drivers/gpu/drm/msm/dp/dp_aux.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * Copyright (c) 2012-2020, The Linux Foundation. All rights reserved.
  */

 #include <linux/delay.h>
 #include <drm/drm_print.h>

 #include "dp_reg.h"
 #include "dp_aux.h"

 #define DP_AUX_ENUM_STR(x)		#x

 struct dp_aux_private {
 	struct device *dev;
 	struct dp_catalog *catalog;

 	struct mutex mutex;
 	struct completion comp;

 	u32 aux_error_num;
 	u32 retry_cnt;
 	bool cmd_busy;
 	bool native;
 	bool read;
 	bool no_send_addr;
 	bool no_send_stop;
 	u32 offset;
 	u32 segment;
 	u32 isr;

 	struct drm_dp_aux dp_aux;
 };

 static const char *dp_aux_get_error(u32 aux_error)
 {
 	switch (aux_error) {
 	case DP_AUX_ERR_NONE:
 		return DP_AUX_ENUM_STR(DP_AUX_ERR_NONE);
 	case DP_AUX_ERR_ADDR:
 		return DP_AUX_ENUM_STR(DP_AUX_ERR_ADDR);
 	case DP_AUX_ERR_TOUT:
 		return DP_AUX_ENUM_STR(DP_AUX_ERR_TOUT);
 	case DP_AUX_ERR_NACK:
 		return DP_AUX_ENUM_STR(DP_AUX_ERR_NACK);
 	case DP_AUX_ERR_DEFER:
 		return DP_AUX_ENUM_STR(DP_AUX_ERR_DEFER);
 	case DP_AUX_ERR_NACK_DEFER:
 		return DP_AUX_ENUM_STR(DP_AUX_ERR_NACK_DEFER);
 	default:
 		return "unknown";
 	}
 }

 static u32 dp_aux_write(struct dp_aux_private *aux,
 			struct drm_dp_aux_msg *msg)
 {
 	u32 data[4], reg, len;
 	u8 *msgdata = msg->buffer;
 	int const AUX_CMD_FIFO_LEN = 128;
 	int i = 0;

 	if (aux->read)
 		len = 4;
 	else
 		len = msg->size + 4;

 	/*
 	 * cmd fifo only has depth of 144 bytes
 	 * limit buf length to 128 bytes here
 	 */
 	if (len > AUX_CMD_FIFO_LEN) {
 		DRM_ERROR("buf size greater than allowed size of 128 bytes\n");
 		return 0;
 	}

 	/* Pack cmd and write to HW */
 	data[0] = (msg->address >> 16) & 0xf; /* addr[19:16] */
 	if (aux->read)
 		data[0] |=  BIT(4); /* R/W */

 	data[1] = (msg->address >> 8) & 0xff;	/* addr[15:8] */
 	data[2] = msg->address & 0xff;		/* addr[7:0] */
 	data[3] = (msg->size - 1) & 0xff;	/* len[7:0] */

 	for (i = 0; i < len; i++) {
 		reg = (i < 4) ? data[i] : msgdata[i - 4];
 		/* index = 0, write */
 		reg = (((reg) << DP_AUX_DATA_OFFSET)
 		       & DP_AUX_DATA_MASK) | DP_AUX_DATA_WRITE;
 		if (i == 0)
 			reg |= DP_AUX_DATA_INDEX_WRITE;
 		aux->catalog->aux_data = reg;
 		dp_catalog_aux_write_data(aux->catalog);
 	}

 	dp_catalog_aux_clear_trans(aux->catalog, false);
 	dp_catalog_aux_clear_hw_interrupts(aux->catalog);

 	reg = 0; /* Transaction number == 1 */
 	if (!aux->native) { /* i2c */
 		reg |= DP_AUX_TRANS_CTRL_I2C;

 		if (aux->no_send_addr)
 			reg |= DP_AUX_TRANS_CTRL_NO_SEND_ADDR;

 		if (aux->no_send_stop)
 			reg |= DP_AUX_TRANS_CTRL_NO_SEND_STOP;
 	}

 	reg |= DP_AUX_TRANS_CTRL_GO;
 	aux->catalog->aux_data = reg;
 	dp_catalog_aux_write_trans(aux->catalog);

 	return len;
 }

 static int dp_aux_cmd_fifo_tx(struct dp_aux_private *aux,
 			      struct drm_dp_aux_msg *msg)
 {
 	u32 ret, len, timeout;
 	int aux_timeout_ms = HZ/4;

