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Message-ID: <CAPTae5JR0ZTFJLXrAYrpTnTEtGybDrjiTy8hAhsLAP+o18M_sw@mail.gmail.com>
Date: Mon, 27 Nov 2017 17:38:02 -0800
From: Badhri Jagan Sridharan <badhri@...gle.com>
To: Adam Thomson <Adam.Thomson.Opensource@...semi.com>
Cc: "heikki.krogerus@...ux.intel.com" <heikki.krogerus@...ux.intel.com>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"dan.carpenter@...cle.com" <dan.carpenter@...cle.com>,
"linux@...ck-us.net" <linux@...ck-us.net>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2 v7] typec: tcpm: Only request matching pdos
On Thu, Nov 23, 2017 at 3:10 AM, Adam Thomson
<Adam.Thomson.Opensource@...semi.com> wrote:
> On 16 November 2017 01:02, 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.
>
> Hi Badhri,
>
> I have some queries on this change. At the moment the src/snk PDOs are hard
> coded in the relevant PD controller driver (e.g. fusb302.c), and the only way
> to update these is to call the tcpm_update_source_capabilities() or
> tcpm_update_sink_capabilities() functions. However there are no real world
Good point ! But I dont see any code which calls this either. I believe
Guenter added this. Guenter do you know ?
> examples in the kernel where this happens. Where are these functions likely to
> be called from, as wherever that is it will need a reference to the port?
> Actually should we be adding DT bindings to set supported src/snk PDOs from FW,
> if you're taking this approach to PDO selection?
>
> This patch also seemingly leaves 'max_snk_mv', 'max_snk_ma' and 'max_snk_mv'
> redundant, although those values can be configured from a PD controller driver
> (e.g. fusb302 actually supports DT bindings which allow these to be set through
> FW). Now these DT bindings are basically made redundant by your change as they
> have no impact. Are we expecting these to be used again in the future, or should
Yes, I think 'max_snk_mv', 'max_snk_ma' and 'max_snk_mw' etc should be removed.
The problem here is that maintaining these values implies that tcpm is
not going to
request pdo based on the sink_caps that are published. All these
values can be derived from
the sink_pdo objects that were declared, hence, they are redundant,
I will update the patch to remove this.
> these be removed? FYI, as part of my PPS patch set I have been using them as
> part of the PPS APDO selection criteria, based on TCPM code prior to your
> modifications, as for PPS we're interested in a wide range of voltages and
> currents but want to stay within the platforms limits.
Arent you defining a new PDO type similar to PDO_FIXED, PDO_VARIABLE etc ?
If so values such as " 'max_snk_mv', 'max_snk_ma' and
'max_snk_mw' " should be part of the APDO object right ? So why would
you still need
'max_snk_mv', 'max_snk_ma' and 'max_snk_mw' ?
>
>>
>> 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>
>>
>> ---
>> 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
>>
>> Changelog since v6:
>> - Added Reviewed-by: Guenter Roeck <linux@...ck-us.net>
>>
>> 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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