drivers/gpu/drm/i915/display/intel_lspcon.c - linux/kernel/git/gregkh/driver-core - Git at Google

 /*
  * Copyright © 2016 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.
  *
  *
  */

 #include <drm/drm_atomic_helper.h>
 #include <drm/drm_dp_dual_mode_helper.h>
 #include <drm/drm_edid.h>

 #include "intel_display_types.h"
 #include "intel_dp.h"
 #include "intel_lspcon.h"

 /* LSPCON OUI Vendor ID(signatures) */
 #define LSPCON_VENDOR_PARADE_OUI 0x001CF8
 #define LSPCON_VENDOR_MCA_OUI 0x0060AD

 /* AUX addresses to write MCA AVI IF */
 #define LSPCON_MCA_AVI_IF_WRITE_OFFSET 0x5C0
 #define LSPCON_MCA_AVI_IF_CTRL 0x5DF
 #define  LSPCON_MCA_AVI_IF_KICKOFF (1 << 0)
 #define  LSPCON_MCA_AVI_IF_HANDLED (1 << 1)

 /* AUX addresses to write Parade AVI IF */
 #define LSPCON_PARADE_AVI_IF_WRITE_OFFSET 0x516
 #define LSPCON_PARADE_AVI_IF_CTRL 0x51E
 #define  LSPCON_PARADE_AVI_IF_KICKOFF (1 << 7)
 #define LSPCON_PARADE_AVI_IF_DATA_SIZE 32

 static struct intel_dp *lspcon_to_intel_dp(struct intel_lspcon *lspcon)
 {
 	struct intel_digital_port *dig_port =
 		container_of(lspcon, struct intel_digital_port, lspcon);

 	return &dig_port->dp;
 }

 static const char *lspcon_mode_name(enum drm_lspcon_mode mode)
 {
 	switch (mode) {
 	case DRM_LSPCON_MODE_PCON:
 		return "PCON";
 	case DRM_LSPCON_MODE_LS:
 		return "LS";
 	case DRM_LSPCON_MODE_INVALID:
 		return "INVALID";
 	default:
 		MISSING_CASE(mode);
 		return "INVALID";
 	}
 }

 static bool lspcon_detect_vendor(struct intel_lspcon *lspcon)
 {
 	struct intel_dp *dp = lspcon_to_intel_dp(lspcon);
 	struct drm_dp_dpcd_ident *ident;
 	u32 vendor_oui;

 	if (drm_dp_read_desc(&dp->aux, &dp->desc, drm_dp_is_branch(dp->dpcd))) {
 		DRM_ERROR("Can't read description\n");
 		return false;
 	}

 	ident = &dp->desc.ident;
 	vendor_oui = (ident->oui[0] << 16) | (ident->oui[1] << 8) |
 		      ident->oui[2];

 	switch (vendor_oui) {
 	case LSPCON_VENDOR_MCA_OUI:
 		lspcon->vendor = LSPCON_VENDOR_MCA;
 		DRM_DEBUG_KMS("Vendor: Mega Chips\n");
 		break;

 	case LSPCON_VENDOR_PARADE_OUI:
 		lspcon->vendor = LSPCON_VENDOR_PARADE;
 		DRM_DEBUG_KMS("Vendor: Parade Tech\n");
 		break;

 	default:
 		DRM_ERROR("Invalid/Unknown vendor OUI\n");
 		return false;
 	}

 	return true;
 }

 static enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon)
 {
 	enum drm_lspcon_mode current_mode;
 	struct i2c_adapter *adapter = &lspcon_to_intel_dp(lspcon)->aux.ddc;

 	if (drm_lspcon_get_mode(adapter, &current_mode)) {
 		DRM_DEBUG_KMS("Error reading LSPCON mode\n");
 		return DRM_LSPCON_MODE_INVALID;
 	}
 	return current_mode;
 }

 static enum drm_lspcon_mode lspcon_wait_mode(struct intel_lspcon *lspcon,
 					     enum drm_lspcon_mode mode)
 {
 	enum drm_lspcon_mode current_mode;

 	current_mode = lspcon_get_current_mode(lspcon);
 	if (current_mode == mode)
 		goto out;

 	DRM_DEBUG_KMS("Waiting for LSPCON mode %s to settle\n",
 		      lspcon_mode_name(mode));

 	wait_for((current_mode = lspcon_get_current_mode(lspcon)) == mode, 400);
 	if (current_mode != mode)
 		DRM_ERROR("LSPCON mode hasn't settled\n");

 out:
 	DRM_DEBUG_KMS("Current LSPCON mode %s\n",
 		      lspcon_mode_name(current_mode));

 	return current_mode;
 }

 static int lspcon_change_mode(struct intel_lspcon *lspcon,
 			      enum drm_lspcon_mode mode)
 {
 	int err;
 	enum drm_lspcon_mode current_mode;
 	struct i2c_adapter *adapter = &lspcon_to_intel_dp(lspcon)->aux.ddc;

 	err = drm_lspcon_get_mode(adapter, &current_mode);
 	if (err) {
 		DRM_ERROR("Error reading LSPCON mode\n");
 		return err;
 	}

