powernow-k8.c

linux-2.6.15.6

/*
 *   (c) 2003, 2004, 2005 Advanced Micro Devices, Inc.
 *  Your use of this code is subject to the terms and conditions of the
 *  GNU general public license version 2. See "COPYING" or
 *  http://www.gnu.org/licenses/gpl.html
 *
 *  Support : [e-mail]
 *
 *  Based on the powernow-k7.c module written by Dave Jones.
 *  (C) 2003 Dave Jones <[e-mail]> on behalf of SuSE Labs
 *  (C) 2004 Dominik Brodowski <[e-mail]>
 *  (C) 2004 Pavel Machek <[e-mail]>
 *  Licensed under the terms of the GNU GPL License version 2.
 *  Based upon datasheets & sample CPUs kindly provided by AMD.
 *
 *  Valuable input gratefully received from Dave Jones, Pavel Machek,
 *  Dominik Brodowski, and others.
 *  Originally developed by Paul Devriendt.
 *  Processor information obtained from Chapter 9 (Power and Thermal Management)
 *  of the "BIOS and Kernel Developer's Guide for the AMD Athlon 64 and AMD
 *  Opteron Processors" available for download from www.amd.com
 *
 *  Tables for specific CPUs can be infrerred from
 *     http://www.amd.com/us-en/assets/content_type/white_papers_and_tech_docs/30430.pdf
 */

#include <linux/kernel.h>
#include <linux/smp.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/cpumask.h>
#include <linux/sched.h>	/* for current / set_cpus_allowed() */

#include <asm/msr.h>
#include <asm/io.h>
#include <asm/delay.h>

#ifdef CONFIG_X86_POWERNOW_K8_ACPI
#include <linux/acpi.h>
#include <acpi/processor.h>
#endif

#define PFX "powernow-k8: "
#define BFX PFX "BIOS error: "
#define VERSION "version 1.50.4"
#include "powernow-k8.h"

/* serialize freq changes  */
static DECLARE_MUTEX(fidvid_sem);

static struct powernow_k8_data *powernow_data[NR_CPUS];

#ifndef CONFIG_SMP
static cpumask_t cpu_core_map[1];
#endif

/* Return a frequency in MHz, given an input fid */
static u32 find_freq_from_fid(u32 fid)
{
	return 800 + (fid * 100);
}

/* Return a frequency in KHz, given an input fid */
static u32 find_khz_freq_from_fid(u32 fid)
{
	return 1000 * find_freq_from_fid(fid);
}

/* Return a voltage in miliVolts, given an input vid */
static u32 find_millivolts_from_vid(struct powernow_k8_data *data, u32 vid)
{
	return 1550-vid*25;
}

/* Return the vco fid for an input fid
 *
 * Each "low" fid has corresponding "high" fid, and you can get to "low" fids
 * only from corresponding high fids. This returns "high" fid corresponding to
 * "low" one.
 */
static u32 convert_fid_to_vco_fid(u32 fid)
{
	if (fid < HI_FID_TABLE_BOTTOM) {
		return 8 + (2 * fid);
	} else {
		return fid;
	}
}

/*
 * Return 1 if the pending bit is set. Unless we just instructed the processor
 * to transition to a new state, seeing this bit set is really bad news.
 */
static int pending_bit_stuck(void)
{
	u32 lo, hi;

	rdmsr(MSR_FIDVID_STATUS, lo, hi);
	return lo & MSR_S_LO_CHANGE_PENDING ? 1 : 0;
}

/*
 * Update the global current fid / vid values from the status msr.
 * Returns 1 on error.
 */
static int query_current_values_with_pending_wait(struct powernow_k8_data *data)
{
	u32 lo, hi;
	u32 i = 0;

	do {
		if (i++ > 10000) {
			dprintk("detected change pending stuck\n");
			return 1;
		}
		rdmsr(MSR_FIDVID_STATUS, lo, hi);
	} while (lo & MSR_S_LO_CHANGE_PENDING);

	data->currvid = hi & MSR_S_HI_CURRENT_VID;
	data->currfid = lo & MSR_S_LO_CURRENT_FID;

	return 0;
}

/* the isochronous relief time */
static void count_off_irt(struct powernow_k8_data *data)
{
	udelay((1 << data->irt) * 10);
	return;
}

/* the voltage stabalization time */
static void count_off_vst(struct powernow_k8_data *data)
{
	udelay(data->vstable * VST_UNITS_20US);
	return;
}

