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/*

 * Copyright © 2009 Keith Packard

 *

 * Permission to use, copy, modify, distribute, and sell this software and its

 * documentation for any purpose is hereby granted without fee, provided that

 * the above copyright notice appear in all copies and that both that copyright

 * notice and this permission notice appear in supporting documentation, and

 * that the name of the copyright holders not be used in advertising or

 * publicity pertaining to distribution of the software without specific,

 * written prior permission.  The copyright holders make no representations

 * about the suitability of this software for any purpose.  It is provided "as

 * is" without express or implied warranty.

 *

 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,

 * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO

 * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR

 * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,

 * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER

 * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE

 * OF THIS SOFTWARE.

 */

#include 

#include 

//#include 

//#include 

#include 

#include 

#include 

#include 

#include 

/**

 * DOC: dp helpers

 *

 * These functions contain some common logic and helpers at various abstraction

 * levels to deal with Display Port sink devices and related things like DP aux

 * channel transfers, EDID reading over DP aux channels, decoding certain DPCD

 * blocks, ...

 */

/* Run a single AUX_CH I2C transaction, writing/reading data as necessary */

static int

i2c_algo_dp_aux_transaction(struct i2c_adapter *adapter, int mode,

			    uint8_t write_byte, uint8_t *read_byte)

{

	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;

	int ret;

	ret = (*algo_data->aux_ch)(adapter, mode,

				   write_byte, read_byte);

	return ret;

}

/*

 * I2C over AUX CH

 */

/*

 * Send the address. If the I2C link is running, this 'restarts'

 * the connection with the new address, this is used for doing

 * a write followed by a read (as needed for DDC)

 */

static int

i2c_algo_dp_aux_address(struct i2c_adapter *adapter, u16 address, bool reading)

{

	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;

	int mode = MODE_I2C_START;

	int ret;

	if (reading)

		mode |= MODE_I2C_READ;

	else

		mode |= MODE_I2C_WRITE;

	algo_data->address = address;

	algo_data->running = true;

	ret = i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL);

	return ret;

}

/*

 * Stop the I2C transaction. This closes out the link, sending

 * a bare address packet with the MOT bit turned off

 */

static void

i2c_algo_dp_aux_stop(struct i2c_adapter *adapter, bool reading)

{

	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;

	int mode = MODE_I2C_STOP;

	if (reading)

		mode |= MODE_I2C_READ;

	else

		mode |= MODE_I2C_WRITE;

	if (algo_data->running) {

		(void) i2c_algo_dp_aux_transaction(adapter, mode, 0, NULL);

		algo_data->running = false;

	}

}

/*

 * Write a single byte to the current I2C address, the

 * the I2C link must be running or this returns -EIO

 */

static int

i2c_algo_dp_aux_put_byte(struct i2c_adapter *adapter, u8 byte)

{

	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;

	int ret;

	if (!algo_data->running)

		return -EIO;

	ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_WRITE, byte, NULL);

	return ret;

}

/*

 * Read a single byte from the current I2C address, the

 * I2C link must be running or this returns -EIO

 */

static int

i2c_algo_dp_aux_get_byte(struct i2c_adapter *adapter, u8 *byte_ret)

{

	struct i2c_algo_dp_aux_data *algo_data = adapter->algo_data;

	int ret;

	if (!algo_data->running)

		return -EIO;

	ret = i2c_algo_dp_aux_transaction(adapter, MODE_I2C_READ, 0, byte_ret);

	return ret;

}

static int

i2c_algo_dp_aux_xfer(struct i2c_adapter *adapter,

		     struct i2c_msg *msgs,

		     int num)

{

	int ret = 0;

	bool reading = false;

	int m;

	int b;

	for (m = 0; m < num; m++) {

		u16 len = msgs[m].len;

		u8 *buf = msgs[m].buf;

		reading = (msgs[m].flags & I2C_M_RD) != 0;

		ret = i2c_algo_dp_aux_address(adapter, msgs[m].addr, reading);

		if (ret < 0)

			break;

		if (reading) {

			for (b = 0; b < len; b++) {

				ret = i2c_algo_dp_aux_get_byte(adapter, &buf[b]);

				if (ret < 0)

					break;

			}

		} else {

			for (b = 0; b < len; b++) {

				ret = i2c_algo_dp_aux_put_byte(adapter, buf[b]);

				if (ret < 0)

					break;

			}

		}

		if (ret < 0)

			break;

	}

	if (ret >= 0)

		ret = num;

	i2c_algo_dp_aux_stop(adapter, reading);

	DRM_DEBUG_KMS("dp_aux_xfer return %d\n", ret);

	return ret;

}

static u32

i2c_algo_dp_aux_functionality(struct i2c_adapter *adapter)

{

	return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL |

	       I2C_FUNC_SMBUS_READ_BLOCK_DATA |

	       I2C_FUNC_SMBUS_BLOCK_PROC_CALL |

	       I2C_FUNC_10BIT_ADDR;

}

static const struct i2c_algorithm i2c_dp_aux_algo = {

	.master_xfer	= i2c_algo_dp_aux_xfer,

	.functionality	= i2c_algo_dp_aux_functionality,

};

static void

i2c_dp_aux_reset_bus(struct i2c_adapter *adapter)