 	if (current_mode == mode) {
 		DRM_DEBUG_KMS("Current mode = desired LSPCON mode\n");
 		return 0;
 	}

 	err = drm_lspcon_set_mode(adapter, mode);
 	if (err < 0) {
 		DRM_ERROR("LSPCON mode change failed\n");
 		return err;
 	}

 	lspcon->mode = mode;
 	DRM_DEBUG_KMS("LSPCON mode changed done\n");
 	return 0;
 }

 static bool lspcon_wake_native_aux_ch(struct intel_lspcon *lspcon)
 {
 	u8 rev;

 	if (drm_dp_dpcd_readb(&lspcon_to_intel_dp(lspcon)->aux, DP_DPCD_REV,
 			      &rev) != 1) {
 		DRM_DEBUG_KMS("Native AUX CH down\n");
 		return false;
 	}

 	DRM_DEBUG_KMS("Native AUX CH up, DPCD version: %d.%d\n",
 		      rev >> 4, rev & 0xf);

 	return true;
 }

 void lspcon_ycbcr420_config(struct drm_connector *connector,
 			    struct intel_crtc_state *crtc_state)
 {
 	const struct drm_display_info *info = &connector->display_info;
 	const struct drm_display_mode *adjusted_mode =
 					&crtc_state->base.adjusted_mode;

 	if (drm_mode_is_420_only(info, adjusted_mode) &&
 	    connector->ycbcr_420_allowed) {
 		crtc_state->port_clock /= 2;
 		crtc_state->output_format = INTEL_OUTPUT_FORMAT_YCBCR444;
 		crtc_state->lspcon_downsampling = true;
 	}
 }

 static bool lspcon_probe(struct intel_lspcon *lspcon)
 {
 	int retry;
 	enum drm_dp_dual_mode_type adaptor_type;
 	struct i2c_adapter *adapter = &lspcon_to_intel_dp(lspcon)->aux.ddc;
 	enum drm_lspcon_mode expected_mode;

 	expected_mode = lspcon_wake_native_aux_ch(lspcon) ?
 			DRM_LSPCON_MODE_PCON : DRM_LSPCON_MODE_LS;

 	/* Lets probe the adaptor and check its type */
 	for (retry = 0; retry < 6; retry++) {
 		if (retry)
 			usleep_range(500, 1000);

 		adaptor_type = drm_dp_dual_mode_detect(adapter);
 		if (adaptor_type == DRM_DP_DUAL_MODE_LSPCON)
 			break;
 	}

 	if (adaptor_type != DRM_DP_DUAL_MODE_LSPCON) {
 		DRM_DEBUG_KMS("No LSPCON detected, found %s\n",
 			       drm_dp_get_dual_mode_type_name(adaptor_type));
 		return false;
 	}

 	/* Yay ... got a LSPCON device */
 	DRM_DEBUG_KMS("LSPCON detected\n");
 	lspcon->mode = lspcon_wait_mode(lspcon, expected_mode);

 	/*
 	 * In the SW state machine, lets Put LSPCON in PCON mode only.
 	 * In this way, it will work with both HDMI 1.4 sinks as well as HDMI
 	 * 2.0 sinks.
 	 */
 	if (lspcon->mode != DRM_LSPCON_MODE_PCON) {
 		if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON) < 0) {
 			DRM_ERROR("LSPCON mode change to PCON failed\n");
 			return false;
 		}
 	}
 	return true;
 }

 static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
 {
 	struct intel_dp *intel_dp = lspcon_to_intel_dp(lspcon);
 	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
 	unsigned long start = jiffies;

 	while (1) {
 		if (intel_digital_port_connected(&dig_port->base)) {
 			DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
 				      jiffies_to_msecs(jiffies - start));
 			return;
 		}

 		if (time_after(jiffies, start + msecs_to_jiffies(1000)))
 			break;

 		usleep_range(10000, 15000);
 	}

 	DRM_DEBUG_KMS("LSPCON DP descriptor mismatch after resume\n");
 }

 static bool lspcon_parade_fw_ready(struct drm_dp_aux *aux)
 {
 	u8 avi_if_ctrl;
 	u8 retry;
 	ssize_t ret;

 	/* Check if LSPCON FW is ready for data */
 	for (retry = 0; retry < 5; retry++) {
 		if (retry)
 			usleep_range(200, 300);

 		ret = drm_dp_dpcd_read(aux, LSPCON_PARADE_AVI_IF_CTRL,
 				       &avi_if_ctrl, 1);
 		if (ret < 0) {
 			DRM_ERROR("Failed to read AVI IF control\n");
 			return false;
 		}

 		if ((avi_if_ctrl & LSPCON_PARADE_AVI_IF_KICKOFF) == 0)
 			return true;
 	}

 	DRM_ERROR("Parade FW not ready to accept AVI IF\n");
 	return false;
 }

 static bool _lspcon_parade_write_infoframe_blocks(struct drm_dp_aux *aux,
 						  u8 *avi_buf)
 {
 	u8 avi_if_ctrl;
 	u8 block_count = 0;
 	u8 *data;
 	u16 reg;
 	ssize_t ret;

 	while (block_count < 4) {
 		if (!lspcon_parade_fw_ready(aux)) {
 			DRM_DEBUG_KMS("LSPCON FW not ready, block %d\n",
 				      block_count);
 			return false;
 		}

 		reg = LSPCON_PARADE_AVI_IF_WRITE_OFFSET;
 		data = avi_buf + block_count * 8;
 		ret = drm_dp_dpcd_write(aux, reg, data, 8);
 		if (ret < 0) {
 			DRM_ERROR("Failed to write AVI IF block %d\n",
 				  block_count);
 			return false;
 		}

