[PATCH] amd76x_pm port to 2.5.70

[PATCH] amd76x_pm port to 2.5.70

[Pasi Savolainen]

Attached is a simplistic port of amd76x_pm to 2.5.70.
There is a mention about being non-preempt safe, and I can't tell
spinlock from semaphore, so can do nada about it.
zwane told me on #kernelnewbies that 

  pm_idle = old_pm_idle; wmb();

should take care about the processor syncing, but I do get total hangs
on rmmod.

There's also the thing that in 2.5.70-mm2 pm_idle doesn't get called at
all unless there's some load. eg. if I load this on boot, before
starting X, /proc/drivers/amd76x_pm stays at 0.


diff -Nru linux-2.5.70/drivers/char/Kconfig linux-2.5.70-mod/drivers/char/Kconfig
--- linux-2.5.70/drivers/char/Kconfig	2003-05-27 04:00:21.000000000 +0300
+++ linux-2.5.70-mod/drivers/char/Kconfig	2003-05-31 20:33:09.000000000 +0300
@@ -737,6 +737,21 @@
 
 	  If unsure, say N.
 
+config AMD76X_PM
+        tristate "AMD76x Native Power Management support"
+        depends on X86 && PCI
+        ---help---
+         This driver enables Power Management on AMD760MP & AMD760MPX chipsets.
+	  This is about same as ACPI C2, except that ACPI folks don't do SMP ATM.
+	  A /proc/drivers/amd76x_pm -statistics file will be created at runtime.
+
+	  To compile this driver as a module ( = code which can be inserted in
+	  and removed from the running kernel whenever you want), say M here
+	  and read <file:Documentation/modules.txt>. The module will be called
+	  amd76x_pm, it cannot be unloaded.	 
+
+	  If unsure, say N.
+
 config NVRAM
 	tristate "/dev/nvram support"
 	---help---
diff -Nru linux-2.5.70/drivers/char/Makefile linux-2.5.70-mod/drivers/char/Makefile
--- linux-2.5.70/drivers/char/Makefile	2003-05-27 04:00:59.000000000 +0300
+++ linux-2.5.70-mod/drivers/char/Makefile	2003-05-31 20:35:43.000000000 +0300
@@ -61,6 +61,7 @@
 obj-$(CONFIG_I8K) += i8k.o
 obj-$(CONFIG_DS1620) += ds1620.o
 obj-$(CONFIG_HW_RANDOM) += hw_random.o
+obj-$(CONFIG_AMD76X_PM) += amd76x_pm.o
 obj-$(CONFIG_QIC02_TAPE) += tpqic02.o
 obj-$(CONFIG_FTAPE) += ftape/
 obj-$(CONFIG_H8) += h8.o
diff -Nru linux-2.5.70/drivers/char/amd76x_pm.c linux-2.5.70-mod/drivers/char/amd76x_pm.c
--- linux-2.5.70/drivers/char/amd76x_pm.c	1970-01-01 02:00:00.000000000 +0200
+++ linux-2.5.70-mod/drivers/char/amd76x_pm.c	2003-05-31 20:55:37.000000000 +0300
@@ -0,0 +1,711 @@
+/*
+ * ACPI style PM for SMP AMD-760MP(X) based systems.
+ * For use until the ACPI project catches up. :-)
+ *
+ * Copyright (C) 2002 Johnathan Hicks <thetech@folkwolf.net>
+ *
+ * History:
+ * 
+ *   20020702 - amd-smp-idle: Tony Lindgren <tony@atomide.com>
+ *	Influenced by Vcool, and LVCool. Rewrote everything from scratch to
+ *	use the PCI features in Linux, and to support SMP systems. Provides
+ *	C2 idling on SMP AMD-760MP systems.
+ *	
+ *   20020722: JH
+ *   	I adapted Tony's code for the AMD-765/766 southbridge and adapted it
+ *   	according to the AMD-768 data sheet to provide the same capability for
+ *   	SMP AMD-760MPX systems. Posted to acpi-devel list.
+ *   	
+ *   20020722: Alan Cox
+ *   	Replaces non-functional amd76x_pm code in -ac tree.
+ *   	
+ *   20020730: JH
+ *   	Added ability to do normal throttling (the non-thermal kind), C3 idling
+ *   	and Power On Suspend (S1 sleep). It would be very easy to tie swsusp
+ *   	into activate_amd76x_SLP(). C3 idling doesn't happen yet; see my note
+ *   	in amd76x_smp_idle(). I've noticed that when NTH and idling are both
+ *   	enabled, my hardware locks and requires a hard reset, so I have
