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From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Ajay Gupta <ajaykuee@gmail.com>
Cc: linux-usb@vger.kernel.org, Ajay Gupta <ajayg@nvidia.com>
Subject: Re: [PATCH v2] usb: typec: ucsi: add support for separate DP altmode devices
Date: Mon, 12 Aug 2019 17:42:32 +0300
Message-ID: <20190812144232.GB4691@kuha.fi.intel.com> (raw)
In-Reply-To: <20190805182413.29362-1-ajayg@nvidia.com>

Hi Ajay,

On Mon, Aug 05, 2019 at 11:24:13AM -0700, Ajay Gupta wrote:
> From: Ajay Gupta <ajayg@nvidia.com>
> 
> CCGx controller used on NVIDIA GPU card has two separate display
> altmode for two DP pin assignments. UCSI specification doesn't
> prohibits using separate display altmode.
> 
> Current UCSI Type-C framework expects only one display altmode for
> all DP pin assignment. This patch squashes two separate display
> altmode into single altmode to support controllers with separate
> display altmode. We first read all the alternate modes of connector
> and then run through it to know if there are separate display
> altmodes. If so, it prepares a new port altmode set after squashing
> two or more separate altmodes into one.

I finally have time to go over this patch. Squashing those two
connector modes into one makes sense to me, but I'm not completely
happy about the quality of the code (although the entire driver has
always been a bit messy). The implementation also feels somehow too
integrated into the core UCSI driver. Give me a few days to think
about improvements. If I don't come up with anything, we'll go forward
with this as is.