/* need to init the control msr to a safe value (for each cpu) */
static void fidvid_msr_init(void)
{
	u32 lo, hi;
	u8 fid, vid;

	rdmsr(MSR_FIDVID_STATUS, lo, hi);
	vid = hi & MSR_S_HI_CURRENT_VID;
	fid = lo & MSR_S_LO_CURRENT_FID;
	lo = fid | (vid << MSR_C_LO_VID_SHIFT);
	hi = MSR_C_HI_STP_GNT_BENIGN;
	dprintk("cpu%d, init lo 0x%x, hi 0x%x\n", smp_processor_id(), lo, hi);
	wrmsr(MSR_FIDVID_CTL, lo, hi);
}


/* write the new fid value along with the other control fields to the msr */
static int write_new_fid(struct powernow_k8_data *data, u32 fid)
{
	u32 lo;
	u32 savevid = data->currvid;
	u32 i = 0;

	if ((fid & INVALID_FID_MASK) || (data->currvid & INVALID_VID_MASK)) {
		printk(KERN_ERR PFX "internal error - overflow on fid write\n");
		return 1;
	}

	lo = fid | (data->currvid << MSR_C_LO_VID_SHIFT) | MSR_C_LO_INIT_FID_VID;

	dprintk("writing fid 0x%x, lo 0x%x, hi 0x%x\n",
		fid, lo, data->plllock * PLL_LOCK_CONVERSION);

	do {
		wrmsr(MSR_FIDVID_CTL, lo, data->plllock * PLL_LOCK_CONVERSION);
		if (i++ > 100) {
			printk(KERN_ERR PFX "internal error - pending bit very stuck - no further pstate changes possible\n");
			return 1;
		}			
	} while (query_current_values_with_pending_wait(data));

	count_off_irt(data);

	if (savevid != data->currvid) {
		printk(KERN_ERR PFX "vid change on fid trans, old 0x%x, new 0x%x\n",
		       savevid, data->currvid);
		return 1;
	}

	if (fid != data->currfid) {
		printk(KERN_ERR PFX "fid trans failed, fid 0x%x, curr 0x%x\n", fid,
		        data->currfid);
		return 1;
	}

	return 0;
}

/* Write a new vid to the hardware */
static int write_new_vid(struct powernow_k8_data *data, u32 vid)
{
	u32 lo;
	u32 savefid = data->currfid;
	int i = 0;

	if ((data->currfid & INVALID_FID_MASK) || (vid & INVALID_VID_MASK)) {
		printk(KERN_ERR PFX "internal error - overflow on vid write\n");
		return 1;
	}

	lo = data->currfid | (vid << MSR_C_LO_VID_SHIFT) | MSR_C_LO_INIT_FID_VID;

	dprintk("writing vid 0x%x, lo 0x%x, hi 0x%x\n",
		vid, lo, STOP_GRANT_5NS);

	do {
		wrmsr(MSR_FIDVID_CTL, lo, STOP_GRANT_5NS);
                if (i++ > 100) {
                        printk(KERN_ERR PFX "internal error - pending bit very stuck - no further pstate changes possible\n");
                        return 1;
                }
	} while (query_current_values_with_pending_wait(data));

	if (savefid != data->currfid) {
		printk(KERN_ERR PFX "fid changed on vid trans, old 0x%x new 0x%x\n",
		       savefid, data->currfid);
		return 1;
	}

	if (vid != data->currvid) {
		printk(KERN_ERR PFX "vid trans failed, vid 0x%x, curr 0x%x\n", vid,
				data->currvid);
		return 1;
	}

	return 0;
}

/*
 * Reduce the vid by the max of step or reqvid.
 * Decreasing vid codes represent increasing voltages:
 * vid of 0 is 1.550V, vid of 0x1e is 0.800V, vid of VID_OFF is off.
 */
static int decrease_vid_code_by_step(struct powernow_k8_data *data, u32 reqvid, u32 step)
{
	if ((data->currvid - reqvid) > step)
		reqvid = data->currvid - step;

	if (write_new_vid(data, reqvid))
		return 1;

	count_off_vst(data);

	return 0;
}

/* Change the fid and vid, by the 3 phases. */
static int transition_fid_vid(struct powernow_k8_data *data, u32 reqfid, u32 reqvid)
{
	if (core_voltage_pre_transition(data, reqvid))
		return 1;

	if (core_frequency_transition(data, reqfid))
		return 1;

	if (core_voltage_post_transition(data, reqvid))
		return 1;

	if (query_current_values_with_pending_wait(data))
		return 1;

