path: root/drivers/net/wireless/rt2x00/rt2800usb.c

/*
	Copyright (C) 2009 Ivo van Doorn <IvDoorn@gmail.com>
	Copyright (C) 2009 Mattias Nissler <mattias.nissler@gmx.de>
	Copyright (C) 2009 Felix Fietkau <nbd@openwrt.org>
	Copyright (C) 2009 Xose Vazquez Perez <xose.vazquez@gmail.com>
	Copyright (C) 2009 Axel Kollhofer <rain_maker@root-forum.org>
	<http://rt2x00.serialmonkey.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.
 */

/*
	Module: rt2800usb
	Abstract: rt2800usb device specific routines.
	Supported chipsets: RT2800U.
 */

#include <linux/crc-ccitt.h>
#include <linux/delay.h>
#include <linux/etherdevice.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/usb.h>

#include "rt2x00.h"
#include "rt2x00usb.h"
#include "rt2800lib.h"
#include "rt2800.h"
#include "rt2800usb.h"

/*
 * Allow hardware encryption to be disabled.
 */
static int modparam_nohwcrypt = 1;
module_param_named(nohwcrypt, modparam_nohwcrypt, bool, S_IRUGO);
MODULE_PARM_DESC(nohwcrypt, "Disable hardware encryption.");

/*
 * Firmware functions
 */
static char *rt2800usb_get_firmware_name(struct rt2x00_dev *rt2x00dev)
{
	return FIRMWARE_RT2870;
}

static bool rt2800usb_check_crc(const u8 *data, const size_t len)
{
	u16 fw_crc;
	u16 crc;

	/*
	 * The last 2 bytes in the firmware array are the crc checksum itself,
	 * this means that we should never pass those 2 bytes to the crc
	 * algorithm.
	 */
	fw_crc = (data[len - 2] << 8 | data[len - 1]);

	/*
	 * Use the crc ccitt algorithm.
	 * This will return the same value as the legacy driver which
	 * used bit ordering reversion on the both the firmware bytes
	 * before input input as well as on the final output.
	 * Obviously using crc ccitt directly is much more efficient.
	 */
	crc = crc_ccitt(~0, data, len - 2);

	/*
	 * There is a small difference between the crc-itu-t + bitrev and
	 * the crc-ccitt crc calculation. In the latter method the 2 bytes
	 * will be swapped, use swab16 to convert the crc to the correct
	 * value.
	 */
	crc = swab16(crc);

	return fw_crc == crc;
}

static int rt2800usb_check_firmware(struct rt2x00_dev *rt2x00dev,
				    const u8 *data, const size_t len)
{
	size_t offset = 0;

	/*
	 * Firmware files:
	 * There are 2 variations of the rt2870 firmware.
	 * a) size: 4kb
	 * b) size: 8kb
	 * Note that (b) contains 2 seperate firmware blobs of 4k
	 * within the file. The first blob is the same firmware as (a),
	 * but the second blob is for the additional chipsets.
	 */
	if (len != 4096 && len != 8192)
		return FW_BAD_LENGTH;

	/*
	 * Check if we need the upper 4kb firmware data or not.
	 */
	if ((len == 4096) &&
	    !rt2x00_rt(rt2x00dev, RT2860) &&
	    !rt2x00_rt(rt2x00dev, RT2872) &&
	    !rt2x00_rt(rt2x00dev, RT3070))
		return FW_BAD_VERSION;

	/*
	 * 8kb firmware files must be checked as if it were
	 * 2 seperate firmware files.
	 */
	while (offset < len) {
		if (!rt2800usb_check_crc(data + offset, 4096))
			return FW_BAD_CRC;

		offset += 4096;
	}

	return FW_OK;
}

static int rt2800usb_load_firmware(struct rt2x00_dev *rt2x00dev,
				   const u8 *data, const size_t len)
{
	unsigned int i;
	int status;
	u32 reg;
	u32 offset;
	u32 length;

	/*
	 * Check which section of the firmware we need.
	 */
	if (rt2x00_rt(rt2x00dev, RT2860) ||
	    rt2x00_rt(rt2x00dev, RT2872) ||
	    rt2x00_rt(rt2x00dev, RT3070)) {
		offset = 0;
		length = 4096;
	} else {
		offset = 4096;
		length = 4096;
	}

	/*
	 * Wait for stable hardware.
	 */
	for (i = 0; i < REGISTER_BUSY_COUNT; i++) {
		rt2800_register_read(rt2x00dev, MAC_CSR0, &reg);
		if (reg && reg != ~0)
			break;
		msleep(