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Message-ID: <20171114170531.GB1030@roeck-us.net>
Date: Tue, 14 Nov 2017 09:05:31 -0800
From: Guenter Roeck <linux@...ck-us.net>
To: Badhri Jagan Sridharan <badhri@...gle.com>
Cc: heikki.krogerus@...ux.intel.com, gregkh@...uxfoundation.org,
dan.carpenter@...cle.com, linux-usb@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2 v6] typec: tcpm: Only request matching pdos
On Sun, Nov 12, 2017 at 04:23:17PM -0800, Badhri Jagan Sridharan wrote:
> At present, TCPM code assumes that local device supports
> variable/batt pdos and always selects the pdo with highest
> possible power within the board limit. This assumption
> might not hold good for all devices. To overcome this,
> this patch makes TCPM only accept a source_pdo when there is
> a matching sink pdo.
>
> For Fixed pdos: The voltage should match between the
> incoming source_cap and the registered snk_pdo
> For Variable/Batt pdos: The incoming source_cap voltage
> range should fall within the registered snk_pdo's voltage
> range.
>
> Also, when the cap_mismatch bit is set, the max_power/current
> should be set to the max_current/power of the sink_pdo.
> This is according to:
>
> "If the Capability Mismatch bit is set to one
> The Maximum Operating Current/Power field may contain a value
> larger than the maximum current/power offered in the Source
> Capabilities message’s PDO as referenced by the Object position field.
> This enables the Sink to indicate that it requires more current/power
> than is being offered. If the Sink requires a different voltage this
> will be indicated by its Sink Capabilities message.
>
> Signed-off-by: Badhri Jagan Sridharan <Badhri@...gle.com>
> Acked-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
/* Though I really dislike this new-world comment style.
* It hurts my eyes and distracts me from the code.
*/
> ---
> Changelog since v1:
> - Rebased the patch on top of drivers/usb/type/tcpm.c
> - Added duplicate pdo check for variable/batt pdo.
> - Fixed tabs as suggested by dan.carpenter@...cle.com
>
> Changelog since v2:
> - Rebase
>
> Changelog since v3:
> - Refactored code fixed formatting issues as suggested
> by heikki.krogerus@...ux.intel.com
>
> Changelog since v4:
> - Rebase
>
> Changelog since v5:
> - handling the sink pdo index as pointer argument in tcpm_pd_select_pdo
> - ACK by heikki.krogerus@...ux.intel.com
>
> drivers/usb/typec/tcpm.c | 163 +++++++++++++++++++++++++++++++++++------------
> 1 file changed, 121 insertions(+), 42 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> index 8b637a4b474b..f4d563ee7690 100644
> --- a/drivers/usb/typec/tcpm.c
> +++ b/drivers/usb/typec/tcpm.c
> @@ -252,6 +252,9 @@ struct tcpm_port {
> unsigned int nr_src_pdo;
> u32 snk_pdo[PDO_MAX_OBJECTS];
> unsigned int nr_snk_pdo;
> + unsigned int nr_fixed; /* number of fixed sink PDOs */
> + unsigned int nr_var; /* number of variable sink PDOs */
> + unsigned int nr_batt; /* number of battery sink PDOs */
> u32 snk_vdo[VDO_MAX_OBJECTS];
> unsigned int nr_snk_vdo;
>
> @@ -1767,39 +1770,90 @@ 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_mw = 0, max_mv = 0, mw = 0, mv = 0, ma = 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_BATT) {
> - mw = pdo_max_power(pdo);
> - } else {
> - ma = min(pdo_max_current(pdo),
> - port->max_snk_ma);
> - mw = ma * 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;
> + if (type == PDO_TYPE_FIXED) {
> + for (j = 0; j < port->nr_fixed; j++) {
> + if (pdo_fixed_voltage(pdo) ==
> + pdo_fixed_voltage(port->snk_pdo[j])) {
> + ma = min_current(pdo, port->snk_pdo[j]);
> + mv = pdo_fixed_voltage(pdo);
> + mw = ma * mv / 1000;
> + if (mw > max_mw ||
> + (mw == max_mw && mv > max_mv)) {
> + ret = 0;
> + *src_pdo = i;
> + *sink_pdo = j;
> + max_mw = mw;
> + max_mv = mv;
> + }
> + /* There could only be one fixed pdo
> + * at a specific voltage level.