 		/*
 		 * Once a block of data is written, we have to inform the FW
 		 * about this by writing into avi infoframe control register:
 		 * - set the kickoff bit[7] to 1
 		 * - write the block no. to bits[1:0]
 		 */
 		reg = LSPCON_PARADE_AVI_IF_CTRL;
 		avi_if_ctrl = LSPCON_PARADE_AVI_IF_KICKOFF | block_count;
 		ret = drm_dp_dpcd_write(aux, reg, &avi_if_ctrl, 1);
 		if (ret < 0) {
 			DRM_ERROR("Failed to update (0x%x), block %d\n",
 				  reg, block_count);
 			return false;
 		}

 		block_count++;
 	}

 	DRM_DEBUG_KMS("Wrote AVI IF blocks successfully\n");
 	return true;
 }

 static bool _lspcon_write_avi_infoframe_parade(struct drm_dp_aux *aux,
 					       const u8 *frame,
 					       ssize_t len)
 {
 	u8 avi_if[LSPCON_PARADE_AVI_IF_DATA_SIZE] = {1, };

 	/*
 	 * Parade's frames contains 32 bytes of data, divided
 	 * into 4 frames:
 	 *	Token byte (first byte of first frame, must be non-zero)
 	 *	HB0 to HB2	 from AVI IF (3 bytes header)
 	 *	PB0 to PB27 from AVI IF (28 bytes data)
 	 * So it should look like this
 	 *	first block: | <token> <HB0-HB2> <DB0-DB3> |
 	 *	next 3 blocks: |<DB4-DB11>|<DB12-DB19>|<DB20-DB28>|
 	 */

 	if (len > LSPCON_PARADE_AVI_IF_DATA_SIZE - 1) {
 		DRM_ERROR("Invalid length of infoframes\n");
 		return false;
 	}

 	memcpy(&avi_if[1], frame, len);

 	if (!_lspcon_parade_write_infoframe_blocks(aux, avi_if)) {
 		DRM_DEBUG_KMS("Failed to write infoframe blocks\n");
 		return false;
 	}

 	return true;
 }

 static bool _lspcon_write_avi_infoframe_mca(struct drm_dp_aux *aux,
 					    const u8 *buffer, ssize_t len)
 {
 	int ret;
 	u32 val = 0;
 	u32 retry;
 	u16 reg;
 	const u8 *data = buffer;

 	reg = LSPCON_MCA_AVI_IF_WRITE_OFFSET;
 	while (val < len) {
 		/* DPCD write for AVI IF can fail on a slow FW day, so retry */
 		for (retry = 0; retry < 5; retry++) {
 			ret = drm_dp_dpcd_write(aux, reg, (void *)data, 1);
 			if (ret == 1) {
 				break;
 			} else if (retry < 4) {
 				mdelay(50);
 				continue;
 			} else {
 				DRM_ERROR("DPCD write failed at:0x%x\n", reg);
 				return false;
 			}
 		}
 		val++; reg++; data++;
 	}

 	val = 0;
 	reg = LSPCON_MCA_AVI_IF_CTRL;
 	ret = drm_dp_dpcd_read(aux, reg, &val, 1);
 	if (ret < 0) {
 		DRM_ERROR("DPCD read failed, address 0x%x\n", reg);
 		return false;
 	}

 	/* Indicate LSPCON chip about infoframe, clear bit 1 and set bit 0 */
 	val &= ~LSPCON_MCA_AVI_IF_HANDLED;
 	val |= LSPCON_MCA_AVI_IF_KICKOFF;

 	ret = drm_dp_dpcd_write(aux, reg, &val, 1);
 	if (ret < 0) {
 		DRM_ERROR("DPCD read failed, address 0x%x\n", reg);
 		return false;
 	}

 	val = 0;
 	ret = drm_dp_dpcd_read(aux, reg, &val, 1);
 	if (ret < 0) {
 		DRM_ERROR("DPCD read failed, address 0x%x\n", reg);
 		return false;
 	}

 	if (val == LSPCON_MCA_AVI_IF_HANDLED)
 		DRM_DEBUG_KMS("AVI IF handled by FW\n");

 	return true;
 }

 void lspcon_write_infoframe(struct intel_encoder *encoder,
 			    const struct intel_crtc_state *crtc_state,
 			    unsigned int type,
 			    const void *frame, ssize_t len)
 {
 	bool ret;
 	struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
 	struct intel_lspcon *lspcon = enc_to_intel_lspcon(&encoder->base);

