Revert "wmi-acer: Clean (A & B) > 0 tests to (A &= B)"

[acer_acpi.git] / wmi-acer.c

/*
 *  WMI to ACPI mapping driver
 *
 *  Copyright (C) 2007 Carlos Corbacho <cathectic@gmail.com>
 *
 *  GUID parsing code from ldm.c is:
 *   Copyright (C) 2001,2002 Richard Russon <ldm@flatcap.org>
 *   Copyright (c) 2001-2007 Anton Altaparmakov
 *   Copyright (C) 2001,2002 Jakob Kemi <jakob.kemi@telia.com>
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or (at
 *  your option) any later version.
 *
 *  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.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 * TODO:
 *
 * 1) Handle method & data blocks flagged as WMIACPI_FLAG_STRING
 *
 * The MS spec says that we should translate the input from "UNICODE to ASCIIZ"
 * and the output from "ASCIIZ to UNICODE". But by UNICODE, they probably mean
 * UTF-16, where as we are using UTF-8/ ASCII here - so, what to do? Converting
 * to UTF-16 is probably pointless, since most of the clients of this mapper
 * will be Linux drivers using UTF-8/ ASCII anyway, not UTF-16.
 *
 * So, for the moment, the mapper should just convert input from UTF-8 to ASCII
 *
 * 2) Handle WMIACPI_FLAG_EVENT - What should we do with the events? We would
 *    also need to handle WExx (expensive events)
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <acpi/acpi_drivers.h>
#include <linux/version.h>

#include "wmi-acer.h"

#define ACPI_WMI_CLASS                  "wmi"

#undef PREFIX
#define PREFIX "ACPI: WMI: "
#define WMI_ERR KERN_ERR PREFIX
#define WMI_NOTICE KERN_NOTICE PREFIX
#define WMI_INFO KERN_INFO PREFIX

#define DEBUG(level, message...) { \
        if (debug >= level) \
                printk(KERN_DEBUG PREFIX message);\
}

/* Workaround needed for older kernels */
#ifndef bool
#define bool int
#endif

MODULE_AUTHOR("Carlos Corbacho");
MODULE_DESCRIPTION("WMI ACPI Interface Driver");
MODULE_LICENSE("GPL");

struct guid_block_t
{
        char guid[16];
        union
        {
                char object_id[2];
                struct
                {
                        unsigned char notification_value;
                        unsigned char reserved;
                };
        };
        u8 instance_count;
        u8 flags;
};

struct guid_list
{
        struct guid_block_t *pointer;
        int total;
};

static struct guid_list guids;
static acpi_handle acpi_wmi_handle;
static int debug;

module_param(debug, int, 0664);
MODULE_PARM_DESC(debug, "Debugging verbosity level (0=least 2=most)");

/*
 * If the GUID is a datablock, we must enable and explicitily disable data
 * collection. If the GUID is an event, we must arm and reenable the event if
 * required
 */
#define WMIACPI_FLAG_EXPENSIVE   0x1
#define WMIACPI_FLAG_METHOD      0x2    /* GUID is a method */

/*
 * Data block is a string, and must be converted from ASCII to Unicode (output)
 * or Unicode to Ascii (input)
 */
#define WMIACPI_FLAG_STRING      0x4
#define WMIACPI_FLAG_EVENT       0x8    /* GUID is an event */

static int acpi_wmi_remove(struct acpi_device *device, int type);
static int acpi_wmi_add(struct acpi_device *device);

#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,23)
const static struct acpi_device_id wmi_device_ids[] = {
        {"PNP0C14", 0},
        {"pnp0c14", 0},
        {"", 0},
};
MODULE_DEVICE_TABLE(acpi, wmi_device_ids);
#endif

static struct acpi_driver acpi_wmi_driver = {
        .name = "wmi",
        .class = ACPI_WMI_CLASS,
#if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,23)
        .ids = wmi_device_ids,
#else
        .ids = "PNP0C14,pnp0c14",
#endif
        .ops = {
                .add = acpi_wmi_add,
                .remove = acpi_wmi_remove,
                },
};

