drivers/gpu/drm/i915/intel_dsi_cmd.c - arm/linux-arm64-legacy - Git at Google

 /*
  * Copyright © 2013 Intel Corporation
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice (including the next
  * paragraph) shall be included in all copies or substantial portions of the
  * Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
  *
  * Author: Jani Nikula <jani.nikula@intel.com>
  */

 #include <linux/export.h>
 #include <drm/drmP.h>
 #include <drm/drm_crtc.h>
 #include <video/mipi_display.h>
 #include "i915_drv.h"
 #include "intel_drv.h"
 #include "intel_dsi.h"
 #include "intel_dsi_cmd.h"

 /*
  * XXX: MIPI_DATA_ADDRESS, MIPI_DATA_LENGTH, MIPI_COMMAND_LENGTH, and
  * MIPI_COMMAND_ADDRESS registers.
  *
  * Apparently these registers provide a MIPI adapter level way to send (lots of)
  * commands and data to the receiver, without having to write the commands and
  * data to MIPI_{HS,LP}_GEN_{CTRL,DATA} registers word by word.
  *
  * Presumably for anything other than MIPI_DCS_WRITE_MEMORY_START and
  * MIPI_DCS_WRITE_MEMORY_CONTINUE (which are used to update the external
  * framebuffer in command mode displays) these are just an optimization that can
  * come later.
  *
  * For memory writes, these should probably be used for performance.
  */

 static void print_stat(struct intel_dsi *intel_dsi)
 {
 	struct drm_encoder *encoder = &intel_dsi->base.base;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	u32 val;

 	val = I915_READ(MIPI_INTR_STAT(pipe));

 #define STAT_BIT(val, bit) (val) & (bit) ? " " #bit : ""
 	DRM_DEBUG_KMS("MIPI_INTR_STAT(%d) = %08x"
 		      "%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s"
 		      "\n", pipe, val,
 		      STAT_BIT(val, TEARING_EFFECT),
 		      STAT_BIT(val, SPL_PKT_SENT_INTERRUPT),
 		      STAT_BIT(val, GEN_READ_DATA_AVAIL),
 		      STAT_BIT(val, LP_GENERIC_WR_FIFO_FULL),
 		      STAT_BIT(val, HS_GENERIC_WR_FIFO_FULL),
 		      STAT_BIT(val, RX_PROT_VIOLATION),
 		      STAT_BIT(val, RX_INVALID_TX_LENGTH),
 		      STAT_BIT(val, ACK_WITH_NO_ERROR),
 		      STAT_BIT(val, TURN_AROUND_ACK_TIMEOUT),
 		      STAT_BIT(val, LP_RX_TIMEOUT),
 		      STAT_BIT(val, HS_TX_TIMEOUT),
 		      STAT_BIT(val, DPI_FIFO_UNDERRUN),
 		      STAT_BIT(val, LOW_CONTENTION),
 		      STAT_BIT(val, HIGH_CONTENTION),
 		      STAT_BIT(val, TXDSI_VC_ID_INVALID),
 		      STAT_BIT(val, TXDSI_DATA_TYPE_NOT_RECOGNISED),
 		      STAT_BIT(val, TXCHECKSUM_ERROR),
 		      STAT_BIT(val, TXECC_MULTIBIT_ERROR),
 		      STAT_BIT(val, TXECC_SINGLE_BIT_ERROR),
 		      STAT_BIT(val, TXFALSE_CONTROL_ERROR),
 		      STAT_BIT(val, RXDSI_VC_ID_INVALID),
 		      STAT_BIT(val, RXDSI_DATA_TYPE_NOT_REGOGNISED),
 		      STAT_BIT(val, RXCHECKSUM_ERROR),
 		      STAT_BIT(val, RXECC_MULTIBIT_ERROR),
 		      STAT_BIT(val, RXECC_SINGLE_BIT_ERROR),
 		      STAT_BIT(val, RXFALSE_CONTROL_ERROR),
 		      STAT_BIT(val, RXHS_RECEIVE_TIMEOUT_ERROR),
 		      STAT_BIT(val, RX_LP_TX_SYNC_ERROR),
 		      STAT_BIT(val, RXEXCAPE_MODE_ENTRY_ERROR),
 		      STAT_BIT(val, RXEOT_SYNC_ERROR),
 		      STAT_BIT(val, RXSOT_SYNC_ERROR),
 		      STAT_BIT(val, RXSOT_ERROR));
 #undef STAT_BIT
 }

 enum dsi_type {
 	DSI_DCS,
 	DSI_GENERIC,
 };