 	/* LSPCON only needs AVI IF */
 	if (type != HDMI_INFOFRAME_TYPE_AVI)
 		return;

 	if (lspcon->vendor == LSPCON_VENDOR_MCA)
 		ret = _lspcon_write_avi_infoframe_mca(&intel_dp->aux,
 						      frame, len);
 	else
 		ret = _lspcon_write_avi_infoframe_parade(&intel_dp->aux,
 							 frame, len);

 	if (!ret) {
 		DRM_ERROR("Failed to write AVI infoframes\n");
 		return;
 	}

 	DRM_DEBUG_DRIVER("AVI infoframes updated successfully\n");
 }

 void lspcon_read_infoframe(struct intel_encoder *encoder,
 			   const struct intel_crtc_state *crtc_state,
 			   unsigned int type,
 			   void *frame, ssize_t len)
 {
 	/* FIXME implement this */
 }

 void lspcon_set_infoframes(struct intel_encoder *encoder,
 			   bool enable,
 			   const struct intel_crtc_state *crtc_state,
 			   const struct drm_connector_state *conn_state)
 {
 	ssize_t ret;
 	union hdmi_infoframe frame;
 	u8 buf[VIDEO_DIP_DATA_SIZE];
 	struct intel_digital_port *dig_port = enc_to_dig_port(&encoder->base);
 	struct intel_lspcon *lspcon = &dig_port->lspcon;
 	const struct drm_display_mode *adjusted_mode =
 		&crtc_state->base.adjusted_mode;

 	if (!lspcon->active) {
 		DRM_ERROR("Writing infoframes while LSPCON disabled ?\n");
 		return;
 	}

 	/* FIXME precompute infoframes */

 	ret = drm_hdmi_avi_infoframe_from_display_mode(&frame.avi,
 						       conn_state->connector,
 						       adjusted_mode);
 	if (ret < 0) {
 		DRM_ERROR("couldn't fill AVI infoframe\n");
 		return;
 	}

 	if (crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR444) {
 		if (crtc_state->lspcon_downsampling)
 			frame.avi.colorspace = HDMI_COLORSPACE_YUV420;
 		else
 			frame.avi.colorspace = HDMI_COLORSPACE_YUV444;
 	} else {
 		frame.avi.colorspace = HDMI_COLORSPACE_RGB;
 	}

 	drm_hdmi_avi_infoframe_quant_range(&frame.avi,
 					   conn_state->connector,
 					   adjusted_mode,
 					   crtc_state->limited_color_range ?
 					   HDMI_QUANTIZATION_RANGE_LIMITED :
 					   HDMI_QUANTIZATION_RANGE_FULL);

 	ret = hdmi_infoframe_pack(&frame, buf, sizeof(buf));
 	if (ret < 0) {
 		DRM_ERROR("Failed to pack AVI IF\n");
 		return;
 	}

 	dig_port->write_infoframe(encoder, crtc_state, HDMI_INFOFRAME_TYPE_AVI,
 				  buf, ret);
 }

 u32 lspcon_infoframes_enabled(struct intel_encoder *encoder,
 			      const struct intel_crtc_state *pipe_config)
 {
 	/* FIXME actually read this from the hw */
 	return enc_to_intel_lspcon(&encoder->base)->active;
 }

 void lspcon_resume(struct intel_lspcon *lspcon)
 {
 	enum drm_lspcon_mode expected_mode;

 	if (lspcon_wake_native_aux_ch(lspcon)) {
 		expected_mode = DRM_LSPCON_MODE_PCON;
 		lspcon_resume_in_pcon_wa(lspcon);
 	} else {
 		expected_mode = DRM_LSPCON_MODE_LS;
 	}

 	if (lspcon_wait_mode(lspcon, expected_mode) == DRM_LSPCON_MODE_PCON)
 		return;

 	if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON))
 		DRM_ERROR("LSPCON resume failed\n");
 	else
 		DRM_DEBUG_KMS("LSPCON resume success\n");
 }

 void lspcon_wait_pcon_mode(struct intel_lspcon *lspcon)
 {
 	lspcon_wait_mode(lspcon, DRM_LSPCON_MODE_PCON);
 }

 bool lspcon_init(struct intel_digital_port *intel_dig_port)
 {
 	struct intel_dp *dp = &intel_dig_port->dp;
 	struct intel_lspcon *lspcon = &intel_dig_port->lspcon;
 	struct drm_device *dev = intel_dig_port->base.base.dev;
 	struct drm_i915_private *dev_priv = to_i915(dev);
 	struct drm_connector *connector = &dp->attached_connector->base;

 	if (!HAS_LSPCON(dev_priv)) {
 		DRM_ERROR("LSPCON is not supported on this platform\n");
 		return false;
 	}

 	lspcon->active = false;
 	lspcon->mode = DRM_LSPCON_MODE_INVALID;

 	if (!lspcon_probe(lspcon)) {
 		DRM_ERROR("Failed to probe lspcon\n");
 		return false;
 	}

 	if (!intel_dp_read_dpcd(dp)) {
 		DRM_ERROR("LSPCON DPCD read failed\n");
 		return false;
 	}

 	if (!lspcon_detect_vendor(lspcon)) {
 		DRM_ERROR("LSPCON vendor detection failed\n");
 		return false;
 	}

 	connector->ycbcr_420_allowed = true;
 	lspcon->active = true;
 	DRM_DEBUG_KMS("Success: LSPCON init\n");
 	return true;
 }
	/*
	* Copyright © 2016 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.
	*
	*
	*/

