Re: [RFC PATCH v2 3/3] usb: typec: tcpm: Support for Alternate Modes

From: Guenter Roeck
Date: Fri Mar 16 2018 - 17:32:17 EST

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On Fri, Mar 09, 2018 at 06:19:18PM +0300, Heikki Krogerus wrote:
> This adds more complete handling of VDMs and registration of
> partner alternate modes, and introduces callbacks for
> alternate mode operations.
>
> Only DFP role is supported for now.
>
> Signed-off-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx>
> ---
> drivers/usb/typec/tcpm.c | 133 +++++++++++++++++++++++++++++++++++++++--------
> 1 file changed, 111 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/usb/typec/tcpm.c b/drivers/usb/typec/tcpm.c
> index bfb843ebffa6..34bf5c1f4d81 100644
> --- a/drivers/usb/typec/tcpm.c
> +++ b/drivers/usb/typec/tcpm.c
> @@ -158,13 +158,14 @@ enum pd_msg_request {
> /* Alternate mode support */
>
> #define SVID_DISCOVERY_MAX 16
> +#define ALTMODE_DISCOVERY_MAX (SVID_DISCOVERY_MAX * MODE_DISCOVERY_MAX)
>
> struct pd_mode_data {
> int svid_index; /* current SVID index */
> int nsvids;
> u16 svids[SVID_DISCOVERY_MAX];
> int altmodes; /* number of alternate modes */
> - struct typec_altmode_desc altmode_desc[SVID_DISCOVERY_MAX];
> + struct typec_altmode_desc altmode_desc[ALTMODE_DISCOVERY_MAX];
> };
>
> struct tcpm_port {
> @@ -280,8 +281,8 @@ struct tcpm_port {
> /* Alternate mode data */
>
> struct pd_mode_data mode_data;
> - struct typec_altmode *partner_altmode[SVID_DISCOVERY_MAX * 6];
> - struct typec_altmode *port_altmode[SVID_DISCOVERY_MAX * 6];
> + struct typec_altmode *partner_altmode[ALTMODE_DISCOVERY_MAX];
> + struct typec_altmode *port_altmode[ALTMODE_DISCOVERY_MAX];
>
> /* Deadline in jiffies to exit src_try_wait state */
> unsigned long max_wait;
> @@ -985,36 +986,53 @@ static void svdm_consume_modes(struct tcpm_port *port, const __le32 *payload,
> pmdata->altmodes, paltmode->svid,
> paltmode->mode, paltmode->vdo);
>
> - port->partner_altmode[pmdata->altmodes] =
> - typec_partner_register_altmode(port->partner, paltmode);
> - if (!port->partner_altmode[pmdata->altmodes]) {
> - tcpm_log(port,
> - "Failed to register modes for SVID 0x%04x",
> - paltmode->svid);
> - return;
> - }
> pmdata->altmodes++;
> }
> }
>
> +static void tcpm_register_partner_altmodes(struct tcpm_port *port)
> +{
> + struct pd_mode_data *modep = &port->mode_data;
> + struct typec_altmode *altmode;
> + int i;
> +
> + for (i = 0; i < modep->altmodes; i++) {
> + altmode = typec_partner_register_altmode(port->partner,
> + &modep->altmode_desc[i]);
> + if (!altmode)
> + tcpm_log(port, "Failed to register partner SVID 0x%04x",
> + modep->altmode_desc[i].svid);
> + port->partner_altmode[i] = altmode;
> + }
> +}
> +
> #define supports_modal(port) PD_IDH_MODAL_SUPP((port)->partner_ident.id_header)
>
> static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
> u32 *response)
> {
> - u32 p0 = le32_to_cpu(payload[0]);
> - int cmd_type = PD_VDO_CMDT(p0);
> - int cmd = PD_VDO_CMD(p0);
> + struct typec_altmode *altmode;
> struct pd_mode_data *modep;
> + u32 p[PD_MAX_PAYLOAD];
> int rlen = 0;
> - u16 svid;
> + int cmd_type;
> + int cmd;
> int i;
>
> + for (i = 0; i < cnt; i++)
> + p[i] = le32_to_cpu(payload[i]);
> +
> + cmd_type = PD_VDO_CMDT(p[0]);
> + cmd = PD_VDO_CMD(p[0]);
> +
> tcpm_log(port, "Rx VDM cmd 0x%x type %d cmd %d len %d",
> - p0, cmd_type, cmd, cnt);
> + p[0], cmd_type, cmd, cnt);
>
> modep = &port->mode_data;
>
> + altmode = typec_match_altmode(port->port_altmode, ALTMODE_DISCOVERY_MAX,
> + PD_VDO_VID(p[0]), PD_VDO_OPOS(p[0]));

This can return NULL ...

> +
> switch (cmd_type) {
> case CMDT_INIT:
> switch (cmd) {
> @@ -1036,17 +1054,21 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
> case CMD_EXIT_MODE:
> break;
> case CMD_ATTENTION:
> - break;
> + typec_altmode_attention(altmode, p[1]);

... and NULL is not handled by typec_altmode_attention().

> + return 0;
> default:
> + if (typec_altmode_vdm(altmode, p[0], &p[1], cnt) ==
> + VDM_OK)

typec_altmode_vdm() returns old fashioned error messages.
Not sure what it is supposed to return, though.