 /* enable or disable command mode hs transmissions */
 void dsi_hs_mode_enable(struct intel_dsi *intel_dsi, bool enable)
 {
 	struct drm_encoder *encoder = &intel_dsi->base.base;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	u32 temp;
 	u32 mask = DBI_FIFO_EMPTY;

 	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == mask, 50))
 		DRM_ERROR("Timeout waiting for DBI FIFO empty\n");

 	temp = I915_READ(MIPI_HS_LP_DBI_ENABLE(pipe));
 	temp &= DBI_HS_LP_MODE_MASK;
 	I915_WRITE(MIPI_HS_LP_DBI_ENABLE(pipe), enable ? DBI_HS_MODE : DBI_LP_MODE);

 	intel_dsi->hs = enable;
 }

 static int dsi_vc_send_short(struct intel_dsi *intel_dsi, int channel,
 			     u8 data_type, u16 data)
 {
 	struct drm_encoder *encoder = &intel_dsi->base.base;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	u32 ctrl_reg;
 	u32 ctrl;
 	u32 mask;

 	DRM_DEBUG_KMS("channel %d, data_type %d, data %04x\n",
 		      channel, data_type, data);

 	if (intel_dsi->hs) {
 		ctrl_reg = MIPI_HS_GEN_CTRL(pipe);
 		mask = HS_CTRL_FIFO_FULL;
 	} else {
 		ctrl_reg = MIPI_LP_GEN_CTRL(pipe);
 		mask = LP_CTRL_FIFO_FULL;
 	}

 	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == 0, 50)) {
 		DRM_ERROR("Timeout waiting for HS/LP CTRL FIFO !full\n");
 		print_stat(intel_dsi);
 	}

 	/*
 	 * Note: This function is also used for long packets, with length passed
 	 * as data, since SHORT_PACKET_PARAM_SHIFT ==
 	 * LONG_PACKET_WORD_COUNT_SHIFT.
 	 */
 	ctrl = data << SHORT_PACKET_PARAM_SHIFT |
 		channel << VIRTUAL_CHANNEL_SHIFT |
 		data_type << DATA_TYPE_SHIFT;

 	I915_WRITE(ctrl_reg, ctrl);

 	return 0;
 }

 static int dsi_vc_send_long(struct intel_dsi *intel_dsi, int channel,
 			    u8 data_type, const u8 *data, int len)
 {
 	struct drm_encoder *encoder = &intel_dsi->base.base;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	u32 data_reg;
 	int i, j, n;
 	u32 mask;

 	DRM_DEBUG_KMS("channel %d, data_type %d, len %04x\n",
 		      channel, data_type, len);

 	if (intel_dsi->hs) {
 		data_reg = MIPI_HS_GEN_DATA(pipe);
 		mask = HS_DATA_FIFO_FULL;
 	} else {
 		data_reg = MIPI_LP_GEN_DATA(pipe);
 		mask = LP_DATA_FIFO_FULL;
 	}

 	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == 0, 50))
 		DRM_ERROR("Timeout waiting for HS/LP DATA FIFO !full\n");

 	for (i = 0; i < len; i += n) {
 		u32 val = 0;
 		n = min_t(int, len - i, 4);

 		for (j = 0; j < n; j++)
 			val |= *data++ << 8 * j;

 		I915_WRITE(data_reg, val);
 		/* XXX: check for data fifo full, once that is set, write 4
 		 * dwords, then wait for not set, then continue. */
 	}

 	return dsi_vc_send_short(intel_dsi, channel, data_type, len);
 }

 static int dsi_vc_write_common(struct intel_dsi *intel_dsi,
 			       int channel, const u8 *data, int len,
 			       enum dsi_type type)
 {
 	int ret;

