gx-suspmod.c

linux-2.6.15.6

static void gx_set_cpuspeed(unsigned int khz)
{
        u8 suscfg, pmer1;
	unsigned int new_khz;
	unsigned long flags;
	struct cpufreq_freqs freqs;


	freqs.cpu = 0;
	freqs.old = gx_get_cpuspeed(0);

	new_khz = gx_validate_speed(khz, &gx_params->on_duration, &gx_params->off_duration);

	freqs.new = new_khz;

	cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
	local_irq_save(flags);

	if (new_khz != stock_freq) {  /* if new khz == 100% of CPU speed, it is special case */
		switch (gx_params->cs55x0->device) {
		case PCI_DEVICE_ID_CYRIX_5530_LEGACY:
			pmer1 = gx_params->pci_pmer1 | IRQ_SPDUP | VID_SPDUP;
			/* FIXME: need to test other values -- Zwane,Miura */
			pci_write_config_byte(gx_params->cs55x0, PCI_IRQTC, 4); /* typical 2 to 4ms */
			pci_write_config_byte(gx_params->cs55x0, PCI_VIDTC, 100);/* typical 50 to 100ms */
			pci_write_config_byte(gx_params->cs55x0, PCI_PMER1, pmer1);

			if (gx_params->pci_rev < 0x10) {   /* CS5530(rev 1.2, 1.3) */
				suscfg = gx_params->pci_suscfg | SUSMOD;
			} else {                           /* CS5530A,B.. */
				suscfg = gx_params->pci_suscfg | SUSMOD | PWRSVE;
			}
			break;
		case PCI_DEVICE_ID_CYRIX_5520:
		case PCI_DEVICE_ID_CYRIX_5510:
			suscfg = gx_params->pci_suscfg | SUSMOD;
			break;
		default:
			local_irq_restore(flags);
			dprintk("fatal: try to set unknown chipset.\n");
			return;
		}
	} else {
		suscfg = gx_params->pci_suscfg & ~(SUSMOD);
		gx_params->off_duration = 0;
		gx_params->on_duration = 0;
		dprintk("suspend modulation disabled: cpu runs 100 percent speed.\n");
	}

	pci_write_config_byte(gx_params->cs55x0, PCI_MODOFF, gx_params->off_duration);
	pci_write_config_byte(gx_params->cs55x0, PCI_MODON, gx_params->on_duration);

        pci_write_config_byte(gx_params->cs55x0, PCI_SUSCFG, suscfg);
        pci_read_config_byte(gx_params->cs55x0, PCI_SUSCFG, &suscfg);

        local_irq_restore(flags);

	gx_params->pci_suscfg = suscfg;

	cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);

        dprintk("suspend modulation w/ duration of ON:%d us, OFF:%d us\n",
                gx_params->on_duration * 32, gx_params->off_duration * 32);
	dprintk("suspend modulation w/ clock speed: %d kHz.\n", freqs.new); 
}

/****************************************************************
 *             High level functions                             *
 ****************************************************************/

/*
 *	cpufreq_gx_verify: test if frequency range is valid 
 *
 *	This function checks if a given frequency range in kHz is valid 
 *      for the hardware supported by the driver. 
 */

static int cpufreq_gx_verify(struct cpufreq_policy *policy)
{
	unsigned int tmp_freq = 0;
	u8 tmp1, tmp2;

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

	policy->cpu = 0;
	cpufreq_verify_within_limits(policy, (stock_freq / max_duration), stock_freq);

	/* it needs to be assured that at least one supported frequency is
	 * within policy->min and policy->max. If it is not, policy->max
	 * needs to be increased until one freuqency is supported.
	 * policy->min may not be decreased, though. This way we guarantee a 
	 * specific processing capacity.
	 */
	tmp_freq = gx_validate_speed(policy->min, &tmp1, &tmp2);
	if (tmp_freq < policy->min) 
		tmp_freq += stock_freq / max_duration;
	policy->min = tmp_freq;
	if (policy->min > policy->max) 
		policy->max = tmp_freq;
	tmp_freq = gx_validate_speed(policy->max, &tmp1, &tmp2);
	if (tmp_freq > policy->max)
		tmp_freq -= stock_freq / max_duration;
	policy->max = tmp_freq;
	if (policy->max < policy->min)
		policy->max = policy->min;
	cpufreq_verify_within_limits(policy, (stock_freq / max_duration), stock_freq);
	
	return 0;
}

/*
 *      cpufreq_gx_target:  
 *
 */
static int cpufreq_gx_target(struct cpufreq_policy *policy,
			     unsigned int target_freq,
			     unsigned int relation)
{
	u8 tmp1, tmp2;
	unsigned int tmp_freq;

