static int acpi_processor_get_performance_states()

in processor_perflib.c [285:390]

• 84 lines of code
• 13 McCabe index (conditional complexity)

static int acpi_processor_get_performance_states(struct acpi_processor *pr)
{
	int result = 0;
	acpi_status status = AE_OK;
	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
	struct acpi_buffer format = { sizeof("NNNNNN"), "NNNNNN" };
	struct acpi_buffer state = { 0, NULL };
	union acpi_object *pss = NULL;
	int i;
	int last_invalid = -1;

	status = acpi_evaluate_object(pr->handle, "_PSS", NULL, &buffer);
	if (ACPI_FAILURE(status)) {
		acpi_evaluation_failure_warn(pr->handle, "_PSS", status);
		return -ENODEV;
	}

	pss = buffer.pointer;
	if (!pss || (pss->type != ACPI_TYPE_PACKAGE)) {
		pr_err("Invalid _PSS data\n");
		result = -EFAULT;
		goto end;
	}

	acpi_handle_debug(pr->handle, "Found %d performance states\n",
			  pss->package.count);

	pr->performance->state_count = pss->package.count;
	pr->performance->states =
	    kmalloc_array(pss->package.count,
			  sizeof(struct acpi_processor_px),
			  GFP_KERNEL);
	if (!pr->performance->states) {
		result = -ENOMEM;
		goto end;
	}

	for (i = 0; i < pr->performance->state_count; i++) {

		struct acpi_processor_px *px = &(pr->performance->states[i]);

		state.length = sizeof(struct acpi_processor_px);
		state.pointer = px;

		acpi_handle_debug(pr->handle, "Extracting state %d\n", i);

		status = acpi_extract_package(&(pss->package.elements[i]),
					      &format, &state);
		if (ACPI_FAILURE(status)) {
			acpi_handle_warn(pr->handle, "Invalid _PSS data: %s\n",
					 acpi_format_exception(status));
			result = -EFAULT;
			kfree(pr->performance->states);
			goto end;
		}

		amd_fixup_frequency(px, i);

		acpi_handle_debug(pr->handle,
				  "State [%d]: core_frequency[%d] power[%d] transition_latency[%d] bus_master_latency[%d] control[0x%x] status[0x%x]\n",
				  i,
				  (u32) px->core_frequency,
				  (u32) px->power,
				  (u32) px->transition_latency,
				  (u32) px->bus_master_latency,
				  (u32) px->control, (u32) px->status);

		/*
		 * Check that ACPI's u64 MHz will be valid as u32 KHz in cpufreq
		 */
		if (!px->core_frequency ||
		    ((u32)(px->core_frequency * 1000) !=
		     (px->core_frequency * 1000))) {
			pr_err(FW_BUG
			       "Invalid BIOS _PSS frequency found for processor %d: 0x%llx MHz\n",
			       pr->id, px->core_frequency);
			if (last_invalid == -1)
				last_invalid = i;
		} else {
			if (last_invalid != -1) {
				/*
				 * Copy this valid entry over last_invalid entry
				 */
				memcpy(&(pr->performance->states[last_invalid]),
				       px, sizeof(struct acpi_processor_px));
				++last_invalid;
			}
		}
	}

	if (last_invalid == 0) {
		pr_err(FW_BUG
			   "No valid BIOS _PSS frequency found for processor %d\n", pr->id);
		result = -EFAULT;
		kfree(pr->performance->states);
		pr->performance->states = NULL;
	}

	if (last_invalid > 0)
		pr->performance->state_count = last_invalid;

end:
	kfree(buffer.pointer);

	return result;
}