/*
 * GUID parsing functions
 */

/**
 * wmi_parse_hexbyte - Convert a ASCII hex number to a byte
 * @src:  Pointer to at least 2 characters to convert.
 *
 * Convert a two character ASCII hex string to a number.
 *
 * Return:  0-255  Success, the byte was parsed correctly
 *          -1     Error, an invalid character was supplied
 */
static int wmi_parse_hexbyte (const u8 *src)
{
        unsigned int x;         /* For correct wrapping */
        int h;

        /* high part */
        if      ((x = src[0] - '0') <= '9'-'0') h = x;
        else if ((x = src[0] - 'a') <= 'f'-'a') h = x+10;
        else if ((x = src[0] - 'A') <= 'F'-'A') h = x+10;
        else return -1;
        h <<= 4;

        /* low part */
        if ((x = src[1] - '0') <= '9'-'0') return h | x;
        if ((x = src[1] - 'a') <= 'f'-'a') return h | (x+10);
        if ((x = src[1] - 'A') <= 'F'-'A') return h | (x+10);
        return -1;
}

/**
 * wmi_swap_bytes - Rearrange GUID bytes to match GUID binary
 * @src:   Memory block holding binary GUID (16 bytes)
 * @dest:  Memory block to hold byte swapped binary GUID (16 bytes)
 *
 * Byte swap a binary GUID to match it's real GUID value
 */
static void wmi_swap_bytes(u8 *src, u8 *dest)
{
        int i;

        for (i = 0; i <= 3; i++)
                memcpy(dest + i, src + (3 - i), 1);

        for (i = 0; i <= 1; i++)
                memcpy(dest + 4 + i, src + (5 - i), 1);

        for (i = 0; i <= 1; i++)
                memcpy(dest + 6 + i, src + (7 - i), 1);

        memcpy(dest + 8, src + 8, 8);
}

/**
 * wmi_parse_guid - Convert GUID from ASCII to binary
 * @src:   36 char string of the form fa50ff2b-f2e8-45de-83fa-65417f2f49ba
 * @dest:  Memory block to hold binary GUID (16 bytes)
 *
 * N.B. The GUID need not be NULL terminated.
 *
 * Return:  'true'   @dest contains binary GUID
 *          'false'  @dest contents are undefined
 */
static bool wmi_parse_guid (const u8 *src, u8 *dest)
{
        static const int size[] = { 4, 2, 2, 2, 6 };
        int i, j, v;

        if (src[8]  != '-' || src[13] != '-' ||
            src[18] != '-' || src[23] != '-')
                return false;

        for (j = 0; j < 5; j++, src++)
                for (i = 0; i < size[j]; i++, src+=2, *dest++ = v)
                        if ((v = wmi_parse_hexbyte (src)) < 0)
                                return false;

        return true;
}

static bool find_guid(const char *guid_string, struct guid_block_t **out)
{
        char tmp[16], guid_input[16];
        struct guid_block_t *block;
        int i;

        DEBUG(2, "find_guid called\n");
        DEBUG(2, "Passing GUID to parser\n");
        wmi_parse_guid(guid_string, tmp);
        wmi_swap_bytes(tmp, guid_input);

        for (i = 0; i < guids.total; i++) {
                block = guids.pointer + i;

                if (memcmp(block->guid, guid_input, 16) == 0) {
                        DEBUG(2, "GUID found - returning block...\n");
                        if (out != NULL)
                                *out = block;
                        return 1;
                }
        }
        return 0;
}

