--- /dev/null
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * USB Typec-C Thunderbolt3 Alternate Mode driver
+ *
+ * Copyright (C) 2019 Intel Corporation
+ * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
+ */
+
+#include <linux/lockdep.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/workqueue.h>
+#include <linux/usb/pd_vdo.h>
+#include <linux/usb/typec_altmode.h>
+#include <linux/usb/typec_tbt.h>
+
+enum tbt_state {
+ TBT_STATE_IDLE,
+ TBT_STATE_SOP_P_ENTER,
+ TBT_STATE_SOP_PP_ENTER,
+ TBT_STATE_ENTER,
+ TBT_STATE_EXIT,
+ TBT_STATE_SOP_PP_EXIT,
+ TBT_STATE_SOP_P_EXIT
+};
+
+struct tbt_altmode {
+ enum tbt_state state;
+ struct typec_cable *cable;
+ struct typec_altmode *alt;
+ struct typec_altmode *plug[2];
+ u32 enter_vdo;
+
+ struct work_struct work;
+ struct mutex lock; /* device lock */
+};
+
+static bool tbt_ready(struct typec_altmode *alt);
+
+static int tbt_enter_mode(struct tbt_altmode *tbt)
+{
+ struct typec_altmode *plug = tbt->plug[TYPEC_PLUG_SOP_P];
+ u32 vdo;
+
+ vdo = tbt->alt->vdo & (TBT_VENDOR_SPECIFIC_B0 | TBT_VENDOR_SPECIFIC_B1);
+ vdo |= tbt->alt->vdo & TBT_INTEL_SPECIFIC_B0;
+ vdo |= TBT_MODE;
+
+ if (plug) {
+ if (typec_cable_is_active(tbt->cable))
+ vdo |= TBT_ENTER_MODE_ACTIVE_CABLE;
+
+ vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_SPEED(plug->vdo));
+ vdo |= plug->vdo & TBT_CABLE_ROUNDED;
+ vdo |= plug->vdo & TBT_CABLE_OPTICAL;
+ vdo |= plug->vdo & TBT_CABLE_RETIMER;
+ vdo |= plug->vdo & TBT_CABLE_LINK_TRAINING;
+ } else {
+ vdo |= TBT_ENTER_MODE_CABLE_SPEED(TBT_CABLE_USB3_PASSIVE);
+ }
+
+ tbt->enter_vdo = vdo;
+ return typec_altmode_enter(tbt->alt, &vdo);
+}
+
+static void tbt_altmode_work(struct work_struct *work)
+{
+ struct tbt_altmode *tbt = container_of(work, struct tbt_altmode, work);
+ int ret;
+
+ mutex_lock(&tbt->lock);
+
+ switch (tbt->state) {
+ case TBT_STATE_SOP_P_ENTER:
+ ret = typec_cable_altmode_enter(tbt->alt, TYPEC_PLUG_SOP_P, NULL);
+ if (ret) {
+ dev_dbg(&tbt->plug[TYPEC_PLUG_SOP_P]->dev,
+ "failed to enter mode (%d)\n", ret);
+ goto disable_plugs;
+ }
+ break;
+ case TBT_STATE_SOP_PP_ENTER:
+ ret = typec_cable_altmode_enter(tbt->alt, TYPEC_PLUG_SOP_PP, NULL);
+ if (ret) {
+ dev_dbg(&tbt->plug[TYPEC_PLUG_SOP_PP]->dev,
+ "failed to enter mode (%d)\n", ret);
+ goto disable_plugs;
+ }
+ break;
+ case TBT_STATE_ENTER:
+ ret = tbt_enter_mode(tbt);
+ if (ret)
+ dev_dbg(&tbt->alt->dev, "failed to enter mode (%d)\n",
+ ret);
+ break;
+ case TBT_STATE_EXIT:
+ typec_altmode_exit(tbt->alt);
+ break;
+ case TBT_STATE_SOP_PP_EXIT:
+ typec_cable_altmode_exit(tbt->alt, TYPEC_PLUG_SOP_PP);
+ break;
+ case TBT_STATE_SOP_P_EXIT:
+ typec_cable_altmode_exit(tbt->alt, TYPEC_PLUG_SOP_P);
+ break;
+ default:
+ break;
+ }
+
+ tbt->state = TBT_STATE_IDLE;
+
+ mutex_unlock(&tbt->lock);
+ return;
+
+disable_plugs:
+ for (int i = TYPEC_PLUG_SOP_PP; i > 0; --i) {
+ if (tbt->plug[i])
+ typec_altmode_put_plug(tbt->plug[i]);
+
+ tbt->plug[i] = NULL;
+ }
+
+ tbt->state = TBT_STATE_ENTER;
+ schedule_work(&tbt->work);
+ mutex_unlock(&tbt->lock);
+}
+
+/*
+ * If SOP' is available, enter that first (which will trigger a VDM response
+ * that will enter SOP" if available and then the port). If entering SOP' fails,
+ * stop attempting to enter either cable altmode (probably not supported) and
+ * directly enter the port altmode.
