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Date: Wed, 9 Feb 2022 23:56:11 -0800
From: Jack Pham <quic_jackp@...cinc.com>
To: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
CC: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Guenter Roeck <linux@...ck-us.net>,
Benson Leung <bleung@...gle.com>,
Prashant Malani <pmalani@...omium.org>,
Jameson Thies <jthies@...gle.com>,
"Regupathy, Rajaram" <rajaram.regupathy@...el.com>,
<linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 3/3] usb: typec: ucsi: Register USB Power Delivery
Capabilities
Hi Heikki,
On Thu, Feb 03, 2022 at 05:46:57PM +0300, Heikki Krogerus wrote:
> UCSI allows the USB PD capabilities to be read with the
> GET_PDO command. This will register those capabilities, and
> that way make them visible to the user space.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
> ---
> drivers/usb/typec/ucsi/ucsi.c | 128 +++++++++++++++++++++++++++++++---
> drivers/usb/typec/ucsi/ucsi.h | 8 +++
> 2 files changed, 125 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index f0c2fa19f3e0f..5149001093c7f 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -568,8 +568,8 @@ static void ucsi_unregister_altmodes(struct ucsi_connector *con, u8 recipient)
> }
> }
>
> -static int ucsi_get_pdos(struct ucsi_connector *con, int is_partner,
> - u32 *pdos, int offset, int num_pdos)
> +static int ucsi_read_pdos(struct ucsi_connector *con, enum typec_role role, int is_partner,
> + u32 *pdos, int offset, int num_pdos)
> {
> struct ucsi *ucsi = con->ucsi;
> u64 command;
> @@ -579,7 +579,7 @@ static int ucsi_get_pdos(struct ucsi_connector *con, int is_partner,
> command |= UCSI_GET_PDOS_PARTNER_PDO(is_partner);
> command |= UCSI_GET_PDOS_PDO_OFFSET(offset);
> command |= UCSI_GET_PDOS_NUM_PDOS(num_pdos - 1);
> - command |= UCSI_GET_PDOS_SRC_PDOS;
> + command |= is_source(role) ? UCSI_GET_PDOS_SRC_PDOS : 0;
> ret = ucsi_send_command(ucsi, command, pdos + offset,
> num_pdos * sizeof(u32));
> if (ret < 0 && ret != -ETIMEDOUT)
> @@ -590,26 +590,39 @@ static int ucsi_get_pdos(struct ucsi_connector *con, int is_partner,
> return ret;
> }
>
> -static int ucsi_get_src_pdos(struct ucsi_connector *con)
> +static int ucsi_get_pdos(struct ucsi_connector *con, enum typec_role role,
> + int is_partner, u32 *pdos)
> {
> + u8 num_pdos;
> int ret;
>
> /* UCSI max payload means only getting at most 4 PDOs at a time */
> - ret = ucsi_get_pdos(con, 1, con->src_pdos, 0, UCSI_MAX_PDOS);
> + ret = ucsi_read_pdos(con, role, is_partner, pdos, 0, UCSI_MAX_PDOS);
> if (ret < 0)
> return ret;
>
> - con->num_pdos = ret / sizeof(u32); /* number of bytes to 32-bit PDOs */
> - if (con->num_pdos < UCSI_MAX_PDOS)
> - return 0;
> + num_pdos = ret / sizeof(u32); /* number of bytes to 32-bit PDOs */
> + if (num_pdos < UCSI_MAX_PDOS)
> + return num_pdos;
>
> /* get the remaining PDOs, if any */
> - ret = ucsi_get_pdos(con, 1, con->src_pdos, UCSI_MAX_PDOS,
> - PDO_MAX_OBJECTS - UCSI_MAX_PDOS);
> + ret = ucsi_read_pdos(con, role, is_partner, pdos, UCSI_MAX_PDOS,
> + PDO_MAX_OBJECTS - UCSI_MAX_PDOS);
> + if (ret < 0)
> + return ret;
> +
> + return ret / sizeof(u32) + num_pdos;
> +}
> +
> +static int ucsi_get_src_pdos(struct ucsi_connector *con)
> +{
> + int ret;
> +
> + ret = ucsi_get_pdos(con, TYPEC_SOURCE, 1, con->src_pdos);
This issues the GET_PDOS command to PPM to get the source PDOs of the
partner...
> if (ret < 0)
> return ret;
>
> - con->num_pdos += ret / sizeof(u32);
> + con->num_pdos += ret;
>
> ucsi_port_psy_changed(con);
>
> @@ -638,6 +651,60 @@ static int ucsi_check_altmodes(struct ucsi_connector *con)
> return ret;
> }
>
> +static int ucsi_register_partner_pdos(struct ucsi_connector *con)
> +{
> + struct pd_desc desc = { con->ucsi->cap.pd_version };
> + struct pd_capabilities *cap;
> + struct pd_caps_desc caps;
> + int ret;
> +
> + con->partner_pd = typec_partner_register_pd(con->partner, &desc);
> + if (IS_ERR(con->partner_pd))
> + return PTR_ERR(con->partner_pd);
> +
> + ret = ucsi_get_pdos(con, TYPEC_SOURCE, 1, caps.pdo);
... and also here.
