Re: [PATCH v2 06/23] drm/amd/display: Support DP tunneling when DPRX detection

[Harry Wentland <harry.wentland@amd.com>]

On 2021-10-05 03:51, Wayne Lin wrote:
> From: Jimmy Kizito <Jimmy.Kizito@amd.com>
> 
> [why & how]
> Add codes for commit "99732e52e7f8 drm/amd/display: Update DPRX detection"
> to support USB4 DP tunneling feature
> 

This patch does a few, seemingly unrelated, changes:
1. Add stub for getting tunneling device data
2. Add check for phy_repeater_cnt < 0xff to LTTPR check
3. Add two more bits of information to DPIA links

Does item 2 have potential to change existing LTTPR behavior? If so,
it might be better in a separate patch to ease potential regressions
in the future. Probably not a big deal here, though.

Suggested title: "Add stub to get DPIA tunneling device data"

Suggested description, something like:
1. Add stub for getting tunneling device data
2. Add check for phy_repeater_cnt < 0xff to LTTPR check
3. Add two more bits of information to DPIA links

Harry

> Reviewed-by: Jun Lei <Jun.Lei@amd.com>
> Acked-by: Wayne Lin <Wayne.Lin@amd.com>
> Acked-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
> Signed-off-by: Jimmy Kizito <Jimmy.Kizito@amd.com>
> ---
>  drivers/gpu/drm/amd/display/dc/Makefile       |  2 +-
>  drivers/gpu/drm/amd/display/dc/core/dc_link.c |  2 +
>  .../gpu/drm/amd/display/dc/core/dc_link_dp.c  |  4 ++
>  .../drm/amd/display/dc/core/dc_link_dpia.c    | 34 +++++++++++++++++
>  .../gpu/drm/amd/display/dc/inc/dc_link_dpia.h | 38 +++++++++++++++++++
>  5 files changed, 79 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c
>  create mode 100644 drivers/gpu/drm/amd/display/dc/inc/dc_link_dpia.h
> 
> diff --git a/drivers/gpu/drm/amd/display/dc/Makefile b/drivers/gpu/drm/amd/display/dc/Makefile
> index 520f58538364..1a0e462bed42 100644
> --- a/drivers/gpu/drm/amd/display/dc/Makefile
> +++ b/drivers/gpu/drm/amd/display/dc/Makefile
> @@ -61,7 +61,7 @@ include $(AMD_DC)
>  
>  DISPLAY_CORE = dc.o  dc_stat.o dc_link.o dc_resource.o dc_hw_sequencer.o dc_sink.o \
>  dc_surface.o dc_link_hwss.o dc_link_dp.o dc_link_ddc.o dc_debug.o dc_stream.o \
> -dc_link_enc_cfg.o dc_link_dpcd.o
> +dc_link_enc_cfg.o dc_link_dpia.o dc_link_dpcd.o
>  
>  ifdef CONFIG_DRM_AMD_DC_DCN
>  DISPLAY_CORE += dc_vm_helper.o
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
> index 66182b8c217b..1c397d5551ba 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c
> @@ -1726,6 +1726,7 @@ static bool dc_link_construct_dpia(struct dc_link *link,
>  	/* Dummy Init for linkid */
>  	link->link_id.type = OBJECT_TYPE_CONNECTOR;
>  	link->link_id.id = CONNECTOR_ID_DISPLAY_PORT;
> +	link->link_id.enum_id = ENUM_ID_1 + init_params->connector_index;
>  	link->is_internal_display = false;
>  	link->connector_signal = SIGNAL_TYPE_DISPLAY_PORT;
>  	LINK_INFO("Connector[%d] description:signal %d\n",
> @@ -1733,6 +1734,7 @@ static bool dc_link_construct_dpia(struct dc_link *link,
>  		  link->connector_signal);
>  
>  	link->ep_type = DISPLAY_ENDPOINT_USB4_DPIA;
> +	link->is_dig_mapping_flexible = true;
>  
>  	/* TODO: Initialize link : funcs->link_init */
>  
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> index 4df71d728319..9bc5f49ea2ec 100644
> --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
> @@ -36,6 +36,7 @@
>  #include "dpcd_defs.h"
>  #include "dc_dmub_srv.h"
>  #include "dce/dmub_hw_lock_mgr.h"
> +#include "inc/dc_link_dpia.h"
>  #include "inc/link_enc_cfg.h"
>  
>  /*Travis*/
> @@ -4582,6 +4583,7 @@ bool dp_retrieve_lttpr_cap(struct dc_link *link)
>  
>  		/* Attempt to train in LTTPR transparent mode if repeater count exceeds 8. */
>  		is_lttpr_present = (dp_convert_to_count(link->dpcd_caps.lttpr_caps.phy_repeater_cnt) != 0 &&
> +				link->dpcd_caps.lttpr_caps.phy_repeater_cnt < 0xff &&
>  				link->dpcd_caps.lttpr_caps.max_lane_count > 0 &&
>  				link->dpcd_caps.lttpr_caps.max_lane_count <= 4 &&
>  				link->dpcd_caps.lttpr_caps.revision.raw >= 0x14);
> @@ -4630,6 +4632,8 @@ static bool retrieve_link_cap(struct dc_link *link)
>  			LINK_AUX_DEFAULT_LTTPR_TIMEOUT_PERIOD);
>  
>  	is_lttpr_present = dp_retrieve_lttpr_cap(link);
> +	/* Read DP tunneling information. */
> +	status = dpcd_get_tunneling_device_data(link);
>  
>  	status = core_link_read_dpcd(link, DP_SET_POWER,
>  			&dpcd_power_state, sizeof(dpcd_power_state));
> diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c
> new file mode 100644
> index 000000000000..183601e300fe
> --- /dev/null
> +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dpia.c
> @@ -0,0 +1,34 @@
> +/*
> + * Copyright 2021 Advanced Micro Devices, Inc.
> + *
> + * 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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.
> + *
> + * Authors: AMD
> + *
> + */
> +
> +#include "dc_link_dpia.h"
> +#include "inc/core_status.h"
> +#include "dc_link.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;
> +}
> diff --git a/drivers/gpu/drm/amd/display/dc/inc/dc_link_dpia.h b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dpia.h
> new file mode 100644
> index 000000000000..8ed0c9f6414b
> --- /dev/null
> +++ b/drivers/gpu/drm/amd/display/dc/inc/dc_link_dpia.h
> @@ -0,0 +1,38 @@
> +/*
> + * Copyright 2021 Advanced Micro Devices, Inc.
> + *
> + * 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 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 COPYRIGHT HOLDER(S) OR AUTHOR(S) 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.
> + *
> + * Authors: AMD
> + *
> + */
> +
> +#ifndef __DC_LINK_DPIA_H__
> +#define __DC_LINK_DPIA_H__
> +
> +/* This module implements functionality for training DPIA links. */
> +
> +struct dc_link;
> +
> +/* Read tunneling device capability from DPCD and update link capability
> + * accordingly.
> + */
> +enum dc_status dpcd_get_tunneling_device_data(struct dc_link *link);
> +
> +#endif /* __DC_LINK_DPIA_H__ */
>