS(enable);
+#endif
return 0;
}
@@ -293,6 +380,69 @@
pci_write_config_byte(pdev_sb, 0x4F, regbyte);
}
+#ifdef AMD76X_C3
+/*
+ * C3 idle support for AMD-768. The idle loop would need some extra
+ * handling for C3, but it would make more sense for ACPI to handle CX level
+ * transitions like it is supposed to. Unfortunately ACPI doesn't do CX
+ * levels on SMP systems yet.
+ */
+static void
+config_amd768_C3(int enable)
+{
+ unsigned char regbyte;
+
+ /* Set C3 options in DevB:3x4F, page 100 in AMD-768 doc */
+ pci_read_config_byte(pdev_sb, 0x4F, ®byte);
+ if(enable)
+ regbyte |= (C3EN /* | ZZ_C3EN | CSLP_C3EN | CSTP_C3EN */);
+ else
+ regbyte ^= C3EN;
+ pci_write_config_byte(pdev_sb, 0x4F, regbyte);
+}
+#endif
+
+#ifdef AMD76X_POS
+/*
+ * Untested Power On Suspend support for AMD-768. This should also be handled
+ * by ACPI.
+ */
+static void
+config_amd768_POS(int enable)
+{
+ unsigned int regdword;
+
+ /* Set POS options in DevB:3x50, page 101 in AMD-768 doc */
+ pci_read_config_dword(pdev_sb, 0x50, ®dword);
+ if(enable)
+ regdword |= (POSEN | CSTP | PSTP | ASTP | DCSTP | CSLP | SUSP);
+ else
+ regdword ^= POSEN;
+ pci_write_config_dword(pdev_sb, 0x50, regdword);
+}
+#endif
+
+
+#ifdef AMD76X_NTH
+/*
+ * Normal Throttling support for AMD-768. There are several settings
+ * that can be set depending on how long you want some of the delays to be.
+ * I'm not sure if this is even neccessary at all as the 766 doesn't need this.
+ */
+static void
+config_amd768_NTH(int enable, int ntper, int thminen)
+{
+ unsigned char regbyte;
+
+ /* DevB:3x40, pg 93 of 768 doc */
+ pci_read_config_byte(pdev_sb, 0x40, ®byte);
+ /* Is it neccessary to use THMINEN at ANY time? */
+ regbyte |= (NTPER(ntper) | THMINEN(thminen));
+ pci_write_config_byte(pdev_sb, 0x40, regbyte);
+}
+#endif
+
+
/*
* Configures the 768 southbridge to support idle calls, and gets
* the processor idle call register location.
@@ -305,10 +455,64 @@
config_PMIO_amd76x(0, 1);
config_amd768_C2(enable);
+#ifdef AMD76X_C3
+ config_amd768_C3(enable);
+#endif
+#ifdef AMD76X_POS
+ config_amd768_POS(enable);
+#endif
+#ifdef AMD76X_NTH
+ config_amd768_NTH(enable, 1, 2);
+#endif
return 0;
}
+#ifdef AMD76X_NTH
+/*
+ * Activate normal throttling via its ACPI register (P_CNT).
+ */
+static void
+activate_amd76x_NTH(int enable, int ratio)
+{
+ unsigned int regdword;
+
+ /* PM10, pg 110 of 768 doc, pg 70 of 766 doc */
+ regdword=inl(amd76x_pm_cfg.NTH_reg);
+ if(enable)
+ regdword |= (NTH_EN | NTH_RATIO(ratio));
+ else
+ regdword ^= NTH_EN;
+ outl(regdword, amd76x_pm_cfg.NTH_reg);
+}
+#endif
+
+#ifdef AMD76X_POS
+/*
+ * Activate sleep state via its ACPI register (PM1_CNT).
+ */
+static void
+activate_amd76x_SLP(int type)
+{
+ unsigned short regshort;
+
+ /* PM04, pg 109 of 768 doc, pg 69 of 766 doc */
+ regshort=inw(amd76x_pm_cfg.slp_reg);
+ regshort |= (SLP_EN | SLP_TYP(type)) ;
+ outw(regshort, amd76x_pm_cfg.slp_reg);
+}
+#endif /* AMD76X_POS */
+#ifdef AMD76X_POS
+/*
+ * Wrapper function to activate POS sleep state.
+ */
+static void
+activate_amd76x_POS(void)
+{
+ activate_amd76x_SLP(1);
+}
+#endif
+
/*
* Idle loop for single processor systems
*/
@@ -321,6 +525,7 @@
amd76x_pm_cfg.orig_idle();
}
+#ifndef AMD76X_NTH
/*
* Idle loop for SMP systems
*
@@ -367,9 +572,30 @@
smp_mb();
if (unlikely(atomic_read(&amd76x_stat.num_idle) ==
num_online)) {
+ #ifdef AMD76X_C3
+ /* Enter C3 if all CPUs are ready for C3.
+ * Enter C2 otherwise.
