/*
 *  Driver for Dell laptop extras
 *
 *  Copyright (c) Red Hat <mjg@redhat.com>
 *
 *  Based on documentation in the libsmbios package, Copyright (C) 2005 Dell
 *  Inc.
 *
 *  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.
 */

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/backlight.h>
#include <linux/err.h>
#include <linux/dmi.h>
#include <linux/io.h>
#include <linux/rfkill.h>
#include <linux/power_supply.h>
#include <linux/acpi.h>
#include "../../firmware/dcdbas.h"

#define BRIGHTNESS_TOKEN 0x7d

/* This structure will be modified by the firmware when we enter
 * system management mode, hence the volatiles */

struct calling_interface_buffer {
	u16 class;
	u16 select;
	volatile u32 input[4];
	volatile u32 output[4];
} __packed;

struct calling_interface_token {
	u16 tokenID;
	u16 location;
	union {
		u16 value;
		u16 stringlength;
	};
};

struct calling_interface_structure {
	struct dmi_header header;
	u16 cmdIOAddress;
	u8 cmdIOCode;
	u32 supportedCmds;
	struct calling_interface_token tokens[];
} __packed;

static int da_command_address;
static int da_command_code;
static int da_num_tokens;
static struct calling_interface_token *da_tokens;

static struct backlight_device *dell_backlight_device;
static struct rfkill *wifi_rfkill;
static struct rfkill *bluetooth_rfkill;
static struct rfkill *wwan_rfkill;

static const struct dmi_system_id __initdata dell_device_table[] = {
	{
		.ident = "Dell laptop",
		.matches = {
			DMI_MATCH(DMI_SYS_VENDOR, "Dell Inc."),
			DMI_MATCH(DMI_CHASSIS_TYPE, "8"),
		},
	},
	{ }
};

static void parse_da_table(const struct dmi_header *dm)
{
	/* Final token is a terminator, so we don't want to copy it */
	int tokens = (dm->length-11)/sizeof(struct calling_interface_token)-1;
	struct calling_interface_structure *table =
		container_of(dm, struct calling_interface_structure, header);

	/* 4 bytes of table header, plus 7 bytes of Dell header, plus at least
	   6 bytes of entry */

	if (dm->length < 17)
		return;

	da_command_address = table->cmdIOAddress;
	da_command_code = table->cmdIOCode;

	da_tokens = krealloc(da_tokens, (da_num_tokens + tokens) *
			     sizeof(struct calling_interface_token),
			     GFP_KERNEL);

	if (!da_tokens)
		return;

	memcpy(da_tokens+da_num_tokens, table->tokens,
	       sizeof(struct calling_interface_token) * tokens);

	da_num_tokens += tokens;
}

static void find_tokens(const struct dmi_header *dm)
{
	switch (dm->type) {
	case 0xd4: /* Indexed IO */
		break;
	case 0xd5: /* Protected Area Type 1 */
		break;
	case 0xd6: /* Protected Area Type 2 */
		break;
	case 0xda: /* Calling interface */
		parse_da_table(dm);
		break;
	}
}

static int find_token_location(int tokenid)
{
	int i;
	for (i = 0; i < da_num_tokens; i++) {
		if (da_tokens[i].tokenID == tokenid)
			return da_tokens[i].location;
	}

	return -1;
}

static struct calling_interface_buffer *
dell_send_request(struct calling_interface_buffer *buffer, int class,
		  int select)
{
	struct smi_cmd command;

	command.magic = SMI_CMD_MAGIC;
	command.command_address = da_command_address;
	command.command_code = da_command_code;
	command.ebx = virt_to_phys(buffer);
	command.ecx = 0x42534931;

	buffer->class = class;
	buffer->select = select;

	dcdbas_smi_request(&command);

	return buffer;
}

/* Derived from information in DellWirelessCtl.cpp:
   Class 17, select 11 is radio control. It returns an array of 32-bit values.

