Re: [PATCH v5 7/8] platform/chrome: cros_ec_typec: Thunderbolt support

[Benson Leung <bleung@google.com>]

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On Fri, Dec 13, 2024 at 03:35:48PM -0800, Abhishek Pandit-Subedi wrote:
> Add support for entering and exiting Thunderbolt alt-mode using AP
> driven alt-mode.
> 
> Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>

Reviewed-by: Benson Leung <bleung@chromium.org>

> ---
> 
> (no changes since v4)
> 
> Changes in v4:
> - Update Makefile + Kconfig to use CONFIG_CROS_EC_TYPEC_ALTMODES
> - Add locking in vdm function
> 
> Changes in v3:
> - Fix usage of TBT sid and mode.
> - Removed unused vdm operations during altmode registration
> 
> Changes in v2:
> - Refactored thunderbolt support into cros_typec_altmode.c
> 
>  drivers/platform/chrome/Kconfig              |  1 +
>  drivers/platform/chrome/cros_ec_typec.c      | 23 ++---
>  drivers/platform/chrome/cros_typec_altmode.c | 88 ++++++++++++++++++++
>  drivers/platform/chrome/cros_typec_altmode.h | 14 ++++
>  4 files changed, 115 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig
> index 23aa594fbb5b..1b2f2bd09662 100644
> --- a/drivers/platform/chrome/Kconfig
> +++ b/drivers/platform/chrome/Kconfig
> @@ -249,6 +249,7 @@ config CROS_EC_TYPEC
>  	depends on USB_ROLE_SWITCH
>  	default MFD_CROS_EC_DEV
>  	select CROS_EC_TYPEC_ALTMODES if TYPEC_DP_ALTMODE
> +	select CROS_EC_TYPEC_ALTMODES if TYPEC_TBT_ALTMODE
>  	help
>  	  If you say Y here, you get support for accessing Type C connector
>  	  information from the Chrome OS EC.
> diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> index 1bcaa7269395..1ac5798d887f 100644
> --- a/drivers/platform/chrome/cros_ec_typec.c
> +++ b/drivers/platform/chrome/cros_ec_typec.c
> @@ -303,18 +303,19 @@ static int cros_typec_register_port_altmodes(struct cros_typec_data *typec,
>  
>  	/*
>  	 * Register TBT compatibility alt mode. The EC will not enter the mode
> -	 * if it doesn't support it, so it's safe to register it unconditionally
> -	 * here for now.
> +	 * if it doesn't support it and it will not enter automatically by
> +	 * design so we can use the |ap_driven_altmode| feature to check if we
> +	 * should register it.
>  	 */
> -	memset(&desc, 0, sizeof(desc));
> -	desc.svid = USB_TYPEC_TBT_SID;
> -	desc.mode = TYPEC_ANY_MODE;
> -	amode = typec_port_register_altmode(port->port, &desc);
> -	if (IS_ERR(amode))
> -		return PTR_ERR(amode);
> -	port->port_altmode[CROS_EC_ALTMODE_TBT] = amode;
> -	typec_altmode_set_drvdata(amode, port);
> -	amode->ops = &port_amode_ops;
> +	if (typec->ap_driven_altmode) {
> +		memset(&desc, 0, sizeof(desc));
> +		desc.svid = USB_TYPEC_TBT_SID;
> +		desc.mode = TBT_MODE;
> +		amode = cros_typec_register_thunderbolt(port, &desc);
> +		if (IS_ERR(amode))
> +			return PTR_ERR(amode);
> +		port->port_altmode[CROS_EC_ALTMODE_TBT] = amode;
> +	}
>  
>  	port->state.alt = NULL;
>  	port->state.mode = TYPEC_STATE_USB;
> diff --git a/drivers/platform/chrome/cros_typec_altmode.c b/drivers/platform/chrome/cros_typec_altmode.c
> index 6e736168ccc3..557340b53af0 100644
> --- a/drivers/platform/chrome/cros_typec_altmode.c
> +++ b/drivers/platform/chrome/cros_typec_altmode.c
> @@ -10,6 +10,7 @@
>  #include <linux/mutex.h>
>  #include <linux/workqueue.h>
>  #include <linux/usb/typec_dp.h>
> +#include <linux/usb/typec_tbt.h>
>  #include <linux/usb/pd_vdo.h>
>  
>  #include "cros_typec_altmode.h"
> @@ -72,6 +73,8 @@ static int cros_typec_altmode_enter(struct typec_altmode *alt, u32 *vdo)
>  
