longhaul.c

这个linux源代码是很全面的~基本完整了~使用c编译的~由于时间问题我没有亲自测试~但就算用来做参考资料也是非常好的

			lo &= ~(1<<28|1<<29);
			switch (newfsb) {
				case 66:	lo |= (1<<28|1<<29); /* 11 */
							break;
				case 100:	lo |= 1<<28;	/* 01 */
							break;
				case 133:	break;	/* 00*/
			}
		}
		wrmsr (MSR_VIA_LONGHAUL, lo, hi);
		__hlt();

		rdmsr (MSR_VIA_LONGHAUL, lo, hi);
		lo &= ~(1<<8);
		lo |= revkey;
		wrmsr (MSR_VIA_LONGHAUL, lo, hi);
		break;
	}

	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}


static void __init longhaul_get_ranges (void)
{
	unsigned long lo, hi, invalue;
	unsigned int minmult=0, maxmult=0, minfsb=0, maxfsb=0;
	unsigned int multipliers[32]= {
		50,30,40,100,55,35,45,95,90,70,80,60,120,75,85,65,
		-1,110,120,-1,135,115,125,105,130,150,160,140,-1,155,-1,145 };
	unsigned int fsb_table[4] = { 133, 100, -1, 66 };

	switch (longhaul) {
	case 1:
		/* Ugh, Longhaul v1 didn't have the min/max MSRs.
		   Assume min=3.0x & max = whatever we booted at. */
		minmult = 30;
		maxmult = longhaul_get_cpu_mult();
		minfsb = maxfsb = current_fsb;
		break;

	case 2 ... 3:
		rdmsr (MSR_VIA_LONGHAUL, lo, hi);

		invalue = (hi & (1<<0|1<<1|1<<2|1<<3));
		if (hi & (1<<11))
			invalue += 16;
		maxmult=multipliers[invalue];

#if 0	/* This is MaxMhz @ Min Voltage. Ignore for now */
		invalue = (hi & (1<<16|1<<17|1<<18|1<<19)) >> 16;
		if (hi & (1<<27))
		invalue += 16;
		minmult = multipliers[invalue];
#else
		minmult = 30; /* as per spec */
#endif

		if (can_scale_fsb==1) {
			invalue = (hi & (1<<9|1<<10)) >> 9;
			maxfsb = fsb_table[invalue];

			invalue = (hi & (1<<25|1<<26)) >> 25;
			minfsb = fsb_table[invalue];

			dprintk (KERN_INFO "longhaul: Min FSB=%d Max FSB=%d\n",
				minfsb, maxfsb);
		} else {
			minfsb = maxfsb = current_fsb;
		}
		break;
	}

	highest_speed = maxmult * maxfsb * 100;
	lowest_speed = minmult * minfsb * 100;

	dprintk (KERN_INFO "longhaul: MinMult(x10)=%d MaxMult(x10)=%d\n",
		minmult, maxmult);
	dprintk (KERN_INFO "longhaul: Lowestspeed=%d Highestspeed=%d\n",
		lowest_speed, highest_speed);
}


static void __init longhaul_setup_voltagescaling (unsigned long lo, unsigned long hi)
{
	int revkey;

	can_scale_voltage = 1;

	minvid = (hi & (1<<20|1<<21|1<<22|1<<23|1<<24)) >> 20; /* 56:52 */
	maxvid = (hi & (1<<4|1<<5|1<<6|1<<7|1<<8)) >> 4;       /* 40:36 */
	vrmrev = (lo & (1<<15))>>15;

	if (vrmrev==0) {
		dprintk (KERN_INFO "longhaul: VRM 8.5 : ");
		memcpy (voltage_table, vrm85scales, sizeof(voltage_table));
		numvscales = (voltage_table[maxvid]-voltage_table[minvid])/25;
	} else {
		dprintk (KERN_INFO "longhaul: Mobile VRM : ");
		memcpy (voltage_table, mobilevrmscales, sizeof(voltage_table));
		numvscales = (voltage_table[maxvid]-voltage_table[minvid])/5;
	}

	/* Current voltage isn't readable at first, so we need to
	   set it to a known value. The spec says to use maxvid */
	revkey = (lo & 0xf)<<4;	/* Rev key. */
	lo &= 0xfe0fff0f;	/* Mask unneeded bits */
	lo |= (1<<9);		/* EnableSoftVID */
	lo |= revkey;		/* Reinsert key */
	lo |= maxvid << 20;
	wrmsr (MSR_VIA_LONGHAUL, lo, hi);
	minvid = voltage_table[minvid];
	maxvid = voltage_table[maxvid];
	dprintk ("Min VID=%d.%03d Max VID=%d.%03d, %d possible voltage scales\n",
		maxvid/1000, maxvid%1000, minvid/1000, minvid%1000, numvscales);
}