	#include <drm/drm_atomic_helper.h>
	#include <drm/drm_dp_dual_mode_helper.h>
	#include <drm/drm_edid.h>

	#include "intel_display_types.h"
	#include "intel_dp.h"
	#include "intel_lspcon.h"

	/* LSPCON OUI Vendor ID(signatures) */
	#define LSPCON_VENDOR_PARADE_OUI 0x001CF8
	#define LSPCON_VENDOR_MCA_OUI 0x0060AD

	/* AUX addresses to write MCA AVI IF */
	#define LSPCON_MCA_AVI_IF_WRITE_OFFSET 0x5C0
	#define LSPCON_MCA_AVI_IF_CTRL 0x5DF
	#define LSPCON_MCA_AVI_IF_KICKOFF (1 << 0)
	#define LSPCON_MCA_AVI_IF_HANDLED (1 << 1)

	/* AUX addresses to write Parade AVI IF */
	#define LSPCON_PARADE_AVI_IF_WRITE_OFFSET 0x516
	#define LSPCON_PARADE_AVI_IF_CTRL 0x51E
	#define LSPCON_PARADE_AVI_IF_KICKOFF (1 << 7)
	#define LSPCON_PARADE_AVI_IF_DATA_SIZE 32

	static struct intel_dp lspcon_to_intel_dp(struct intel_lspcon lspcon)
	{
	struct intel_digital_port *dig_port =
	container_of(lspcon, struct intel_digital_port, lspcon);

	return &dig_port->dp;
	}

	static const char *lspcon_mode_name(enum drm_lspcon_mode mode)
	{
	switch (mode) {
	case DRM_LSPCON_MODE_PCON:
	return "PCON";
	case DRM_LSPCON_MODE_LS:
	return "LS";
	case DRM_LSPCON_MODE_INVALID:
	return "INVALID";
	default:
	MISSING_CASE(mode);
	return "INVALID";
	}
	}

	static bool lspcon_detect_vendor(struct intel_lspcon *lspcon)
	{
	struct intel_dp *dp = lspcon_to_intel_dp(lspcon);
	struct drm_dp_dpcd_ident *ident;
	u32 vendor_oui;

	if (drm_dp_read_desc(&dp->aux, &dp->desc, drm_dp_is_branch(dp->dpcd))) {
	DRM_ERROR("Can't read description\n");
	return false;
	}

	ident = &dp->desc.ident;
	vendor_oui = (ident->oui[0] << 16) \| (ident->oui[1] << 8) \|
	ident->oui[2];

	switch (vendor_oui) {
	case LSPCON_VENDOR_MCA_OUI:
	lspcon->vendor = LSPCON_VENDOR_MCA;
	DRM_DEBUG_KMS("Vendor: Mega Chips\n");
	break;

	case LSPCON_VENDOR_PARADE_OUI:
	lspcon->vendor = LSPCON_VENDOR_PARADE;
	DRM_DEBUG_KMS("Vendor: Parade Tech\n");
	break;

	default:
	DRM_ERROR("Invalid/Unknown vendor OUI\n");
	return false;
	}

	return true;
	}

	static enum drm_lspcon_mode lspcon_get_current_mode(struct intel_lspcon *lspcon)
	{
	enum drm_lspcon_mode current_mode;
	struct i2c_adapter *adapter = &lspcon_to_intel_dp(lspcon)->aux.ddc;

	if (drm_lspcon_get_mode(adapter, &current_mode)) {
	DRM_DEBUG_KMS("Error reading LSPCON mode\n");
	return DRM_LSPCON_MODE_INVALID;
	}
	return current_mode;
	}

	static enum drm_lspcon_mode lspcon_wait_mode(struct intel_lspcon *lspcon,
	enum drm_lspcon_mode mode)
	{
	enum drm_lspcon_mode current_mode;

	current_mode = lspcon_get_current_mode(lspcon);
	if (current_mode == mode)
	goto out;

