/*
 * Twofish for CryptoAPI
 *
 * Originally Twofish for GPG
 * By Matthew Skala <mskala@ansuz.sooke.bc.ca>, July 26, 1998
 * 256-bit key length added March 20, 1999
 * Some modifications to reduce the text size by Werner Koch, April, 1998
 * Ported to the kerneli patch by Marc Mutz <Marc@Mutz.com>
 * Ported to CryptoAPI by Colin Slater <hoho@tacomeat.net>
 *
 * The original author has disclaimed all copyright interest in this
 * code and thus put it in the public domain. The subsequent authors 
 * have put this under the GNU General Public License.
 *
 * 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, see <http://www.gnu.org/licenses/>.
 *
 *
 * This code is a "clean room" implementation, written from the paper
 * _Twofish: A 128-Bit Block Cipher_ by Bruce Schneier, John Kelsey,
 * Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson, available
 * through http://www.counterpane.com/twofish.html
 *
 * For background information on multiplication in finite fields, used for
 * the matrix operations in the key schedule, see the book _Contemporary
 * Abstract Algebra_ by Joseph A. Gallian, especially chapter 22 in the
 * Third Edition.
 */

#include <asm/byteorder.h>
#include <crypto/twofish.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/crypto.h>
#include <linux/bitops.h>

/* Macros to compute the g() function in the encryption and decryption
 * rounds.  G1 is the straight g() function; G2 includes the 8-bit
 * rotation for the high 32-bit word. */

#define G1(a) \
     (ctx->s[0][(a) & 0xFF]) ^ (ctx->s[1][((a) >> 8) & 0xFF]) \
   ^ (ctx->s[2][((a) >> 16) & 0xFF]) ^ (ctx->s[3][(a) >> 24])

#define G2(b) \
     (ctx->s[1][(b) & 0xFF]) ^ (ctx->s[2][((b) >> 8) & 0xFF]) \
   ^ (ctx->s[3][((b) >> 16) & 0xFF]) ^ (ctx->s[0][(b) >> 24])

/* Encryption and decryption Feistel rounds.  Each one calls the two g()
 * macros, does the PHT, and performs the XOR and the appropriate bit
 * rotations.  The parameters are the round number (used to select subkeys),
 * and the four 32-bit chunks of the text. */

#define ENCROUND(n, a, b, c, d) \
   x = G1 (a); y = G2 (b); \
   x += y; y += x + ctx->k[2 * (n) + 1]; \
   (c) ^= x + ctx->k[2 * (n)]; \
   (c) = ror32((c), 1); \
   (d) = rol32((d), 1) ^ y

#define DECROUND(n, a, b, c, d) \
   x = G1 (a); y = G2 (b); \
   x += y; y += x; \
   (d) ^= y + ctx->k[2 * (n) + 1]; \
   (d) = ror32((d), 1); \
   (c) = rol32((c), 1); \
   (c) ^= (x + ctx->k[2 * (n)])

/* Encryption and decryption cycles; each one is simply two Feistel rounds
 * with the 32-bit chunks re-ordered to simulate the "swap" */

#define ENCCYCLE(n) \
   ENCROUND (2 * (n), a, b, c, d); \
   ENCROUND (2 * (n) + 1, c, d, a, b)

#define DECCYCLE(n) \
   DECROUND (2 * (n) + 1, c, d, a, b); \
   DECROUND (2 * (n), a, b, c, d)

/* Macros to convert the input and output bytes into 32-bit words,
 * and simultaneously perform the whitening step.  INPACK packs word
 * number n into the variable named by x, using whitening subkey number m.
 * OUTUNPACK unpacks word number n from the variable named by x, using
 * whitening subkey number m. */

#define INPACK(n, x, m) \
   x = le32_to_cpu(src[n]) ^ ctx->w[m]

#define OUTUNPACK(n, x, m) \
   x ^= ctx->w[m]; \
   dst[n] = cpu_to_le32(x)



/* Encrypt one block.  in and out may be the same. */
static void twofish_encrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	struct twofish_ctx *ctx = crypto_tfm_ctx(tfm);
	const __le32 *src = (const __le32 *)in;
	__le32 *dst = (__le32 *)out;

	/* The four 32-bit chunks of the text. */
	u32 a, b, c, d;
	
	/* Temporaries used by the round function. */
	u32 x, y;

	/* Input whitening and packing. */
	INPACK (0, a, 0);
	INPACK (1, b, 1);
	INPACK (2, c, 2);
	INPACK (3, d, 3);
	
	/* Encryption Feistel cycles. */
	ENCCYCLE (0);
	ENCCYCLE (1);
	ENCCYCLE (2);
	ENCCYCLE (3);
	ENCCYCLE (4);
	ENCCYCLE (5);
	ENCCYCLE (6);
	ENCCYCLE (7);
	
	/* Output whitening and unpacking. */
	OUTUNPACK (0, c, 4);
	OUTUNPACK (1, d, 5);
	OUTUNPACK (2, a, 6);
	OUTUNPACK (3, b, 7);
	