+ *   	#ifndefed around the idle loop setting to prevent this. POS locks it up
+ *   	too, both ought to be fixable. I've also noticed that idling and NTH
+ *   	make some interference that is picked up by the onboard sound chip on
+ *   	my ASUS A7M266-D motherboard.
+ *
+ *   20030531: Pasi Savolainen
+ *   	Simple port to 2.5
+ *   	Added /proc/driver/amd76x_pm for making nice graphs with mrtg.
+ *   	Cannot unload this without crash.
+ *
+ *
+ * TODO: Thermal throttling (TTH).
+ * 	 /proc interface for normal throttling level.
+ * 	 /proc interface for POS.
+ *
+ *
+ *    <Notes from 20020722-ac revision>
+ *
+ * Processor idle mode module for AMD SMP 760MP(X) based systems
+ *
+ * Copyright (C) 2002 Tony Lindgren <tony@atomide.com>
+ *                    Johnathan Hicks (768 support)
+ *
+ * Using this module saves about 70 - 90W of energy in the idle mode compared
+ * to the default idle mode. Waking up from the idle mode is fast to keep the
+ * system response time good. Currently no CPU load calculation is done, the
+ * system exits the idle mode if the idle function runs twice on the same
+ * processor in a row. This only works on SMP systems, but maybe the idle mode
+ * enabling can be integrated to ACPI to provide C2 mode at some point.
+ *
+ * NOTE: Currently there's a bug somewhere where the reading the
+ *       P_LVL2 for the first time causes the system to sleep instead of 
+ *       idling. This means that you need to hit the power button once to
+ *       wake the system after loading the module for the first time after
+ *       reboot. After that the system idles as supposed.
+ *
+ *
+ * Influenced by Vcool, and LVCool. Rewrote everything from scratch to
+ * use the PCI features in Linux, and to support SMP systems.
+ * 
+ * Currently only tested on a TYAN S2460 (760MP) system (Tony) and an
+ * ASUS A7M266-D (760MPX) system (Johnathan). Adding support for other Athlon
+ * SMP or single processor systems should be easy if desired.
+ *
+ * This software is licensed under GNU General Public License Version 2 
+ * as specified in file COPYING in the Linux kernel source tree main 
+ * directory.
+ * 
+ *   </Notes from 20020722-ac revision>
+ */
+
+
+#include <linux/config.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/delay.h>
+#include <linux/pm.h>
+#include <linux/device.h>
+#include <linux/init.h>
+#include <linux/proc_fs.h>
+
+#include <linux/amd76x_pm.h>
+
+#define VERSION	"20030531"
+
+// #define AMD76X_C3  1
+// #define AMD76X_NTH 1
+// #define AMD76X_POS 1
+
+
+extern void default_idle(void);
+static void amd76x_smp_idle(void);
+static int amd76x_pm_main(void);
+static int __devinit amd_nb_init(struct pci_dev *pdev,
+				 const struct pci_device_id *ent);
+
+static void amd_nb_remove(struct pci_dev *pdev);
+
+
+static struct pci_dev *pdev_nb;
+static struct pci_dev *pdev_sb;
+static spinlock_t amd76x_pm_lock; /* for device access */
+
+struct PM_cfg {
+	unsigned int status_reg;
+	unsigned int C2_reg;
+	unsigned int C3_reg;
+	unsigned int NTH_reg;
+	unsigned int slp_reg;
+	unsigned int resume_reg;
+	void (*orig_idle) (void);
+	void (*curr_idle) (void);
+	unsigned long C2_cnt, C3_cnt;
+	int last_pr;
+        unsigned long lazy_idle;
+};
+static struct PM_cfg amd76x_pm_cfg;
+
+struct cpu_idle_state {
+	int idle;
+	int count;
+};
+static struct cpu_idle_state prs[2];
+
+static struct pci_device_id  __devinitdata amd_nb_tbl[] = {
+	{PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_FE_GATE_700C, PCI_ANY_ID, PCI_ANY_ID,},
+	{0,}
+};
+
+static struct pci_device_id  __devinitdata amd_sb_tbl[] = {