+ */
+static int tbt_enter_modes_ordered(struct typec_altmode *alt)
+{
+ struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+ int ret = 0;
+
+ lockdep_assert_held(&tbt->lock);
+
+ if (!tbt_ready(tbt->alt))
+ return -ENODEV;
+
+ if (tbt->plug[TYPEC_PLUG_SOP_P]) {
+ ret = typec_cable_altmode_enter(alt, TYPEC_PLUG_SOP_P, NULL);
+ if (ret < 0) {
+ for (int i = TYPEC_PLUG_SOP_PP; i > 0; --i) {
+ if (tbt->plug[i])
+ typec_altmode_put_plug(tbt->plug[i]);
+
+ tbt->plug[i] = NULL;
+ }
+ } else {
+ return ret;
+ }
+ }
+
+ return tbt_enter_mode(tbt);
+}
+
+static int tbt_cable_altmode_vdm(struct typec_altmode *alt,
+ enum typec_plug_index sop, const u32 hdr,
+ const u32 *vdo, int count)
+{
+ struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+ int cmd_type = PD_VDO_CMDT(hdr);
+ int cmd = PD_VDO_CMD(hdr);
+
+ mutex_lock(&tbt->lock);
+
+ if (tbt->state != TBT_STATE_IDLE) {
+ mutex_unlock(&tbt->lock);
+ return -EBUSY;
+ }
+
+ switch (cmd_type) {
+ case CMDT_RSP_ACK:
+ switch (cmd) {
+ case CMD_ENTER_MODE:
+ /*
+ * Following the order described in USB Type-C Spec
+ * R2.0 Section 6.7.3: SOP', SOP", then port.
+ */
+ if (sop == TYPEC_PLUG_SOP_P) {
+ if (tbt->plug[TYPEC_PLUG_SOP_PP])
+ tbt->state = TBT_STATE_SOP_PP_ENTER;
+ else
+ tbt->state = TBT_STATE_ENTER;
+ } else if (sop == TYPEC_PLUG_SOP_PP)
+ tbt->state = TBT_STATE_ENTER;
+
+ break;
+ case CMD_EXIT_MODE:
+ /* Exit in opposite order: Port, SOP", then SOP'. */
+ if (sop == TYPEC_PLUG_SOP_PP)
+ tbt->state = TBT_STATE_SOP_P_EXIT;
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+
+ if (tbt->state != TBT_STATE_IDLE)
+ schedule_work(&tbt->work);
+
+ mutex_unlock(&tbt->lock);
+ return 0;
+}
+
+static int tbt_altmode_vdm(struct typec_altmode *alt,
+ const u32 hdr, const u32 *vdo, int count)
+{
+ struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+ struct typec_thunderbolt_data data;
+ int cmd_type = PD_VDO_CMDT(hdr);
+ int cmd = PD_VDO_CMD(hdr);
+
+ mutex_lock(&tbt->lock);
+
+ if (tbt->state != TBT_STATE_IDLE) {
+ mutex_unlock(&tbt->lock);
+ return -EBUSY;
+ }
+
+ switch (cmd_type) {
+ case CMDT_RSP_ACK:
+ /* Port altmode is last to enter and first to exit. */
+ switch (cmd) {
+ case CMD_ENTER_MODE:
+ memset(&data, 0, sizeof(data));
+
+ data.device_mode = tbt->alt->vdo;
+ data.enter_vdo = tbt->enter_vdo;
+ if (tbt->plug[TYPEC_PLUG_SOP_P])
+ data.cable_mode = tbt->plug[TYPEC_PLUG_SOP_P]->vdo;
+
+ typec_altmode_notify(alt, TYPEC_STATE_MODAL, &data);
+ break;
+ case CMD_EXIT_MODE:
+ if (tbt->plug[TYPEC_PLUG_SOP_PP])
+ tbt->state = TBT_STATE_SOP_PP_EXIT;
+ else if (tbt->plug[TYPEC_PLUG_SOP_P])
+ tbt->state = TBT_STATE_SOP_P_EXIT;
+ break;
+ }
+ break;
+ case CMDT_RSP_NAK:
+ switch (cmd) {
+ case CMD_ENTER_MODE:
+ dev_warn(&alt->dev, "Enter Mode refused\n");
+ break;
+ default:
+ break;
+ }
+ break;
+ default:
+ break;
+ }
+
+ if (tbt->state != TBT_STATE_IDLE)
+ schedule_work(&tbt->work);
+
+ mutex_unlock(&tbt->lock);
+
