Re: [PATCH v2 1/1] usb: typec: ucsi: Check capabilities before cable and identity discovery

From: Heikki Krogerus
Date: Mon Mar 18 2024 - 07:11:46 EST


On Fri, Mar 15, 2024 at 05:18:35PM +0000, Jameson Thies wrote:
> Check the UCSI_CAP_GET_PD_MESSAGE bit before sending GET_PD_MESSAGE to
> discover partner and cable identity, check UCSI_CAP_CABLE_DETAILS before
> sending GET_CABLE_PROPERTY to discover the cable and check
> UCSI_CAP_ALT_MODE_DETAILS before registering the a cable plug. Additionally,
> move 8 bits from reserved_1 to features in the ucsi_capability struct. This
> makes the field 16 bits, still 8 short of the 24 bits allocated for it in
> UCSI v3.0, but it will not overflow because UCSI only defines 14 bits in
> bmOptionalFeatures.
>
> Fixes: 38ca416597b0 ("usb: typec: ucsi: Register cables based on GET_CABLE_PROPERTY")
> Link: https://lore.kernel.org/linux-usb/44e8142f-d9b3-487b-83fe-39deadddb492@xxxxxxxxxx
> Suggested-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
> Signed-off-by: Jameson Thies <jthies@xxxxxxxxxx>

Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>

> ---
> Confirmed a device which supports GET_PD_MESSAGE, GET_CABLE_PROPERTY and
> GET_ALTERNATE_MODES still requested identity and cable information.
>
> drivers/usb/typec/ucsi/ucsi.c | 34 +++++++++++++++++++++-------------
> drivers/usb/typec/ucsi/ucsi.h | 5 +++--
> 2 files changed, 24 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> index cf52cb34d2859..958dc82989b60 100644
> --- a/drivers/usb/typec/ucsi/ucsi.c
> +++ b/drivers/usb/typec/ucsi/ucsi.c
> @@ -1133,17 +1133,21 @@ static int ucsi_check_cable(struct ucsi_connector *con)
> if (ret < 0)
> return ret;
>
> - ret = ucsi_get_cable_identity(con);
> - if (ret < 0)
> - return ret;
> + if (con->ucsi->cap.features & UCSI_CAP_GET_PD_MESSAGE) {
> + ret = ucsi_get_cable_identity(con);
> + if (ret < 0)
> + return ret;
> + }
>
> - ret = ucsi_register_plug(con);
> - if (ret < 0)
> - return ret;
> + if (con->ucsi->cap.features & UCSI_CAP_ALT_MODE_DETAILS) {
> + ret = ucsi_register_plug(con);
> + if (ret < 0)
> + return ret;
>
> - ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_SOP_P);
> - if (ret < 0)
> - return ret;
> + ret = ucsi_register_altmodes(con, UCSI_RECIPIENT_SOP_P);
> + if (ret < 0)
> + return ret;
> + }
>
> return 0;
> }
> @@ -1189,8 +1193,10 @@ static void ucsi_handle_connector_change(struct work_struct *work)
> ucsi_register_partner(con);
> ucsi_partner_task(con, ucsi_check_connection, 1, HZ);
> ucsi_partner_task(con, ucsi_check_connector_capability, 1, HZ);
> - ucsi_partner_task(con, ucsi_get_partner_identity, 1, HZ);
> - ucsi_partner_task(con, ucsi_check_cable, 1, HZ);
> + if (con->ucsi->cap.features & UCSI_CAP_GET_PD_MESSAGE)
> + ucsi_partner_task(con, ucsi_get_partner_identity, 1, HZ);
> + if (con->ucsi->cap.features & UCSI_CAP_CABLE_DETAILS)
> + ucsi_partner_task(con, ucsi_check_cable, 1, HZ);
>
> if (UCSI_CONSTAT_PWR_OPMODE(con->status.flags) ==
> UCSI_CONSTAT_PWR_OPMODE_PD)
> @@ -1589,8 +1595,10 @@ static int ucsi_register_port(struct ucsi *ucsi, struct ucsi_connector *con)
> ucsi_register_partner(con);
> ucsi_pwr_opmode_change(con);
> ucsi_port_psy_changed(con);
> - ucsi_get_partner_identity(con);
> - ucsi_check_cable(con);
> + if (con->ucsi->cap.features & UCSI_CAP_GET_PD_MESSAGE)
> + ucsi_get_partner_identity(con);
> + if (con->ucsi->cap.features & UCSI_CAP_CABLE_DETAILS)
> + ucsi_check_cable(con);
> }
>
> /* Only notify USB controller if partner supports USB data */
> diff --git a/drivers/usb/typec/ucsi/ucsi.h b/drivers/usb/typec/ucsi/ucsi.h
> index 32daf5f586505..0e7c92eb1b227 100644
> --- a/drivers/usb/typec/ucsi/ucsi.h
> +++ b/drivers/usb/typec/ucsi/ucsi.h
> @@ -206,7 +206,7 @@ struct ucsi_capability {
> #define UCSI_CAP_ATTR_POWER_OTHER BIT(10)
> #define UCSI_CAP_ATTR_POWER_VBUS BIT(14)
> u8 num_connectors;
> - u8 features;
> + u16 features;
> #define UCSI_CAP_SET_UOM BIT(0)
> #define UCSI_CAP_SET_PDM BIT(1)
> #define UCSI_CAP_ALT_MODE_DETAILS BIT(2)
> @@ -215,7 +215,8 @@ struct ucsi_capability {
> #define UCSI_CAP_CABLE_DETAILS BIT(5)
> #define UCSI_CAP_EXT_SUPPLY_NOTIFICATIONS BIT(6)
> #define UCSI_CAP_PD_RESET BIT(7)
> - u16 reserved_1;
> +#define UCSI_CAP_GET_PD_MESSAGE BIT(8)
> + u8 reserved_1;
> u8 num_alt_modes;
> u8 reserved_2;
> u16 bc_version;
> --
> 2.44.0.291.gc1ea87d7ee-goog

--
heikki