 	if (len == 0) {
 		BUG_ON(type == DSI_GENERIC);
 		ret = dsi_vc_send_short(intel_dsi, channel,
 					MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM,
 					0);
 	} else if (len == 1) {
 		ret = dsi_vc_send_short(intel_dsi, channel,
 					type == DSI_GENERIC ?
 					MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM :
 					MIPI_DSI_DCS_SHORT_WRITE, data[0]);
 	} else if (len == 2) {
 		ret = dsi_vc_send_short(intel_dsi, channel,
 					type == DSI_GENERIC ?
 					MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM :
 					MIPI_DSI_DCS_SHORT_WRITE_PARAM,
 					(data[1] << 8) | data[0]);
 	} else {
 		ret = dsi_vc_send_long(intel_dsi, channel,
 				       type == DSI_GENERIC ?
 				       MIPI_DSI_GENERIC_LONG_WRITE :
 				       MIPI_DSI_DCS_LONG_WRITE, data, len);
 	}

 	return ret;
 }

 int dsi_vc_dcs_write(struct intel_dsi *intel_dsi, int channel,
 		     const u8 *data, int len)
 {
 	return dsi_vc_write_common(intel_dsi, channel, data, len, DSI_DCS);
 }

 int dsi_vc_generic_write(struct intel_dsi *intel_dsi, int channel,
 			 const u8 *data, int len)
 {
 	return dsi_vc_write_common(intel_dsi, channel, data, len, DSI_GENERIC);
 }

 static int dsi_vc_dcs_send_read_request(struct intel_dsi *intel_dsi,
 					int channel, u8 dcs_cmd)
 {
 	return dsi_vc_send_short(intel_dsi, channel, MIPI_DSI_DCS_READ,
 				 dcs_cmd);
 }

 static int dsi_vc_generic_send_read_request(struct intel_dsi *intel_dsi,
 					    int channel, u8 *reqdata,
 					    int reqlen)
 {
 	u16 data;
 	u8 data_type;

 	switch (reqlen) {
 	case 0:
 		data_type = MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM;
 		data = 0;
 		break;
 	case 1:
 		data_type = MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM;
 		data = reqdata[0];
 		break;
 	case 2:
 		data_type = MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM;
 		data = (reqdata[1] << 8) | reqdata[0];
 		break;
 	default:
 		BUG();
 	}

 	return dsi_vc_send_short(intel_dsi, channel, data_type, data);
 }

 static int dsi_read_data_return(struct intel_dsi *intel_dsi,
 				u8 *buf, int buflen)
 {
 	struct drm_encoder *encoder = &intel_dsi->base.base;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	int i, len = 0;
 	u32 data_reg, val;

 	if (intel_dsi->hs) {
 		data_reg = MIPI_HS_GEN_DATA(pipe);
 	} else {
 		data_reg = MIPI_LP_GEN_DATA(pipe);
 	}

 	while (len < buflen) {
 		val = I915_READ(data_reg);
 		for (i = 0; i < 4 && len < buflen; i++, len++)
 			buf[len] = val >> 8 * i;
 	}

 	return len;
 }

 int dsi_vc_dcs_read(struct intel_dsi *intel_dsi, int channel, u8 dcs_cmd,
 		    u8 *buf, int buflen)
 {
 	struct drm_encoder *encoder = &intel_dsi->base.base;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	u32 mask;
 	int ret;

 	/*
 	 * XXX: should issue multiple read requests and reads if request is
 	 * longer than MIPI_MAX_RETURN_PKT_SIZE
 	 */

 	I915_WRITE(MIPI_INTR_STAT(pipe), GEN_READ_DATA_AVAIL);

 	ret = dsi_vc_dcs_send_read_request(intel_dsi, channel, dcs_cmd);
 	if (ret)
 		return ret;

 	mask = GEN_READ_DATA_AVAIL;
 	if (wait_for((I915_READ(MIPI_INTR_STAT(pipe)) & mask) == mask, 50))
 		DRM_ERROR("Timeout waiting for read data.\n");

 	ret = dsi_read_data_return(intel_dsi, buf, buflen);
 	if (ret < 0)
 		return ret;

 	if (ret != buflen)
 		return -EIO;

 	return 0;
 }

 int dsi_vc_generic_read(struct intel_dsi *intel_dsi, int channel,
 			u8 *reqdata, int reqlen, u8 *buf, int buflen)
 {
 	struct drm_encoder *encoder = &intel_dsi->base.base;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	u32 mask;
 	int ret;

 	/*
 	 * XXX: should issue multiple read requests and reads if request is
 	 * longer than MIPI_MAX_RETURN_PKT_SIZE
 	 */

