static int powernow_acpi_init()

in powernow-k7.c [296:431]

• 103 lines of code
• 18 McCabe index (conditional complexity)

static int powernow_acpi_init(void)
{
	int i;
	int retval = 0;
	union powernow_acpi_control_t pc;

	if (acpi_processor_perf != NULL && powernow_table != NULL) {
		retval = -EINVAL;
		goto err0;
	}

	acpi_processor_perf = kzalloc(sizeof(*acpi_processor_perf), GFP_KERNEL);
	if (!acpi_processor_perf) {
		retval = -ENOMEM;
		goto err0;
	}

	if (!zalloc_cpumask_var(&acpi_processor_perf->shared_cpu_map,
								GFP_KERNEL)) {
		retval = -ENOMEM;
		goto err05;
	}

	if (acpi_processor_register_performance(acpi_processor_perf, 0)) {
		retval = -EIO;
		goto err1;
	}

	if (acpi_processor_perf->control_register.space_id !=
			ACPI_ADR_SPACE_FIXED_HARDWARE) {
		retval = -ENODEV;
		goto err2;
	}

	if (acpi_processor_perf->status_register.space_id !=
			ACPI_ADR_SPACE_FIXED_HARDWARE) {
		retval = -ENODEV;
		goto err2;
	}

	number_scales = acpi_processor_perf->state_count;

	if (number_scales < 2) {
		retval = -ENODEV;
		goto err2;
	}

	powernow_table = kzalloc((sizeof(*powernow_table) *
				(number_scales + 1)), GFP_KERNEL);
	if (!powernow_table) {
		retval = -ENOMEM;
		goto err2;
	}

	pc.val = (unsigned long) acpi_processor_perf->states[0].control;
	for (i = 0; i < number_scales; i++) {
		u8 fid, vid;
		struct acpi_processor_px *state =
			&acpi_processor_perf->states[i];
		unsigned int speed, speed_mhz;

		pc.val = (unsigned long) state->control;
		pr_debug("acpi:  P%d: %d MHz %d mW %d uS control %08x SGTC %d\n",
			 i,
			 (u32) state->core_frequency,
			 (u32) state->power,
			 (u32) state->transition_latency,
			 (u32) state->control,
			 pc.bits.sgtc);

		vid = pc.bits.vid;
		fid = pc.bits.fid;

		powernow_table[i].frequency = fsb * fid_codes[fid] / 10;
		powernow_table[i].driver_data = fid; /* lower 8 bits */
		powernow_table[i].driver_data |= (vid << 8); /* upper 8 bits */

		speed = powernow_table[i].frequency;
		speed_mhz = speed / 1000;

		/* processor_perflib will multiply the MHz value by 1000 to
		 * get a KHz value (e.g. 1266000). However, powernow-k7 works
		 * with true KHz values (e.g. 1266768). To ensure that all
		 * powernow frequencies are available, we must ensure that
		 * ACPI doesn't restrict them, so we round up the MHz value
		 * to ensure that perflib's computed KHz value is greater than
		 * or equal to powernow's KHz value.
		 */
		if (speed % 1000 > 0)
			speed_mhz++;

		if ((fid_codes[fid] % 10) == 5) {
			if (have_a0 == 1)
				invalidate_entry(i);
		}

		pr_debug("   FID: 0x%x (%d.%dx [%dMHz])  "
			 "VID: 0x%x (%d.%03dV)\n", fid, fid_codes[fid] / 10,
			 fid_codes[fid] % 10, speed_mhz, vid,
			 mobile_vid_table[vid]/1000,
			 mobile_vid_table[vid]%1000);

		if (state->core_frequency != speed_mhz) {
			state->core_frequency = speed_mhz;
			pr_debug("   Corrected ACPI frequency to %d\n",
				speed_mhz);
		}

		if (latency < pc.bits.sgtc)
			latency = pc.bits.sgtc;

		if (speed < minimum_speed)
			minimum_speed = speed;
		if (speed > maximum_speed)
			maximum_speed = speed;
	}

	powernow_table[i].frequency = CPUFREQ_TABLE_END;
	powernow_table[i].driver_data = 0;

	/* notify BIOS that we exist */
	acpi_processor_notify_smm(THIS_MODULE);

	return 0;

err2:
	acpi_processor_unregister_performance(0);
err1:
	free_cpumask_var(acpi_processor_perf->shared_cpu_map);
err05:
	kfree(acpi_processor_perf);
err0:
	pr_warn("ACPI perflib can not be used on this platform\n");
	acpi_processor_perf = NULL;
	return retval;
}