   result[0]: return code
   result[1]:
     Bit 0:      Hardware switch supported
     Bit 1:      Wifi locator supported
     Bit 2:      Wifi is supported
     Bit 3:      Bluetooth is supported
     Bit 4:      WWAN is supported
     Bit 5:      Wireless keyboard supported
     Bits 6-7:   Reserved
     Bit 8:      Wifi is installed
     Bit 9:      Bluetooth is installed
     Bit 10:     WWAN is installed
     Bits 11-15: Reserved
     Bit 16:     Hardware switch is on
     Bit 17:     Wifi is blocked
     Bit 18:     Bluetooth is blocked
     Bit 19:     WWAN is blocked
     Bits 20-31: Reserved
   result[2]: NVRAM size in bytes
   result[3]: NVRAM format version number
*/

static int dell_rfkill_set(int radio, enum rfkill_state state)
{
	struct calling_interface_buffer buffer;
	int disable = (state == RFKILL_STATE_UNBLOCKED) ? 0 : 1;

	memset(&buffer, 0, sizeof(struct calling_interface_buffer));
	buffer.input[0] = (1 | (radio<<8) | (disable << 16));
	dell_send_request(&buffer, 17, 11);

	return 0;
}

static int dell_wifi_set(void *data, enum rfkill_state state)
{
	return dell_rfkill_set(1, state);
}

static int dell_bluetooth_set(void *data, enum rfkill_state state)
{
	return dell_rfkill_set(2, state);
}

static int dell_wwan_set(void *data, enum rfkill_state state)
{
	return dell_rfkill_set(3, state);
}

static int dell_rfkill_get(int bit, enum rfkill_state *state)
{
	struct calling_interface_buffer buffer;
	int status;
	int new_state = RFKILL_STATE_HARD_BLOCKED;

	memset(&buffer, 0, sizeof(struct calling_interface_buffer));
	dell_send_request(&buffer, 17, 11);
	status = buffer.output[1];

	if (status & (1<<16))
		new_state = RFKILL_STATE_SOFT_BLOCKED;

	if (status & (1<<bit))
		*state = new_state;
	else
		*state = RFKILL_STATE_UNBLOCKED;

	return 0;
}

static int dell_wifi_get(void *data, enum rfkill_state *state)
{
	return dell_rfkill_get(17, state);
}

static int dell_bluetooth_get(void *data, enum rfkill_state *state)
{
	return dell_rfkill_get(18, state);
}

static int dell_wwan_get(void *data, enum rfkill_state *state)
{
	return dell_rfkill_get(19, state);
}

static int dell_setup_rfkill(void)
{
	struct calling_interface_buffer buffer;
	int status;
	int ret;

	memset(&buffer, 0, sizeof(struct calling_interface_buffer));
	dell_send_request(&buffer, 17, 11);
	status = buffer.output[1];

	if ((status & (1<<2|1<<8)) == (1<<2|1<<8)) {
		wifi_rfkill = rfkill_allocate(NULL, RFKILL_TYPE_WLAN);
		if (!wifi_rfkill)
			goto err_wifi;
		wifi_rfkill->name = "dell-wifi";
		wifi_rfkill->toggle_radio = dell_wifi_set;
		wifi_rfkill->get_state = dell_wifi_get;
		ret = rfkill_register(wifi_rfkill);
		if (ret)
			goto err_wifi;
	}

	if ((status & (1<<3|1<<9)) == (1<<3|1<<9)) {
		bluetooth_rfkill = rfkill_allocate(NULL, RFKILL_TYPE_BLUETOOTH);
		if (!bluetooth_rfkill)
			goto err_bluetooth;
		bluetooth_rfkill->name = "dell-bluetooth";
		bluetooth_rfkill->toggle_radio = dell_bluetooth_set;
		bluetooth_rfkill->get_state = dell_bluetooth_get;
		ret = rfkill_register(bluetooth_rfkill);
		if (ret)
			goto err_bluetooth;
	}

	if ((status & (1<<4|1<<10)) == (1<<4|1<<10)) {
		wwan_rfkill = rfkill_allocate(NULL, RFKILL_TYPE_WWAN);
		if (!wwan_rfkill)
			goto err_wwan;
		wwan_rfkill->name = "dell-wwan";
		wwan_rfkill->toggle_radio = dell_wwan_set;
		wwan_rfkill->get_state = dell_wwan_get;
		ret = rfkill_register(wwan_rfkill);
		if (ret)
			goto err_wwan;
	}