	DRM_DEBUG_KMS("Waiting for LSPCON mode %s to settle\n",
	lspcon_mode_name(mode));

	wait_for((current_mode = lspcon_get_current_mode(lspcon)) == mode, 400);
	if (current_mode != mode)
	DRM_ERROR("LSPCON mode hasn't settled\n");

	out:
	DRM_DEBUG_KMS("Current LSPCON mode %s\n",
	lspcon_mode_name(current_mode));

	return current_mode;
	}

	static int lspcon_change_mode(struct intel_lspcon *lspcon,
	enum drm_lspcon_mode mode)
	{
	int err;
	enum drm_lspcon_mode current_mode;
	struct i2c_adapter *adapter = &lspcon_to_intel_dp(lspcon)->aux.ddc;

	err = drm_lspcon_get_mode(adapter, &current_mode);
	if (err) {
	DRM_ERROR("Error reading LSPCON mode\n");
	return err;
	}

	if (current_mode == mode) {
	DRM_DEBUG_KMS("Current mode = desired LSPCON mode\n");
	return 0;
	}

	err = drm_lspcon_set_mode(adapter, mode);
	if (err < 0) {
	DRM_ERROR("LSPCON mode change failed\n");
	return err;
	}

	lspcon->mode = mode;
	DRM_DEBUG_KMS("LSPCON mode changed done\n");
	return 0;
	}

	static bool lspcon_wake_native_aux_ch(struct intel_lspcon *lspcon)
	{
	u8 rev;

	if (drm_dp_dpcd_readb(&lspcon_to_intel_dp(lspcon)->aux, DP_DPCD_REV,
	&rev) != 1) {
	DRM_DEBUG_KMS("Native AUX CH down\n");
	return false;
	}

	DRM_DEBUG_KMS("Native AUX CH up, DPCD version: %d.%d\n",
	rev >> 4, rev & 0xf);

	return true;
	}

	void lspcon_ycbcr420_config(struct drm_connector *connector,
	struct intel_crtc_state *crtc_state)
	{
	const struct drm_display_info *info = &connector->display_info;
	const struct drm_display_mode *adjusted_mode =
	&crtc_state->base.adjusted_mode;

	if (drm_mode_is_420_only(info, adjusted_mode) &&
	connector->ycbcr_420_allowed) {
	crtc_state->port_clock /= 2;
	crtc_state->output_format = INTEL_OUTPUT_FORMAT_YCBCR444;
	crtc_state->lspcon_downsampling = true;
	}
	}

	static bool lspcon_probe(struct intel_lspcon *lspcon)
	{
	int retry;
	enum drm_dp_dual_mode_type adaptor_type;
	struct i2c_adapter *adapter = &lspcon_to_intel_dp(lspcon)->aux.ddc;
	enum drm_lspcon_mode expected_mode;

	expected_mode = lspcon_wake_native_aux_ch(lspcon) ?
	DRM_LSPCON_MODE_PCON : DRM_LSPCON_MODE_LS;

	/* Lets probe the adaptor and check its type */
	for (retry = 0; retry < 6; retry++) {
	if (retry)
	usleep_range(500, 1000);

	adaptor_type = drm_dp_dual_mode_detect(adapter);
	if (adaptor_type == DRM_DP_DUAL_MODE_LSPCON)
	break;
	}

	if (adaptor_type != DRM_DP_DUAL_MODE_LSPCON) {
	DRM_DEBUG_KMS("No LSPCON detected, found %s\n",
	drm_dp_get_dual_mode_type_name(adaptor_type));
	return false;
	}

	/* Yay ... got a LSPCON device */
	DRM_DEBUG_KMS("LSPCON detected\n");
	lspcon->mode = lspcon_wait_mode(lspcon, expected_mode);

	/*
	* In the SW state machine, lets Put LSPCON in PCON mode only.
	* In this way, it will work with both HDMI 1.4 sinks as well as HDMI
	* 2.0 sinks.
	*/
	if (lspcon->mode != DRM_LSPCON_MODE_PCON) {
	if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON) < 0) {
	DRM_ERROR("LSPCON mode change to PCON failed\n");
	return false;
	}
	}
	return true;
	}

	static void lspcon_resume_in_pcon_wa(struct intel_lspcon *lspcon)
	{
	struct intel_dp *intel_dp = lspcon_to_intel_dp(lspcon);
	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);
	unsigned long start = jiffies;

	while (1) {
	if (intel_digital_port_connected(&dig_port->base)) {
	DRM_DEBUG_KMS("LSPCON recovering in PCON mode after %u ms\n",
	jiffies_to_msecs(jiffies - start));
	return;
	}

	if (time_after(jiffies, start + msecs_to_jiffies(1000)))
	break;

	usleep_range(10000, 15000);
	}

	DRM_DEBUG_KMS("LSPCON DP descriptor mismatch after resume\n");
	}

	static bool lspcon_parade_fw_ready(struct drm_dp_aux *aux)
	{
	u8 avi_if_ctrl;
	u8 retry;
	ssize_t ret;

	/* Check if LSPCON FW is ready for data */
	for (retry = 0; retry < 5; retry++) {
	if (retry)
	usleep_range(200, 300);

	ret = drm_dp_dpcd_read(aux, LSPCON_PARADE_AVI_IF_CTRL,
	&avi_if_ctrl, 1);
	if (ret < 0) {
	DRM_ERROR("Failed to read AVI IF control\n");
	return false;
	}

	if ((avi_if_ctrl & LSPCON_PARADE_AVI_IF_KICKOFF) == 0)
	return true;
	}

	DRM_ERROR("Parade FW not ready to accept AVI IF\n");
	return false;
	}

	static bool _lspcon_parade_write_infoframe_blocks(struct drm_dp_aux *aux,
	u8 *avi_buf)
	{
	u8 avi_if_ctrl;
	u8 block_count = 0;
	u8 *data;
	u16 reg;
	ssize_t ret;

	while (block_count < 4) {
	if (!lspcon_parade_fw_ready(aux)) {
	DRM_DEBUG_KMS("LSPCON FW not ready, block %d\n",
	block_count);
	return false;
	}

	reg = LSPCON_PARADE_AVI_IF_WRITE_OFFSET;
	data = avi_buf + block_count * 8;
	ret = drm_dp_dpcd_write(aux, reg, data, 8);
	if (ret < 0) {
	DRM_ERROR("Failed to write AVI IF block %d\n",
	block_count);
	return false;
	}