>  	if (adata->sid == USB_TYPEC_DP_SID)
>  		req.mode_to_enter = CROS_EC_ALTMODE_DP;
> +	else if (adata->sid == USB_TYPEC_TBT_SID)
> +		req.mode_to_enter = CROS_EC_ALTMODE_TBT;
>  	else
>  		return -EOPNOTSUPP;
>  
> @@ -196,6 +199,56 @@ static int cros_typec_displayport_vdm(struct typec_altmode *alt, u32 header,
>  	return 0;
>  }
>  
> +static int cros_typec_thunderbolt_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;
> +
> +	svdm_version = typec_altmode_get_svdm_version(alt);
> +	if (svdm_version < 0)
> +		return svdm_version;
> +
> +	mutex_lock(&adata->lock);
> +
> +	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);
> +
> +		switch (cmd) {
> +		case CMD_ENTER_MODE:
> +			/* Don't respond to the enter mode vdm because it
> +			 * triggers mux configuration. This is handled directly
> +			 * by the cros_ec_typec driver so the Thunderbolt driver
> +			 * doesn't need to be involved.
> +			 */
> +			break;
> +		default:
> +			adata->header |= VDO_CMDT(CMDT_RSP_ACK);
> +			schedule_work(&adata->work);
> +			break;
> +		}
> +
> +		break;
> +	default:
> +		break;
> +	}
> +
> +	mutex_unlock(&adata->lock);
> +	return 0;
> +}
> +
> +
>  static int cros_typec_altmode_vdm(struct typec_altmode *alt, u32 header,
>  				      const u32 *data, int count)
>  {
> @@ -207,6 +260,9 @@ static int cros_typec_altmode_vdm(struct typec_altmode *alt, u32 header,
>  	if (adata->sid == USB_TYPEC_DP_SID)
>  		return cros_typec_displayport_vdm(alt, header, data, count);
>  
> +	if (adata->sid == USB_TYPEC_TBT_SID)
> +		return cros_typec_thunderbolt_vdm(alt, header, data, count);
> +
>  	return -EINVAL;
>  }
>  
> @@ -283,3 +339,35 @@ cros_typec_register_displayport(struct cros_typec_port *port,
>  	return alt;
>  }
>  #endif
> +
> +#if IS_ENABLED(CONFIG_TYPEC_TBT_ALTMODE)
> +struct typec_altmode *
> +cros_typec_register_thunderbolt(struct cros_typec_port *port,
> +				struct typec_altmode_desc *desc)
> +{
> +	struct typec_altmode *alt;
> +	struct cros_typec_altmode_data *adata;
> +
> +	alt = typec_port_register_altmode(port->port, desc);
> +	if (IS_ERR(alt))
> +		return alt;
> +
> +	adata = devm_kzalloc(&alt->dev, sizeof(*adata), GFP_KERNEL);
> +	if (!adata) {
> +		typec_unregister_altmode(alt);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	INIT_WORK(&adata->work, cros_typec_altmode_work);
> +	adata->alt = alt;
> +	adata->port = port;
> +	adata->ap_mode_entry = true;
> +	adata->sid = desc->svid;
> +	adata->mode = desc->mode;
> +
> +	typec_altmode_set_ops(alt, &cros_typec_altmode_ops);
> +	typec_altmode_set_drvdata(alt, adata);
> +
> +	return alt;
> +}
> +#endif
> diff --git a/drivers/platform/chrome/cros_typec_altmode.h b/drivers/platform/chrome/cros_typec_altmode.h
> index ed00ee7a402b..3f2aa95d065a 100644
> --- a/drivers/platform/chrome/cros_typec_altmode.h
> +++ b/drivers/platform/chrome/cros_typec_altmode.h
> @@ -34,4 +34,18 @@ static inline int cros_typec_displayport_status_update(struct typec_altmode *alt
>  	return 0;
>  }
>  #endif
> +
> +#if IS_ENABLED(CONFIG_TYPEC_TBT_ALTMODE)
> +struct typec_altmode *
> +cros_typec_register_thunderbolt(struct cros_typec_port *port,
> +				struct typec_altmode_desc *desc);
> +#else
> +static inline struct typec_altmode *
> +cros_typec_register_thunderbolt(struct cros_typec_port *port,
> +				struct typec_altmode_desc *desc)
> +{
> +	return typec_port_register_altmode(port->port, desc);
> +}
> +#endif
> +
>  #endif /* __CROS_TYPEC_ALTMODE_H__ */
> -- 
> 2.47.1.613.gc27f4b7a9f-goog
> 
> 

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