+ */
+ if (unlikely(atomic_read(&amd76x_stat.num_C2) ==
+ num_online)) {
+ /* Invoke C3 */
+ prs[cpu].C3_cnt++;
+ inb(amd76x_pm_cfg.C3_reg);
+ } else {
+ /* Invoke C2 */
+ prs[cpu].C2_cnt++;
+ inb(amd76x_pm_cfg.C2_reg);
+ /* Now we are ready for C3 */
+ if (!prs[cpu].C2_active) {
+ prs[cpu].C2_active = 1;
+ atomic_inc(&amd76x_stat.num_C2);
+ }
+ }
+ #else
/* Invoke C2 */
prs[cpu].C2_cnt++;
inb(amd76x_pm_cfg.C2_reg);
+ #endif
smp_mb();
atomic_dec(&amd76x_stat.num_idle);
prs[cpu].idle_count = 0;
@@ -380,13 +606,24 @@
smp_mb();
atomic_dec(&amd76x_stat.num_idle);
+#ifdef AMD76X_C3
+ /* We haven't been in C2/C3 if we are here. We are no longer
+ * ready for C3.
+ */
+ if (prs[cpu].C2_active) {
+ prs[cpu].C2_active = 0;
+ atomic_dec(&amd76x_stat.num_C2);
+ }
+#endif
prs[cpu].idle_count = 0;
local_irq_enable();
}
+#endif
/*
* sysfs support, RW
*/
+#ifndef AMD76X_NTH
static int
show_watch_irqs(char *buf, struct kernel_param *kp)
{
@@ -460,8 +697,26 @@
return sprintf(buf,"%u\n", C2_cnt);
}
+#ifdef AMD76X_C3
+static ssize_t
+show_C3_cnt (struct device *dev, struct device_attribute *attr,
+ char *buf)
+{
+ unsigned int C3_cnt = 0;
+ int i;
+ for_each_online_cpu(i)
+ C3_cnt += prs[i].C3_cnt;
+ return sprintf(buf,"%u\n", C3_cnt);
+}
+#endif
+
static DEVICE_ATTR(C2_cnt, S_IRUGO,
show_C2_cnt, NULL);
+#ifdef AMD76X_C3
+static DEVICE_ATTR(C3_cnt, S_IRUGO,
+ show_C3_cnt, NULL);
+#endif
+#endif
static void
setup_watch(void)
@@ -519,7 +774,9 @@
static int
amd76x_pm_main(void)
{
+#ifndef AMD76X_NTH
int i;
+#endif
amd76x_pm_cfg.orig_idle = 0;
if(lazy_idle == 0)
@@ -572,13 +829,16 @@
switch (pdev_nb->device) {
case PCI_DEVICE_ID_AMD_FE_GATE_700C: /* AMD-762 */
config_amd762(1);
+#ifndef AMD76X_NTH
amd76x_pm_cfg.curr_idle = amd76x_smp_idle;
+#endif
break;
default:
printk(KERN_ERR "amd76x_pm: No northbridge to initialize\n");
break;
}
+#ifndef AMD76X_NTH
if(num_online_cpus() == 1) {
amd76x_pm_cfg.curr_idle = amd76x_up_idle;
printk(KERN_ERR "amd76x_pm: UP machine detected. ACPI is your friend.\n");
@@ -591,6 +851,10 @@
for (i = 0; i < NR_CPUS; i++) {
prs[i].idle_count = 0;
prs[i].C2_cnt = 0;
+ #ifdef AMD76X_C3
+ prs[i].C3_cnt = 0;
+ prs[i].C2_active = 0;
+ #endif
}
amd76x_pm_cfg.orig_idle = pm_idle;
@@ -600,7 +864,20 @@
/* sysfs */
device_create_file(&pdev_nb->dev, &dev_attr_C2_cnt);
+#ifdef AMD76X_C3
+ device_create_file(&pdev_nb->dev, &dev_attr_C3_cnt);
+#endif
+#endif
+#ifdef AMD76X_NTH
+ /* Turn NTH on with maxium throttling for testing. */
+ activate_amd76x_NTH(1, 1);
+#endif
+
+#ifdef AMD76X_POS
+ /* Testing here only. */
+ activate_amd76x_POS();
+#endif
setup_watch();
return 0;
@@ -618,9 +895,15 @@
static void __exit
amd76x_pm_cleanup(void)
{
+#ifndef AMD76X_NTH
int i;
unsigned int C2_cnt = 0;
+#ifdef AMD76X_C3
+ unsigned int C3_cnt = 0;
+#endif
+#endif
+#ifndef AMD76X_NTH
pm_idle = amd76x_pm_cfg.orig_idle;
cpu_idle_wait();
@@ -629,11 +912,28 @@
/* This isn't really needed. */
for_each_online_cpu(i) {
C2_cnt += prs[i].C2_cnt;
+#ifdef AMD76X_C3
+ C3_cnt += prs[i].C3_cnt;
+#endif
}
+#ifdef AMD76X_C3
+ printk(KERN_INFO "amd76x_pm: %u C2 calls, %u C3 calls\n",
+ C2_cnt, C3_cnt);
+#else
printk(KERN_INFO "amd76x_pm: %u C2 calls\n", C2_cnt);
+#endif
/* remove sysfs */
device_remove_file(&pdev_nb->dev, &dev_attr_C2_cnt);
+#ifdef AMD76X_C3
+ device_remove_file(&pdev_nb->dev, &dev_attr_C3_cnt);
+#endif
+#endif
+
+#ifdef AMD76X_NTH
+ /* Turn NTH off*/
+ activate_amd76x_NTH(0, 0);
+#endif
irqwatch.schedule = 0;
flush_scheduled_work();
-
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