Hi
> -----Original Message-----
> From: Guenter Roeck [mailto:li...@roeck-us.net]
> Sent: 2018年4月13日 23:58
> To: Jun Li <jun...@nxp.com>
> Cc: gre...@linuxfoundation.org; robh...@kernel.org;
> heikki.kroge...@linux.intel.com; hdego...@redhat.com; rmf...@gmail.com;
> yueyao....@gmail.com; linux-usb@vger.kernel.org; dl-linux-imx
> <linux-...@nxp.com>
> Subject: Re: [PATCH v4 1/5] usb: typec: tcpm: pdo matching optimization
>
> On Fri, Apr 13, 2018 at 10:18:41PM +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 <hdego...@redhat.com>
> > Signed-off-by: Li Jun <jun...@nxp.com>
> > ---
> > drivers/usb/typec/tcpm.c | 102
> > ++++++++++++++++++++++++++++++-----------------
> > 1 file changed, 65 insertions(+), 37 deletions(-)
> >
> > diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c index
> > 677d121..c127339 100644
> > --- a/drivers/usb/typec/tcpm.c
> > +++ b/drivers/usb/typec/tcpm.c
> > @@ -1772,40 +1772,65 @@ 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;
> > 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;
> > + }
> > + break;
> > + }
> > }
> > +
>
> Nitpick, but that added empty line is uneceessary.
Will remove it.
>
> > }
> >
> > return ret;
> > @@ -1816,13 +1841,14 @@ 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;
> >
> > - index = tcpm_pd_select_pdo(port);
> > - if (index < 0)
> > + if (tcpm_pd_select_pdo(port, &snk_pdo_index, &src_pdo_index) < 0)
> > return -EINVAL;
>
> This may save you a variable, but tcpm_pd_select_pdo() may at some point
> return a different error. Either case, this may trigger a static analyzer
> warning that
> you are overriding a return value.
I will add a variable for this.
>
> Besides, does this even work ? I don't see where the function would return
> anything but -EINVAL.
Sorry, I had this patch tested, but forgot sync a change to this patch set,
ret = 0 is missed.
Thanks
Jun
>
> > - pdo = port->source_caps[index];
> > +
> > + 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 +1856,28 @@ 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 +1886,16 @@ 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
> >
