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Message-ID: <zrgmtbmln3dyjzi7qsweptmeihijwbe6jqmsg2w2bcnzeaeprs@2u2emyenm23w>
Date: Thu, 31 Oct 2024 20:54:23 +0200
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Cc: heikki.krogerus@...ux.intel.com, tzungbi@...nel.org, 
	linux-usb@...r.kernel.org, chrome-platform@...ts.linux.dev, jthies@...gle.com, 
	akuchynski@...gle.com, pmalani@...omium.org, Benson Leung <bleung@...omium.org>, 
	Guenter Roeck <groeck@...omium.org>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 5/7] platform/chrome: cros_ec_typec: Displayport
 support

On Wed, Oct 30, 2024 at 02:28:36PM -0700, Abhishek Pandit-Subedi wrote:
> Add support for entering and exiting displayport alt-mode on systems
> using AP driven alt-mode.
> 
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> ---
> 
> Changes in v2:
> - Refactored displayport into cros_typec_altmode.c to extract common
>   implementation between altmodes

Thanks!

> 
>  MAINTAINERS                                  |   3 +
>  drivers/platform/chrome/Makefile             |   3 +-
>  drivers/platform/chrome/cros_ec_typec.c      |  13 +-
>  drivers/platform/chrome/cros_ec_typec.h      |   1 +
>  drivers/platform/chrome/cros_typec_altmode.c | 277 +++++++++++++++++++
>  drivers/platform/chrome/cros_typec_altmode.h |  34 +++
>  6 files changed, 329 insertions(+), 2 deletions(-)
>  create mode 100644 drivers/platform/chrome/cros_typec_altmode.c
>  create mode 100644 drivers/platform/chrome/cros_typec_altmode.h
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index e9659a5a7fb3..de99bcbda7d4 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -5369,9 +5369,12 @@ F:	include/linux/platform_data/cros_usbpd_notify.h
>  
>  CHROMEOS EC USB TYPE-C DRIVER
>  M:	Prashant Malani <pmalani@...omium.org>
> +M:	Benson Leung <bleung@...omium.org>
> +M:	Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
>  L:	chrome-platform@...ts.linux.dev
>  S:	Maintained
>  F:	drivers/platform/chrome/cros_ec_typec.*
> +F:	drivers/platform/chrome/cros_typec_altmode.*
>  F:	drivers/platform/chrome/cros_typec_switch.c
>  F:	drivers/platform/chrome/cros_typec_vdm.*
>  
> diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile
> index 2dcc6ccc2302..8b007404c024 100644
> --- a/drivers/platform/chrome/Makefile
> +++ b/drivers/platform/chrome/Makefile
> @@ -17,8 +17,9 @@ obj-$(CONFIG_CROS_EC_RPMSG)		+= cros_ec_rpmsg.o
>  obj-$(CONFIG_CROS_EC_SPI)		+= cros_ec_spi.o
>  obj-$(CONFIG_CROS_EC_UART)		+= cros_ec_uart.o
>  cros_ec_lpcs-objs			:= cros_ec_lpc.o cros_ec_lpc_mec.o
> -cros-ec-typec-objs			:= cros_ec_typec.o cros_typec_vdm.o
> +cros-ec-typec-objs			:= cros_ec_typec.o cros_typec_vdm.o cros_typec_altmode.o
>  obj-$(CONFIG_CROS_EC_TYPEC)		+= cros-ec-typec.o
> +
>  obj-$(CONFIG_CROS_EC_LPC)		+= cros_ec_lpcs.o
>  obj-$(CONFIG_CROS_EC_PROTO)		+= cros_ec_proto.o cros_ec_trace.o
>  obj-$(CONFIG_CROS_KBD_LED_BACKLIGHT)	+= cros_kbd_led_backlight.o
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index 0c8db11bd8a4..7997e7136c4c 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -18,6 +18,7 @@
