[PATCH v11 08/14] usb: otg: add OTG/dual-role core

From: Roger Quadros
Date: Mon Jun 13 2016 - 03:56:59 EST

It provides APIs for the following tasks

- Registering an OTG/dual-role capable controller
- Registering Host and Gadget controllers to OTG core
- Providing inputs to and kicking the OTG state machine

Provide a dual-role device (DRD) state machine.
DRD mode is a reduced functionality OTG mode. In this mode
we don't support SRP, HNP and dynamic role-swap.

In DRD operation, the controller mode (Host or Peripheral)
is decided based on the ID pin status. Once a cable plug (Type-A
or Type-B) is attached the controller selects the state
and doesn't change till the cable in unplugged and a different
cable type is inserted.

As we don't need most of the complex OTG states and OTG timers
we implement a lean DRD state machine in usb-otg.c.
The DRD state machine is only interested in 2 hardware inputs
'id' and 'b_sess_vld'.

Signed-off-by: Roger Quadros <rogerq@xxxxxx>
---
v11:
- remove usb_otg_kick_fsm().
- typo fixes: structa/structure, upto/up to.
- remove "obj-$(CONFIG_USB_OTG_CORE) += common/" from Makefile.

drivers/usb/Kconfig | 18 +
drivers/usb/common/Makefile | 6 +-
drivers/usb/common/usb-otg.c | 877 +++++++++++++++++++++++++++++++++++++++++++
drivers/usb/core/Kconfig | 14 -
drivers/usb/gadget/Kconfig | 1 +
include/linux/usb/gadget.h | 2 +
include/linux/usb/hcd.h | 1 +
include/linux/usb/otg-fsm.h | 7 +
include/linux/usb/otg.h | 174 ++++++++-
9 files changed, 1070 insertions(+), 30 deletions(-)
create mode 100644 drivers/usb/common/usb-otg.c

diff --git a/drivers/usb/Kconfig b/drivers/usb/Kconfig
index 8689dcb..ed596ec 100644
--- a/drivers/usb/Kconfig
+++ b/drivers/usb/Kconfig
@@ -32,6 +32,23 @@ if USB_SUPPORT
config USB_COMMON
tristate

+config USB_OTG_CORE
+ tristate
+
+config USB_OTG
+ bool "OTG/Dual-role support"
+ depends on PM && USB && USB_GADGET
+ default n
+ ---help---
+ The most notable feature of USB OTG is support for a
+ "Dual-Role" device, which can act as either a device
+ or a host. The initial role is decided by the type of
+ plug inserted and can be changed later when two dual
+ role devices talk to each other.
+
+ Select this only if your board has Mini-AB/Micro-AB
+ connector.
+
config USB_ARCH_HAS_HCD
def_bool y

@@ -40,6 +57,7 @@ config USB
tristate "Support for Host-side USB"
depends on USB_ARCH_HAS_HCD
select USB_COMMON
+ select USB_OTG_CORE
select NLS # for UTF-8 strings
---help---
Universal Serial Bus (USB) is a specification for a serial bus
diff --git a/drivers/usb/common/Makefile b/drivers/usb/common/Makefile
index f8f2c88..5122b3f 100644
--- a/drivers/usb/common/Makefile
+++ b/drivers/usb/common/Makefile
@@ -7,5 +7,7 @@ usb-common-y += common.o
usb-common-$(CONFIG_USB_LED_TRIG) += led.o