+	{PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_VIPER_7413, PCI_ANY_ID, PCI_ANY_ID,},
+	{PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_VIPER_7443, PCI_ANY_ID, PCI_ANY_ID,},
+	{0,}
+};
+
+static struct pci_driver amd_nb_driver = {
+	.name     = "amd76x_pm-nb",
+	.id_table = amd_nb_tbl,
+	.probe    = amd_nb_init,
+	.remove   = __devexit_p(amd_nb_remove),
+};
+
+static int __devinit
+amd_nb_init(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	pdev_nb = pdev;
+	printk(KERN_INFO "amd76x_pm: Initializing northbridge %s\n",
+		pdev_nb->dev.name);	
+	return 0;
+}
+
+static void __devexit
+amd_nb_remove(struct pci_dev *pdev)
+{
+}
+
+
+
+
+/*
+ * Configures the AMD-762 northbridge to support PM calls
+ */
+static int
+config_amd762(int enable)
+{
+	unsigned int regdword;
+
+	/* Enable STPGNT in BIU Status/Control for cpu0 */
+	pci_read_config_dword(pdev_nb, 0x60, &regdword);
+	regdword |= (1 << 17);
+	pci_write_config_dword(pdev_nb, 0x60, regdword);
+
+	/* Enable STPGNT in BIU Status/Control for cpu1 */
+	pci_read_config_dword(pdev_nb, 0x68, &regdword);
+	regdword |= (1 << 17);
+	pci_write_config_dword(pdev_nb, 0x68, regdword);
+
+	/* DRAM refresh enable */
+	pci_read_config_dword(pdev_nb, 0x58, &regdword);
+	regdword &= ~(1 << 19);
+	pci_write_config_dword(pdev_nb, 0x58, regdword);
+
+	/* Self refresh enable */
+	pci_read_config_dword(pdev_nb, 0x70, &regdword);
+	regdword |= (1 << 18);
+	pci_write_config_dword(pdev_nb, 0x70, regdword);
+
+	return 0;
+}
+
+
+/*
+ * Get the base PMIO address and set the pm registers in amd76x_pm_cfg.
+ */
+static void
+amd76x_get_PM(void)
+{
+	unsigned int regdword;
+
+	/* Get the address for pm status, P_LVL2, etc */
+	pci_read_config_dword(pdev_sb, 0x58, &regdword);
+	regdword &= 0xff80;
+	amd76x_pm_cfg.status_reg = (regdword + 0x00);
+	amd76x_pm_cfg.slp_reg =    (regdword + 0x04);
+	amd76x_pm_cfg.NTH_reg =    (regdword + 0x10);
+	amd76x_pm_cfg.C2_reg =     (regdword + 0x14);
+	amd76x_pm_cfg.C3_reg =     (regdword + 0x15);
+	amd76x_pm_cfg.resume_reg = (regdword + 0x16); /* N/A for 768 */
+}
+
+
+/*
+ * En/Disable PMIO and configure W4SG & STPGNT.
+ */
+static int
+config_PMIO_amd76x(int is_766, int enable)
+{
+	unsigned char regbyte;
+
+	/* Clear W4SG, and set PMIOEN, if using a 765/766 set STPGNT as well.
+	 * AMD-766: C3A41; page 59 in AMD-766 doc
+	 * AMD-768: DevB:3x41C; page 94 in AMD-768 doc */
+	pci_read_config_byte(pdev_sb, 0x41, &regbyte);
+	if(enable) {
+		regbyte |= ((0 << 0) | (is_766?1:0 << 1) | (1 << 7));
+	}
+	else {
+		regbyte |= (0 << 7);
+	}
+	pci_write_config_byte(pdev_sb, 0x41, regbyte);
+	return 0;
+}
+
+/*
+ * C2 idle support for AMD-766.
+ */
+static void
+config_amd766_C2(int enable)
+{
+	unsigned int regdword;
+
+	/* Set C2 options in C3A50, page 63 in AMD-766 doc */
+	pci_read_config_dword(pdev_sb, 0x50, &regdword);
+	if(enable) {
+		regdword &= ~((DCSTOP_EN | CPUSTP_EN | PCISTP_EN | SUSPND_EN |
+					CPURST_EN) << C2_REGS);
+		regdword |= (STPCLK_EN	/* ~ 20 Watt savings max */
+			 |  CPUSLP_EN)	/* Additional ~ 70 Watts max! */
+			 << C2_REGS;
+	}
+	else
+		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, &regdword);
+	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, &regdword);
+	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.
+ */
+static int
+config_amd766(int enable)
+{
+	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;
+}
+
+
+/*
+ * C2 idling support for AMD-768.
+ */
+static void
+config_amd768_C2(int enable)
+{
+	unsigned char regbyte;
+
+	/* Set C2 options in DevB:3x4F, page 100 in AMD-768 doc */