/*
 * Externally callable WMI functions
 */
acpi_status wmi_acer_evaluate_method(const char *guid_string, u32 instance,
u32 method_id, const struct acpi_buffer *in, struct acpi_buffer *out)
{
        struct guid_block_t *block = NULL;
        acpi_status status;
        struct acpi_object_list input;
        union acpi_object wm_params[3];
        char method[4] = "WM";

        if (!find_guid(guid_string, &block))
                return AE_BAD_ADDRESS;

        if (!block->flags & WMIACPI_FLAG_METHOD) {
                DEBUG(2, "GUID is not a method\n");
                return AE_BAD_DATA;
        }

        input.count = 2;
        input.pointer = wm_params;
        wm_params[0].type = ACPI_TYPE_INTEGER;
        wm_params[0].integer.value = instance;
        wm_params[1].type = ACPI_TYPE_INTEGER;
        wm_params[1].integer.value = method_id;

        if (in != NULL) {
                input.count = 3;
                wm_params[2].type = ACPI_TYPE_BUFFER;
                wm_params[2].buffer.length = in->length;
                wm_params[2].buffer.pointer = in->pointer;
        }

        strncat(method, block->object_id, 2);
        strcat(method, "\0");
        DEBUG(2, "Object to call is %s\n", method);

        status = acpi_evaluate_object(acpi_wmi_handle, method, &input, out);

        if ((block->flags & WMIACPI_FLAG_STRING) > 0) {
                /* Convert output from ASCIIZ to Unicode */
                return AE_NOT_IMPLEMENTED;
        }

        return status;
}
EXPORT_SYMBOL(wmi_acer_evaluate_method);

acpi_status wmi_acer_query_block(const char *guid_string, u32 instance,
u32 method_id, struct acpi_buffer *out)
{
        struct guid_block_t *block = NULL;
        acpi_status status;
        struct acpi_object_list input, wc_input;
        union acpi_object wc_params[1], wq_params[1];
        char method[4] = "WQ";
        char wc_method[4] = "WC";

        if (guid_string == NULL || out == NULL)
                return AE_BAD_PARAMETER;

        if (!find_guid(guid_string, &block))
                return AE_BAD_ADDRESS;

        /* Check GUID is a data block */
        if ((block->flags & (WMIACPI_FLAG_EVENT | WMIACPI_FLAG_METHOD)) > 0)
                return AE_BAD_ADDRESS;

        input.count = 1;
        input.pointer = wq_params;
        wq_params[0].type = ACPI_TYPE_INTEGER;
        wq_params[0].integer.value = instance;

        /*
         * If WMIACPI_FLAG_EXPENSIVE, call the relevant WCxx method first to
         * enable collection
         */
        /* FIXME - should INTEGER be STRING? */
        if ((block->flags & WMIACPI_FLAG_EXPENSIVE) > 0) {
                wc_input.count = 1;
                wc_input.pointer = wc_params;
                wc_params[0].type = ACPI_TYPE_INTEGER;
                wc_params[0].integer.value = instance;

                strncat(wc_method, block->object_id, 2);
                strcat(wc_method, "\0");

                status = acpi_evaluate_object(acpi_wmi_handle, wc_method,
                        &wc_input, NULL);

                if (ACPI_FAILURE(status))
                        return AE_ERROR;
        }

        strncat(method, block->object_id, 2);
        strcat(method, "\0");
        DEBUG(2, "Object to call is %s\n", method);

        status = acpi_evaluate_object(acpi_wmi_handle, method, NULL, out);

        /*
         * If WMIACPI_FLAG_EXPENSIVE, call the relevant WCxx method, even if
         * the WQxx method failed - we should disable collection anyway
         */
        if ((block->flags & WMIACPI_FLAG_EXPENSIVE) > 0) {
                wc_params[0].integer.value = 0x0;
                status = acpi_evaluate_object(acpi_wmi_handle,
                wc_method, &wc_input, NULL);
        }

        if (ACPI_SUCCESS(status)) {
                /* Convert output from ASCIIZ to Unicode */
                if ((block->flags & WMIACPI_FLAG_STRING) > 0)
                        return AE_NOT_IMPLEMENTED;
        }

        return status;
}
EXPORT_SYMBOL(wmi_acer_query_block);

acpi_status wmi_acer_set_block(const char *guid_string, u32 instance, u32 method_id,
const struct acpi_buffer *in)
{
        struct guid_block_t *block = NULL;
        struct acpi_object_list input;
        union acpi_object params[2];
        char method[4] = "WS";

        if (guid_string == NULL || in == NULL)
                return AE_BAD_DATA;

        if (!find_guid(guid_string, &block))
                return AE_BAD_ADDRESS;

