static int __init pcc_cpufreq_do_osc()

in pcc-cpufreq.c [300:385]

• 72 lines of code
• 11 McCabe index (conditional complexity)

static int __init pcc_cpufreq_do_osc(acpi_handle *handle)
{
	acpi_status status;
	struct acpi_object_list input;
	struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
	union acpi_object in_params[4];
	union acpi_object *out_obj;
	u32 capabilities[2];
	u32 errors;
	u32 supported;
	int ret = 0;

	input.count = 4;
	input.pointer = in_params;
	in_params[0].type               = ACPI_TYPE_BUFFER;
	in_params[0].buffer.length      = 16;
	in_params[0].buffer.pointer     = OSC_UUID;
	in_params[1].type               = ACPI_TYPE_INTEGER;
	in_params[1].integer.value      = 1;
	in_params[2].type               = ACPI_TYPE_INTEGER;
	in_params[2].integer.value      = 2;
	in_params[3].type               = ACPI_TYPE_BUFFER;
	in_params[3].buffer.length      = 8;
	in_params[3].buffer.pointer     = (u8 *)&capabilities;

	capabilities[0] = OSC_QUERY_ENABLE;
	capabilities[1] = 0x1;

	status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
	if (ACPI_FAILURE(status))
		return -ENODEV;

	if (!output.length)
		return -ENODEV;

	out_obj = output.pointer;
	if (out_obj->type != ACPI_TYPE_BUFFER) {
		ret = -ENODEV;
		goto out_free;
	}

	errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
	if (errors) {
		ret = -ENODEV;
		goto out_free;
	}

	supported = *((u32 *)(out_obj->buffer.pointer + 4));
	if (!(supported & 0x1)) {
		ret = -ENODEV;
		goto out_free;
	}

	kfree(output.pointer);
	capabilities[0] = 0x0;
	capabilities[1] = 0x1;

	status = acpi_evaluate_object(*handle, "_OSC", &input, &output);
	if (ACPI_FAILURE(status))
		return -ENODEV;

	if (!output.length)
		return -ENODEV;

	out_obj = output.pointer;
	if (out_obj->type != ACPI_TYPE_BUFFER) {
		ret = -ENODEV;
		goto out_free;
	}

	errors = *((u32 *)out_obj->buffer.pointer) & ~(1 << 0);
	if (errors) {
		ret = -ENODEV;
		goto out_free;
	}

	supported = *((u32 *)(out_obj->buffer.pointer + 4));
	if (!(supported & 0x1)) {
		ret = -ENODEV;
		goto out_free;
	}

out_free:
	kfree(output.pointer);
	return ret;
}