+	pci_read_config_byte(pdev_sb, 0x4F, &regbyte);
+	if(enable)
+		regbyte |= C2EN;
+	else
+		regbyte ^= C2EN;
+	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, &regbyte);
+	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, &regdword);
+	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, &regbyte);
+	/* 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.
+ */
+static int
+config_amd768(int enable)
+{
+	amd76x_get_PM();
+
+	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
+
+
+/*
+ * 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);
+}
+
+
+#ifdef AMD76X_POS
+/*
+ * Wrapper function to activate POS sleep state.
+ */
+static void
+activate_amd76x_POS(void)
+{
+	activate_amd76x_SLP(1);
+}
+#endif
+
+
+#if 0
+/*
+ * Idle loop for single processor systems
+ */
+void
+amd76x_up_idle(void)
+{
+	// FIXME: Optionally add non-smp idle loop here
+}
+#endif
+
+
+/*
+ * Idle loop for SMP systems, supports currently only 2 processors.
+ *
+ * Note; for 2.5 folks - not pre-empt safe
+ */
+static void
+amd76x_smp_idle(void)
+{
+	/*
+	 * Exit idle mode immediately if the CPU does not change.
+	 * Usually that means that we have some load on another CPU.
+	 */
+
+	if (prs[0].idle && prs[1].idle && amd76x_pm_cfg.last_pr == smp_processor_id()) {
+		prs[0].idle = 0;
+		prs[1].idle = 0;
+		/* This looks redundent as it was just checked in the if() */
+		/* amd76x_pm_cfg.last_pr = smp_processor_id(); */
+		return;
+	}
+
+	prs[smp_processor_id()].count++;
+
+	/* Don't start the idle mode immediately */
+	// if (prs[smp_processor_id()].count >= LAZY_IDLE_DELAY) {
+	if (prs[smp_processor_id()].count >= amd76x_pm_cfg.lazy_idle) {
+	    // if (prs[smp_processor_id()].count >= 100) {
+
+		/* Put the current processor into idle mode */
+		prs[smp_processor_id()].idle =
+			(prs[smp_processor_id()].idle ? 2 : 1);
+
+		/* Only idle if both processors are idle */
+		if ((prs[0].idle==1) && (prs[1].idle==1)) {
+			amd76x_pm_cfg.C2_cnt++;
+			inb(amd76x_pm_cfg.C2_reg);
+		}
+	#ifdef AMD76X_C3
+		/*
+		 * JH: I've not been able to get into here. Could this have
+		 * something to do with the way the kernel handles the idle
+		 * loop, or and error that I've made?
+		 */
+		else if ((prs[0].idle==2) && (prs[1].idle==2)) {
+			amd76x_pm_cfg.C3_cnt++;
+			inb(amd76x_pm_cfg.C3_reg);
+		}
+	#endif
+
+		prs[smp_processor_id()].count = 0;
+
+	}
+	amd76x_pm_cfg.last_pr = smp_processor_id();
+}
+
+/*
+ *    Info exported through "/proc/driver/amd76x_pm"
+ */
+static int amd76x_pm_proc_output (char *buf)
+{
+    char *p = buf;
+    p += sprintf(p, "%lu\n", amd76x_pm_cfg.C2_cnt);
+    return p - buf;
+}
+
+static int amd76x_pm_read_proc(char *page, char **start, off_t off,
+			       int count, int *eof, void *data)
+{
+    int len = amd76x_pm_proc_output(page);
+    if (len <= off+count) *eof = 1;
+    *start = page+off;
+    len -= off;
+    if(len>count) len = count;
+    if(len<0) len=0;
+    return len;
+}
+/*
+ * Finds and initializes the bridges, and then sets the idle function
+ */
+static int
+amd76x_pm_main(void)
+{
+	int found;
+	amd76x_pm_cfg.orig_idle = 0;
+	amd76x_pm_cfg.lazy_idle = LAZY_IDLE_DELAY;	
+
+	spin_lock_init(&amd76x_pm_lock);
+
+	/* Find northbridge */
+	found = pci_module_init(&amd_nb_driver);
+	if (found < 0) {
+		printk(KERN_ERR "amd76x_pm: Could not find northbridge\n");
+		return 1;
+	}
+
+	/* Find southbridge */
+	pci_for_each_dev(pdev_sb) {
+	    if(pci_match_device(amd_sb_tbl, pdev_sb) != NULL)
+		goto found_sb;
+	}
+	printk(KERN_ERR "amd76x_pm: Could not find southbridge\n");