 	I915_WRITE(MIPI_INTR_STAT(pipe), GEN_READ_DATA_AVAIL);

 	ret = dsi_vc_generic_send_read_request(intel_dsi, channel, reqdata,
 					       reqlen);
 	if (ret)
 		return ret;

 	mask = GEN_READ_DATA_AVAIL;
 	if (wait_for((I915_READ(MIPI_INTR_STAT(pipe)) & mask) == mask, 50))
 		DRM_ERROR("Timeout waiting for read data.\n");

 	ret = dsi_read_data_return(intel_dsi, buf, buflen);
 	if (ret < 0)
 		return ret;

 	if (ret != buflen)
 		return -EIO;

 	return 0;
 }

 /*
  * send a video mode command
  *
  * XXX: commands with data in MIPI_DPI_DATA?
  */
 int dpi_send_cmd(struct intel_dsi *intel_dsi, u32 cmd, bool hs)
 {
 	struct drm_encoder *encoder = &intel_dsi->base.base;
 	struct drm_device *dev = encoder->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
 	enum pipe pipe = intel_crtc->pipe;
 	u32 mask;

 	/* XXX: pipe, hs */
 	if (hs)
 		cmd &= ~DPI_LP_MODE;
 	else
 		cmd |= DPI_LP_MODE;

 	/* clear bit */
 	I915_WRITE(MIPI_INTR_STAT(pipe), SPL_PKT_SENT_INTERRUPT);

 	/* XXX: old code skips write if control unchanged */
 	if (cmd == I915_READ(MIPI_DPI_CONTROL(pipe)))
 		DRM_ERROR("Same special packet %02x twice in a row.\n", cmd);

 	I915_WRITE(MIPI_DPI_CONTROL(pipe), cmd);

 	mask = SPL_PKT_SENT_INTERRUPT;
 	if (wait_for((I915_READ(MIPI_INTR_STAT(pipe)) & mask) == mask, 100))
 		DRM_ERROR("Video mode command 0x%08x send failed.\n", cmd);

 	return 0;
 }
	/*
	* Copyright © 2013 Intel Corporation
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice (including the next
	* paragraph) shall be included in all copies or substantial portions of the
	* Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
	* DEALINGS IN THE SOFTWARE.
	*
	* Author: Jani Nikula <jani.nikula@intel.com>
	*/

	#include <linux/export.h>
	#include <drm/drmP.h>
	#include <drm/drm_crtc.h>
	#include <video/mipi_display.h>
	#include "i915_drv.h"
	#include "intel_drv.h"
	#include "intel_dsi.h"
	#include "intel_dsi_cmd.h"

	/*
	* XXX: MIPI_DATA_ADDRESS, MIPI_DATA_LENGTH, MIPI_COMMAND_LENGTH, and
	* MIPI_COMMAND_ADDRESS registers.
	*
	* Apparently these registers provide a MIPI adapter level way to send (lots of)
	* commands and data to the receiver, without having to write the commands and
	* data to MIPI_{HS,LP}_GEN_{CTRL,DATA} registers word by word.
	*
	* Presumably for anything other than MIPI_DCS_WRITE_MEMORY_START and
	* MIPI_DCS_WRITE_MEMORY_CONTINUE (which are used to update the external
	* framebuffer in command mode displays) these are just an optimization that can
	* come later.
	*
	* For memory writes, these should probably be used for performance.
	*/

	static void print_stat(struct intel_dsi *intel_dsi)
	{
	struct drm_encoder *encoder = &intel_dsi->base.base;
	struct drm_device *dev = encoder->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
	enum pipe pipe = intel_crtc->pipe;
	u32 val;

	val = I915_READ(MIPI_INTR_STAT(pipe));

