[v5,1/5] usb: typec: tcpm: pdo matching optimization

[Heikki Krogerus <heikki.krogerus@linux.intel.com>]

Hi,

On Mon, Apr 16, 2018 at 02:54:33PM +0800, Li Jun wrote:
> This patch is a combination of commit 57e6f0d7b804
> ("typec: tcpm: Only request matching pdos") and source
> pdo selection optimization based on it, instead of only
> compare between the same pdo type of sink and source,
> we should check source pdo voltage range is within the
> voltage range of one sink pdo.
> 
> Reviewed-by: Hans de Goede <hdegoede@redhat.com>
> Signed-off-by: Li Jun <jun.li@nxp.com>

I don't see any problem with this, but I hope Guenter has time to
check it.

Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>

> ---
>  drivers/usb/typec/tcpm.c | 105 ++++++++++++++++++++++++++++++-----------------
>  1 file changed, 67 insertions(+), 38 deletions(-)
> 
> diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> index 677d121..048b953 100644
> --- a/drivers/usb/typec/tcpm.c
> +++ b/drivers/usb/typec/tcpm.c
> @@ -1772,39 +1772,63 @@ static int tcpm_pd_check_request(struct tcpm_port *port)
>  	return 0;
>  }
>  
> -static int tcpm_pd_select_pdo(struct tcpm_port *port)
> +#define min_power(x, y) min(pdo_max_power(x), pdo_max_power(y))
> +#define min_current(x, y) min(pdo_max_current(x), pdo_max_current(y))
> +
> +static int tcpm_pd_select_pdo(struct tcpm_port *port, int *sink_pdo,
> +			      int *src_pdo)
>  {
> -	unsigned int i, max_mw = 0, max_mv = 0;
> +	unsigned int i, j, max_src_mv = 0, min_src_mv = 0, max_mw = 0,
> +		     max_mv = 0, src_mw = 0, src_ma = 0, max_snk_mv = 0,
> +		     min_snk_mv = 0;

Don't resend because of this comment, but just for the record, you are
declaring here so many variables at once that it is not easy to see
what you are introducing (at least for me). It is OK to declare every
variable even separately.