+	return -ENODEV;
+
+ found_sb:
+	
+	if(!pdev_sb)
+	    return -ENODEV;
+
+	/* Init southbridge */
+	switch (pdev_sb->device) {
+	case PCI_DEVICE_ID_AMD_VIPER_7413:	/* AMD-765 or 766 */
+		config_amd766(1);
+		break;
+	case PCI_DEVICE_ID_AMD_VIPER_7443:	/* AMD-768 */
+		config_amd768(1);
+		break;
+	default:
+		printk(KERN_ERR "amd76x_pm: No southbridge to initialize\n");
+		break;
+	}
+
+	/* Init northbridge and queue the new idle function */
+	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 (!amd76x_pm_cfg.curr_idle) {
+		printk(KERN_ERR "amd76x_pm: Idle function not changed\n");
+		return 1;
+	}
+
+	amd76x_pm_cfg.orig_idle = pm_idle;
+	pm_idle = amd76x_pm_cfg.curr_idle;
+	wmb();
+	
+	/* proc IF */
+	create_proc_read_entry("driver/amd76x_pm", 
+			       0, 0, amd76x_pm_read_proc, NULL);
+
+#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
+
+	return 0;
+}
+
+
+static int __init
+amd76x_pm_init(void)
+{
+	printk(KERN_INFO "amd76x_pm: Version %s\n", VERSION);
+	return amd76x_pm_main();
+}
+
+
+static void __exit
+amd76x_pm_cleanup(void)
+{
+#ifndef AMD76X_NTH
+	pm_idle = amd76x_pm_cfg.orig_idle;
+	wmb();
+	//__asm__ __volatile__ ("wbinvd;"); // propagate through SMP
+
+	/* This isn't really needed. */
+	printk(KERN_INFO "amd76x_pm: %lu C2 calls\n", amd76x_pm_cfg.C2_cnt);
+
+#ifdef AMD76X_C3
+	printk(KERN_INFO "amd76x_pm: %lu C3 calls\n", amd76x_pm_cfg.C3_cnt);
+#endif
+
+	remove_proc_entry("driver/amd76x_pm", NULL);
+
+	/* 
+	 * FIXME: We want to wait until all CPUs have set the new
+	 * idle function, otherwise we will oops. This may not be
+	 * the right way to do it, but seems to work.
+	 *
+	 * - Best answer is going to be to ban unload, but when its debugged
+	 *   --- Alan
+	 */
+	schedule();
+	mdelay(1000);
+#endif
+
+#ifdef AMD76X_NTH
+	/* Turn NTH off*/
+	activate_amd76x_NTH(0, 0);
+#endif
+
+	pci_unregister_driver(&amd_nb_driver);
+}
+
+
+MODULE_LICENSE("GPL");
+module_init(amd76x_pm_init);
+module_exit(amd76x_pm_cleanup);
diff -Nru linux-2.5.70/include/linux/amd76x_pm.h linux-2.5.70-mod/include/linux/amd76x_pm.h
--- linux-2.5.70/include/linux/amd76x_pm.h	1970-01-01 02:00:00.000000000 +0200
+++ linux-2.5.70-mod/include/linux/amd76x_pm.h	2003-05-31 20:23:04.000000000 +0300
@@ -0,0 +1,59 @@
+/* 
+ * Begin 765/766
+ */
+/* C2/C3/POS options in C3A50, page 63 in AMD-766 doc */
+#define ZZ_CACHE_EN	1
+#define DCSTOP_EN	(1 << 1)
+#define STPCLK_EN	(1 << 2)
+#define CPUSTP_EN	(1 << 3)
+#define PCISTP_EN	(1 << 4)
+#define CPUSLP_EN	(1 << 5)
+#define SUSPND_EN	(1 << 6)
+#define CPURST_EN	(1 << 7)
+
+#define C2_REGS		0
+#define C3_REGS		8
+#define POS_REGS	16	
+/*
+ * End 765/766
+ */
+
+
+/*
+ * Begin 768
+ */
+/* C2/C3 options in DevB:3x4F, page 100 in AMD-768 doc */
+#define C2EN		1
+#define C3EN		(1 << 1)
+#define ZZ_C3EN		(1 << 2)
+#define CSLP_C3EN	(1 << 3)
+#define CSTP_C3EN	(1 << 4)
+
+/* POS options in DevB:3x50, page 101 in AMD-768 doc */
+#define POSEN	1
+#define CSTP	(1 << 2)
+#define PSTP	(1 << 3)
+#define ASTP	(1 << 4)
+#define DCSTP	(1 << 5)
+#define CSLP	(1 << 6)
+#define SUSP	(1 << 8)
+#define MSRSM	(1 << 14)
+#define PITRSM	(1 << 15)
+
+/* NTH options DevB:3x40, pg 93 of 768 doc */
+#define NTPER(x) (x << 3)
+#define THMINEN(x) (x << 4)
+
+/*
+ * End 768
+ */
+
+/* NTH activate. PM10, pg 110 of 768 doc, pg 70 of 766 doc */
+#define NTH_RATIO(x) (x << 1)
+#define NTH_EN (1 << 4)
+
+/* Sleep state. PM04, pg 109 of 768 doc, pg 69 of 766 doc */
+#define SLP_EN (1 << 13)
+#define SLP_TYP(x) (x << 10)
+
+#define LAZY_IDLE_DELAY	800	/* 0: Best savings,  3000: More responsive */