static inline unsigned int longhaul_statecount_fsb(struct cpufreq_policy *policy, unsigned int fsb) {
	unsigned int i, count = 0;

	for(i=0; i<numscales; i++) {
		if ((clock_ratio[i] != -1) &&
		    ((clock_ratio[i] * fsb * 100) <= policy->max) &&
		    ((clock_ratio[i] * fsb * 100) >= policy->min))
			count++;
	}

	return count;
}


static int longhaul_verify(struct cpufreq_policy *policy)
{
	unsigned int    number_states = 0;
	unsigned int    i;
	unsigned int    fsb_index = 0;
	unsigned int    tmpfreq = 0;
	unsigned int    newmax = -1;

	if (!policy || !longhaul_driver)
		return -EINVAL;

	policy->cpu = 0;
	cpufreq_verify_within_limits(policy, lowest_speed, highest_speed);

	if (can_scale_fsb==1) {
		for (fsb_index=0; fsb_search_table[fsb_index]!=-1; fsb_index++)
			number_states += longhaul_statecount_fsb(policy, fsb_search_table[fsb_index]);
	} else
		number_states = longhaul_statecount_fsb(policy, current_fsb);

	if (number_states)
		return 0;

	/* get frequency closest above current policy->max */
	if (can_scale_fsb==1) {
		for (fsb_index=0; fsb_search_table[fsb_index] != -1; fsb_index++)
			for(i=0; i<numscales; i++) {
				if (clock_ratio[i] == -1)
					continue;

				tmpfreq = clock_ratio[i] * fsb_search_table[fsb_index];
				if ((tmpfreq > policy->max) &&
				    (tmpfreq < newmax))
					newmax = tmpfreq;
			}
	} else {
		for(i=0; i<numscales; i++) {
			if (clock_ratio[i] == -1)
				continue;

			tmpfreq = clock_ratio[i] * current_fsb;
			if ((tmpfreq > policy->max) &&
			    (tmpfreq < newmax))
				newmax = tmpfreq;
			}
	}

	policy->max = newmax;

	cpufreq_verify_within_limits(policy, lowest_speed, highest_speed);

	return 0;
}


static int longhaul_get_best_freq_for_fsb(struct cpufreq_policy *policy, 
					  unsigned int min_mult, 
					  unsigned int max_mult, 
					  unsigned int fsb, 
					  unsigned int *new_mult)
{
	unsigned int optimal = 0;
	unsigned int found_optimal = 0;
	unsigned int i;

	switch(policy->policy) {
	case CPUFREQ_POLICY_POWERSAVE:
		optimal = max_mult;
		break;
	case CPUFREQ_POLICY_PERFORMANCE:
		optimal = min_mult;
	}

	for(i=0; i<numscales; i++) {
		unsigned int freq = fsb * clock_ratio[i] * 100;
		if ((freq > policy->max) ||
		    (freq < policy->min))
			continue;
		switch(policy->policy) {
		case CPUFREQ_POLICY_POWERSAVE:
			if (clock_ratio[i] < clock_ratio[optimal]) {
				found_optimal = 1;
				optimal = i;
			}
			break;
		case CPUFREQ_POLICY_PERFORMANCE:
			if (clock_ratio[i] > clock_ratio[optimal]) {
				found_optimal = 1;
				optimal = i;
			}
			break;
		}
	}
		
	if (found_optimal) {
		*new_mult = optimal;
		return 1;
	}
	return 0;
}


static int longhaul_setpolicy (struct cpufreq_policy *policy)
{
	unsigned int    i;
	unsigned int    fsb_index = 0;
	unsigned int    new_fsb = 0;
	unsigned int    new_clock_ratio = 0;
	unsigned int    min_mult = 0;
	unsigned int    max_mult = 0;


	if (!longhaul_driver)
		return -EINVAL;

	if (policy->policy==CPUFREQ_POLICY_PERFORMANCE)
		fsb_search_table = perf_fsb_table;
	else
		fsb_search_table = power_fsb_table;

	for(i=0;i<numscales;i++) {
		if (clock_ratio[max_mult] < clock_ratio[i])
				max_mult = i;
		else if (clock_ratio[min_mult] > clock_ratio[i])
				min_mult = i;
	}

	if (can_scale_fsb==1) {
		unsigned int found = 0;
		for (fsb_index=0; fsb_search_table[fsb_index]!=-1; fsb_index++)
		{
			if (longhaul_get_best_freq_for_fsb(policy, 
			              min_mult, max_mult, 
				      fsb_search_table[fsb_index], 
				      &new_clock_ratio)) {
				new_fsb = fsb_search_table[fsb_index];
				break;
			}
		}
		if (!found)
			return -EINVAL;
	} else {
		new_fsb = current_fsb;
		if (!longhaul_get_best_freq_for_fsb(policy, min_mult, 
			     max_mult, new_fsb, &new_clock_ratio))
			return -EINVAL;
	}