 	reinit_completion(&aux->comp);

 	len = dp_aux_write(aux, msg);
 	if (len == 0) {
 		DRM_ERROR("DP AUX write failed\n");
 		return -EINVAL;
 	}

 	timeout = wait_for_completion_timeout(&aux->comp, aux_timeout_ms);
 	if (!timeout) {
 		DRM_ERROR("aux %s timeout\n", (aux->read ? "read" : "write"));
 		return -ETIMEDOUT;
 	}

 	if (aux->aux_error_num == DP_AUX_ERR_NONE) {
 		ret = len;
 	} else {
 		DRM_ERROR_RATELIMITED("aux err: %s\n",
 			dp_aux_get_error(aux->aux_error_num));

 		ret = -EINVAL;
 	}

 	return ret;
 }

 static void dp_aux_cmd_fifo_rx(struct dp_aux_private *aux,
 		struct drm_dp_aux_msg *msg)
 {
 	u32 data;
 	u8 *dp;
 	u32 i, actual_i;
 	u32 len = msg->size;

 	dp_catalog_aux_clear_trans(aux->catalog, true);

 	data = DP_AUX_DATA_INDEX_WRITE; /* INDEX_WRITE */
 	data |= DP_AUX_DATA_READ;  /* read */

 	aux->catalog->aux_data = data;
 	dp_catalog_aux_write_data(aux->catalog);

 	dp = msg->buffer;

 	/* discard first byte */
 	data = dp_catalog_aux_read_data(aux->catalog);

 	for (i = 0; i < len; i++) {
 		data = dp_catalog_aux_read_data(aux->catalog);
 		*dp++ = (u8)((data >> DP_AUX_DATA_OFFSET) & 0xff);

 		actual_i = (data >> DP_AUX_DATA_INDEX_OFFSET) & 0xFF;
 		if (i != actual_i)
 			DRM_ERROR("Index mismatch: expected %d, found %d\n",
 				i, actual_i);
 	}
 }

 static void dp_aux_native_handler(struct dp_aux_private *aux)
 {
 	u32 isr = aux->isr;

 	if (isr & DP_INTR_AUX_I2C_DONE)
 		aux->aux_error_num = DP_AUX_ERR_NONE;
 	else if (isr & DP_INTR_WRONG_ADDR)
 		aux->aux_error_num = DP_AUX_ERR_ADDR;
 	else if (isr & DP_INTR_TIMEOUT)
 		aux->aux_error_num = DP_AUX_ERR_TOUT;
 	if (isr & DP_INTR_NACK_DEFER)
 		aux->aux_error_num = DP_AUX_ERR_NACK;
 	if (isr & DP_INTR_AUX_ERROR) {
 		aux->aux_error_num = DP_AUX_ERR_PHY;
 		dp_catalog_aux_clear_hw_interrupts(aux->catalog);
 	}

 	complete(&aux->comp);
 }

 static void dp_aux_i2c_handler(struct dp_aux_private *aux)
 {
 	u32 isr = aux->isr;

 	if (isr & DP_INTR_AUX_I2C_DONE) {
 		if (isr & (DP_INTR_I2C_NACK | DP_INTR_I2C_DEFER))
 			aux->aux_error_num = DP_AUX_ERR_NACK;
 		else
 			aux->aux_error_num = DP_AUX_ERR_NONE;
 	} else {
 		if (isr & DP_INTR_WRONG_ADDR)
 			aux->aux_error_num = DP_AUX_ERR_ADDR;
 		else if (isr & DP_INTR_TIMEOUT)
 			aux->aux_error_num = DP_AUX_ERR_TOUT;
 		if (isr & DP_INTR_NACK_DEFER)
 			aux->aux_error_num = DP_AUX_ERR_NACK_DEFER;
 		if (isr & DP_INTR_I2C_NACK)
 			aux->aux_error_num = DP_AUX_ERR_NACK;
 		if (isr & DP_INTR_I2C_DEFER)
 			aux->aux_error_num = DP_AUX_ERR_DEFER;
 		if (isr & DP_INTR_AUX_ERROR) {
 			aux->aux_error_num = DP_AUX_ERR_PHY;
 			dp_catalog_aux_clear_hw_interrupts(aux->catalog);
 		}
 	}

 	complete(&aux->comp);
 }

 static void dp_aux_update_offset_and_segment(struct dp_aux_private *aux,
 					     struct drm_dp_aux_msg *input_msg)
 {
 	u32 edid_address = 0x50;
 	u32 segment_address = 0x30;
 	bool i2c_read = input_msg->request &
 		(DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
 	u8 *data;

 	if (aux->native || i2c_read || ((input_msg->address != edid_address) &&
 		(input_msg->address != segment_address)))
 		return;


 	data = input_msg->buffer;
 	if (input_msg->address == segment_address)
 		aux->segment = *data;
 	else
 		aux->offset = *data;
 }