-- 
Psi -- <http://iki.fi/psavo>

Re: [PATCH] amd76x_pm port to 2.5.70

[Zwane Mwaikambo]

On Sat, 31 May 2003, Pasi Savolainen wrote:

> Attached is a simplistic port of amd76x_pm to 2.5.70.
> There is a mention about being non-preempt safe, and I can't tell
> spinlock from semaphore, so can do nada about it.
> zwane told me on #kernelnewbies that 
> 
>   pm_idle = old_pm_idle; wmb();
> 
> should take care about the processor syncing, but I do get total hangs
> on rmmod.

pm_idle = NULL_or_previous_handler;
synchronize_kernel();
unload_module;

> +amd76x_up_idle(void)
> +{
> +	// FIXME: Optionally add non-smp idle loop here
> +}
> +#endif

This is going to really suck power wise, at least do a rep_nop or some 
such otherwise you spin in a tight polling loop around need_resched.

> +static void
> +amd76x_smp_idle(void)
> +{
> +	/*
> +	 * Exit idle mode immediately if the CPU does not change.
> +	 * Usually that means that we have some load on another CPU.
> +	 */
> +
> +	if (prs[0].idle && prs[1].idle && amd76x_pm_cfg.last_pr == smp_processor_id()) {
> +		prs[0].idle = 0;
> +		prs[1].idle = 0;
> +		/* This looks redundent as it was just checked in the if() */
> +		/* amd76x_pm_cfg.last_pr = smp_processor_id(); */

One is a comparison the other an assignment, what's going on here?