	if ((reqfid != data->currfid) || (reqvid != data->currvid)) {
		printk(KERN_ERR PFX "failed (cpu%d): req 0x%x 0x%x, curr 0x%x 0x%x\n",
				smp_processor_id(),
				reqfid, reqvid, data->currfid, data->currvid);
		return 1;
	}

	dprintk("transitioned (cpu%d): new fid 0x%x, vid 0x%x\n",
		smp_processor_id(), data->currfid, data->currvid);

	return 0;
}

/* Phase 1 - core voltage transition ... setup voltage */
static int core_voltage_pre_transition(struct powernow_k8_data *data, u32 reqvid)
{
	u32 rvosteps = data->rvo;
	u32 savefid = data->currfid;
	u32 maxvid, lo;

	dprintk("ph1 (cpu%d): start, currfid 0x%x, currvid 0x%x, reqvid 0x%x, rvo 0x%x\n",
		smp_processor_id(),
		data->currfid, data->currvid, reqvid, data->rvo);

	rdmsr(MSR_FIDVID_STATUS, lo, maxvid);
	maxvid = 0x1f & (maxvid >> 16);
	dprintk("ph1 maxvid=0x%x\n", maxvid);
	if (reqvid < maxvid) /* lower numbers are higher voltages */
		reqvid = maxvid;

	while (data->currvid > reqvid) {
		dprintk("ph1: curr 0x%x, req vid 0x%x\n",
			data->currvid, reqvid);
		if (decrease_vid_code_by_step(data, reqvid, data->vidmvs))
			return 1;
	}

	while ((rvosteps > 0) && ((data->rvo + data->currvid) > reqvid)) {
		if (data->currvid == maxvid) {
			rvosteps = 0;
		} else {
			dprintk("ph1: changing vid for rvo, req 0x%x\n",
				data->currvid - 1);
			if (decrease_vid_code_by_step(data, data->currvid - 1, 1))
				return 1;
			rvosteps--;
		}
	}

	if (query_current_values_with_pending_wait(data))
		return 1;

	if (savefid != data->currfid) {
		printk(KERN_ERR PFX "ph1 err, currfid changed 0x%x\n", data->currfid);
		return 1;
	}

	dprintk("ph1 complete, currfid 0x%x, currvid 0x%x\n",
		data->currfid, data->currvid);

	return 0;
}

/* Phase 2 - core frequency transition */
static int core_frequency_transition(struct powernow_k8_data *data, u32 reqfid)
{
	u32 vcoreqfid, vcocurrfid, vcofiddiff, savevid = data->currvid;

	if ((reqfid < HI_FID_TABLE_BOTTOM) && (data->currfid < HI_FID_TABLE_BOTTOM)) {
		printk(KERN_ERR PFX "ph2: illegal lo-lo transition 0x%x 0x%x\n",
			reqfid, data->currfid);
		return 1;
	}

	if (data->currfid == reqfid) {
		printk(KERN_ERR PFX "ph2 null fid transition 0x%x\n", data->currfid);
		return 0;
	}

	dprintk("ph2 (cpu%d): starting, currfid 0x%x, currvid 0x%x, reqfid 0x%x\n",
		smp_processor_id(),
		data->currfid, data->currvid, reqfid);

	vcoreqfid = convert_fid_to_vco_fid(reqfid);
	vcocurrfid = convert_fid_to_vco_fid(data->currfid);
	vcofiddiff = vcocurrfid > vcoreqfid ? vcocurrfid - vcoreqfid
	    : vcoreqfid - vcocurrfid;

	while (vcofiddiff > 2) {
		if (reqfid > data->currfid) {
			if (data->currfid > LO_FID_TABLE_TOP) {
				if (write_new_fid(data, data->currfid + 2)) {
					return 1;
				}
			} else {
				if (write_new_fid
				    (data, 2 + convert_fid_to_vco_fid(data->currfid))) {
					return 1;
				}
			}
		} else {
			if (write_new_fid(data, data->currfid - 2))
				return 1;
		}

		vcocurrfid = convert_fid_to_vco_fid(data->currfid);
		vcofiddiff = vcocurrfid > vcoreqfid ? vcocurrfid - vcoreqfid
		    : vcoreqfid - vcocurrfid;
	}

	if (write_new_fid(data, reqfid))
		return 1;

	if (query_current_values_with_pending_wait(data))
		return 1;

	if (data->currfid != reqfid) {
		printk(KERN_ERR PFX
			"ph2: mismatch, failed fid transition, curr 0x%x, req 0x%x\n",