 /**
  * dp_aux_transfer_helper() - helper function for EDID read transactions
  *
  * @aux: DP AUX private structure
  * @input_msg: input message from DRM upstream APIs
  * @send_seg: send the segment to sink
  *
  * return: void
  *
  * This helper function is used to fix EDID reads for non-compliant
  * sinks that do not handle the i2c middle-of-transaction flag correctly.
  */
 static void dp_aux_transfer_helper(struct dp_aux_private *aux,
 				   struct drm_dp_aux_msg *input_msg,
 				   bool send_seg)
 {
 	struct drm_dp_aux_msg helper_msg;
 	u32 message_size = 0x10;
 	u32 segment_address = 0x30;
 	u32 const edid_block_length = 0x80;
 	bool i2c_mot = input_msg->request & DP_AUX_I2C_MOT;
 	bool i2c_read = input_msg->request &
 		(DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);

 	if (!i2c_mot || !i2c_read || (input_msg->size == 0))
 		return;

 	/*
 	 * Sending the segment value and EDID offset will be performed
 	 * from the DRM upstream EDID driver for each block. Avoid
 	 * duplicate AUX transactions related to this while reading the
 	 * first 16 bytes of each block.
 	 */
 	if (!(aux->offset % edid_block_length) || !send_seg)
 		goto end;

 	aux->read = false;
 	aux->cmd_busy = true;
 	aux->no_send_addr = true;
 	aux->no_send_stop = true;

 	/*
 	 * Send the segment address for every i2c read in which the
 	 * middle-of-tranaction flag is set. This is required to support EDID
 	 * reads of more than 2 blocks as the segment address is reset to 0
 	 * since we are overriding the middle-of-transaction flag for read
 	 * transactions.
 	 */

 	if (aux->segment) {
 		memset(&helper_msg, 0, sizeof(helper_msg));
 		helper_msg.address = segment_address;
 		helper_msg.buffer = &aux->segment;
 		helper_msg.size = 1;
 		dp_aux_cmd_fifo_tx(aux, &helper_msg);
 	}

 	/*
 	 * Send the offset address for every i2c read in which the
 	 * middle-of-transaction flag is set. This will ensure that the sink
 	 * will update its read pointer and return the correct portion of the
 	 * EDID buffer in the subsequent i2c read trasntion triggered in the
 	 * native AUX transfer function.
 	 */
 	memset(&helper_msg, 0, sizeof(helper_msg));
 	helper_msg.address = input_msg->address;
 	helper_msg.buffer = &aux->offset;
 	helper_msg.size = 1;
 	dp_aux_cmd_fifo_tx(aux, &helper_msg);

 end:
 	aux->offset += message_size;
 	if (aux->offset == 0x80 || aux->offset == 0x100)
 		aux->segment = 0x0; /* reset segment at end of block */
 }

 /*
  * This function does the real job to process an AUX transaction.
  * It will call aux_reset() function to reset the AUX channel,
  * if the waiting is timeout.
  */
 static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
 			       struct drm_dp_aux_msg *msg)
 {
 	ssize_t ret;
 	int const aux_cmd_native_max = 16;
 	int const aux_cmd_i2c_max = 128;
 	int const retry_count = 5;
 	struct dp_aux_private *aux = container_of(dp_aux,
 		struct dp_aux_private, dp_aux);

 	mutex_lock(&aux->mutex);

 	aux->native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);

 	/* Ignore address only message */
 	if ((msg->size == 0) || (msg->buffer == NULL)) {
 		msg->reply = aux->native ?
 			DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
 		ret = msg->size;
 		goto unlock_exit;
 	}