	return 0;
err_wwan:
	if (wwan_rfkill)
		rfkill_free(wwan_rfkill);
	if (bluetooth_rfkill) {
		rfkill_unregister(bluetooth_rfkill);
		bluetooth_rfkill = NULL;
	}
err_bluetooth:
	if (bluetooth_rfkill)
		rfkill_free(bluetooth_rfkill);
	if (wifi_rfkill) {
		rfkill_unregister(wifi_rfkill);
		wifi_rfkill = NULL;
	}
err_wifi:
	if (wifi_rfkill)
		rfkill_free(wifi_rfkill);

	return ret;
}

static int dell_send_intensity(struct backlight_device *bd)
{
	struct calling_interface_buffer buffer;

	memset(&buffer, 0, sizeof(struct calling_interface_buffer));
	buffer.input[0] = find_token_location(BRIGHTNESS_TOKEN);
	buffer.input[1] = bd->props.brightness;

	if (buffer.input[0] == -1)
		return -ENODEV;

	if (power_supply_is_system_supplied() > 0)
		dell_send_request(&buffer, 1, 2);
	else
		dell_send_request(&buffer, 1, 1);

	return 0;
}

static int dell_get_intensity(struct backlight_device *bd)
{
	struct calling_interface_buffer buffer;

	memset(&buffer, 0, sizeof(struct calling_interface_buffer));
	buffer.input[0] = find_token_location(BRIGHTNESS_TOKEN);

	if (buffer.input[0] == -1)
		return -ENODEV;

	if (power_supply_is_system_supplied() > 0)
		dell_send_request(&buffer, 0, 2);
	else
		dell_send_request(&buffer, 0, 1);

	return buffer.output[1];
}

static struct backlight_ops dell_ops = {
	.get_brightness = dell_get_intensity,
	.update_status  = dell_send_intensity,
};

static int __init dell_init(void)
{
	struct calling_interface_buffer buffer;
	int max_intensity = 0;
	int ret;

	if (!dmi_check_system(dell_device_table))
		return -ENODEV;

	dmi_walk(find_tokens);

	if (!da_tokens)  {
		printk(KERN_INFO "dell-laptop: Unable to find dmi tokens\n");
		return -ENODEV;
	}

	ret = dell_setup_rfkill();

	if (ret) {
		printk(KERN_WARNING "dell-laptop: Unable to setup rfkill\n");
		goto out;
	}

#ifdef CONFIG_ACPI
	/* In the event of an ACPI backlight being available, don't
	 * register the platform controller.
	 */
	if (acpi_video_backlight_support())
		return 0;
#endif

	memset(&buffer, 0, sizeof(struct calling_interface_buffer));
	buffer.input[0] = find_token_location(BRIGHTNESS_TOKEN);

	if (buffer.input[0] != -1) {
		dell_send_request(&buffer, 0, 2);
		max_intensity = buffer.output[3];
	}

	if (max_intensity) {
		dell_backlight_device = backlight_device_register(
			"dell_backlight",
			NULL, NULL,
			&dell_ops);

		if (IS_ERR(dell_backlight_device)) {
			ret = PTR_ERR(dell_backlight_device);
			dell_backlight_device = NULL;
			goto out;
		}

		dell_backlight_device->props.max_brightness = max_intensity;
		dell_backlight_device->props.brightness =
			dell_get_intensity(dell_backlight_device);
		backlight_update_status(dell_backlight_device);
	}

	return 0;
out:
	if (wifi_rfkill)
		rfkill_unregister(wifi_rfkill);
	if (bluetooth_rfkill)
		rfkill_unregister(bluetooth_rfkill);
	if (wwan_rfkill)
		rfkill_unregister(wwan_rfkill);
	kfree(da_tokens);
	return ret;
}

static void __exit dell_exit(void)
{
	backlight_device_unregister(dell_backlight_device);
	if (wifi_rfkill)
		rfkill_unregister(wifi_rfkill);
	if (bluetooth_rfkill)
		rfkill_unregister(bluetooth_rfkill);
	if (wwan_rfkill)
		rfkill_unregister(wwan_rfkill);
}

module_init(dell_init);
module_exit(dell_exit);

MODULE_AUTHOR("Matthew Garrett <mjg@redhat.com>");
MODULE_DESCRIPTION("Dell laptop driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("dmi:*svnDellInc.:*:ct8:*");