	#define STAT_BIT(val, bit) (val) & (bit) ? " " #bit : ""
	DRM_DEBUG_KMS("MIPI_INTR_STAT(%d) = %08x"
	"%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s"
	"\n", pipe, val,
	STAT_BIT(val, TEARING_EFFECT),
	STAT_BIT(val, SPL_PKT_SENT_INTERRUPT),
	STAT_BIT(val, GEN_READ_DATA_AVAIL),
	STAT_BIT(val, LP_GENERIC_WR_FIFO_FULL),
	STAT_BIT(val, HS_GENERIC_WR_FIFO_FULL),
	STAT_BIT(val, RX_PROT_VIOLATION),
	STAT_BIT(val, RX_INVALID_TX_LENGTH),
	STAT_BIT(val, ACK_WITH_NO_ERROR),
	STAT_BIT(val, TURN_AROUND_ACK_TIMEOUT),
	STAT_BIT(val, LP_RX_TIMEOUT),
	STAT_BIT(val, HS_TX_TIMEOUT),
	STAT_BIT(val, DPI_FIFO_UNDERRUN),
	STAT_BIT(val, LOW_CONTENTION),
	STAT_BIT(val, HIGH_CONTENTION),
	STAT_BIT(val, TXDSI_VC_ID_INVALID),
	STAT_BIT(val, TXDSI_DATA_TYPE_NOT_RECOGNISED),
	STAT_BIT(val, TXCHECKSUM_ERROR),
	STAT_BIT(val, TXECC_MULTIBIT_ERROR),
	STAT_BIT(val, TXECC_SINGLE_BIT_ERROR),
	STAT_BIT(val, TXFALSE_CONTROL_ERROR),
	STAT_BIT(val, RXDSI_VC_ID_INVALID),
	STAT_BIT(val, RXDSI_DATA_TYPE_NOT_REGOGNISED),
	STAT_BIT(val, RXCHECKSUM_ERROR),
	STAT_BIT(val, RXECC_MULTIBIT_ERROR),
	STAT_BIT(val, RXECC_SINGLE_BIT_ERROR),
	STAT_BIT(val, RXFALSE_CONTROL_ERROR),
	STAT_BIT(val, RXHS_RECEIVE_TIMEOUT_ERROR),
	STAT_BIT(val, RX_LP_TX_SYNC_ERROR),
	STAT_BIT(val, RXEXCAPE_MODE_ENTRY_ERROR),
	STAT_BIT(val, RXEOT_SYNC_ERROR),
	STAT_BIT(val, RXSOT_SYNC_ERROR),
	STAT_BIT(val, RXSOT_ERROR));
	#undef STAT_BIT
	}

	enum dsi_type {
	DSI_DCS,
	DSI_GENERIC,
	};

	/* enable or disable command mode hs transmissions */
	void dsi_hs_mode_enable(struct intel_dsi *intel_dsi, bool enable)
	{
	struct drm_encoder *encoder = &intel_dsi->base.base;
	struct drm_device *dev = encoder->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
	enum pipe pipe = intel_crtc->pipe;
	u32 temp;
	u32 mask = DBI_FIFO_EMPTY;

	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == mask, 50))
	DRM_ERROR("Timeout waiting for DBI FIFO empty\n");

	temp = I915_READ(MIPI_HS_LP_DBI_ENABLE(pipe));
	temp &= DBI_HS_LP_MODE_MASK;
	I915_WRITE(MIPI_HS_LP_DBI_ENABLE(pipe), enable ? DBI_HS_MODE : DBI_LP_MODE);

	intel_dsi->hs = enable;
	}

	static int dsi_vc_send_short(struct intel_dsi *intel_dsi, int channel,
	u8 data_type, u16 data)
	{
	struct drm_encoder *encoder = &intel_dsi->base.base;
	struct drm_device *dev = encoder->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
	enum pipe pipe = intel_crtc->pipe;
	u32 ctrl_reg;
	u32 ctrl;
	u32 mask;

	DRM_DEBUG_KMS("channel %d, data_type %d, data %04x\n",
	channel, data_type, data);

	if (intel_dsi->hs) {
	ctrl_reg = MIPI_HS_GEN_CTRL(pipe);
	mask = HS_CTRL_FIFO_FULL;
	} else {
	ctrl_reg = MIPI_LP_GEN_CTRL(pipe);
	mask = LP_CTRL_FIFO_FULL;
	}

	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == 0, 50)) {
	DRM_ERROR("Timeout waiting for HS/LP CTRL FIFO !full\n");
	print_stat(intel_dsi);
	}

	/*
	* Note: This function is also used for long packets, with length passed
	* as data, since SHORT_PACKET_PARAM_SHIFT ==
	* LONG_PACKET_WORD_COUNT_SHIFT.
	*/
	ctrl = data << SHORT_PACKET_PARAM_SHIFT \|
	channel << VIRTUAL_CHANNEL_SHIFT \|
	data_type << DATA_TYPE_SHIFT;