}

/* Decrypt one block.  in and out may be the same. */
static void twofish_decrypt(struct crypto_tfm *tfm, u8 *out, const u8 *in)
{
	struct twofish_ctx *ctx = crypto_tfm_ctx(tfm);
	const __le32 *src = (const __le32 *)in;
	__le32 *dst = (__le32 *)out;
  
	/* The four 32-bit chunks of the text. */
	u32 a, b, c, d;
	
	/* Temporaries used by the round function. */
	u32 x, y;
	
	/* Input whitening and packing. */
	INPACK (0, c, 4);
	INPACK (1, d, 5pre { line-height: 125%; }
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/*
 * Copyright (C) 2006-2008 Michael Hennerich, Analog Devices Inc.
 *
 * Description:	AD7877 based touchscreen, sensor (ADCs), DAC and GPIO driver
 * Based on:	ads7846.c
 *
 * Bugs:        Enter bugs at http://blackfin.uclinux.org/
 *
 * 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, see the file COPYING, or write
 * to the Free Software Foundation, Inc.,
 * 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * History:
 * Copyright (c) 2005 David Brownell
 * Copyright (c) 2006 Nokia Corporation
 * Various changes: Imre Deak <imre.deak@nokia.com>
 *
 * Using code from:
 *  - corgi_ts.c
 *	Copyright (C) 2004-2005 Richard Purdie
 *  - omap_ts.[hc], ads7846.h, ts_osk.c
 *	Copyright (C) 2002 MontaVista Software
 *	Copyright (C) 2004 Texas Instruments
 *	Copyright (C) 2005 Dirk Behme
 */


#include <linux/device.h>
#include <linux/delay.h>
#include <linux/input.h>
#include <linux/interrupt.h>
#include <linux/pm.h>
#include <linux/slab.h>
#include <linux/spi/spi.h>
#include <linux/spi/ad7877.h>
#include <linux/module.h>
#include <asm/irq.h>

#define	TS_PEN_UP_TIMEOUT	msecs_to_jiffies(100)

#define MAX_SPI_FREQ_HZ			20000000
#define	MAX_12BIT			((1<<12)-1)

#define AD7877_REG_ZEROS			0
#define AD7877_REG_CTRL1			1
#define AD7877_REG_CTRL2			2
#define AD7877_REG_ALERT			3
#define AD7877_REG_AUX1HIGH			4
#define AD7877_REG_AUX1LOW			5
#define AD7877_REG_BAT1HIGH			6
#define AD7877_REG_BAT1LOW			7
#define AD7877_REG_BAT2HIGH			8
#define AD7877_REG_BAT2LOW			9
#define AD7877_REG_TEMP1HIGH			10
#define AD7877_REG_TEMP1LOW			11
#define AD7877_REG_SEQ0				12
#define AD7877_REG_SEQ1				13
#define AD7877_REG_DAC				14
#define AD7877_REG_NONE1			15
#define AD7877_REG_EXTWRITE			15
#define AD7877_REG_XPLUS			16
#define AD7877_REG_YPLUS			17
#define AD7877_REG_Z2				18
#define AD7877_REG_aux1				19
#define AD7877_REG_aux2				20
#define AD7877_REG_aux3				21
#define AD7877_REG_bat1				22
#define AD7877_REG_bat2				23
#define AD7877_REG_temp1			24
#define AD7877_REG_temp2			25
#define AD7877_REG_Z1				26
#define AD7877_REG_GPIOCTRL1			27
#define AD7877_REG_GPIOCTRL2			28
#define AD7877_REG_GPIODATA			29
#define AD7877_REG_NONE2			30
#define AD7877_REG_NONE3			31

#define AD7877_SEQ_YPLUS_BIT			(1<<11)
#define AD7877_SEQ_XPLUS_BIT			(1<<10)
#define AD7877_SEQ_Z2_BIT			(1<<9)
#define AD7877_SEQ_AUX1_BIT			(1<<8)
#define AD7877_SEQ_AUX2_BIT			(1<<7)
#define AD7877_SEQ_AUX3_BIT			(1<<6)
#define AD7877_SEQ_BAT1_BIT			(1<<5)
#define AD7877_SEQ_BAT2_BIT			(1<<4)
#define AD7877_SEQ_TEMP1_BIT			(1<<3)
#define AD7877_SEQ_TEMP2_BIT			(1<<2)
#define AD7877_SEQ_Z1_BIT			(1<<1)

enum {
	AD7877_SEQ_YPOS  = 0,
	AD7877_SEQ_XPOS  = 1,
	AD7877_SEQ_Z2    = 2,
	AD7877_SEQ_AUX1  = 3,
	AD7877_SEQ_AUX2  = 4,
	AD7877_SEQ_AUX3  = 5,
	AD7877_SEQ_BAT1  = 6,
	AD7877_SEQ_BAT2  = 7,
	AD7877_SEQ_TEMP1 = 8,
	AD7877_SEQ_TEMP2 = 9,
	AD7877_SEQ_Z1    = 10,
	AD7877_NR_SENSE  = 11,
};

/* DAC Register Default RANGE 0 to Vcc, Volatge Mode, DAC On */
#define AD7877_DAC_CONF			0x1