> Signed-off-by: Ajay Gupta <ajayg@nvidia.com>
> ---
> Original discussion on this issue is at [1]
> 
> Change from v1->v2
> 	- Fix ucsi->ppm NULL check in ucsi_sync based on
> 	comment from an automated email from someone (I lost the email).
> 
> 1. https://marc.info/?l=linux-usb&m=154905866830998&w=2
> 
>  drivers/usb/typec/ucsi/ucsi.c | 212 ++++++++++++++++++++++++++++++++--
>  drivers/usb/typec/ucsi/ucsi.h |  12 ++
>  2 files changed, 217 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index ba288b964dc8..68ea66fcaa0e 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -39,11 +39,37 @@
>   */
>  #define UCSI_SWAP_TIMEOUT_MS	5000
>  
> +static void ucsi_update_get_current_cam_cmd(struct ucsi_connector *con,
> +					    struct ucsi_data *data)
> +{
> +	u8 cam, new_cam;
> +
> +	if (data->cci.data_length == 0x1) {
> +		cam = data->message_in[0];
> +		new_cam = con->port_alt[cam].linked_idx;
> +		data->message_in[0] = new_cam;
> +		con->new_port_alt[new_cam].active_idx = cam;
> +	}
> +}
> +
>  static inline int ucsi_sync(struct ucsi *ucsi)
>  {
> -	if (ucsi->ppm && ucsi->ppm->sync)
> -		return ucsi->ppm->sync(ucsi->ppm);
> -	return 0;
> +	struct ucsi_connector *con = ucsi->connector;
> +	struct ucsi_data *data;
> +	int ret = 0;
> +
> +	if (ucsi->ppm && ucsi->ppm->sync) {
> +		ret = ucsi->ppm->sync(ucsi->ppm);
> +		if (ret)
> +			return ret;
> +
> +		data = ucsi->ppm->data;
> +		if (data->ctrl.alt.cmd == UCSI_GET_CURRENT_CAM &&
> +		    con->has_multiple_dp)
> +			ucsi_update_get_current_cam_cmd(con, data);
> +	}
> +
> +	return ret;
>  }
>  
>  static int ucsi_command(struct ucsi *ucsi, struct ucsi_control *ctrl)
> @@ -101,14 +127,65 @@ static int ucsi_ack(struct ucsi *ucsi, u8 ack)
>  	return ret;
>  }
>  
> +static void ucsi_update_set_new_cam_cmd(struct ucsi_connector *con,
> +					struct ucsi_control *ctrl)
> +{
> +	struct new_ucsi_altmode *new_port, *port;
> +	struct typec_altmode *alt = NULL;
> +	u64 cmd;
> +	u8 new_cam, cam, pin;
> +	bool enter_new_mode;
> +	int i, j, k = 0xff;
> +
> +	cmd = ctrl->raw_cmd;
> +	new_cam = (cmd >> 24) & 0xff;
> +	new_port = &con->new_port_alt[new_cam];
> +	cam = new_port->linked_idx;
> +	enter_new_mode = (cmd >> 23) & 1;
> +
> +	if (cam == UCSI_MULTI_LINKED_INDEX) {
> +		if (enter_new_mode) {
> +			port = con->port_alt;
> +			for (i = 0; con->partner_altmode[i]; i++) {
> +				alt = con->partner_altmode[i];
> +				if (alt->svid == new_port->svid)
> +					break;
> +			}
> +			for (j = 0; port[j].svid; j++) {
> +				pin = DP_CONF_GET_PIN_ASSIGN(port[j].mid);
> +				if (alt && port[j].svid == alt->svid &&
> +				    (pin & DP_CONF_GET_PIN_ASSIGN(alt->vdo))) {
> +					/* prioritize pin E->D->C */
> +					if (k == 0xff || (k != 0xff && pin >
> +					    DP_CONF_GET_PIN_ASSIGN(port[k].mid))
> +					    ) {
> +						k = j;
> +					}
> +				}
> +			}
> +			cam = k;
> +			new_port->active_idx = cam;
> +		} else {
> +			cam = new_port->active_idx;
> +		}
> +	}
> +	cmd &= ~(0xff << 24);
> +	cmd |= (cam << 24);
> +	ctrl->raw_cmd = cmd;
> +}
> +
>  static int ucsi_run_command(struct ucsi *ucsi, struct ucsi_control *ctrl,
>  			    void *data, size_t size)
>  {
>  	struct ucsi_control _ctrl;
> +	struct ucsi_connector *con = ucsi->connector;
>  	u8 data_length;
>  	u16 error;
>  	int ret;
>  
> +	if (ctrl->alt.cmd == UCSI_SET_NEW_CAM && con->has_multiple_dp)
> +		ucsi_update_set_new_cam_cmd(con, ctrl);
> +
>  	ret = ucsi_command(ucsi, ctrl);
>  	if (ret)
>  		goto err;
> @@ -364,10 +441,24 @@ static int ucsi_register_altmodes(struct ucsi_connector *con, u8 recipient)
>  
>  	for (i = 0; i < max_altmodes;) {
>  		memset(alt, 0, sizeof(alt));
> -		UCSI_CMD_GET_ALTERNATE_MODES(ctrl, recipient, con->num, i, 1);
> -		len = ucsi_run_command(con->ucsi, &ctrl, alt, sizeof(alt));
> -		if (len <= 0)
> -			return len;
> +
> +		if (recipient == UCSI_RECIPIENT_CON) {
> +			if (con->has_multiple_dp) {
> +				alt[0].svid = con->new_port_alt[i].svid;
> +				alt[0].mid = con->new_port_alt[i].mid;
> +			} else {
> +				alt[0].svid = con->port_alt[i].svid;
> +				alt[0].mid = con->port_alt[i].mid;
> +			}
> +			len = sizeof(alt[0]);
> +		} else {
> +			UCSI_CMD_GET_ALTERNATE_MODES(ctrl, recipient,
> +						     con->num, i, 1);
> +			len = ucsi_run_command(con->ucsi, &ctrl, alt,
> +					       sizeof(alt));
> +			if (len <= 0)
> +				return len;
> +		}
>  
>  		/*
>  		 * This code is requesting one alt mode at a time, but some PPMs
> @@ -521,6 +612,103 @@ static void ucsi_partner_change(struct ucsi_connector *con)