> + if (ret < 0)
> + return ret;
> +
> + if (ret < PDO_MAX_OBJECTS)
> + caps.pdo[ret] = 0;
> + caps.role = TYPEC_SOURCE;
> +
> + cap = pd_register_capabilities(con->partner_pd, &caps);
> + if (IS_ERR(cap))
> + return PTR_ERR(cap);
> +
> + ret = typec_partner_set_pd_capabilities(con->partner, cap);
> + if (ret) {
> + pd_unregister_capabilities(cap);
> + return ret;
> + }
> +
> + con->partner_source_caps = cap;
> +
> + ret = ucsi_get_pdos(con, TYPEC_SINK, 1, caps.pdo);
> + if (ret <= 0)
> + return ret;
> +
> + if (ret < PDO_MAX_OBJECTS)
> + caps.pdo[ret] = 0;
> + caps.role = TYPEC_SINK;
> +
> + cap = pd_register_capabilities(con->partner_pd, &caps);
> + if (IS_ERR(cap))
> + return PTR_ERR(cap);
> +
> + ret = typec_partner_set_pd_capabilities(con->partner, cap);
> + if (ret) {
> + pd_unregister_capabilities(cap);
> + return ret;
> + }
> +
> + con->partner_sink_caps = cap;
> +
> + return 0;
> +}
> +
> static void ucsi_pwr_opmode_change(struct ucsi_connector *con)
> {
> switch (UCSI_CONSTAT_PWR_OPMODE(con->status.flags)) {
> @@ -646,6 +713,7 @@ static void ucsi_pwr_opmode_change(struct ucsi_connector *con)
> typec_set_pwr_opmode(con->port, TYPEC_PWR_MODE_PD);
> ucsi_partner_task(con, ucsi_get_src_pdos, 30, 0);
> ucsi_partner_task(con, ucsi_check_altmodes, 30, 0);
> + ucsi_partner_task(con, ucsi_register_partner_pdos, 1, HZ);
And, both ucsi_get_src_pdos() and ucsi_register_partner_pdos() are
scheduled to run here...
> break;
> case UCSI_CONSTAT_PWR_OPMODE_TYPEC1_5:
> con->rdo = 0;
> @@ -704,6 +772,17 @@ static void ucsi_unregister_partner(struct ucsi_connector *con)
> if (!con->partner)
> return;
>
> + typec_partner_unset_pd_capabilities(con->partner, TYPEC_SINK);
> + pd_unregister_capabilities(con->partner_sink_caps);
> + con->partner_sink_caps = NULL;
> +
> + typec_partner_unset_pd_capabilities(con->partner, TYPEC_SOURCE);
> + pd_unregister_capabilities(con->partner_source_caps);
> + con->partner_source_caps = NULL;
> +
> + typec_partner_unregister_pd(con->partner);
> + con->partner_pd = NULL;
> +
> ucsi_unregister_altmodes(con, UCSI_RECIPIENT_SOP);
> typec_unregister_partner(con->partner);
> con->partner = NULL;
> @@ -1037,6 +1116,8 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
> u64 command;
> char *name;
> int ret;
> + struct pd_desc desc = { ucsi->cap.pd_version };
> + struct pd_caps_desc caps;
>
> name = kasprintf(GFP_KERNEL, "%s-con%d", dev_name(ucsi->dev), con->num);
> if (!name)
> @@ -1103,6 +1184,24 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
> goto out;
> }
>
> + con->pd = typec_port_register_pd(con->port, &desc);
> +
> + ret = ucsi_get_pdos(con, TYPEC_SOURCE, 0, caps.pdo);
> + if (ret > 0) {
> + caps.pdo[ret] = 0;
> + caps.role = TYPEC_SOURCE;
> + con->source_caps = pd_register_capabilities(con->pd, &caps);
> + typec_port_set_pd_capabilities(con->port, con->source_caps);
> + }
> +
> + ret = ucsi_get_pdos(con, TYPEC_SINK, 0, caps.pdo);
> + if (ret > 0) {
> + caps.pdo[ret] = 0;
> + caps.role = TYPEC_SINK;
> + con->sink_caps = pd_register_capabilities(con->pd, &caps);
> + typec_port_set_pd_capabilities(con->port, con->sink_caps);
> + }
> +
> /* Alternate modes */
> ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_CON);
> if (ret) {
> @@ -1169,6 +1268,7 @@ static int ucsi_register_port(struct ucsi *ucsi, int index)
> UCSI_CONSTAT_PWR_OPMODE_PD) {
> ucsi_get_src_pdos(con);
> ucsi_check_altmodes(con);
> + ucsi_register_partner_pdos(con);
... as well as here.
So wouldn't this result in the PPM issuing the same PD Get_Source_Cap
message twice to the port partner (in either case of initial port
registration or op mode change)? Could we just consolidate them to just
issue GET_PDOS only once and take care of populating the partner's
Source Caps for both the pd_capabilties as well as power_supply purposes
from a single helper?
Another aside, thinking back to a previous patch [1] I had proposed a
few months ago, another question I had is whether it is proper to even
issue a Get_Source_Cap message to sink-only devices, as we did encounter
certain DisplayPort adapters that don't like when that happens.
Wondering if it could be possible to limit calling the GET_PDOS command
unless we know the partner is capable of operating in that particular
power role. e.g. don't call get_src_pdos() if partner is sink-only.
Or is this the kind of thing that the PPM is supposed to be able to
figure out and allow OPM to naively issue the command regardless, and
just get an error/empty return?
[1] https://lore.kernel.org/all/20211027064842.6901-1-quic_jackp@quicinc.com/
Thanks,
Jack
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