>  
>  #include "cros_ec_typec.h"
>  #include "cros_typec_vdm.h"
> +#include "cros_typec_altmode.h"
>  
>  #define DRV_NAME "cros-ec-typec"
>  
> @@ -293,12 +294,16 @@ static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
>  	desc.svid = USB_TYPEC_DP_SID;
>  	desc.mode = USB_TYPEC_DP_MODE;
>  	desc.vdo = DP_PORT_VDO;
> -	amode = typec_port_register_altmode(port->port, &desc);
> +	amode = cros_typec_register_displayport(port, &desc,
> +						typec->ap_driven_altmode);
>  	if (IS_ERR(amode))
>  		return PTR_ERR(amode);
>  	port->port_altmode[CROS_EC_ALTMODE_DP] = amode;
> +
> +#if !IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
>  	typec_altmode_set_drvdata(amode, port);
>  	amode->ops = &port_amode_ops;
> +#endif
>  
>  	/*
>  	 * Register TBT compatibility alt mode. The EC will not enter the mode
> @@ -575,6 +580,10 @@ static int cros_typec_enable_dp(struct cros_typec_data *typec,
>  	if (!ret)
>  		ret = typec_mux_set(port->mux, &port->state);
>  
> +	if (!ret)
> +		cros_typec_displayport_status_update(port->state.alt,
> +						     port->state.data);
> +
>  	return ret;
>  }
>  
> @@ -1254,6 +1263,8 @@ static int cros_typec_probe(struct platform_device *pdev)
>  
>  	typec->typec_cmd_supported = cros_ec_check_features(ec_dev, EC_FEATURE_TYPEC_CMD);
>  	typec->needs_mux_ack = cros_ec_check_features(ec_dev, EC_FEATURE_TYPEC_MUX_REQUIRE_AP_ACK);
> +	typec->ap_driven_altmode = cros_ec_check_features(
> +		ec_dev, EC_FEATURE_TYPEC_REQUIRE_AP_MODE_ENTRY);
>  
>  	ret = cros_ec_cmd(typec->ec, 0, EC_CMD_USB_PD_PORTS, NULL, 0,
>  			  &resp, sizeof(resp));
> diff --git a/drivers/platform/chrome/cros_ec_typec.h b/drivers/platform/chrome/cros_ec_typec.h
> index deda180a646f..9fd5342bb0ad 100644
> --- a/drivers/platform/chrome/cros_ec_typec.h
> +++ b/drivers/platform/chrome/cros_ec_typec.h
> @@ -39,6 +39,7 @@ struct cros_typec_data {
>  	struct work_struct port_work;
>  	bool typec_cmd_supported;
>  	bool needs_mux_ack;
> +	bool ap_driven_altmode;
>  };
>  
>  /* Per port data. */
> diff --git a/drivers/platform/chrome/cros_typec_altmode.c b/drivers/platform/chrome/cros_typec_altmode.c
> new file mode 100644
> index 000000000000..af2f077674f1
> --- /dev/null
> +++ b/drivers/platform/chrome/cros_typec_altmode.c
> @@ -0,0 +1,277 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Alt-mode implementation on ChromeOS EC.
> + *
> + * Copyright 2024 Google LLC
> + * Author: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
> + */
> +#include "cros_ec_typec.h"
> +
> +#include <linux/usb/typec_dp.h>
> +#include <linux/usb/pd_vdo.h>
> +
> +#include "cros_typec_altmode.h"
> +
> +struct cros_typec_dp_data {
> +	struct typec_displayport_data data;
> +
> +	bool configured;
> +	bool pending_status_update;
> +};
> +
> +struct cros_typec_altmode_data {
> +	struct work_struct work;
> +	struct cros_typec_port *port;
> +	struct typec_altmode *alt;
> +	bool ap_mode_entry;
> +
> +	u32 header;
> +	u32 *vdo_data;
> +	u8 vdo_size;
> +
> +	u16 sid;
> +	u8 mode;
> +
> +	union am_specific {
> +		struct cros_typec_dp_data dp;
> +	} am_data;

