/* * acpi_lpat.c - LPAT table processing functions * * Copyright (C) 2015 Intel Corporation. All rights reserved. * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version * 2 as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <linux/export.h> #include <linux/acpi.h> #include <acpi/acpi_lpat.h> /** * acpi_lpat_raw_to_temp(): Return temperature from raw value through * LPAT conversion table * * @lpat_table: the temperature_raw mapping table structure * @raw: the raw value, used as a key to get the temerature from the * above mapping table * * A positive converted temperarure value will be returned on success, * a negative errno will be returned in error cases. */ int acpi_lpat_raw_to_temp(struct acpi_lpat_conversion_table *lpat_table, int raw) { int i, delta_temp, delta_raw, temp; struct acpi_lpat *lpat = lpat_table->lpat; for (i = 0; i < lpat_table->lpat_count - 1; i++) { if ((raw >= lpat[i].raw && raw <= lpat[i+1].raw) || (raw <= lpat[i].raw && raw >= lpat[i+1].raw)) break; } if (i == lpat_table->lpat_count - 1) return -ENOENT; delta_temp = lpat[i+1].temp - lpat[i].temp; delta_raw = lpat[i+1].raw - lpat[i].raw; temp = lpat[i].temp + (raw - lpat[i].raw) * delta_temp / delta_raw; return temp; } EXPORT_SYMBOL_GPL(acpi_lpat_raw_to_temp); /** * acpi_lpat_temp_to_raw(): Return raw value from temperature through * LPAT conversion table * * @lpat: the temperature_raw mapping table * @temp: the temperature, used as a key to get the raw value from the * above mapping table * * A positive converted temperature value will be returned on success, * a negative errno will be returned in error cases. */ int acpi_lpat_temp_to_raw(struct acpi_lpat_conversion_table *lpat_table, int temp) { int i, delta_temp, delta_raw, raw; struct acpi_lpat *lpat = lpat_table->lpat; for (i = 0; i < lpat_table->lpat_count - 1; i++) { if (temp >= lpat[i].temp && temp <= lpat[i+1].temp) break; } if (i == lpat_table->lpat_count - 1) return -ENOENT; delta_temp = lpat[i+1].temp - lpat[i].temp; delta_raw = lpat[i+1].raw - lpat[i].raw; raw = lpat[i].raw + (temp - lpat[i].temp) * delta_raw / delta_temp; return raw; } EXPORT_SYMBOL_GPL(acpi_lpat_temp_to_raw); /** * acpi_lpat_get_conversion_table(): Parse ACPI LPAT table if present. * * @handle: Handle to acpi device * * Parse LPAT table to a struct of type acpi_lpat_table. On success * it returns a pointer to newly allocated table. This table must * be freed by the caller when finished processing, using a call to * acpi_lpat_free_conversion_table. */ struct acpi_lpat_conversion_table *acpi_lpat_get_conversion_table(acpi_handle handle) { struct acpi_lpat_conversion_table *lpat_table = NULL; struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; union acpi_object *obj_p, *obj_e; int *lpat, i; acpi_status status; status = acpi_evaluate_object(handle, "LPAT", NULL, &buffer); if (ACPI_FAILURE(status)) return NULL; obj_p = (union acpi_object *)buffer.pointer; if (!obj_p || (obj_p->type != ACPI_TYPE_PACKAGE) || (obj_p->package.count % 2) || (obj_p->package.count < 4)) goto out; lpat = kcalloc(obj_p->package.count, sizeof(int), GFP_KERNEL); if (!lpat) goto out; for (i = 0; i < obj_p->package.count; i++) { obj_e = &obj_p->package.elements[i]; if (obj_e->type != ACPI_TYPE_INTEGER) { kfree(lpat); goto out; } lpat[i] = (s64)obj_e->integer.value; } lpat_table = kzalloc(sizeof(*lpat_table), GFP_KERNEL); if (!lpat_table) { kfree(lpat); goto out; } lpat_table->lpat = (struct acpi_lpat *)lpat; lpat_table->lpat_count = obj_p->package.count / 2; out: kfree(buffer.pointer); return lpat_table; } EXPORT_SYMBOL_GPL(acpi_lpat_get_conversion_table); /** * acpi_lpat_free_conversion_table(): Free LPAT table. * * @lpat_table: the temperature_raw mapping table structure * * Frees the LPAT table previously allocated by a call to * acpi_lpat_get_conversion_table. */ void acpi_lpat_free_conversion_table(struct acpi_lpat_conversion_table *lpat_table) { if (lpat_table) { kfree(lpat_table->lpat); kfree(lpat_table); } } EXPORT_SYMBOL_GPL(acpi_lpat_free_conversion_table);