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Date: Thu, 2 Nov 2017 13:00:44 +0200
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Badhri Jagan Sridharan <badhri@...gle.com>
Cc: gregkh@...uxfoundation.org, linux-usb@...r.kernel.org,
dan.carpenter@...cle.com, Guenter Roeck <linux@...ck-us.net>,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] typec: tcpm: Only request matching pdos
Hi,
+Dan and Guenter
I'm sorry for the late reply. These slipped under my radar. I do
have a one more proposal below, and a few nits..
On Wed, Oct 18, 2017 at 01:22:48PM -0700, 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>
> ---
> 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
>
> drivers/usb/typec/tcpm.c | 155 ++++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 120 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> index e3f8b3da46b0..1b37333dc63b 100644
> --- a/drivers/usb/typec/tcpm.c
> +++ b/drivers/usb/typec/tcpm.c
> @@ -261,6 +261,9 @@ 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;
>
> @@ -1762,39 +1765,92 @@ static int tcpm_pd_check_request(struct tcpm_port *port)
> return 0;
> }
>
> -static int tcpm_pd_select_pdo(struct tcpm_port *port)
> +static void tcpm_pd_evaluate_pdo(struct tcpm_port *port, int src_pdo_index,
> + int snk_pdo_index, int *max_mw, int *max_mv,
> + int *selected_src_pdo,
> + int *matching_snk_pdo)
> {
> - unsigned int i, max_mw = 0, max_mv = 0;
> + unsigned int mv = 0, ma = 0, mw = 0;
> + u32 src_pdo = port->source_caps[src_pdo_index];
> + u32 snk_pdo = port->snk_pdo[snk_pdo_index];
> + enum pd_pdo_type type = pdo_type(src_pdo);
> +
> + mv = (type == PDO_TYPE_FIXED) ? pdo_fixed_voltage(src_pdo) :
> + pdo_min_voltage(src_pdo);
> +
> + if (type == PDO_TYPE_BATT) {
> + mw = min(pdo_max_power(src_pdo), pdo_max_power(snk_pdo));
> + } else {
> + ma = min(pdo_max_current(src_pdo), pdo_max_current(snk_pdo));
> + mw = ma * mv / 1000;
> + }
> +
> + /* Perfer higher voltages if available */
> + if (mw > *max_mw || (mw == *max_mw && mv > *max_mv)) {
> + *selected_src_pdo = src_pdo_index;
> + *matching_snk_pdo = snk_pdo_index;
> + *max_mw = mw;
> + *max_mv = mv;
> + }
> +}
> +
> +static int tcpm_pd_select_pdo(struct tcpm_port *port, int *sink_pdo)
> +{
> + unsigned int i, j, max_mw = 0, max_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_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])) {
> + tcpm_pd_evaluate_pdo(port, i, j,
> + &max_mw, &max_mv,
> + &ret, sink_pdo);
> + /* 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])) {
> + tcpm_pd_evaluate_pdo(port, i, j,
> + &max_mw, &max_mv,
> + &ret, sink_pdo);
> + }
> + }
> + } 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])) {
> + tcpm_pd_evaluate_pdo(port, i, j,
> + &max_mw, &max_mv,
> + &ret, sink_pdo);
> + }
> + }
> }
Wouldn't it make sense to call tcpm_pd_evaluate_pdo() here ones and
run those nested loops there? You are already checking the type there
in any case.
> }
>
> @@ -1806,13 +1862,14 @@ 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 index, snk_pdo_index;
> + u32 pdo, matching_snk_pdo;
>
> - index = tcpm_pd_select_pdo(port);
> + index = tcpm_pd_select_pdo(port, &snk_pdo_index);
> if (index < 0)
> return -EINVAL;
> pdo = port->source_caps[index];
> + matching_snk_pdo = port->snk_pdo[snk_pdo_index];
> type = pdo_type(pdo);
>
> if (type == PDO_TYPE_FIXED)
> @@ -1820,26 +1877,32 @@ 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(pdo_max_power(pdo), pdo_max_power(matching_snk_pdo));
> + ma = 1000 * mw / mv;
> } else {
> ma = min(pdo_max_current(pdo),
> - 1000 * port->max_snk_mw / mv);
> + pdo_max_current(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) {
> + if (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);
> + }
How about:
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);
Though, that does not make it any more readable. Just a proposal.
> }
>
> tcpm_log(port, "cc=%d cc1=%d cc2=%d vbus=%d vconn=%s polarity=%d",
> @@ -3588,6 +3651,19 @@ 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)
Please align that properly.
> +{
> + 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;
> @@ -3633,6 +3709,15 @@ 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);
Ditto.
> + port->nr_var = nr_type_pdos(port->snk_pdo,
> + port->nr_snk_pdo,
> + PDO_TYPE_VAR);
Ditto.
> + port->nr_batt = nr_type_pdos(port->snk_pdo,
> + port->nr_snk_pdo,
> + PDO_TYPE_BATT);
Ditto.
Thanks,
--
heikki
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