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

	policy->cpu = 0;

	tmp_freq = gx_validate_speed(target_freq, &tmp1, &tmp2);
	while (tmp_freq < policy->min) {
		tmp_freq += stock_freq / max_duration;
		tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
	}
	while (tmp_freq > policy->max) {
		tmp_freq -= stock_freq / max_duration;
		tmp_freq = gx_validate_speed(tmp_freq, &tmp1, &tmp2);
	}

	gx_set_cpuspeed(tmp_freq);

	return 0;
}

static int cpufreq_gx_cpu_init(struct cpufreq_policy *policy)
{
	unsigned int maxfreq, curfreq;

	if (!policy || policy->cpu != 0)
		return -ENODEV;

	/* determine maximum frequency */
	if (pci_busclk) {
		maxfreq = pci_busclk * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
	} else if (cpu_khz) {
		maxfreq = cpu_khz;
	} else {
		maxfreq = 30000 * gx_freq_mult[getCx86(CX86_DIR1) & 0x0f];
	}
	stock_freq = maxfreq;
	curfreq = gx_get_cpuspeed(0);

	dprintk("cpu max frequency is %d.\n", maxfreq);
	dprintk("cpu current frequency is %dkHz.\n",curfreq);

	/* setup basic struct for cpufreq API */
	policy->cpu = 0;

	if (max_duration < POLICY_MIN_DIV)
		policy->min = maxfreq / max_duration;
	else
		policy->min = maxfreq / POLICY_MIN_DIV;
	policy->max = maxfreq;
	policy->cur = curfreq;
	policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
	policy->cpuinfo.min_freq = maxfreq / max_duration;
	policy->cpuinfo.max_freq = maxfreq;
	policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;

	return 0;
}

/* 
 * cpufreq_gx_init:
 *   MediaGX/Geode GX initialize cpufreq driver
 */
static struct cpufreq_driver gx_suspmod_driver = {
	.get		= gx_get_cpuspeed,
	.verify		= cpufreq_gx_verify,
	.target		= cpufreq_gx_target,
	.init		= cpufreq_gx_cpu_init,
	.name		= "gx-suspmod",
	.owner		= THIS_MODULE,
};

static int __init cpufreq_gx_init(void)
{
	int ret;
	struct gxfreq_params *params;
	struct pci_dev *gx_pci;
	u32 class_rev;

	/* Test if we have the right hardware */
	if ((gx_pci = gx_detect_chipset()) == NULL) 
		return -ENODEV;

	/* check whether module parameters are sane */
	if (max_duration > 0xff)
		max_duration = 0xff;

	dprintk("geode suspend modulation available.\n");

	params = kmalloc(sizeof(struct gxfreq_params), GFP_KERNEL);
	if (params == NULL)
		return -ENOMEM;
	memset(params, 0, sizeof(struct gxfreq_params));

	params->cs55x0 = gx_pci;
	gx_params = params;

	/* keep cs55x0 configurations */
	pci_read_config_byte(params->cs55x0, PCI_SUSCFG, &(params->pci_suscfg));
	pci_read_config_byte(params->cs55x0, PCI_PMER1, &(params->pci_pmer1));
	pci_read_config_byte(params->cs55x0, PCI_PMER2, &(params->pci_pmer2));
	pci_read_config_byte(params->cs55x0, PCI_MODON, &(params->on_duration));
	pci_read_config_byte(params->cs55x0, PCI_MODOFF, &(params->off_duration));
        pci_read_config_dword(params->cs55x0, PCI_CLASS_REVISION, &class_rev);
	params->pci_rev = class_rev && 0xff;

	if ((ret = cpufreq_register_driver(&gx_suspmod_driver))) { 
		kfree(params);
		return ret;                   /* register error! */
	}

	return 0;
}

static void __exit cpufreq_gx_exit(void)
{
	cpufreq_unregister_driver(&gx_suspmod_driver);
	pci_dev_put(gx_params->cs55x0);
	kfree(gx_params);
}

MODULE_AUTHOR ("Hiroshi Miura <[e-mail]>");
MODULE_DESCRIPTION ("Cpufreq driver for Cyrix MediaGX and NatSemi Geode");
MODULE_LICENSE ("GPL");

module_init(cpufreq_gx_init);
module_exit(cpufreq_gx_exit);