/* If gpio3 is set AUX3/GPIO3 acts as GPIO Output */
#define AD7877_EXTW_GPIO_3_CONF		0x1C4
#define AD7877_EXTW_GPIO_DATA		0x200

/* Control REG 2 */
#define AD7877_TMR(x)			((x & 0x3) << 0)
#define AD7877_REF(x)			((x & 0x1) << 2)
#define AD7877_POL(x)			((x & 0x1) << 3)
#define AD7877_FCD(x)			((x & 0x3) << 4)
#define AD7877_PM(x)			((x & 0x3) << 6)
#define AD7877_ACQ(x)			((x & 0x3) << 8)
#define AD7877_AVG(x)			((x & 0x3) << 10)

/* Control REG 1 */
#define	AD7877_SER			(1 << 11)	/* non-differential */
#define	AD7877_DFR			(0 << 11)	/* differential */

#define AD7877_MODE_NOC  (0)	/* Do not convert */
#define AD7877_MODE_SCC  (1)	/* Single channel conversion */
#define AD7877_MODE_SEQ0 (2)	/* Sequence 0 in Slave Mode */
#define AD7877_MODE_SEQ1 (3)	/* Sequence 1 in Master Mode */

#define AD7877_CHANADD(x)		((x&0xF)<<7)
#define AD7877_READADD(x)		((x)<<2)
#define AD7877_WRITEADD(x)		((x)<<12)

#define AD7877_READ_CHAN(x) (AD7877_WRITEADD(AD7877_REG_CTRL1) | AD7877_SER | \
		AD7877_MODE_SCC | AD7877_CHANADD(AD7877_REG_ ## x) | \
		AD7877_READADD(AD7877_REG_ ## x))

#define AD7877_MM_SEQUENCE (AD7877_SEQ_YPLUS_BIT | AD7877_SEQ_XPLUS_BIT | \
		AD7877_SEQ_Z2_BIT | AD7877_SEQ_Z1_BIT)

/*
 * Non-touchscreen sensors only use single-ended conversions.
 */

struct ser_req {
	u16			reset;
	u16			ref_on;
	u16			command;
	struct spi_message	msg;
	struct spi_transfer	xfer[6];

	/*
	 * DMA (thus cache coherency maintenance) requires the
	 * transfer buffers to live in their own cache lines.
	 */
	u16 sample ____cacheline_aligned;
};

struct ad7877 {
	struct input_dev	*input;
	char			phys[32];

	struct spi_device	*spi;
	u16			model;
	u16			vref_delay_usecs;
	u16			x_plate_ohms;
	u16			pressure_max;

	u16			cmd_crtl1;
	u16			cmd_crtl2;
	u16			cmd_dummy;
	u16			dac;

	u8			stopacq_polarity;
	u8			first_conversion_delay;
	u8			acquisition_time;
	u8			averaging;
	u8			pen_down_acc_interval;

	struct spi_transfer	xfer[AD7877_NR_SENSE + 2];
	struct spi_message	msg;

	struct mutex		mutex;
	bool			disabled;	/* P: mutex */
	bool			gpio3;		/* P: mutex */
	bool			gpio4;		/* P: mutex */

	spinlock_t		lock;
	struct timer_list	timer;		/* P: lock */

	/*
	 * DMA (thus cache coherency maintenance) requires the
	 * transfer buffers to live in their own cache lines.
	 */
	u16 conversion_data[AD7877_NR_SENSE] ____cacheline_aligned;
};

static bool gpio3;
module_param(gpio3, bool, 0);
MODULE_PARM_DESC(gpio3, "If gpio3 is set to 1 AUX3 acts as GPIO3");

static int ad7877_read(struct spi_device *spi, u16 reg)
{
	struct ser_req *req;
	int status, ret;

	req = kzalloc(sizeof *req, GFP_KERNEL);
	if (!req)
		return -ENOMEM;

	spi_message_init(&req->msg);

	req->command = (u16) (AD7877_WRITEADD(AD7877_REG_CTRL1) |
			AD7877_READADD(reg));
	req->xfer[0].tx_buf = &req->command;
	req->xfer[0].len = 2;
	req->xfer[0].cs_change = 1;

	req->xfer[1].rx_buf = &req->sample;
	req->xfer[1].len = 2;

	spi_message_add_tail(&req->xfer[0], &req->msg);
	spi_message_add_tail(&req->xfer[1], &req->msg);

	status = spi_sync(spi, &req->msg);
	ret = status ? : req->sample;

	kfree(req);

	return ret;
}

static int ad7877_write(struct spi_device *spi, u16 reg, u16 val)
{
	struct ser_req *req;
	int status;

	req = kzalloc(sizeof *req, GFP_KERNEL);
	if (!req)
		return -ENOMEM;

	spi_message_init(&req->msg);

	req->command = (u16) (AD7877_WRITEADD(reg) | (val & MAX_12BIT));
	req->xfer[0].tx_buf = &req->command;
	req->xfer[0].len = 2;

	spi_message_add_tail(&req->xfer[0], &req->msg);

	status = spi_sync(spi,