{

	(void) i2c_algo_dp_aux_address(adapter, 0, false);

	(void) i2c_algo_dp_aux_stop(adapter, false);

}

static int

i2c_dp_aux_prepare_bus(struct i2c_adapter *adapter)

{

	adapter->algo = &i2c_dp_aux_algo;

	adapter->retries = 3;

	i2c_dp_aux_reset_bus(adapter);

	return 0;

}

/**

 * i2c_dp_aux_add_bus() - register an i2c adapter using the aux ch helper

 * @adapter: i2c adapter to register

 *

 * This registers an i2c adapater that uses dp aux channel as it's underlaying

 * transport. The driver needs to fill out the &i2c_algo_dp_aux_data structure

 * and store it in the algo_data member of the @adapter argument. This will be

 * used by the i2c over dp aux algorithm to drive the hardware.

 *

 * RETURNS:

 * 0 on success, -ERRNO on failure.

 */

int

i2c_dp_aux_add_bus(struct i2c_adapter *adapter)

{

	int error;

	error = i2c_dp_aux_prepare_bus(adapter);

	if (error)

		return error;

	error = i2c_add_adapter(adapter);

	return error;

}

EXPORT_SYMBOL(i2c_dp_aux_add_bus);

/* Helpers for DP link training */

static u8 dp_link_status(const u8 link_status[DP_LINK_STATUS_SIZE], int r)

{

	return link_status[r - DP_LANE0_1_STATUS];

}

static u8 dp_get_lane_status(const u8 link_status[DP_LINK_STATUS_SIZE],

			     int lane)

{

	int i = DP_LANE0_1_STATUS + (lane >> 1);

	int s = (lane & 1) * 4;

	u8 l = dp_link_status(link_status, i);

	return (l >> s) & 0xf;

}

bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE],

			  int lane_count)

{

	u8 lane_align;

	u8 lane_status;

	int lane;

	lane_align = dp_link_status(link_status,

				    DP_LANE_ALIGN_STATUS_UPDATED);

	if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0)

		return false;

	for (lane = 0; lane < lane_count; lane++) {

		lane_status = dp_get_lane_status(link_status, lane);

		if ((lane_status & DP_CHANNEL_EQ_BITS) != DP_CHANNEL_EQ_BITS)

			return false;

	}

	return true;

}

EXPORT_SYMBOL(drm_dp_channel_eq_ok);

bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],

			      int lane_count)

{

	int lane;

	u8 lane_status;

	for (lane = 0; lane < lane_count; lane++) {

		lane_status = dp_get_lane_status(link_status, lane);

		if ((lane_status & DP_LANE_CR_DONE) == 0)

			return false;

	}

	return true;

}

EXPORT_SYMBOL(drm_dp_clock_recovery_ok);

u8 drm_dp_get_adjust_request_voltage(const u8 link_status[DP_LINK_STATUS_SIZE],

				     int lane)

{

	int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);

	int s = ((lane & 1) ?

		 DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT :

		 DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT);

	u8 l = dp_link_status(link_status, i);

	return ((l >> s) & 0x3) << DP_TRAIN_VOLTAGE_SWING_SHIFT;

}

EXPORT_SYMBOL(drm_dp_get_adjust_request_voltage);

u8 drm_dp_get_adjust_request_pre_emphasis(const u8 link_status[DP_LINK_STATUS_SIZE],

					  int lane)

{

	int i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);

	int s = ((lane & 1) ?

		 DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT :

		 DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT);

	u8 l = dp_link_status(link_status, i);

	return ((l >> s) & 0x3) << DP_TRAIN_PRE_EMPHASIS_SHIFT;

}

EXPORT_SYMBOL(drm_dp_get_adjust_request_pre_emphasis);

void drm_dp_link_train_clock_recovery_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) {

	if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0)

		udelay(100);

	else

		mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4);

}

EXPORT_SYMBOL(drm_dp_link_train_clock_recovery_delay);

void drm_dp_link_train_channel_eq_delay(const u8 dpcd[DP_RECEIVER_CAP_SIZE]) {

	if (dpcd[DP_TRAINING_AUX_RD_INTERVAL] == 0)

		udelay(400);

	else

		mdelay(dpcd[DP_TRAINING_AUX_RD_INTERVAL] * 4);

}

EXPORT_SYMBOL(drm_dp_link_train_channel_eq_delay);

u8 drm_dp_link_rate_to_bw_code(int link_rate)

{

	switch (link_rate) {

	case 162000:

	default:

		return DP_LINK_BW_1_62;

	case 270000:

		return DP_LINK_BW_2_7;

	case 540000:

		return DP_LINK_BW_5_4;

	}

}

EXPORT_SYMBOL(drm_dp_link_rate_to_bw_code);

int drm_dp_bw_code_to_link_rate(u8 link_bw)

{

	switch (link_bw) {

	case DP_LINK_BW_1_62:

	default:

		return 162000;

	case DP_LINK_BW_2_7:

		return 270000;

	case DP_LINK_BW_5_4:

		return 540000;

	}

}

EXPORT_SYMBOL(drm_dp_bw_code_to_link_rate);