 	/* msg sanity check */
 	if ((aux->native && (msg->size > aux_cmd_native_max)) ||
 		(msg->size > aux_cmd_i2c_max)) {
 		DRM_ERROR("%s: invalid msg: size(%zu), request(%x)\n",
 			__func__, msg->size, msg->request);
 		ret = -EINVAL;
 		goto unlock_exit;
 	}

 	dp_aux_update_offset_and_segment(aux, msg);
 	dp_aux_transfer_helper(aux, msg, true);

 	aux->read = msg->request & (DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
 	aux->cmd_busy = true;

 	if (aux->read) {
 		aux->no_send_addr = true;
 		aux->no_send_stop = false;
 	} else {
 		aux->no_send_addr = true;
 		aux->no_send_stop = true;
 	}

 	ret = dp_aux_cmd_fifo_tx(aux, msg);

 	if (ret < 0) {
 		if (aux->native) {
 			aux->retry_cnt++;
 			if (!(aux->retry_cnt % retry_count))
 				dp_catalog_aux_update_cfg(aux->catalog);
 			dp_catalog_aux_reset(aux->catalog);
 		}
 		usleep_range(400, 500); /* at least 400us to next try */
 		goto unlock_exit;
 	}

 	if (aux->aux_error_num == DP_AUX_ERR_NONE) {
 		if (aux->read)
 			dp_aux_cmd_fifo_rx(aux, msg);

 		msg->reply = aux->native ?
 			DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
 	} else {
 		/* Reply defer to retry */
 		msg->reply = aux->native ?
 			DP_AUX_NATIVE_REPLY_DEFER : DP_AUX_I2C_REPLY_DEFER;
 	}

 	/* Return requested size for success or retry */
 	ret = msg->size;
 	aux->retry_cnt = 0;

 unlock_exit:
 	aux->cmd_busy = false;
 	mutex_unlock(&aux->mutex);
 	return ret;
 }

 void dp_aux_isr(struct drm_dp_aux *dp_aux)
 {
 	struct dp_aux_private *aux;

 	if (!dp_aux) {
 		DRM_ERROR("invalid input\n");
 		return;
 	}

 	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

 	aux->isr = dp_catalog_aux_get_irq(aux->catalog);

 	if (!aux->cmd_busy)
 		return;

 	if (aux->native)
 		dp_aux_native_handler(aux);
 	else
 		dp_aux_i2c_handler(aux);
 }

 void dp_aux_reconfig(struct drm_dp_aux *dp_aux)
 {
 	struct dp_aux_private *aux;

 	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

 	dp_catalog_aux_update_cfg(aux->catalog);
 	dp_catalog_aux_reset(aux->catalog);
 }

 void dp_aux_init(struct drm_dp_aux *dp_aux)
 {
 	struct dp_aux_private *aux;

 	if (!dp_aux) {
 		DRM_ERROR("invalid input\n");
 		return;
 	}

 	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

 	dp_catalog_aux_enable(aux->catalog, true);
 	aux->retry_cnt = 0;
 }

 void dp_aux_deinit(struct drm_dp_aux *dp_aux)
 {
 	struct dp_aux_private *aux;

 	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

 	dp_catalog_aux_enable(aux->catalog, false);
 }

 int dp_aux_register(struct drm_dp_aux *dp_aux)
 {
 	struct dp_aux_private *aux;
 	int ret;

 	if (!dp_aux) {
 		DRM_ERROR("invalid input\n");
 		return -EINVAL;
 	}

 	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

 	aux->dp_aux.name = "dpu_dp_aux";
 	aux->dp_aux.dev = aux->dev;
 	aux->dp_aux.transfer = dp_aux_transfer;
 	ret = drm_dp_aux_register(&aux->dp_aux);
 	if (ret) {
 		DRM_ERROR("%s: failed to register drm aux: %d\n", __func__,
 				ret);
 		return ret;
 	}

 	return 0;
 }

 void dp_aux_unregister(struct drm_dp_aux *dp_aux)
 {
 	drm_dp_aux_unregister(dp_aux);
 }

 struct drm_dp_aux *dp_aux_get(struct device *dev, struct dp_catalog *catalog)
 {
 	struct dp_aux_private *aux;

 	if (!catalog) {
 		DRM_ERROR("invalid input\n");
 		return ERR_PTR(-ENODEV);
 	}

 	aux = devm_kzalloc(dev, sizeof(*aux), GFP_KERNEL);
 	if (!aux)
 		return ERR_PTR(-ENOMEM);

 	init_completion(&aux->comp);
 	aux->cmd_busy = false;
 	mutex_init(&aux->mutex);

 	aux->dev = dev;
 	aux->catalog = catalog;
 	aux->retry_cnt = 0;

 	return &aux->dp_aux;
 }

 void dp_aux_put(struct drm_dp_aux *dp_aux)
 {
 	struct dp_aux_private *aux;

 	if (!dp_aux)
 		return;