	I915_WRITE(ctrl_reg, ctrl);

	return 0;
	}

	static int dsi_vc_send_long(struct intel_dsi *intel_dsi, int channel,
	u8 data_type, const u8 *data, int len)
	{
	struct drm_encoder *encoder = &intel_dsi->base.base;
	struct drm_device *dev = encoder->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
	enum pipe pipe = intel_crtc->pipe;
	u32 data_reg;
	int i, j, n;
	u32 mask;

	DRM_DEBUG_KMS("channel %d, data_type %d, len %04x\n",
	channel, data_type, len);

	if (intel_dsi->hs) {
	data_reg = MIPI_HS_GEN_DATA(pipe);
	mask = HS_DATA_FIFO_FULL;
	} else {
	data_reg = MIPI_LP_GEN_DATA(pipe);
	mask = LP_DATA_FIFO_FULL;
	}

	if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(pipe)) & mask) == 0, 50))
	DRM_ERROR("Timeout waiting for HS/LP DATA FIFO !full\n");

	for (i = 0; i < len; i += n) {
	u32 val = 0;
	n = min_t(int, len - i, 4);

	for (j = 0; j < n; j++)
	val \|= data++ << 8 j;

	I915_WRITE(data_reg, val);
	/* XXX: check for data fifo full, once that is set, write 4
	* dwords, then wait for not set, then continue. */
	}

	return dsi_vc_send_short(intel_dsi, channel, data_type, len);
	}

	static int dsi_vc_write_common(struct intel_dsi *intel_dsi,
	int channel, const u8 *data, int len,
	enum dsi_type type)
	{
	int ret;

	if (len == 0) {
	BUG_ON(type == DSI_GENERIC);
	ret = dsi_vc_send_short(intel_dsi, channel,
	MIPI_DSI_GENERIC_SHORT_WRITE_0_PARAM,
	0);
	} else if (len == 1) {
	ret = dsi_vc_send_short(intel_dsi, channel,
	type == DSI_GENERIC ?
	MIPI_DSI_GENERIC_SHORT_WRITE_1_PARAM :
	MIPI_DSI_DCS_SHORT_WRITE, data[0]);
	} else if (len == 2) {
	ret = dsi_vc_send_short(intel_dsi, channel,
	type == DSI_GENERIC ?
	MIPI_DSI_GENERIC_SHORT_WRITE_2_PARAM :
	MIPI_DSI_DCS_SHORT_WRITE_PARAM,
	(data[1] << 8) \| data[0]);
	} else {
	ret = dsi_vc_send_long(intel_dsi, channel,
	type == DSI_GENERIC ?
	MIPI_DSI_GENERIC_LONG_WRITE :
	MIPI_DSI_DCS_LONG_WRITE, data, len);
	}

	return ret;
	}

	int dsi_vc_dcs_write(struct intel_dsi *intel_dsi, int channel,
	const u8 *data, int len)
	{
	return dsi_vc_write_common(intel_dsi, channel, data, len, DSI_DCS);
	}

	int dsi_vc_generic_write(struct intel_dsi *intel_dsi, int channel,
	const u8 *data, int len)
	{
	return dsi_vc_write_common(intel_dsi, channel, data, len, DSI_GENERIC);
	}

	static int dsi_vc_dcs_send_read_request(struct intel_dsi *intel_dsi,
	int channel, u8 dcs_cmd)
	{
	return dsi_vc_send_short(intel_dsi, channel, MIPI_DSI_DCS_READ,
	dcs_cmd);
	}

	static int dsi_vc_generic_send_read_request(struct intel_dsi *intel_dsi,
	int channel, u8 *reqdata,
	int reqlen)
	{
	u16 data;
	u8 data_type;

	switch (reqlen) {
	case 0:
	data_type = MIPI_DSI_GENERIC_READ_REQUEST_0_PARAM;
	data = 0;
	break;
	case 1:
	data_type = MIPI_DSI_GENERIC_READ_REQUEST_1_PARAM;
	data = reqdata[0];
	break;
	case 2:
	data_type = MIPI_DSI_GENERIC_READ_REQUEST_2_PARAM;
	data = (reqdata[1] << 8) \| reqdata[0];
	break;
	default:
	BUG();
	}