	longhaul_setstate(new_clock_ratio, new_fsb);

	return 0;
}


static int __init longhaul_init (void)
{
	struct cpuinfo_x86 *c = cpu_data;
	unsigned int currentspeed;
	static int currentmult;
	unsigned long lo, hi;
	int ret;
	struct cpufreq_driver *driver;

	if ((c->x86_vendor != X86_VENDOR_CENTAUR) || (c->x86 !=6) )
		return -ENODEV;

	switch (c->x86_model) {
	case 6:		/* VIA C3 Samuel C5A */
		longhaul=1;
		memcpy (clock_ratio, longhaul1_clock_ratio, sizeof(longhaul1_clock_ratio));
		memcpy (eblcr_table, samuel1_eblcr, sizeof(samuel1_eblcr));
		break;

	case 7:		/* C5B / C5C */
		switch (c->x86_mask) {
		case 0:
			longhaul=1;
			memcpy (clock_ratio, longhaul1_clock_ratio, sizeof(longhaul1_clock_ratio));
			memcpy (eblcr_table, samuel2_eblcr, sizeof(samuel2_eblcr));
			break;
		case 1 ... 15:
			longhaul=2;
			memcpy (clock_ratio, longhaul2_clock_ratio, sizeof(longhaul2_clock_ratio));
			memcpy (eblcr_table, ezra_eblcr, sizeof(ezra_eblcr));
			break;
		}
		break;

	case 8:		/* C5M/C5N */
		return -ENODEV; // Waiting on updated docs from VIA before this is usable
		longhaul=3;
		numscales=32;
		memcpy (clock_ratio, longhaul3_clock_ratio, sizeof(longhaul3_clock_ratio));
		memcpy (eblcr_table, c5m_eblcr, sizeof(c5m_eblcr));
		break;

	default:
		printk (KERN_INFO "longhaul: Unknown VIA CPU. Contact [e-mail]\n");
		return -ENODEV;
	}

	printk (KERN_INFO "longhaul: VIA CPU detected. Longhaul version %d supported\n", longhaul);

	current_fsb = longhaul_get_cpu_fsb();
	currentmult = longhaul_get_cpu_mult();
	currentspeed = currentmult * current_fsb * 100;

	dprintk (KERN_INFO "longhaul: CPU currently at %dMHz (%d x %d.%d)\n",
		(currentspeed/1000), current_fsb, currentmult/10, currentmult%10);

	if (longhaul==2 || longhaul==3) {
		rdmsr (MSR_VIA_LONGHAUL, lo, hi);
		if ((lo & (1<<0)) && (dont_scale_voltage==0))
			longhaul_setup_voltagescaling (lo, hi);

		if ((lo & (1<<1)) && (dont_scale_fsb==0) && (current_fsb==0))
			can_scale_fsb = 1;
	}

	longhaul_get_ranges();

	driver = kmalloc(sizeof(struct cpufreq_driver) + 
			 NR_CPUS * sizeof(struct cpufreq_policy), GFP_KERNEL);
	if (!driver)
		return -ENOMEM;

	driver->policy = (struct cpufreq_policy *) (driver + 1);

#ifdef CONFIG_CPU_FREQ_24_API
	driver->cpu_cur_freq[0] = currentspeed;
#endif

	driver->verify    = &longhaul_verify;
	driver->setpolicy = &longhaul_setpolicy;

	driver->policy[0].cpu = 0;
	driver->policy[0].min = (unsigned int) lowest_speed;
	driver->policy[0].max = (unsigned int) highest_speed;
	driver->policy[0].policy = CPUFREQ_POLICY_PERFORMANCE;
	driver->policy[0].cpuinfo.min_freq = (unsigned int) lowest_speed;
	driver->policy[0].cpuinfo.max_freq = (unsigned int) highest_speed;
	driver->policy[0].cpuinfo.transition_latency = CPUFREQ_ETERNAL;

	longhaul_driver = driver;

	ret = cpufreq_register(driver);
	if (ret) {
		longhaul_driver = NULL;
		kfree(driver);
	}

	return ret;
}


static void __exit longhaul_exit (void)
{
	if (longhaul_driver) {
		cpufreq_unregister();
		kfree(longhaul_driver);
	}
}

MODULE_PARM (dont_scale_fsb, "i");
MODULE_PARM (dont_scale_voltage, "i");
MODULE_PARM (current_fsb, "i");

MODULE_AUTHOR ("Dave Jones <[e-mail]>");
MODULE_DESCRIPTION ("Longhaul driver for VIA Cyrix processors.");
MODULE_LICENSE ("GPL");

module_init(longhaul_init);
module_exit(longhaul_exit);