	/*
	* Once a block of data is written, we have to inform the FW
	* about this by writing into avi infoframe control register:
	* - set the kickoff bit[7] to 1
	* - write the block no. to bits[1:0]
	*/
	reg = LSPCON_PARADE_AVI_IF_CTRL;
	avi_if_ctrl = LSPCON_PARADE_AVI_IF_KICKOFF \| block_count;
	ret = drm_dp_dpcd_write(aux, reg, &avi_if_ctrl, 1);
	if (ret < 0) {
	DRM_ERROR("Failed to update (0x%x), block %d\n",
	reg, block_count);
	return false;
	}

	block_count++;
	}

	DRM_DEBUG_KMS("Wrote AVI IF blocks successfully\n");
	return true;
	}

	static bool _lspcon_write_avi_infoframe_parade(struct drm_dp_aux *aux,
	const u8 *frame,
	ssize_t len)
	{
	u8 avi_if[LSPCON_PARADE_AVI_IF_DATA_SIZE] = {1, };

	/*
	* Parade's frames contains 32 bytes of data, divided
	* into 4 frames:
	* Token byte (first byte of first frame, must be non-zero)
	* HB0 to HB2 from AVI IF (3 bytes header)
	* PB0 to PB27 from AVI IF (28 bytes data)
	* So it should look like this
	* first block: \| <token> <HB0-HB2> <DB0-DB3> \|
	* next 3 blocks: \|<DB4-DB11>\|<DB12-DB19>\|<DB20-DB28>\|
	*/

	if (len > LSPCON_PARADE_AVI_IF_DATA_SIZE - 1) {
	DRM_ERROR("Invalid length of infoframes\n");
	return false;
	}

	memcpy(&avi_if[1], frame, len);

	if (!_lspcon_parade_write_infoframe_blocks(aux, avi_if)) {
	DRM_DEBUG_KMS("Failed to write infoframe blocks\n");
	return false;
	}

	return true;
	}

	static bool _lspcon_write_avi_infoframe_mca(struct drm_dp_aux *aux,
	const u8 *buffer, ssize_t len)
	{
	int ret;
	u32 val = 0;
	u32 retry;
	u16 reg;
	const u8 *data = buffer;

	reg = LSPCON_MCA_AVI_IF_WRITE_OFFSET;
	while (val < len) {
	/* DPCD write for AVI IF can fail on a slow FW day, so retry */
	for (retry = 0; retry < 5; retry++) {
	ret = drm_dp_dpcd_write(aux, reg, (void *)data, 1);
	if (ret == 1) {
	break;
	} else if (retry < 4) {
	mdelay(50);
	continue;
	} else {
	DRM_ERROR("DPCD write failed at:0x%x\n", reg);
	return false;
	}
	}
	val++; reg++; data++;
	}

	val = 0;
	reg = LSPCON_MCA_AVI_IF_CTRL;
	ret = drm_dp_dpcd_read(aux, reg, &val, 1);
	if (ret < 0) {
	DRM_ERROR("DPCD read failed, address 0x%x\n", reg);
	return false;
	}

	/* Indicate LSPCON chip about infoframe, clear bit 1 and set bit 0 */
	val &= ~LSPCON_MCA_AVI_IF_HANDLED;
	val \|= LSPCON_MCA_AVI_IF_KICKOFF;

	ret = drm_dp_dpcd_write(aux, reg, &val, 1);
	if (ret < 0) {
	DRM_ERROR("DPCD read failed, address 0x%x\n", reg);
	return false;
	}

	val = 0;
	ret = drm_dp_dpcd_read(aux, reg, &val, 1);
	if (ret < 0) {
	DRM_ERROR("DPCD read failed, address 0x%x\n", reg);
	return false;
	}

	if (val == LSPCON_MCA_AVI_IF_HANDLED)
	DRM_DEBUG_KMS("AVI IF handled by FW\n");

	return true;
	}

	void lspcon_write_infoframe(struct intel_encoder *encoder,
	const struct intel_crtc_state *crtc_state,
	unsigned int type,
	const void *frame, ssize_t len)
	{
	bool ret;
	struct intel_dp *intel_dp = enc_to_intel_dp(&encoder->base);
	struct intel_lspcon *lspcon = enc_to_intel_lspcon(&encoder->base);

