longhaul.c

linux-2.6.15.6

			if (longhaul.bits.MaxMHzBR4)
				invalue += 16;
			maxmult=multipliers[invalue];

			invalue = longhaul.bits.MinMHzBR;
			if (longhaul.bits.MinMHzBR4 == 1)
				minmult = 30;
			else
				minmult = multipliers[invalue];
			fsb = eblcr_fsb_table_v2[longhaul.bits.MaxMHzFSB];
			break;
		}

		/* Nehemiah */
		if (cpu_model==CPU_NEHEMIAH) {
			rdmsrl (MSR_VIA_LONGHAUL, longhaul.val);

			/*
			 * TODO: This code works, but raises a lot of questions.
			 * - Some Nehemiah's seem to have broken Min/MaxMHzBR's.
			 *   We get around this by using a hardcoded multiplier of 4.0x
			 *   for the minimimum speed, and the speed we booted up at for the max.
			 *   This is done in longhaul_get_cpu_mult() by reading the EBLCR register.
			 * - According to some VIA documentation EBLCR is only
			 *   in pre-Nehemiah C3s. How this still works is a mystery.
			 *   We're possibly using something undocumented and unsupported,
			 *   But it works, so we don't grumble.
			 */
			minmult=40;
			maxmult=longhaul_get_cpu_mult();

			/* Starting with the 1.2GHz parts, theres a 200MHz bus. */
			if ((cpu_khz/1000) > 1200)
				fsb = 200;
			else
				fsb = eblcr_fsb_table_v2[longhaul.bits.MaxMHzFSB];
			break;
		}
	}

	dprintk ("MinMult:%d.%dx MaxMult:%d.%dx\n",
		 minmult/10, minmult%10, maxmult/10, maxmult%10);

	if (fsb == -1) {
		printk (KERN_INFO PFX "Invalid (reserved) FSB!\n");
		return -EINVAL;
	}

	highest_speed = calc_speed(maxmult);
	lowest_speed = calc_speed(minmult);
	dprintk ("FSB:%dMHz  Lowest speed: %s   Highest speed:%s\n", fsb,
		 print_speed(lowest_speed/1000), 
		 print_speed(highest_speed/1000));

	if (lowest_speed == highest_speed) {
		printk (KERN_INFO PFX "highestspeed == lowest, aborting.\n");
		return -EINVAL;
	}
	if (lowest_speed > highest_speed) {
		printk (KERN_INFO PFX "nonsense! lowest (%d > %d) !\n",
			lowest_speed, highest_speed);
		return -EINVAL;
	}

	longhaul_table = kmalloc((numscales + 1) * sizeof(struct cpufreq_frequency_table), GFP_KERNEL);
	if(!longhaul_table)
		return -ENOMEM;

	for (j=0; j < numscales; j++) {
		unsigned int ratio;
		ratio = clock_ratio[j];
		if (ratio == -1)
			continue;
		if (ratio > maxmult || ratio < minmult)
			continue;
		longhaul_table[k].frequency = calc_speed(ratio);
		longhaul_table[k].index	= j;
		k++;
	}

	longhaul_table[k].frequency = CPUFREQ_TABLE_END;
	if (!k) {
		kfree (longhaul_table);
		return -EINVAL;
	}

	return 0;
}


static void __init longhaul_setup_voltagescaling(void)
{
	union msr_longhaul longhaul;

	rdmsrl (MSR_VIA_LONGHAUL, longhaul.val);

	if (!(longhaul.bits.RevisionID & 1))
		return;

	minvid = longhaul.bits.MinimumVID;
	maxvid = longhaul.bits.MaximumVID;
	vrmrev = longhaul.bits.VRMRev;

	if (minvid == 0 || maxvid == 0) {
		printk (KERN_INFO PFX "Bogus values Min:%d.%03d Max:%d.%03d. "
					"Voltage scaling disabled.\n",
					minvid/1000, minvid%1000, maxvid/1000, maxvid%1000);
		return;
	}

	if (minvid == maxvid) {
		printk (KERN_INFO PFX "Claims to support voltage scaling but min & max are "
				"both %d.%03d. Voltage scaling disabled\n",
				maxvid/1000, maxvid%1000);
		return;
	}

	if (vrmrev==0) {
		dprintk ("VRM 8.5\n");
		memcpy (voltage_table, vrm85scales, sizeof(voltage_table));
		numvscales = (voltage_table[maxvid]-voltage_table[minvid])/25;
	} else {
		dprintk ("Mobile VRM\n");
		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 */
	longhaul.bits.RevisionKey = longhaul.bits.RevisionID;	/* FIXME: This is bad. */
	longhaul.bits.EnableSoftVID = 1;
	longhaul.bits.SoftVID = maxvid;
	wrmsrl (MSR_VIA_LONGHAUL, longhaul.val);

	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);

	can_scale_voltage = 1;
}


static int longhaul_verify(struct cpufreq_policy *policy)
{
	return cpufreq_frequency_table_verify(policy, longhaul_table);
}


static int longhaul_target(struct cpufreq_policy *policy,
			    unsigned int target_freq, unsigned int relation)
{
	unsigned int table_index = 0;
	unsigned int new_clock_ratio = 0;

	if (cpufreq_frequency_table_target(policy, longhaul_table, target_freq, relation, &table_index))
		return -EINVAL;

	new_clock_ratio = longhaul_table[table_index].index & 0xFF;

	longhaul_setstate(new_clock_ratio);

	return 0;
}


static unsigned int longhaul_get(unsigned int cpu)
{
	if (cpu)
		return 0;
	return calc_speed(longhaul_get_cpu_mult());
}