+ return 0;
+}
+
+static int tbt_altmode_activate(struct typec_altmode *alt, int activate)
+{
+ struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+ int ret;
+
+ mutex_lock(&tbt->lock);
+
+ if (activate)
+ ret = tbt_enter_modes_ordered(alt);
+ else
+ ret = typec_altmode_exit(alt);
+
+ mutex_unlock(&tbt->lock);
+
+ return ret;
+}
+
+static const struct typec_altmode_ops tbt_altmode_ops = {
+ .vdm = tbt_altmode_vdm,
+ .activate = tbt_altmode_activate
+};
+
+static const struct typec_cable_ops tbt_cable_ops = {
+ .vdm = tbt_cable_altmode_vdm,
+};
+
+static int tbt_altmode_probe(struct typec_altmode *alt)
+{
+ struct tbt_altmode *tbt;
+
+ tbt = devm_kzalloc(&alt->dev, sizeof(*tbt), GFP_KERNEL);
+ if (!tbt)
+ return -ENOMEM;
+
+ INIT_WORK(&tbt->work, tbt_altmode_work);
+ mutex_init(&tbt->lock);
+ tbt->alt = alt;
+
+ alt->desc = "Thunderbolt3";
+ typec_altmode_set_drvdata(alt, tbt);
+ typec_altmode_set_ops(alt, &tbt_altmode_ops);
+
+ if (tbt_ready(alt)) {
+ if (tbt->plug[TYPEC_PLUG_SOP_P])
+ tbt->state = TBT_STATE_SOP_P_ENTER;
+ else if (tbt->plug[TYPEC_PLUG_SOP_PP])
+ tbt->state = TBT_STATE_SOP_PP_ENTER;
+ else
+ tbt->state = TBT_STATE_ENTER;
+ schedule_work(&tbt->work);
+ }
+
+ return 0;
+}
+
+static void tbt_altmode_remove(struct typec_altmode *alt)
+{
+ struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+
+ for (int i = TYPEC_PLUG_SOP_PP; i > 0; --i) {
+ if (tbt->plug[i])
+ typec_altmode_put_plug(tbt->plug[i]);
+ }
+
+ if (tbt->cable)
+ typec_cable_put(tbt->cable);
+}
+
+static bool tbt_ready(struct typec_altmode *alt)
+{
+ struct tbt_altmode *tbt = typec_altmode_get_drvdata(alt);
+ struct typec_altmode *plug;
+
+ if (tbt->cable)
+ return true;
+
+ /* Thunderbolt 3 requires a cable with eMarker */
+ tbt->cable = typec_cable_get(typec_altmode2port(tbt->alt));
+ if (!tbt->cable)
+ return false;
+
+ /* We accept systems without SOP' or SOP''. This means the port altmode
+ * driver will be responsible for properly ordering entry/exit.
+ */
+ for (int i = 0; i < TYPEC_PLUG_SOP_PP + 1; i++) {
+ plug = typec_altmode_get_plug(tbt->alt, i);
+ if (IS_ERR(plug))
+ continue;
+
+ if (!plug || plug->svid != USB_TYPEC_TBT_SID)
+ break;
+
+ plug->desc = "Thunderbolt3";
+ plug->cable_ops = &tbt_cable_ops;
+ typec_altmode_set_drvdata(plug, tbt);
+
+ tbt->plug[i] = plug;
+ }
+
+ return true;
+}
+
+static const struct typec_device_id tbt_typec_id[] = {
+ { USB_TYPEC_TBT_SID },
+ { }
+};
+MODULE_DEVICE_TABLE(typec, tbt_typec_id);
+
+static struct typec_altmode_driver tbt_altmode_driver = {
+ .id_table = tbt_typec_id,
+ .probe = tbt_altmode_probe,
+ .remove = tbt_altmode_remove,
+ .driver = {
+ .name = "typec-thunderbolt",
+ }
+};
+module_typec_altmode_driver(tbt_altmode_driver);
+
+MODULE_AUTHOR("Heikki Krogerus <heikki.krogerus@linux.intel.com>");
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Thunderbolt3 USB Type-C Alternate Mode");
projects / users / hch / misc.git / commitdiff