Can this be done other way around?

struct cros_typec_dp_altmode_data {
  struct cros_typec_altmode_data base;
  struct cros_typec_dp_data dp;
};

> +};
> +
> +static void cros_typec_altmode_work(struct work_struct *work)
> +{
> +	struct cros_typec_altmode_data *data =
> +		container_of(work, struct cros_typec_altmode_data, work);
> +
> +	if (typec_altmode_vdm(data->alt, data->header, data->vdo_data,
> +			      data->vdo_size))
> +		dev_err(&data->alt->dev, "VDM 0x%x failed", data->header);
> +
> +	data->header = 0;
> +	data->vdo_data = NULL;
> +	data->vdo_size = 0;
> +}
> +
> +static int cros_typec_altmode_enter(struct typec_altmode *alt, u32 *vdo)
> +{
> +	struct cros_typec_altmode_data *data = typec_altmode_get_drvdata(alt);
> +	struct ec_params_typec_control req = {
> +		.port = data->port->port_num,
> +		.command = TYPEC_CONTROL_COMMAND_ENTER_MODE,
> +	};
> +	int svdm_version;
> +	int ret;
> +
> +	if (!data->ap_mode_entry) {
> +		const struct typec_altmode *partner =
> +			typec_altmode_get_partner(alt);
> +		dev_warn(&partner->dev,
> +			 "EC does not support ap driven mode entry\n");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	if (data->sid == USB_TYPEC_DP_SID)
> +		req.mode_to_enter = CROS_EC_ALTMODE_DP;
> +	else
> +		return -EOPNOTSUPP;
> +
> +	ret = cros_ec_cmd(data->port->typec_data->ec, 0, EC_CMD_TYPEC_CONTROL,
> +			  &req, sizeof(req), NULL, 0);
> +	if (ret < 0)
> +		return ret;
> +
> +	svdm_version = typec_altmode_get_svdm_version(alt);
> +	if (svdm_version < 0)
> +		return svdm_version;
> +
> +	data->header = VDO(data->sid, 1, svdm_version, CMD_ENTER_MODE);
> +	data->header |= VDO_OPOS(data->mode);
> +	data->header |= VDO_CMDT(CMDT_RSP_ACK);
> +
> +	data->vdo_data = NULL;
> +	data->vdo_size = 1;
> +
> +	schedule_work(&data->work);
> +
> +	return ret;
> +}
> +
> +static int cros_typec_altmode_exit(struct typec_altmode *alt)
> +{
> +	struct cros_typec_altmode_data *data = typec_altmode_get_drvdata(alt);
> +	struct ec_params_typec_control req = {
> +		.port = data->port->port_num,
> +		.command = TYPEC_CONTROL_COMMAND_EXIT_MODES,
> +	};
> +	int svdm_version;
> +	int ret;
> +
> +	if (!data->ap_mode_entry) {
> +		const struct typec_altmode *partner =
> +			typec_altmode_get_partner(alt);
> +		dev_warn(&partner->dev,
> +			 "EC does not support ap driven mode entry\n");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	ret = cros_ec_cmd(data->port->typec_data->ec, 0, EC_CMD_TYPEC_CONTROL,
> +			  &req, sizeof(req), NULL, 0);
> +
> +	if (ret < 0)
> +		return ret;
> +
> +	svdm_version = typec_altmode_get_svdm_version(alt);
> +	if (svdm_version < 0)
> +		return svdm_version;
> +
> +	data->header = VDO(data->sid, 1, svdm_version, CMD_EXIT_MODE);
> +	data->header |= VDO_OPOS(data->mode);
> +	data->header |= VDO_CMDT(CMDT_RSP_ACK);
> +
> +	data->vdo_data = NULL;
> +	data->vdo_size = 1;
> +
> +	schedule_work(&data->work);
> +
> +	return ret;
> +}
> +
> +static int cros_typec_displayport_vdm(struct typec_altmode *alt, u32 header,
> +				      const u32 *data, int count)
> +{
> +	struct cros_typec_altmode_data *adata = typec_altmode_get_drvdata(alt);
> +
> +	int cmd_type = PD_VDO_CMDT(header);
> +	int cmd = PD_VDO_CMD(header);
> +	int svdm_version;
> +
> +	if (!adata->ap_mode_entry) {
> +		const struct typec_altmode *partner =
> +			typec_altmode_get_partner(alt);
> +		dev_warn(&partner->dev,
> +			 "EC does not support ap driven mode entry\n");
> +		return -EOPNOTSUPP;
> +	}
> +
> +	svdm_version = typec_altmode_get_svdm_version(alt);
> +	if (svdm_version < 0)
> +		return svdm_version;
> +
> +	switch (cmd_type) {
> +	case CMDT_INIT:
> +		if (PD_VDO_SVDM_VER(header) < svdm_version) {
> +			typec_partner_set_svdm_version(adata->port->partner,
> +						       PD_VDO_SVDM_VER(header));
> +			svdm_version = PD_VDO_SVDM_VER(header);
> +		}
> +
> +		adata->header = VDO(adata->sid, 1, svdm_version, cmd);
> +		adata->header |= VDO_OPOS(adata->mode);
> +
> +		/*
> +		 * DP_CMD_CONFIGURE: We can't actually do anything with the
> +		 * provided VDO yet so just send back an ACK.
> +		 *
> +		 * DP_CMD_STATUS_UPDATE: We wait for Mux changes to send
> +		 * DPStatus Acks.
> +		 */
> +		switch (cmd) {
> +		case DP_CMD_CONFIGURE:
> +			adata->am_data.dp.data.conf = *data;
