Commit 178fbb6d authored by Jimmy Kizito's avatar Jimmy Kizito Committed by Alex Deucher
Browse files

drm/amd/display: Implement DPIA training loop 



[Why]
Training of DPIA link differs enough from that of conventional
DP link to warrant a separate implementation.

[How]
- Implement top-level of DPIA training loop.
- Make functions shared between DP and DPIA link training "public".

Reviewed-by: default avatarJun Lei <Jun.Lei@amd.com>
Acked-by: default avatarWayne Lin <Wayne.Lin@amd.com>
Acked-by: default avatarNicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Acked-by: default avatarHarry Wentland <harry.wentland@amd.com>
Signed-off-by: default avatarJimmy Kizito <Jimmy.Kizito@amd.com>
Signed-off-by: default avatarAlex Deucher <alexander.deucher@amd.com>
parent edfb2693

drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c

+0 −17
Original line number Diff line number Diff line
@@ -2318,23 +2318,6 @@ enum link_training_result dc_link_dp_perform_link_training( 
	return status;

}



/*

 * Train DP tunneling link for USB4 DPIA display endpoint.

 *

 * DPIA equivalent of dc_link_dp_perfrorm_link_training.

 */

enum link_training_result dc_link_dpia_perform_link_training(struct dc_link *link,

	const struct dc_link_settings *link_setting,

	bool skip_video_pattern)

{

	enum link_training_result status;



	/** @todo Always fail until USB4 DPIA training implemented. */

	status = LINK_TRAINING_CR_FAIL_LANE0;



	return status;

}



bool perform_link_training_with_retries(

	const struct dc_link_settings *link_setting,

	bool skip_video_pattern,

drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c

+109 −0
Original line number Diff line number Diff line
@@ -24,12 +24,121 @@ 
 *

 */



#include "dc.h"

#include "dc_link_dpia.h"

#include "inc/core_status.h"

#include "dc_link.h"

#include "dc_link_dp.h"



enum dc_status dpcd_get_tunneling_device_data(struct dc_link *link)

{

	/** @todo Read corresponding DPCD region and update link caps. */

	return DC_OK;

}



/* Configure link as prescribed in link_setting; set LTTPR mode; and

 * Initialize link training settings.

 */

static enum link_training_result dpia_configure_link(struct dc_link *link,

		const struct dc_link_settings *link_setting,

		struct link_training_settings *lt_settings)

{

	enum link_training_result result;



	/** @todo Fail until implemented. */

	result = LINK_TRAINING_ABORT;



	return result;

}



/* Execute clock recovery phase of link training for specified hop in display

 * path.

 */

static enum link_training_result dpia_training_cr_phase(struct dc_link *link,

		struct link_training_settings *lt_settings,

		uint32_t hop)

{

	enum link_training_result result;



	/** @todo Fail until implemented. */

	result = LINK_TRAINING_ABORT;



	return result;

}



/* Execute equalization phase of link training for specified hop in display

 * path.

 */

static enum link_training_result dpia_training_eq_phase(struct dc_link *link,

		struct link_training_settings *lt_settings,

		uint32_t hop)

{

	enum link_training_result result;



	/** @todo Fail until implemented. */

	result = LINK_TRAINING_ABORT;



	return result;

}



/* End training of specified hop in display path. */

static enum link_training_result dpia_training_end(struct dc_link *link,

		uint32_t hop)

{

	enum link_training_result result;



	/** @todo Fail until implemented. */

	result = LINK_TRAINING_ABORT;



	return result;

}



enum link_training_result dc_link_dpia_perform_link_training(struct dc_link *link,

	const struct dc_link_settings *link_setting,

	bool skip_video_pattern)

{

	enum link_training_result result;

	struct link_training_settings lt_settings;

	uint8_t repeater_cnt = 0; /* Number of hops/repeaters in display path. */

	uint8_t repeater_id; /* Current hop. */



	/* Configure link as prescribed in link_setting and set LTTPR mode. */

	result = dpia_configure_link(link, link_setting, &lt_settings);

	if (result != LINK_TRAINING_SUCCESS)

		return result;



	if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT)

		repeater_cnt = dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt);



	/* Train each hop in turn starting with the one closest to DPTX.

	 * In transparent or non-LTTPR mode, train only the final hop (DPRX).

	 */

	for (repeater_id = repeater_cnt; repeater_id >= 0; repeater_id--) {

		/* Clock recovery. */

		result = dpia_training_cr_phase(link, &lt_settings, repeater_id);

		if (result != LINK_TRAINING_SUCCESS)

			break;



		/* Equalization. */

		result = dpia_training_eq_phase(link, &lt_settings, repeater_id);

		if (result != LINK_TRAINING_SUCCESS)

			break;



		/* Stop training hop. */

		result = dpia_training_end(link, repeater_id);

		if (result != LINK_TRAINING_SUCCESS)

			break;

	}



	/* Double-check link status if training successful; gracefully stop

	 * training of current hop if training failed for any reason other than

	 * sink unplug.

	 */

	if (result == LINK_TRAINING_SUCCESS) {

		msleep(5);

		result = dp_check_link_loss_status(link, &lt_settings);

	} else if (result != LINK_TRAINING_ABORT) {

		dpia_training_end(link, repeater_id);

	}

	return result;

}

drivers/gpu/drm/amd/display/dc/inc/dc_link_dpia.h

+10 −0
Original line number Diff line number Diff line
@@ -30,10 +30,20 @@ 
/* This module implements functionality for training DPIA links. */



struct dc_link;

struct dc_link_settings;



/* Read tunneling device capability from DPCD and update link capability

 * accordingly.

 */

enum dc_status dpcd_get_tunneling_device_data(struct dc_link *link);



/* Train DP tunneling link for USB4 DPIA display endpoint.

 * DPIA equivalent of dc_link_dp_perfrorm_link_training.

 * Aborts link training upon detection of sink unplug.

 */

enum link_training_result

dc_link_dpia_perform_link_training(struct dc_link *link,

	const struct dc_link_settings *link_setting,

	bool skip_video_pattern);



#endif /* __DC_LINK_DPIA_H__ */

drivers/gpu/drm/amd/display/dc/os_types.h

+1 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ 
#include <linux/kref.h>

#include <linux/types.h>

#include <linux/slab.h>

#include <linux/delay.h>



#include <asm/byteorder.h>