 	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

 	mutex_destroy(&aux->mutex);

 	devm_kfree(aux->dev, aux);
 }
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* Copyright (c) 2012-2020, The Linux Foundation. All rights reserved.
	*/

	#include <linux/delay.h>
	#include <drm/drm_print.h>

	#include "dp_reg.h"
	#include "dp_aux.h"

	#define DP_AUX_ENUM_STR(x) #x

	struct dp_aux_private {
	struct device *dev;
	struct dp_catalog *catalog;

	struct mutex mutex;
	struct completion comp;

	u32 aux_error_num;
	u32 retry_cnt;
	bool cmd_busy;
	bool native;
	bool read;
	bool no_send_addr;
	bool no_send_stop;
	u32 offset;
	u32 segment;
	u32 isr;

	struct drm_dp_aux dp_aux;
	};

	static const char *dp_aux_get_error(u32 aux_error)
	{
	switch (aux_error) {
	case DP_AUX_ERR_NONE:
	return DP_AUX_ENUM_STR(DP_AUX_ERR_NONE);
	case DP_AUX_ERR_ADDR:
	return DP_AUX_ENUM_STR(DP_AUX_ERR_ADDR);
	case DP_AUX_ERR_TOUT:
	return DP_AUX_ENUM_STR(DP_AUX_ERR_TOUT);
	case DP_AUX_ERR_NACK:
	return DP_AUX_ENUM_STR(DP_AUX_ERR_NACK);
	case DP_AUX_ERR_DEFER:
	return DP_AUX_ENUM_STR(DP_AUX_ERR_DEFER);
	case DP_AUX_ERR_NACK_DEFER:
	return DP_AUX_ENUM_STR(DP_AUX_ERR_NACK_DEFER);
	default:
	return "unknown";
	}
	}

	static u32 dp_aux_write(struct dp_aux_private *aux,
	struct drm_dp_aux_msg *msg)
	{
	u32 data[4], reg, len;
	u8 *msgdata = msg->buffer;
	int const AUX_CMD_FIFO_LEN = 128;
	int i = 0;

	if (aux->read)
	len = 4;
	else
	len = msg->size + 4;

	/*
	* cmd fifo only has depth of 144 bytes
	* limit buf length to 128 bytes here
	*/
	if (len > AUX_CMD_FIFO_LEN) {
	DRM_ERROR("buf size greater than allowed size of 128 bytes\n");
	return 0;
	}

	/* Pack cmd and write to HW */
	data[0] = (msg->address >> 16) & 0xf; /* addr[19:16] */
	if (aux->read)
	data[0] \|= BIT(4); /* R/W */

	data[1] = (msg->address >> 8) & 0xff; /* addr[15:8] */
	data[2] = msg->address & 0xff; /* addr[7:0] */
	data[3] = (msg->size - 1) & 0xff; /* len[7:0] */

	for (i = 0; i < len; i++) {
	reg = (i < 4) ? data[i] : msgdata[i - 4];
	/* index = 0, write */
	reg = (((reg) << DP_AUX_DATA_OFFSET)
	& DP_AUX_DATA_MASK) \| DP_AUX_DATA_WRITE;
	if (i == 0)
	reg \|= DP_AUX_DATA_INDEX_WRITE;
	aux->catalog->aux_data = reg;
	dp_catalog_aux_write_data(aux->catalog);
	}

	dp_catalog_aux_clear_trans(aux->catalog, false);
	dp_catalog_aux_clear_hw_interrupts(aux->catalog);

	reg = 0; /* Transaction number == 1 */
	if (!aux->native) { /* i2c */
	reg \|= DP_AUX_TRANS_CTRL_I2C;

	if (aux->no_send_addr)
	reg \|= DP_AUX_TRANS_CTRL_NO_SEND_ADDR;

	if (aux->no_send_stop)
	reg \|= DP_AUX_TRANS_CTRL_NO_SEND_STOP;
	}

	reg \|= DP_AUX_TRANS_CTRL_GO;
	aux->catalog->aux_data = reg;
	dp_catalog_aux_write_trans(aux->catalog);

	return len;
	}

	static int dp_aux_cmd_fifo_tx(struct dp_aux_private *aux,
	struct drm_dp_aux_msg *msg)
	{
	u32 ret, len, timeout;
	int aux_timeout_ms = HZ/4;