> +			adata->header |= VDO_CMDT(CMDT_RSP_ACK);
> +			adata->am_data.dp.configured = true;
> +			schedule_work(&adata->work);
> +			break;
> +		case DP_CMD_STATUS_UPDATE:
> +			adata->am_data.dp.pending_status_update = true;
> +			break;
> +		default:
> +			adata->header |= VDO_CMDT(CMDT_RSP_ACK);
> +			schedule_work(&adata->work);
> +			break;
> +		}
> +
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	return 0;
> +}
> +
> +static int cros_typec_altmode_vdm(struct typec_altmode *alt, u32 header,
> +				      const u32 *data, int count)
> +{
> +	struct cros_typec_altmode_data *adata = typec_altmode_get_drvdata(alt);
> +
> +	if (adata->sid == USB_TYPEC_DP_SID)
> +		return cros_typec_displayport_vdm(alt, header, data, count);
> +
> +	return -EINVAL;
> +}
> +
> +static const struct typec_altmode_ops cros_typec_altmode_ops = {
> +	.enter = cros_typec_altmode_enter,
> +	.exit = cros_typec_altmode_exit,
> +	.vdm = cros_typec_altmode_vdm,
> +};
> +
> +#if IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
> +int cros_typec_displayport_status_update(struct typec_altmode *altmode,
> +					 struct typec_displayport_data *data)
> +{
> +	struct cros_typec_altmode_data *adata =
> +		typec_altmode_get_drvdata(altmode);
> +
> +	if (!adata->am_data.dp.pending_status_update) {
> +		dev_dbg(&altmode->dev,
> +			"Got DPStatus without a pending request");
> +		return 0;
> +	}
> +
> +	if (adata->am_data.dp.configured && adata->am_data.dp.data.conf != data->conf)
> +		dev_dbg(&altmode->dev,
> +			"DP Conf doesn't match. Requested 0x%04x, Actual 0x%04x",
> +			adata->am_data.dp.data.conf, data->conf);
> +
> +	adata->am_data.dp.data = *data;
> +	adata->am_data.dp.pending_status_update = false;
> +	adata->header |= VDO_CMDT(CMDT_RSP_ACK);
> +	adata->vdo_data = &adata->am_data.dp.data.status;
> +	adata->vdo_size = 2;
> +
> +	schedule_work(&adata->work);
> +	return 0;
> +}
> +
> +struct typec_altmode *
> +cros_typec_register_displayport(struct cros_typec_port *port,
> +				struct typec_altmode_desc *desc,
> +				bool ap_mode_entry)
> +{
> +	struct typec_altmode *alt;
> +	struct cros_typec_altmode_data *data;
> +
> +	alt = typec_port_register_altmode(port->port, desc);
> +	if (IS_ERR(alt))
> +		return alt;
> +
> +	data = devm_kzalloc(&alt->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data) {
> +		typec_unregister_altmode(alt);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	INIT_WORK(&data->work, cros_typec_altmode_work);
> +	data->alt = alt;
> +	data->port = port;
> +	data->ap_mode_entry = ap_mode_entry;
> +	data->sid = USB_TYPEC_DP_SID;
> +	data->mode = USB_TYPEC_DP_MODE;
> +
> +	data->am_data.dp.configured = false;
> +	typec_altmode_set_ops(alt, &cros_typec_altmode_ops);
> +	typec_altmode_set_drvdata(alt, data);
> +
> +	return alt;
> +}
> +#endif
> diff --git a/drivers/platform/chrome/cros_typec_altmode.h b/drivers/platform/chrome/cros_typec_altmode.h
> new file mode 100644
> index 000000000000..c6f8fb02c99c
> --- /dev/null
> +++ b/drivers/platform/chrome/cros_typec_altmode.h
> @@ -0,0 +1,34 @@
> +/* SPDX-License-Identifier: GPL-2.0-only */
> +
> +#ifndef __CROS_TYPEC_ALTMODE_H__
> +#define __CROS_TYPEC_ALTMODE_H__
> +
> +struct cros_typec_port;
> +struct typec_altmode;
> +struct typec_altmode_desc;
> +struct typec_displayport_data;
> +
> +#if IS_ENABLED(CONFIG_TYPEC_DP_ALTMODE)
> +struct typec_altmode *
> +cros_typec_register_displayport(struct cros_typec_port *port,
> +				struct typec_altmode_desc *desc,
> +				bool ap_mode_entry);
> +
> +int cros_typec_displayport_status_update(struct typec_altmode *altmode,
> +					 struct typec_displayport_data *data);
> +#else
> +static inline struct typec_altmode *
> +cros_typec_register_displayport(struct cros_typec_port *port,
> +				struct typec_altmode_desc *desc,
> +				bool ap_mode_entry)
> +{
> +	return typec_port_register_altmode(port->port, desc);
> +}
> +
> +static inline int cros_typec_displayport_status_update(struct typec_altmode *altmode,
> +					 struct typec_displayport_data *data)
> +{
> +	return 0;
> +}
> +#endif
> +#endif /* __CROS_TYPEC_ALTMODE_H__ */
> -- 
> 2.47.0.163.g1226f6d8fa-goog
> 

-- 
With best wishes
Dmitry

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