> +static void __exit
> +amd76x_pm_cleanup(void)
> +{
> +#ifndef AMD76X_NTH
> +	pm_idle = amd76x_pm_cfg.orig_idle;
> +	wmb();
> +	//__asm__ __volatile__ ("wbinvd;"); // propagate through SMP

synchronize_kernel() here, then you should be safe to unload.

-- 
function.linuxpower.ca

Re: [PATCH] amd76x_pm port to 2.5.70

[Dave Jones]

On Sat, May 31, 2003 at 09:33:21PM +0300, Pasi Savolainen wrote:
 > +	/* Clear W4SG, and set PMIOEN, if using a 765/766 set STPGNT as well.
 > +	 * AMD-766: C3A41; page 59 in AMD-766 doc
 > +	 * AMD-768: DevB:3x41C; page 94 in AMD-768 doc */
 > +	pci_read_config_byte(pdev_sb, 0x41, &regbyte);
 > +	if(enable) {
 > +		regbyte |= ((0 << 0) | (is_766?1:0 << 1) | (1 << 7));
                         ^^^^^^
 
This looks totally bogus. If you want that bit clearing, you need
to AND its inverse, not OR it.  The second statement also looks a
bit funny to the eye.
								 
 > +	}
 > +	else {
 > +		regbyte |= (0 << 7);

Ditto.
 
 > +/*
 > + * Idle loop for SMP systems, supports currently only 2 processors.
 > + *
 > + * Note; for 2.5 folks - not pre-empt safe

Indeed.

 > +static void
 > +amd76x_smp_idle(void)
 > +{
 > +	/*
 > +	 * Exit idle mode immediately if the CPU does not change.
 > +	 * Usually that means that we have some load on another CPU.
 > +	 */
 > +
 > +	if (prs[0].idle && prs[1].idle && amd76x_pm_cfg.last_pr == smp_processor_id()) {
 > +		prs[0].idle = 0;
 > +		prs[1].idle = 0;
 > +		/* This looks redundent as it was just checked in the if() */
 > +		/* amd76x_pm_cfg.last_pr = smp_processor_id(); */

except with preemption, it may have changed. This needs to be fixed,
as noted in the function header. Either get_cpu(),put_cpu() or explicit
preempt_enable/disable()		

 > +
 > +/*
 > + *    Info exported through "/proc/driver/amd76x_pm"

This should really be using sysfs. Adding extra junk to /proc is
somewhat frowned upon, and with the other PM stuff now living in
sysfs, that seems to be the way forward.

 > +static void __exit
 > +amd76x_pm_cleanup(void)
 > +{
 > +#ifndef AMD76X_NTH
 > +	pm_idle = amd76x_pm_cfg.orig_idle;
 > +	wmb();
 > +	//__asm__ __volatile__ ("wbinvd;"); // propagate through SMP

Not sure why this was there, is it noted in the 766 spec to flush
the cache ? if so, it needs to be reenabled, and used with on_each_cpu()

 > +	/* 
 > +	 * FIXME: We want to wait until all CPUs have set the new
 > +	 * idle function, otherwise we will oops. This may not be
 > +	 * the right way to do it, but seems to work.
 > +	 *
 > +	 * - Best answer is going to be to ban unload, but when its debugged
 > +	 *   --- Alan
 > +	 */
 > +	schedule();
 > +	mdelay(1000);

Ummmm, oh-kay. That's a little funky. Look at how the MTRR driver
does its synchronisation, it maybe sucky, but it looks a little
cleaner than this IMO.


 > +#define LAZY_IDLE_DELAY	800	/* 0: Best savings,  3000: More responsive */

Sounds like possible candidate for something that should be exposed
via sysfs.


		Dave

Re: [PATCH] amd76x_pm port to 2.5.70

[Pasi Savolainen]

* Dave Jones <davej@codemonkey.org.uk>:
> On Sat, May 31, 2003 at 09:33:21PM +0300, Pasi Savolainen wrote:
> > +	/* Clear W4SG, and set PMIOEN, if using a 765/766 set STPGNT as well.
> > +	 * AMD-766: C3A41; page 59 in AMD-766 doc
> > +	 * AMD-768: DevB:3x41C; page 94 in AMD-768 doc */
> > +	pci_read_config_byte(pdev_sb, 0x41, &regbyte);
> > +	if(enable) {
> > +		regbyte |= ((0 << 0) | (is_766?1:0 << 1) | (1 << 7));
>                          ^^^^^^
>  
> This looks totally bogus. If you want that bit clearing, you need
> to AND its inverse, not OR it.  The second statement also looks a
> bit funny to the eye.