> + return 0;
> break;
> }
> if (rlen >= 1) {
> - response[0] = p0 | VDO_CMDT(CMDT_RSP_ACK);
> + response[0] = p[0] | VDO_CMDT(CMDT_RSP_ACK);
> } else if (rlen == 0) {
> - response[0] = p0 | VDO_CMDT(CMDT_RSP_NAK);
> + response[0] = p[0] | VDO_CMDT(CMDT_RSP_NAK);
> rlen = 1;
> } else {
> - response[0] = p0 | VDO_CMDT(CMDT_RSP_BUSY);
> + response[0] = p[0] | VDO_CMDT(CMDT_RSP_BUSY);
> rlen = 1;
> }
> break;
> @@ -1079,20 +1101,26 @@ static int tcpm_pd_svdm(struct tcpm_port *port, const __le32 *payload, int cnt,
> svdm_consume_modes(port, payload, cnt);
> modep->svid_index++;
> if (modep->svid_index < modep->nsvids) {
> - svid = modep->svids[modep->svid_index];
> + u16 svid = modep->svids[modep->svid_index];
> response[0] = VDO(svid, 1, CMD_DISCOVER_MODES);
> rlen = 1;
> } else {
> - /* enter alternate mode if/when implemented */
> + tcpm_register_partner_altmodes(port);
> }
> break;
> case CMD_ENTER_MODE:
> + typec_altmode_enter(altmode);

typec_altmode_enter() don't handle altmode == NULL.
No error handling ?

> + break;
> + case CMD_EXIT_MODE:
> + typec_altmode_exit(altmode);

Doesn't handle NULL. Error handling ?

> break;
> default:
> + typec_altmode_vdm(altmode, p[0], &p[1], cnt);
> break;
> }
> break;
> default:
> + typec_altmode_vdm(altmode, p[0], &p[1], cnt);
> break;
> }
>
> @@ -1352,6 +1380,47 @@ static int tcpm_validate_caps(struct tcpm_port *port, const u32 *pdo,
> return 0;
> }
>
> +static void tcpm_altmode_enter(struct typec_altmode *altmode)
> +{
> + struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> + u32 header;
> +
> + header = VDO(altmode->svid, 1, CMD_ENTER_MODE);
> + header |= VDO_OPOS(altmode->mode);
> +
> + tcpm_queue_vdm(port, header, NULL, 0);
> + mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +}
> +
> +static void tcpm_altmode_exit(struct typec_altmode *altmode)
> +{
> + struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> + u32 header;
> +
> + header = VDO(altmode->svid, 1, CMD_EXIT_MODE);
> + header |= VDO_OPOS(altmode->mode);
> +
> + tcpm_queue_vdm(port, header, NULL, 0);
> + mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +}
> +
> +static int tcpm_altmode_vdm(struct typec_altmode *altmode,
> + u32 header, const u32 *data, int count)
> +{
> + struct tcpm_port *port = typec_altmode_get_drvdata(altmode);
> +
> + tcpm_queue_vdm(port, header, data, count - 1);
> + mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> +
> + return 0;
> +}
> +
> +static const struct typec_altmode_ops tcpm_altmode_ops = {
> + .enter = tcpm_altmode_enter,
> + .exit = tcpm_altmode_exit,
> + .vdm = tcpm_altmode_vdm,
> +};
> +
> /*
> * PD (data, control) command handling functions
> */
> @@ -3479,6 +3548,23 @@ static void tcpm_init(struct tcpm_port *port)
> tcpm_set_state(port, PORT_RESET, 0);
> }
>
> +static int tcpm_activate_mode(struct typec_altmode *alt, int activate)
> +{
> + struct tcpm_port *port = typec_altmode_get_drvdata(alt);
> + u32 header;
> +
> + header = VDO(cpu_to_le16(alt->svid), 1,
> + activate ? CMD_ENTER_MODE : CMD_EXIT_MODE);
> + header |= VDO_OPOS(alt->mode);
> +
> + mutex_lock(&port->lock);
> + tcpm_queue_vdm(port, header, NULL, 0);
> + mod_delayed_work(port->wq, &port->vdm_state_machine, 0);
> + mutex_unlock(&port->lock);

Some of the above functions are port mutex protected, some are not.
Is this on purpose ?

> +
> + return 0;
> +}
> +
> static int tcpm_port_type_set(const struct typec_capability *cap,
> enum typec_port_type type)
> {
> @@ -3671,6 +3757,7 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
> port->typec_caps.pr_set = tcpm_pr_set;
> port->typec_caps.vconn_set = tcpm_vconn_set;
> port->typec_caps.try_role = tcpm_try_role;
> + port->typec_caps.activate_mode = tcpm_activate_mode;
> port->typec_caps.port_type_set = tcpm_port_type_set;
>
> port->partner_desc.identity = &port->partner_ident;
> @@ -3703,6 +3790,8 @@ struct tcpm_port *tcpm_register_port(struct device *dev, struct tcpc_dev *tcpc)
> dev_name(dev), paltmode->svid);
> break;
> }
> + typec_altmode_set_drvdata(alt, port);
> + typec_altmode_register_ops(alt, &tcpm_altmode_ops);
> port->port_altmode[i] = alt;
> i++;
> paltmode++;
> --
> 2.16.1
>

Next message: Steve Wise: "RE: [PATCH v3 18/18] infiniband: cxgb4: Eliminate duplicate barriers on weakly-ordered archs"
Previous message: Linus Torvalds: "Re: [PATCH] mm: add config for readahead window"
Next in thread: Heikki Krogerus: "Re: [RFC PATCH v2 3/3] usb: typec: tcpm: Support for Alternate Modes"
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