> + * So breaking here.
> + */
> + break;
> + }
> + }
> + } else if (type == PDO_TYPE_BATT) {
> + for (j = port->nr_fixed;
> + j < port->nr_fixed +
> + port->nr_batt;
> + j++) {
> + if (pdo_min_voltage(pdo) >=
> + pdo_min_voltage(port->snk_pdo[j]) &&
> + pdo_max_voltage(pdo) <=
> + pdo_max_voltage(port->snk_pdo[j])) {
> + mw = min_power(pdo, port->snk_pdo[j]);
> + mv = pdo_min_voltage(pdo);
> + if (mw > max_mw ||
> + (mw == max_mw && mv > max_mv)) {
> + ret = 0;
> + *src_pdo = i;
> + *sink_pdo = j;
> + max_mw = mw;
> + max_mv = mv;
> + }
> + }
> + }
> + } else if (type == PDO_TYPE_VAR) {
> + for (j = port->nr_fixed +
> + port->nr_batt;
> + j < port->nr_fixed +
> + port->nr_batt +
> + port->nr_var;
> + j++) {
> + if (pdo_min_voltage(pdo) >=
> + pdo_min_voltage(port->snk_pdo[j]) &&
> + pdo_max_voltage(pdo) <=
> + pdo_max_voltage(port->snk_pdo[j])) {
> + ma = min_current(pdo, port->snk_pdo[j]);
> + mv = pdo_min_voltage(pdo);
> + mw = ma * mv / 1000;
> + if (mw > max_mw ||
> + (mw == max_mw && mv > max_mv)) {
> + ret = 0;
> + *src_pdo = i;
> + *sink_pdo = j;
> + max_mw = mw;
> + max_mv = mv;
> + }
> + }
> + }
> }
> }
>
> @@ -1811,13 +1865,14 @@ 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;
> - 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)
> @@ -1825,26 +1880,28 @@ 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",
> @@ -1853,16 +1910,16 @@ 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]" : "");
> }
>
> @@ -3593,6 +3650,19 @@ int tcpm_update_sink_capabilities(struct tcpm_port *port, const u32 *pdo,
> }
> EXPORT_SYMBOL_GPL(tcpm_update_sink_capabilities);
>
> +static int nr_type_pdos(const u32 *pdo, unsigned int nr_pdo,
> + enum pd_pdo_type type)
> +{
> + int count = 0;
> + int i;
> +
> + for (i = 0; i < nr_pdo; i++) {
> + if (pdo_type(pdo[i]) == type)
> + count++;
> + }
> + return count;
> +}
> +
> struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
> {
> struct tcpm_port *port;
> @@ -3638,6 +3708,15 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
> tcpc->config->nr_src_pdo);
> port->nr_snk_pdo = tcpm_copy_pdos(port->snk_pdo, tcpc->config->snk_pdo,
> tcpc->config->nr_snk_pdo);
> + port->nr_fixed = nr_type_pdos(port->snk_pdo,
> + port->nr_snk_pdo,
> + PDO_TYPE_FIXED);
> + port->nr_var = nr_type_pdos(port->snk_pdo,
> + port->nr_snk_pdo,
> + PDO_TYPE_VAR);
> + port->nr_batt = nr_type_pdos(port->snk_pdo,
> + port->nr_snk_pdo,
> + PDO_TYPE_BATT);
> port->nr_snk_vdo = tcpm_copy_vdos(port->snk_vdo, tcpc->config->snk_vdo,
> tcpc->config->nr_snk_vdo);
>
> --
> 2.15.0.448.gf294e3d99a-goog
>
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