usb: typec: tcpm: Properly interrupt VDM AMS

When a VDM AMS is interrupted by Messages other than VDM, the AMS needs
to be finished properly. Also start a VDM AMS if receiving SVDM Commands
from the port partner to complement the functionality of tcpm_vdm_ams().

Fixes: 0908c5aca31e ("usb: typec: tcpm: AMS and Collision Avoidance")
Cc: stable <stable@vger.kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Acked-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Kyle Tso <kyletso@google.com>
Link: https://lore.kernel.org/r/20210523015855.1785484-2-kyletso@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 8fdfd7f..6ea5df3 100644 (file)
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -1550,6 +1550,8 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
                        if (PD_VDO_SVDM_VER(p[0]) < svdm_version)
                                typec_partner_set_svdm_version(port->partner,
                                                               PD_VDO_SVDM_VER(p[0]));
+
+                       tcpm_ams_start(port, DISCOVER_IDENTITY);
                        /* 6.4.4.3.1: Only respond as UFP (device) */
                        if (port->data_role == TYPEC_DEVICE &&
                            port->nr_snk_vdo) {
@@ -1568,14 +1570,19 @@ static int tcpm_pd_svdm(struct tcpm_port *port, struct typec_altmode *adev,
                        }
                        break;
                case CMD_DISCOVER_SVID:
+                       tcpm_ams_start(port, DISCOVER_SVIDS);
                        break;
                case CMD_DISCOVER_MODES:
+                       tcpm_ams_start(port, DISCOVER_MODES);
                        break;
                case CMD_ENTER_MODE:
+                       tcpm_ams_start(port, DFP_TO_UFP_ENTER_MODE);
                        break;
                case CMD_EXIT_MODE:
+                       tcpm_ams_start(port, DFP_TO_UFP_EXIT_MODE);
                        break;
                case CMD_ATTENTION:
+                       tcpm_ams_start(port, ATTENTION);
                        /* Attention command does not have response */
                        *adev_action = ADEV_ATTENTION;
                        return 0;
@@ -2287,6 +2294,12 @@ static void tcpm_pd_data_request(struct tcpm_port *port,
        bool frs_enable;
        int ret;
 
+       if (tcpm_vdm_ams(port) && type != PD_DATA_VENDOR_DEF) {
+               port->vdm_state = VDM_STATE_ERR_BUSY;
+               tcpm_ams_finish(port);
+               mod_vdm_delayed_work(port, 0);
+       }
+
        switch (type) {
        case PD_DATA_SOURCE_CAP:
                for (i = 0; i < cnt; i++)
@@ -2459,6 +2472,16 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
        enum pd_ctrl_msg_type type = pd_header_type_le(msg->header);
        enum tcpm_state next_state;
 
+       /*
+        * Stop VDM state machine if interrupted by other Messages while NOT_SUPP is allowed in
+        * VDM AMS if waiting for VDM responses and will be handled later.
+        */
+       if (tcpm_vdm_ams(port) && type != PD_CTRL_NOT_SUPP && type != PD_CTRL_GOOD_CRC) {
+               port->vdm_state = VDM_STATE_ERR_BUSY;
+               tcpm_ams_finish(port);
+               mod_vdm_delayed_work(port, 0);
+       }
+
        switch (type) {
        case PD_CTRL_GOOD_CRC:
        case PD_CTRL_PING:
@@ -2717,6 +2740,13 @@ static void tcpm_pd_ext_msg_request(struct tcpm_port *port,
        enum pd_ext_msg_type type = pd_header_type_le(msg->header);
        unsigned int data_size = pd_ext_header_data_size_le(msg->ext_msg.header);
 
+       /* stopping VDM state machine if interrupted by other Messages */
+       if (tcpm_vdm_ams(port)) {
+               port->vdm_state = VDM_STATE_ERR_BUSY;
+               tcpm_ams_finish(port);
+               mod_vdm_delayed_work(port, 0);
+       }
+
        if (!(le16_to_cpu(msg->ext_msg.header) & PD_EXT_HDR_CHUNKED)) {
                tcpm_pd_handle_msg(port, PD_MSG_CTRL_NOT_SUPP, NONE_AMS);
                tcpm_log(port, "Unchunked extended messages unsupported");