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Date: Mon, 19 Mar 2018 14:15:19 +0200
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Guenter Roeck <linux@...ck-us.net>
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Hans de Goede <hdegoede@...hat.com>, Jun Li <jun.li@....com>,
"Regupathy, Rajaram" <rajaram.regupathy@...el.com>,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [RFC PATCH v2 3/3] usb: typec: tcpm: Support for Alternate Modes
Hi Guenter,
On Fri, Mar 16, 2018 at 02:32:06PM -0700, Guenter Roeck wrote:
> 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@...ux.intel.com>
> > ---
> > 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().
True.
> > + 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.
The idea was that the alternate mode driver can inform the port driver
that it not support a specific VDM. In that case we need to NAK.
I'll think about this a bit more.
> > + 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.
True. I'll fix that as well.
> No error handling ?
>
> > + break;
> > + case CMD_EXIT_MODE:
> > + typec_altmode_exit(altmode);
>
> Doesn't handle NULL. Error handling ?
True, and I'll add error handling for there.
> > 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 ?
No. The plan is to always use the mutex.
I can't call typec_altmode_enter/exit() directly from tcpm_pd_svdm()
because the alternate mode drivers may call typec_altmode_enter() from
their probe drivers. I guess the solution is that instead of directly
calling typec_altmode_enter/exit() from tcpm_pm_svdm(), we schedule a
work where we call them. Or would you have some better ideas for this?
For this RFC I just hacked it and didn't use the mutex in
tcpm_altmode_enter/exit().
Thanks for reviewing these,
--
heikki
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