	reinit_completion(&aux->comp);

	len = dp_aux_write(aux, msg);
	if (len == 0) {
	DRM_ERROR("DP AUX write failed\n");
	return -EINVAL;
	}

	timeout = wait_for_completion_timeout(&aux->comp, aux_timeout_ms);
	if (!timeout) {
	DRM_ERROR("aux %s timeout\n", (aux->read ? "read" : "write"));
	return -ETIMEDOUT;
	}

	if (aux->aux_error_num == DP_AUX_ERR_NONE) {
	ret = len;
	} else {
	DRM_ERROR_RATELIMITED("aux err: %s\n",
	dp_aux_get_error(aux->aux_error_num));

	ret = -EINVAL;
	}

	return ret;
	}

	static void dp_aux_cmd_fifo_rx(struct dp_aux_private *aux,
	struct drm_dp_aux_msg *msg)
	{
	u32 data;
	u8 *dp;
	u32 i, actual_i;
	u32 len = msg->size;

	dp_catalog_aux_clear_trans(aux->catalog, true);

	data = DP_AUX_DATA_INDEX_WRITE; /* INDEX_WRITE */
	data \|= DP_AUX_DATA_READ; /* read */

	aux->catalog->aux_data = data;
	dp_catalog_aux_write_data(aux->catalog);

	dp = msg->buffer;

	/* discard first byte */
	data = dp_catalog_aux_read_data(aux->catalog);

	for (i = 0; i < len; i++) {
	data = dp_catalog_aux_read_data(aux->catalog);
	*dp++ = (u8)((data >> DP_AUX_DATA_OFFSET) & 0xff);

	actual_i = (data >> DP_AUX_DATA_INDEX_OFFSET) & 0xFF;
	if (i != actual_i)
	DRM_ERROR("Index mismatch: expected %d, found %d\n",
	i, actual_i);
	}
	}

	static void dp_aux_native_handler(struct dp_aux_private *aux)
	{
	u32 isr = aux->isr;

	if (isr & DP_INTR_AUX_I2C_DONE)
	aux->aux_error_num = DP_AUX_ERR_NONE;
	else if (isr & DP_INTR_WRONG_ADDR)
	aux->aux_error_num = DP_AUX_ERR_ADDR;
	else if (isr & DP_INTR_TIMEOUT)
	aux->aux_error_num = DP_AUX_ERR_TOUT;
	if (isr & DP_INTR_NACK_DEFER)
	aux->aux_error_num = DP_AUX_ERR_NACK;
	if (isr & DP_INTR_AUX_ERROR) {
	aux->aux_error_num = DP_AUX_ERR_PHY;
	dp_catalog_aux_clear_hw_interrupts(aux->catalog);
	}

	complete(&aux->comp);
	}

	static void dp_aux_i2c_handler(struct dp_aux_private *aux)
	{
	u32 isr = aux->isr;

	if (isr & DP_INTR_AUX_I2C_DONE) {
	if (isr & (DP_INTR_I2C_NACK \| DP_INTR_I2C_DEFER))
	aux->aux_error_num = DP_AUX_ERR_NACK;
	else
	aux->aux_error_num = DP_AUX_ERR_NONE;
	} else {
	if (isr & DP_INTR_WRONG_ADDR)
	aux->aux_error_num = DP_AUX_ERR_ADDR;
	else if (isr & DP_INTR_TIMEOUT)
	aux->aux_error_num = DP_AUX_ERR_TOUT;
	if (isr & DP_INTR_NACK_DEFER)
	aux->aux_error_num = DP_AUX_ERR_NACK_DEFER;
	if (isr & DP_INTR_I2C_NACK)
	aux->aux_error_num = DP_AUX_ERR_NACK;
	if (isr & DP_INTR_I2C_DEFER)
	aux->aux_error_num = DP_AUX_ERR_DEFER;
	if (isr & DP_INTR_AUX_ERROR) {
	aux->aux_error_num = DP_AUX_ERR_PHY;
	dp_catalog_aux_clear_hw_interrupts(aux->catalog);
	}
	}

	complete(&aux->comp);
	}

	static void dp_aux_update_offset_and_segment(struct dp_aux_private *aux,
	struct drm_dp_aux_msg *input_msg)
	{
	u32 edid_address = 0x50;
	u32 segment_address = 0x30;
	bool i2c_read = input_msg->request &
	(DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
	u8 *data;

	if (aux->native \|\| i2c_read \|\| ((input_msg->address != edid_address) &&
	(input_msg->address != segment_address)))
	return;


	data = input_msg->buffer;
	if (input_msg->address == segment_address)
	aux->segment = *data;
	else
	aux->offset = *data;
	}