>  		ucsi_altmode_update_active(con);
>  }
>  
> +static void ucsi_update_con_altmodes(struct ucsi_connector *con)
> +{
> +	int max_altmodes = con->ucsi->cap.num_alt_modes;
> +	struct new_ucsi_altmode *alt, *new_alt;
> +	int i, j, k = 0;
> +	bool found = false;
> +
> +	alt = con->port_alt;
> +	new_alt = con->new_port_alt;
> +	memset(con->new_port_alt, 0, sizeof(con->new_port_alt));
> +
> +	for (i = 0; i < max_altmodes; i++) {
> +		if (!alt[i].svid)
> +			break;
> +
> +		/* already checked and considered */
> +		if (alt[i].checked)
> +			continue;
> +
> +		if (!DP_CONF_GET_PIN_ASSIGN(alt[i].mid)) {
> +			/* Found Non DP altmode */
> +			new_alt[k].svid = alt[i].svid;
> +			new_alt[k].mid |= alt[i].mid;
> +			new_alt[k].linked_idx = i;
> +			alt[i].linked_idx = k;
> +			k++;
> +			continue;
> +		}
> +
> +		for (j = i + 1; j < max_altmodes; j++) {
> +			if (alt[i].svid != alt[j].svid ||
> +			    !DP_CONF_GET_PIN_ASSIGN(alt[j].mid)) {
> +				continue;
> +			} else {
> +				/* Found duplicate DP mode */
> +				new_alt[k].svid = alt[i].svid;
> +				new_alt[k].mid |= alt[i].mid | alt[j].mid;
> +				new_alt[k].linked_idx = UCSI_MULTI_LINKED_INDEX;
> +				alt[i].linked_idx = k;
> +				alt[j].linked_idx = k;
> +				alt[j].checked = true;
> +				found = true;
> +			}
> +		}
> +		if (found) {
> +			con->has_multiple_dp = true;
> +		} else {
> +			/* Didn't find any duplicate DP altmode */
> +			new_alt[k].svid = alt[i].svid;
> +			new_alt[k].mid |= alt[i].mid;
> +			new_alt[k].linked_idx = i;
> +			alt[i].linked_idx = k;
> +		}
> +		k++;
> +	}
> +}
> +
> +static int ucsi_get_altmodes(struct ucsi_connector *con)
> +{
> +	int max_altmodes = con->ucsi->cap.num_alt_modes;
> +	struct ucsi_altmode alt[2];
> +	struct ucsi_control ctrl;
> +	int num = 1;
> +	int len;
> +	int j;
> +	int i;
> +	int k = 0;
> +
> +	memset(con->port_alt, 0, sizeof(con->port_alt));
> +
> +	for (i = 0; i < max_altmodes;) {
> +		memset(alt, 0, sizeof(alt));
> +		UCSI_CMD_GET_ALTERNATE_MODES(ctrl, UCSI_RECIPIENT_CON,
> +					     con->num, i, 1);
> +		len = ucsi_run_command(con->ucsi, &ctrl, alt, sizeof(alt));
> +		if (len <= 0)
> +			return len;
> +
> +		/*
> +		 * This code is requesting one alt mode at a time, but some PPMs
> +		 * may still return two.
> +		 */
> +		num = len / sizeof(alt[0]);
> +		i += num;
> +
> +		for (j = 0; j < num; j++) {
> +			if (!alt[j].svid)
> +				return 0;
> +
> +			con->port_alt[k].mid = alt[j].mid;
> +			con->port_alt[k].svid = alt[j].svid;
> +			k++;
> +		}
> +	}
> +	return 0;
> +}
> +
>  static void ucsi_connector_change(struct work_struct *work)
>  {
>  	struct ucsi_connector *con = container_of(work, struct ucsi_connector,
> @@ -851,6 +1039,16 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
>  	if (IS_ERR(con->port))
>  		return PTR_ERR(con->port);
>  
> +	/* Get Alternate modes */
> +	ret = ucsi_get_altmodes(con);
> +	if (ret) {
> +		dev_err(ucsi->dev,
> +			"%s: con%d failed (%d)to get port alternate modes\n",
> +			__func__, con->num, ret);
> +		return 0;
> +	}
> +	ucsi_update_con_altmodes(con);
> +
>  	/* Alternate modes */
>  	ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_CON);
>  	if (ret)
> diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
> index de87d0b8319d..7bbdf83c8d4a 100644
> --- a/drivers/usb/typec/ucsi/ucsi.h
> +++ b/drivers/usb/typec/ucsi/ucsi.h
> @@ -274,6 +274,15 @@ struct ucsi_connector_capability {
>  	u8:6; /* reserved */
>  } __packed;
>  
> +struct new_ucsi_altmode {
> +	u16 svid;
> +	u32 mid;
> +	u8 linked_idx;
> +	u8 active_idx;
> +#define UCSI_MULTI_LINKED_INDEX	(0xff)
> +	bool checked;
> +} __packed;
> +
>  struct ucsi_altmode {
>  	u16 svid;
>  	u32 mid;
> @@ -408,6 +417,7 @@ struct ucsi {
>  
>  struct ucsi_connector {
>  	int num;
> +	bool has_multiple_dp;
>  
>  	struct ucsi *ucsi;
>  	struct mutex lock; /* port lock */
> @@ -424,6 +434,8 @@ struct ucsi_connector {
>  
>  	struct ucsi_connector_status status;
>  	struct ucsi_connector_capability cap;
> +	struct new_ucsi_altmode port_alt[UCSI_MAX_ALTMODES];
> +	struct new_ucsi_altmode new_port_alt[UCSI_MAX_ALTMODES];
>  };
>  
>  int ucsi_send_command(struct ucsi *ucsi, struct ucsi_control *ctrl,
> -- 
> 2.17.1

thanks,

-- 
heikki

  reply index

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-05 18:24 Ajay Gupta
2019-08-12 14:42 ` Heikki Krogerus [this message]
2019-08-15 15:36 ` Heikki Krogerus
2019-08-19 22:23   ` Ajay Gupta
2019-08-26  7:36     ` Heikki Krogerus

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