>  	int ret = -EINVAL;
>  
>  	/*
> -	 * Select the source PDO providing the most power while staying within
> -	 * the board's voltage limits. Prefer PDO providing exp
> +	 * Select the source PDO providing the most power which has a
> +	 * matchig sink cap.
>  	 */
>  	for (i = 0; i < port->nr_source_caps; i++) {
>  		u32 pdo = port->source_caps[i];
>  		enum pd_pdo_type type = pdo_type(pdo);
> -		unsigned int mv, ma, mw;
>  
> -		if (type == PDO_TYPE_FIXED)
> -			mv = pdo_fixed_voltage(pdo);
> -		else
> -			mv = pdo_min_voltage(pdo);
> +		if (type == PDO_TYPE_FIXED) {
> +			max_src_mv = pdo_fixed_voltage(pdo);
> +			min_src_mv = max_src_mv;
> +		} else {
> +			max_src_mv = pdo_max_voltage(pdo);
> +			min_src_mv = pdo_min_voltage(pdo);
> +		}
>  
>  		if (type == PDO_TYPE_BATT) {
> -			mw = pdo_max_power(pdo);
> +			src_mw = pdo_max_power(pdo);
>  		} else {
> -			ma = min(pdo_max_current(pdo),
> -				 port->max_snk_ma);
> -			mw = ma * mv / 1000;
> +			src_ma = pdo_max_current(pdo);
> +			src_mw = src_ma * min_src_mv / 1000;
>  		}
>  
> -		/* Perfer higher voltages if available */
> -		if ((mw > max_mw || (mw == max_mw && mv > max_mv)) &&
> -		    mv <= port->max_snk_mv) {
> -			ret = i;
> -			max_mw = mw;
> -			max_mv = mv;
> +		for (j = 0; j < port->nr_snk_pdo; j++) {
> +			pdo = port->snk_pdo[j];
> +
> +			if (pdo_type(pdo) == PDO_TYPE_FIXED) {
> +				min_snk_mv = pdo_fixed_voltage(pdo);
> +				max_snk_mv = pdo_fixed_voltage(pdo);
> +			} else {
> +				min_snk_mv = pdo_min_voltage(pdo);
> +				max_snk_mv = pdo_max_voltage(pdo);
> +			}
> +
> +			if (max_src_mv <= max_snk_mv &&
> +				min_src_mv >= min_snk_mv) {
> +				/* Prefer higher voltages if available */
> +				if ((src_mw == max_mw && min_src_mv > max_mv) ||
> +							src_mw > max_mw) {
> +					*src_pdo = i;
> +					*sink_pdo = j;
> +					max_mw = src_mw;
> +					max_mv = min_src_mv;
> +					ret = 0;
> +				}
> +			}
>  		}
>  	}
>  
> @@ -1816,13 +1840,16 @@ static int tcpm_pd_build_request(struct tcpm_port *port, u32 *rdo)
>  	unsigned int mv, ma, mw, flags;
>  	unsigned int max_ma, max_mw;
>  	enum pd_pdo_type type;
> -	int index;
> -	u32 pdo;
> +	int src_pdo_index, snk_pdo_index;
> +	u32 pdo, matching_snk_pdo;
> +	int ret;
>  
> -	index = tcpm_pd_select_pdo(port);
> -	if (index < 0)
> -		return -EINVAL;
> -	pdo = port->source_caps[index];
> +	ret = tcpm_pd_select_pdo(port, &snk_pdo_index, &src_pdo_index);
> +	if (ret < 0)
> +		return ret;
> +
> +	pdo = port->source_caps[src_pdo_index];
> +	matching_snk_pdo = port->snk_pdo[snk_pdo_index];
>  	type = pdo_type(pdo);
>  
>  	if (type == PDO_TYPE_FIXED)
> @@ -1830,26 +1857,28 @@ static int tcpm_pd_build_request(struct tcpm_port *port, u32 *rdo)
>  	else
>  		mv = pdo_min_voltage(pdo);
>  
> -	/* Select maximum available current within the board's power limit */
> +	/* Select maximum available current within the sink pdo's limit */
>  	if (type == PDO_TYPE_BATT) {
> -		mw = pdo_max_power(pdo);
> -		ma = 1000 * min(mw, port->max_snk_mw) / mv;
> +		mw = min_power(pdo, matching_snk_pdo);
> +		ma = 1000 * mw / mv;
>  	} else {
> -		ma = min(pdo_max_current(pdo),
> -			 1000 * port->max_snk_mw / mv);
> +		ma = min_current(pdo, matching_snk_pdo);
> +		mw = ma * mv / 1000;
>  	}
> -	ma = min(ma, port->max_snk_ma);
>  
>  	flags = RDO_USB_COMM | RDO_NO_SUSPEND;
>  
>  	/* Set mismatch bit if offered power is less than operating power */
> -	mw = ma * mv / 1000;
>  	max_ma = ma;
>  	max_mw = mw;
>  	if (mw < port->operating_snk_mw) {
>  		flags |= RDO_CAP_MISMATCH;
> -		max_mw = port->operating_snk_mw;
> -		max_ma = max_mw * 1000 / mv;
> +		if (type == PDO_TYPE_BATT &&
> +		    (pdo_max_power(matching_snk_pdo) > pdo_max_power(pdo)))
> +			max_mw = pdo_max_power(matching_snk_pdo);
> +		else if (pdo_max_current(matching_snk_pdo) >
> +			 pdo_max_current(pdo))
> +			max_ma = pdo_max_current(matching_snk_pdo);
>  	}
>  
>  	tcpm_log(port, "cc=%d cc1=%d cc2=%d vbus=%d vconn=%s polarity=%d",
> @@ -1858,16 +1887,16 @@ static int tcpm_pd_build_request(struct tcpm_port *port, u32 *rdo)
>  		 port->polarity);
>  
>  	if (type == PDO_TYPE_BATT) {
> -		*rdo = RDO_BATT(index + 1, mw, max_mw, flags);
> +		*rdo = RDO_BATT(src_pdo_index + 1, mw, max_mw, flags);
>  
>  		tcpm_log(port, "Requesting PDO %d: %u mV, %u mW%s",
> -			 index, mv, mw,
> +			 src_pdo_index, mv, mw,
>  			 flags & RDO_CAP_MISMATCH ? " [mismatch]" : "");
>  	} else {
> -		*rdo = RDO_FIXED(index + 1, ma, max_ma, flags);
> +		*rdo = RDO_FIXED(src_pdo_index + 1, ma, max_ma, flags);
>  
>  		tcpm_log(port, "Requesting PDO %d: %u mV, %u mA%s",
> -			 index, mv, ma,
> +			 src_pdo_index, mv, ma,
>  			 flags & RDO_CAP_MISMATCH ? " [mismatch]" : "");
>  	}
>  
> -- 
> 2.7.4