        /* Check GUID is a data block */
        if ((block->flags & (WMIACPI_FLAG_EVENT | WMIACPI_FLAG_METHOD)) > 0)
                return AE_BAD_ADDRESS;

        input.count = 2;
        input.pointer = params;
        params[0].type = ACPI_TYPE_INTEGER;
        params[0].integer.value = instance;
        params[1].type = ACPI_TYPE_BUFFER;
        params[1].buffer.length = in->length;
        params[1].buffer.pointer = in->pointer;

        /* Convert input from Unicode to ASCIIZ */
        if ((block->flags & WMIACPI_FLAG_STRING) > 0)
                return AE_NOT_IMPLEMENTED;

        strncat(method, block->object_id, 2);
        strcat(method, "\0");
        DEBUG(2, "Object to call is %s\n", method);

        return acpi_evaluate_object(acpi_wmi_handle, method, &input, NULL);
}
EXPORT_SYMBOL(wmi_acer_set_block);

bool wmi_acer_has_guid(char *guid_string)
{
        return find_guid(guid_string, NULL);
}
EXPORT_SYMBOL(wmi_acer_has_guid);

/*
 * Parse the _WDG method for the data blocks
 */
static acpi_status parse_wdg(void)
{
        struct acpi_buffer out = {ACPI_ALLOCATE_BUFFER, NULL};
        union acpi_object *obj;
        acpi_status status;

        status = acpi_evaluate_object(acpi_wmi_handle, "_WDG", NULL, &out);

        if (ACPI_FAILURE(status))
                return status;

        obj = (union acpi_object *) out.pointer;

        if (obj->type != ACPI_TYPE_BUFFER)
                return AE_ERROR;

        guids.pointer = kzalloc(obj->buffer.length, GFP_KERNEL);
        memcpy(guids.pointer, obj->buffer.pointer, obj->buffer.length);
        guids.total = obj->buffer.length / sizeof(struct guid_block_t);

        kfree(out.pointer);

        return status;
}

static void acpi_wmi_notify(acpi_handle handle, u32 event, void *data)
{
        int i;
        struct guid_block_t *block;

        DEBUG(1, "Notifier triggered\n");

        for (i = 0; i < guids.total; i++) {
                block = guids.pointer + i;

                /* FIXME - the last comparison may be broken */
                if ((block->flags & WMIACPI_FLAG_EVENT) > 0 &&
                        block->notification_value == event) {
                        /* Should we generate an event? And how do we pass the results of _WED? */
                }
        }
}

static int acpi_wmi_add(struct acpi_device *device)
{
        acpi_status status;

        acpi_wmi_handle = device->handle;

        status = acpi_install_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
                acpi_wmi_notify, device);

        if (ACPI_FAILURE(status)) {
                ACPI_DEBUG_PRINT((ACPI_DB_ERROR,
                                  "Error installing notify handler\n"));
                return -ENODEV;
        }

        status = parse_wdg();

        if (ACPI_FAILURE(status))
                return -ENODEV;

        return 0;
}

static int acpi_wmi_remove(struct acpi_device *device, int type)
{
        acpi_remove_notify_handler(device->handle, ACPI_DEVICE_NOTIFY,
                acpi_wmi_notify);

        return 0;
}

static int __init acpi_wmi_init(void)
{
        acpi_status result;

        if (acpi_disabled)
                return -ENODEV;

        result = acpi_bus_register_driver(&acpi_wmi_driver);

        if (ACPI_FAILURE(result))
                return -ENODEV;

        printk(KERN_INFO PREFIX "Interface device found\n");
        printk(KERN_INFO PREFIX "Mapper loaded\n");

        return 0;
}

static void __exit acpi_wmi_exit(void)
{
        if (guids.pointer)
                kfree(guids.pointer);
        acpi_bus_unregister_driver(&acpi_wmi_driver);
        printk(KERN_INFO PREFIX "Mapper unloaded\n");
}

module_init(acpi_wmi_init);
module_exit(acpi_wmi_exit);