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

	switch (c->x86_model) {
	case 6:
		cpu_model = CPU_SAMUEL;
		cpuname = "C3 'Samuel' [C5A]";
		longhaul_version = TYPE_LONGHAUL_V1;
		memcpy (clock_ratio, samuel1_clock_ratio, sizeof(samuel1_clock_ratio));
		memcpy (eblcr_table, samuel1_eblcr, sizeof(samuel1_eblcr));
		break;

	case 7:
		longhaul_version = TYPE_LONGHAUL_V1;
		switch (c->x86_mask) {
		case 0:
			cpu_model = CPU_SAMUEL2;
			cpuname = "C3 'Samuel 2' [C5B]";
			/* Note, this is not a typo, early Samuel2's had Samuel1 ratios. */
			memcpy (clock_ratio, samuel1_clock_ratio, sizeof(samuel1_clock_ratio));
			memcpy (eblcr_table, samuel2_eblcr, sizeof(samuel2_eblcr));
			break;
		case 1 ... 15:
			if (c->x86_mask < 8) {
				cpu_model = CPU_SAMUEL2;
				cpuname = "C3 'Samuel 2' [C5B]";
			} else {
				cpu_model = CPU_EZRA;
				cpuname = "C3 'Ezra' [C5C]";
			}
			memcpy (clock_ratio, ezra_clock_ratio, sizeof(ezra_clock_ratio));
			memcpy (eblcr_table, ezra_eblcr, sizeof(ezra_eblcr));
			break;
		}
		break;

	case 8:
		cpu_model = CPU_EZRA_T;
		cpuname = "C3 'Ezra-T' [C5M]";
		longhaul_version = TYPE_POWERSAVER;
		numscales=32;
		memcpy (clock_ratio, ezrat_clock_ratio, sizeof(ezrat_clock_ratio));
		memcpy (eblcr_table, ezrat_eblcr, sizeof(ezrat_eblcr));
		break;

	case 9:
		cpu_model = CPU_NEHEMIAH;
		longhaul_version = TYPE_POWERSAVER;
		numscales=32;
		switch (c->x86_mask) {
		case 0 ... 1:
			cpuname = "C3 'Nehemiah A' [C5N]";
			memcpy (clock_ratio, nehemiah_a_clock_ratio, sizeof(nehemiah_a_clock_ratio));
			memcpy (eblcr_table, nehemiah_a_eblcr, sizeof(nehemiah_a_eblcr));
			break;
		case 2 ... 4:
			cpuname = "C3 'Nehemiah B' [C5N]";
			memcpy (clock_ratio, nehemiah_b_clock_ratio, sizeof(nehemiah_b_clock_ratio));
			memcpy (eblcr_table, nehemiah_b_eblcr, sizeof(nehemiah_b_eblcr));
			break;
		case 5 ... 15:
			cpuname = "C3 'Nehemiah C' [C5N]";
			memcpy (clock_ratio, nehemiah_c_clock_ratio, sizeof(nehemiah_c_clock_ratio));
			memcpy (eblcr_table, nehemiah_c_eblcr, sizeof(nehemiah_c_eblcr));
			break;
		}
		break;

	default:
		cpuname = "Unknown";
		break;
	}

	printk (KERN_INFO PFX "VIA %s CPU detected.  ", cpuname);
	switch (longhaul_version) {
	case TYPE_LONGHAUL_V1:
	case TYPE_LONGHAUL_V2:
		printk ("Longhaul v%d supported.\n", longhaul_version);
		break;
	case TYPE_POWERSAVER:
		printk ("Powersaver supported.\n");
		break;
	};

	ret = longhaul_get_ranges();
	if (ret != 0)
		return ret;

	if ((longhaul_version==TYPE_LONGHAUL_V2 || longhaul_version==TYPE_POWERSAVER) &&
		 (dont_scale_voltage==0))
		longhaul_setup_voltagescaling();

	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
	policy->cpuinfo.transition_latency = 200000;	/* nsec */
	policy->cur = calc_speed(longhaul_get_cpu_mult());

	ret = cpufreq_frequency_table_cpuinfo(policy, longhaul_table);
	if (ret)
		return ret;

	cpufreq_frequency_table_get_attr(longhaul_table, policy->cpu);

	return 0;
}

static int __devexit longhaul_cpu_exit(struct cpufreq_policy *policy)
{
	cpufreq_frequency_table_put_attr(policy->cpu);
	return 0;
}

static struct freq_attr* longhaul_attr[] = {
	&cpufreq_freq_attr_scaling_available_freqs,
	NULL,
};

static struct cpufreq_driver longhaul_driver = {
	.verify	= longhaul_verify,
	.target	= longhaul_target,
	.get	= longhaul_get,
	.init	= longhaul_cpu_init,
	.exit	= __devexit_p(longhaul_cpu_exit),
	.name	= "longhaul",
	.owner	= THIS_MODULE,
	.attr	= longhaul_attr,
};


static int __init longhaul_init(void)
{
	struct cpuinfo_x86 *c = cpu_data;

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

	switch (c->x86_model) {
	case 6 ... 9:
		return cpufreq_register_driver(&longhaul_driver);
	default:
		printk (KERN_INFO PFX "Unknown VIA CPU. Contact [e-mail]\n");
	}

	return -ENODEV;
}


static void __exit longhaul_exit(void)
{
	int i=0;

	for (i=0; i < numscales; i++) {
		if (clock_ratio[i] == maxmult) {
			longhaul_setstate(i);
			break;
		}
	}

	cpufreq_unregister_driver(&longhaul_driver);
	kfree(longhaul_table);
}

module_param (dont_scale_voltage, int, 0644);
MODULE_PARM_DESC(dont_scale_voltage, "Don't scale voltage of processor");

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);