	/* LSPCON only needs AVI IF */
	if (type != HDMI_INFOFRAME_TYPE_AVI)
	return;

	if (lspcon->vendor == LSPCON_VENDOR_MCA)
	ret = _lspcon_write_avi_infoframe_mca(&intel_dp->aux,
	frame, len);
	else
	ret = _lspcon_write_avi_infoframe_parade(&intel_dp->aux,
	frame, len);

	if (!ret) {
	DRM_ERROR("Failed to write AVI infoframes\n");
	return;
	}

	DRM_DEBUG_DRIVER("AVI infoframes updated successfully\n");
	}

	void lspcon_read_infoframe(struct intel_encoder *encoder,
	const struct intel_crtc_state *crtc_state,
	unsigned int type,
	void *frame, ssize_t len)
	{
	/* FIXME implement this */
	}

	void lspcon_set_infoframes(struct intel_encoder *encoder,
	bool enable,
	const struct intel_crtc_state *crtc_state,
	const struct drm_connector_state *conn_state)
	{
	ssize_t ret;
	union hdmi_infoframe frame;
	u8 buf[VIDEO_DIP_DATA_SIZE];
	struct intel_digital_port *dig_port = enc_to_dig_port(&encoder->base);
	struct intel_lspcon *lspcon = &dig_port->lspcon;
	const struct drm_display_mode *adjusted_mode =
	&crtc_state->base.adjusted_mode;

	if (!lspcon->active) {
	DRM_ERROR("Writing infoframes while LSPCON disabled ?\n");
	return;
	}

	/* FIXME precompute infoframes */

	ret = drm_hdmi_avi_infoframe_from_display_mode(&frame.avi,
	conn_state->connector,
	adjusted_mode);
	if (ret < 0) {
	DRM_ERROR("couldn't fill AVI infoframe\n");
	return;
	}

	if (crtc_state->output_format == INTEL_OUTPUT_FORMAT_YCBCR444) {
	if (crtc_state->lspcon_downsampling)
	frame.avi.colorspace = HDMI_COLORSPACE_YUV420;
	else
	frame.avi.colorspace = HDMI_COLORSPACE_YUV444;
	} else {
	frame.avi.colorspace = HDMI_COLORSPACE_RGB;
	}

	drm_hdmi_avi_infoframe_quant_range(&frame.avi,
	conn_state->connector,
	adjusted_mode,
	crtc_state->limited_color_range ?
	HDMI_QUANTIZATION_RANGE_LIMITED :
	HDMI_QUANTIZATION_RANGE_FULL);

	ret = hdmi_infoframe_pack(&frame, buf, sizeof(buf));
	if (ret < 0) {
	DRM_ERROR("Failed to pack AVI IF\n");
	return;
	}

	dig_port->write_infoframe(encoder, crtc_state, HDMI_INFOFRAME_TYPE_AVI,
	buf, ret);
	}

	u32 lspcon_infoframes_enabled(struct intel_encoder *encoder,
	const struct intel_crtc_state *pipe_config)
	{
	/* FIXME actually read this from the hw */
	return enc_to_intel_lspcon(&encoder->base)->active;
	}

	void lspcon_resume(struct intel_lspcon *lspcon)
	{
	enum drm_lspcon_mode expected_mode;

	if (lspcon_wake_native_aux_ch(lspcon)) {
	expected_mode = DRM_LSPCON_MODE_PCON;
	lspcon_resume_in_pcon_wa(lspcon);
	} else {
	expected_mode = DRM_LSPCON_MODE_LS;
	}

	if (lspcon_wait_mode(lspcon, expected_mode) == DRM_LSPCON_MODE_PCON)
	return;

	if (lspcon_change_mode(lspcon, DRM_LSPCON_MODE_PCON))
	DRM_ERROR("LSPCON resume failed\n");
	else
	DRM_DEBUG_KMS("LSPCON resume success\n");
	}

	void lspcon_wait_pcon_mode(struct intel_lspcon *lspcon)
	{
	lspcon_wait_mode(lspcon, DRM_LSPCON_MODE_PCON);
	}

	bool lspcon_init(struct intel_digital_port *intel_dig_port)
	{
	struct intel_dp *dp = &intel_dig_port->dp;
	struct intel_lspcon *lspcon = &intel_dig_port->lspcon;
	struct drm_device *dev = intel_dig_port->base.base.dev;
	struct drm_i915_private *dev_priv = to_i915(dev);
	struct drm_connector *connector = &dp->attached_connector->base;

	if (!HAS_LSPCON(dev_priv)) {
	DRM_ERROR("LSPCON is not supported on this platform\n");
	return false;
	}

	lspcon->active = false;
	lspcon->mode = DRM_LSPCON_MODE_INVALID;

	if (!lspcon_probe(lspcon)) {
	DRM_ERROR("Failed to probe lspcon\n");
	return false;
	}

	if (!intel_dp_read_dpcd(dp)) {
	DRM_ERROR("LSPCON DPCD read failed\n");
	return false;
	}

	if (!lspcon_detect_vendor(lspcon)) {
	DRM_ERROR("LSPCON vendor detection failed\n");
	return false;
	}

	connector->ycbcr_420_allowed = true;
	lspcon->active = true;
	DRM_DEBUG_KMS("Success: LSPCON init\n");
	return true;
	}