	/**
	* dp_aux_transfer_helper() - helper function for EDID read transactions
	*
	* @aux: DP AUX private structure
	* @input_msg: input message from DRM upstream APIs
	* @send_seg: send the segment to sink
	*
	* return: void
	*
	* This helper function is used to fix EDID reads for non-compliant
	* sinks that do not handle the i2c middle-of-transaction flag correctly.
	*/
	static void dp_aux_transfer_helper(struct dp_aux_private *aux,
	struct drm_dp_aux_msg *input_msg,
	bool send_seg)
	{
	struct drm_dp_aux_msg helper_msg;
	u32 message_size = 0x10;
	u32 segment_address = 0x30;
	u32 const edid_block_length = 0x80;
	bool i2c_mot = input_msg->request & DP_AUX_I2C_MOT;
	bool i2c_read = input_msg->request &
	(DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);

	if (!i2c_mot \|\| !i2c_read \|\| (input_msg->size == 0))
	return;

	/*
	* Sending the segment value and EDID offset will be performed
	* from the DRM upstream EDID driver for each block. Avoid
	* duplicate AUX transactions related to this while reading the
	* first 16 bytes of each block.
	*/
	if (!(aux->offset % edid_block_length) \|\| !send_seg)
	goto end;

	aux->read = false;
	aux->cmd_busy = true;
	aux->no_send_addr = true;
	aux->no_send_stop = true;

	/*
	* Send the segment address for every i2c read in which the
	* middle-of-tranaction flag is set. This is required to support EDID
	* reads of more than 2 blocks as the segment address is reset to 0
	* since we are overriding the middle-of-transaction flag for read
	* transactions.
	*/

	if (aux->segment) {
	memset(&helper_msg, 0, sizeof(helper_msg));
	helper_msg.address = segment_address;
	helper_msg.buffer = &aux->segment;
	helper_msg.size = 1;
	dp_aux_cmd_fifo_tx(aux, &helper_msg);
	}

	/*
	* Send the offset address for every i2c read in which the
	* middle-of-transaction flag is set. This will ensure that the sink
	* will update its read pointer and return the correct portion of the
	* EDID buffer in the subsequent i2c read trasntion triggered in the
	* native AUX transfer function.
	*/
	memset(&helper_msg, 0, sizeof(helper_msg));
	helper_msg.address = input_msg->address;
	helper_msg.buffer = &aux->offset;
	helper_msg.size = 1;
	dp_aux_cmd_fifo_tx(aux, &helper_msg);

	end:
	aux->offset += message_size;
	if (aux->offset == 0x80 \|\| aux->offset == 0x100)
	aux->segment = 0x0; /* reset segment at end of block */
	}

	/*
	* This function does the real job to process an AUX transaction.
	* It will call aux_reset() function to reset the AUX channel,
	* if the waiting is timeout.
	*/
	static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux,
	struct drm_dp_aux_msg *msg)
	{
	ssize_t ret;
	int const aux_cmd_native_max = 16;
	int const aux_cmd_i2c_max = 128;
	int const retry_count = 5;
	struct dp_aux_private *aux = container_of(dp_aux,
	struct dp_aux_private, dp_aux);

	mutex_lock(&aux->mutex);

	aux->native = msg->request & (DP_AUX_NATIVE_WRITE & DP_AUX_NATIVE_READ);

	/* Ignore address only message */
	if ((msg->size == 0) \|\| (msg->buffer == NULL)) {
	msg->reply = aux->native ?
	DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
	ret = msg->size;
	goto unlock_exit;
	}