AFAICT, it's 'for future expansion', NMC. I'll trim it down. Either way,
that enable seems to work, at least on my machine. As I don't know much
about it, I can't say what's right/wrong.
(I don't have the spec. Only code that does desired thing)

> > +static void
> > +amd76x_smp_idle(void)
> > +{
> > +	/*
> > +	 * Exit idle mode immediately if the CPU does not change.
> > +	 * Usually that means that we have some load on another CPU.
> > +	 */
> > +
> > +	if (prs[0].idle && prs[1].idle && amd76x_pm_cfg.last_pr == smp_processor_id()) {
> > +		prs[0].idle = 0;
> > +		prs[1].idle = 0;
> > +		/* This looks redundent as it was just checked in the if() */
> > +		/* amd76x_pm_cfg.last_pr = smp_processor_id(); */
> 
> except with preemption, it may have changed. This needs to be fixed,
> as noted in the function header. Either get_cpu(),put_cpu() or explicit
> preempt_enable/disable()		

This is idle loop, like we're not doing anything, and if somebody is to
preempt us, then it sure means we're not supposed to idle.

Second point is (I'm _really_ on thin ground here..) that if we get_cpu()
here, and other CPU is sleeping, then it'd be woken up sooner, for cache
will need syncing.

> > +/*
> > + *    Info exported through "/proc/driver/amd76x_pm"
> 
> This should really be using sysfs. Adding extra junk to /proc is
> somewhat frowned upon, and with the other PM stuff now living in
> sysfs, that seems to be the way forward.

done.

> 
> > +static void __exit
> > +amd76x_pm_cleanup(void)
> > +{
> > +#ifndef AMD76X_NTH
> > +	pm_idle = amd76x_pm_cfg.orig_idle;
> > +	wmb();
> > +	//__asm__ __volatile__ ("wbinvd;"); // propagate through SMP
> 
> Not sure why this was there, is it noted in the 766 spec to flush
> the cache ? if so, it needs to be reenabled, and used with on_each_cpu()

Zwane told me to use synchronize_kernel(); it cured my crashes on rmmod
amd76x_pm. -> hack removed.

> Sounds like possible candidate for something that should be exposed
> via sysfs.

done.

Iteration n at
<http://varg.dyndns.org/psi/files/misc/amd76x_pm-2.5.70.patch.bz2>

/sys/devices/pci0/00:00.0/C2_cnt  (ro) number of C2 calls made.
/sys/devices/pci0/00:00.0/lazy_idle (rw) number of successfull idle
 calls to be made before entering C2.


-- 
   Psi -- <http://www.iki.fi/pasi.savolainen>

Re: [PATCH] amd76x_pm port to 2.5.70

[Jason Lunz]

psavo@iki.fi said:
> +++ linux-2.5.70-mod/drivers/char/amd76x_pm.c	2003-05-31 20:55:37.000000000 +0300

What is this thing doing in drivers/char? It has nothing whatsoever to
do with char devices. Couldn't this be handled by the ACPI idle loop?

Jason

Re: [PATCH] amd76x_pm port to 2.5.70

[Alan Cox]

On Sul, 2003-06-01 at 16:27, Jason Lunz wrote:
> psavo@iki.fi said:
> > +++ linux-2.5.70-mod/drivers/char/amd76x_pm.c	2003-05-31 20:55:37.000000000 +0300
> 
> What is this thing doing in drivers/char? It has nothing whatsoever to
> do with char devices. Couldn't this be handled by the ACPI idle loop?

RTFS 8)

Its an alternative driver to the ACPI driver. I'm not sure where it
should go but in 2.4 its in drivers/char. 2.5.x puts the other PM
drivers in arch/i386 so maybe that is where it belongs