	return dsi_vc_send_short(intel_dsi, channel, data_type, data);
	}

	static int dsi_read_data_return(struct intel_dsi *intel_dsi,
	u8 *buf, int buflen)
	{
	struct drm_encoder *encoder = &intel_dsi->base.base;
	struct drm_device *dev = encoder->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
	enum pipe pipe = intel_crtc->pipe;
	int i, len = 0;
	u32 data_reg, val;

	if (intel_dsi->hs) {
	data_reg = MIPI_HS_GEN_DATA(pipe);
	} else {
	data_reg = MIPI_LP_GEN_DATA(pipe);
	}

	while (len < buflen) {
	val = I915_READ(data_reg);
	for (i = 0; i < 4 && len < buflen; i++, len++)
	buf[len] = val >> 8 * i;
	}

	return len;
	}

	int dsi_vc_dcs_read(struct intel_dsi *intel_dsi, int channel, u8 dcs_cmd,
	u8 *buf, int buflen)
	{
	struct drm_encoder *encoder = &intel_dsi->base.base;
	struct drm_device *dev = encoder->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
	enum pipe pipe = intel_crtc->pipe;
	u32 mask;
	int ret;

	/*
	* XXX: should issue multiple read requests and reads if request is
	* longer than MIPI_MAX_RETURN_PKT_SIZE
	*/

	I915_WRITE(MIPI_INTR_STAT(pipe), GEN_READ_DATA_AVAIL);

	ret = dsi_vc_dcs_send_read_request(intel_dsi, channel, dcs_cmd);
	if (ret)
	return ret;

	mask = GEN_READ_DATA_AVAIL;
	if (wait_for((I915_READ(MIPI_INTR_STAT(pipe)) & mask) == mask, 50))
	DRM_ERROR("Timeout waiting for read data.\n");

	ret = dsi_read_data_return(intel_dsi, buf, buflen);
	if (ret < 0)
	return ret;

	if (ret != buflen)
	return -EIO;

	return 0;
	}

	int dsi_vc_generic_read(struct intel_dsi *intel_dsi, int channel,
	u8 reqdata, int reqlen, u8 buf, int buflen)
	{
	struct drm_encoder *encoder = &intel_dsi->base.base;
	struct drm_device *dev = encoder->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
	enum pipe pipe = intel_crtc->pipe;
	u32 mask;
	int ret;

	/*
	* XXX: should issue multiple read requests and reads if request is
	* longer than MIPI_MAX_RETURN_PKT_SIZE
	*/

	I915_WRITE(MIPI_INTR_STAT(pipe), GEN_READ_DATA_AVAIL);

	ret = dsi_vc_generic_send_read_request(intel_dsi, channel, reqdata,
	reqlen);
	if (ret)
	return ret;

	mask = GEN_READ_DATA_AVAIL;
	if (wait_for((I915_READ(MIPI_INTR_STAT(pipe)) & mask) == mask, 50))
	DRM_ERROR("Timeout waiting for read data.\n");

	ret = dsi_read_data_return(intel_dsi, buf, buflen);
	if (ret < 0)
	return ret;

	if (ret != buflen)
	return -EIO;

	return 0;
	}

	/*
	* send a video mode command
	*
	* XXX: commands with data in MIPI_DPI_DATA?
	*/
	int dpi_send_cmd(struct intel_dsi *intel_dsi, u32 cmd, bool hs)
	{
	struct drm_encoder *encoder = &intel_dsi->base.base;
	struct drm_device *dev = encoder->dev;
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
	enum pipe pipe = intel_crtc->pipe;
	u32 mask;

	/* XXX: pipe, hs */
	if (hs)
	cmd &= ~DPI_LP_MODE;
	else
	cmd \|= DPI_LP_MODE;

	/* clear bit */
	I915_WRITE(MIPI_INTR_STAT(pipe), SPL_PKT_SENT_INTERRUPT);

	/* XXX: old code skips write if control unchanged */
	if (cmd == I915_READ(MIPI_DPI_CONTROL(pipe)))
	DRM_ERROR("Same special packet %02x twice in a row.\n", cmd);

	I915_WRITE(MIPI_DPI_CONTROL(pipe), cmd);

	mask = SPL_PKT_SENT_INTERRUPT;
	if (wait_for((I915_READ(MIPI_INTR_STAT(pipe)) & mask) == mask, 100))
	DRM_ERROR("Video mode command 0x%08x send failed.\n", cmd);

	return 0;
	}