	/* msg sanity check */
	if ((aux->native && (msg->size > aux_cmd_native_max)) \|\|
	(msg->size > aux_cmd_i2c_max)) {
	DRM_ERROR("%s: invalid msg: size(%zu), request(%x)\n",
	__func__, msg->size, msg->request);
	ret = -EINVAL;
	goto unlock_exit;
	}

	dp_aux_update_offset_and_segment(aux, msg);
	dp_aux_transfer_helper(aux, msg, true);

	aux->read = msg->request & (DP_AUX_I2C_READ & DP_AUX_NATIVE_READ);
	aux->cmd_busy = true;

	if (aux->read) {
	aux->no_send_addr = true;
	aux->no_send_stop = false;
	} else {
	aux->no_send_addr = true;
	aux->no_send_stop = true;
	}

	ret = dp_aux_cmd_fifo_tx(aux, msg);

	if (ret < 0) {
	if (aux->native) {
	aux->retry_cnt++;
	if (!(aux->retry_cnt % retry_count))
	dp_catalog_aux_update_cfg(aux->catalog);
	dp_catalog_aux_reset(aux->catalog);
	}
	usleep_range(400, 500); /* at least 400us to next try */
	goto unlock_exit;
	}

	if (aux->aux_error_num == DP_AUX_ERR_NONE) {
	if (aux->read)
	dp_aux_cmd_fifo_rx(aux, msg);

	msg->reply = aux->native ?
	DP_AUX_NATIVE_REPLY_ACK : DP_AUX_I2C_REPLY_ACK;
	} else {
	/* Reply defer to retry */
	msg->reply = aux->native ?
	DP_AUX_NATIVE_REPLY_DEFER : DP_AUX_I2C_REPLY_DEFER;
	}

	/* Return requested size for success or retry */
	ret = msg->size;
	aux->retry_cnt = 0;

	unlock_exit:
	aux->cmd_busy = false;
	mutex_unlock(&aux->mutex);
	return ret;
	}

	void dp_aux_isr(struct drm_dp_aux *dp_aux)
	{
	struct dp_aux_private *aux;

	if (!dp_aux) {
	DRM_ERROR("invalid input\n");
	return;
	}

	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

	aux->isr = dp_catalog_aux_get_irq(aux->catalog);

	if (!aux->cmd_busy)
	return;

	if (aux->native)
	dp_aux_native_handler(aux);
	else
	dp_aux_i2c_handler(aux);
	}

	void dp_aux_reconfig(struct drm_dp_aux *dp_aux)
	{
	struct dp_aux_private *aux;

	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

	dp_catalog_aux_update_cfg(aux->catalog);
	dp_catalog_aux_reset(aux->catalog);
	}

	void dp_aux_init(struct drm_dp_aux *dp_aux)
	{
	struct dp_aux_private *aux;

	if (!dp_aux) {
	DRM_ERROR("invalid input\n");
	return;
	}

	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

	dp_catalog_aux_enable(aux->catalog, true);
	aux->retry_cnt = 0;
	}

	void dp_aux_deinit(struct drm_dp_aux *dp_aux)
	{
	struct dp_aux_private *aux;

	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

	dp_catalog_aux_enable(aux->catalog, false);
	}

	int dp_aux_register(struct drm_dp_aux *dp_aux)
	{
	struct dp_aux_private *aux;
	int ret;

	if (!dp_aux) {
	DRM_ERROR("invalid input\n");
	return -EINVAL;
	}

	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

	aux->dp_aux.name = "dpu_dp_aux";
	aux->dp_aux.dev = aux->dev;
	aux->dp_aux.transfer = dp_aux_transfer;
	ret = drm_dp_aux_register(&aux->dp_aux);
	if (ret) {
	DRM_ERROR("%s: failed to register drm aux: %d\n", __func__,
	ret);
	return ret;
	}

	return 0;
	}

	void dp_aux_unregister(struct drm_dp_aux *dp_aux)
	{
	drm_dp_aux_unregister(dp_aux);
	}

	struct drm_dp_aux dp_aux_get(struct device dev, struct dp_catalog *catalog)
	{
	struct dp_aux_private *aux;

	if (!catalog) {
	DRM_ERROR("invalid input\n");
	return ERR_PTR(-ENODEV);
	}

	aux = devm_kzalloc(dev, sizeof(*aux), GFP_KERNEL);
	if (!aux)
	return ERR_PTR(-ENOMEM);

	init_completion(&aux->comp);
	aux->cmd_busy = false;
	mutex_init(&aux->mutex);

	aux->dev = dev;
	aux->catalog = catalog;
	aux->retry_cnt = 0;

	return &aux->dp_aux;
	}

	void dp_aux_put(struct drm_dp_aux *dp_aux)
	{
	struct dp_aux_private *aux;

	if (!dp_aux)
	return;

	aux = container_of(dp_aux, struct dp_aux_private, dp_aux);

	mutex_destroy(&aux->mutex);

	devm_kfree(aux->dev, aux);
	}