obj-$(CONFIG_USB_ULPI_BUS) += ulpi.o
-usbotg-y := usb-otg-fsm.o
-obj-$(CONFIG_USB_OTG) += usbotg.o
+ifeq ($(CONFIG_USB_OTG),y)
+usbotg-y := usb-otg.o usb-otg-fsm.o
+obj-$(CONFIG_USB_OTG_CORE) += usbotg.o
+endif
diff --git a/drivers/usb/common/usb-otg.c b/drivers/usb/common/usb-otg.c
new file mode 100644
index 0000000..a23ab1e
--- /dev/null
+++ b/drivers/usb/common/usb-otg.c
@@ -0,0 +1,877 @@
+/**
+ * drivers/usb/common/usb-otg.c - USB OTG core
+ *
+ * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com
+ * Author: Roger Quadros <rogerq@xxxxxx>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/usb/of.h>
+#include <linux/usb/otg.h>
+#include <linux/usb/gadget.h>
+#include <linux/workqueue.h>
+
+/* OTG device list */
+LIST_HEAD(otg_list);
+static DEFINE_MUTEX(otg_list_mutex);
+
+static int usb_otg_hcd_is_primary_hcd(struct usb_hcd *hcd)
+{
+ if (!hcd->primary_hcd)
+ return 1;
+ return hcd == hcd->primary_hcd;
+}
+
+/**
+ * usb_otg_get_data() - get usb_otg data structure
+ * @otg_dev: OTG controller device
+ *
+ * Check if the OTG device is in our OTG list and return
+ * usb_otg data, else NULL.
+ *
+ * otg_list_mutex must be held.
+ *
+ * Return: usb_otg data on success, NULL otherwise.
+ */
+static struct usb_otg *usb_otg_get_data(struct device *otg_dev)
+{
+ struct usb_otg *otg;
+
+ if (!otg_dev)
+ return NULL;
+
+ list_for_each_entry(otg, &otg_list, list) {
+ if (otg->dev == otg_dev)
+ return otg;
+ }
+
+ return NULL;
+}
+
+/**
+ * usb_otg_start_host() - start/stop the host controller
+ * @otg: usb_otg instance
+ * @on: true to start, false to stop
+ *
+ * Start/stop the USB host controller. This function is meant
+ * for use by the OTG controller driver.
+ *
+ * Return: 0 on success, error value otherwise.
+ */
+int usb_otg_start_host(struct usb_otg *otg, int on)
+{
+ struct otg_hcd_ops *hcd_ops = otg->hcd_ops;
+ int ret;
+
+ dev_dbg(otg->dev, "otg: %s %d\n", __func__, on);
+ if (!otg->host) {
+ WARN_ONCE(1, "otg: fsm running without host\n");
+ return 0;
+ }
+
+ if (on) {
+ if (otg->flags & OTG_FLAG_HOST_RUNNING)
+ return 0;
+
+ /* start host */
+ ret = hcd_ops->add(otg->primary_hcd.hcd,
+ otg->primary_hcd.irqnum,
+ otg->primary_hcd.irqflags);
+ if (ret) {
+ dev_err(otg->dev, "otg: host add failed %d\n", ret);
+ return ret;
+ }
+
+ if (otg->shared_hcd.hcd) {
+ ret = hcd_ops->add(otg->shared_hcd.hcd,
+ otg->shared_hcd.irqnum,
+ otg->shared_hcd.irqflags);
+ if (ret) {
+ dev_err(otg->dev, "otg: shared host add failed %d\n",
+ ret);
+ hcd_ops->remove(otg->primary_hcd.hcd);
+ return ret;
+ }
+ }
+ otg->flags |= OTG_FLAG_HOST_RUNNING;
+ } else {
+ if (!(otg->flags & OTG_FLAG_HOST_RUNNING))
+ return 0;
+
+ otg->flags &= ~OTG_FLAG_HOST_RUNNING;
+
+ /* stop host */
+ if (otg->shared_hcd.hcd)
+ hcd_ops->remove(otg->shared_hcd.hcd);
+
+ hcd_ops->remove(otg->primary_hcd.hcd);
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_otg_start_host);
+
+/**
+ * usb_otg_start_gadget() - start/stop the gadget controller
+ * @otg: usb_otg instance
+ * @on: true to start, false to stop
+ *
+ * Start/stop the USB gadget controller. This function is meant
+ * for use by the OTG controller driver.
+ *
+ * Return: 0 on success, error value otherwise.
+ */
+int usb_otg_start_gadget(struct usb_otg *otg, int on)
+{
+ struct usb_gadget *gadget = otg->gadget;
+ int ret;
+
+ dev_dbg(otg->dev, "otg: %s %d\n", __func__, on);
+ if (!gadget) {
+ WARN_ONCE(1, "otg: fsm running without gadget\n");
+ return 0;
+ }
+
+ if (on) {
+ if (otg->flags & OTG_FLAG_GADGET_RUNNING)
+ return 0;
+
+ ret = otg->gadget_ops->start(otg->gadget);
+ if (ret) {
+ dev_err(otg->dev, "otg: gadget start failed: %d\n",
+ ret);
+ return ret;
+ }
+
+ otg->flags |= OTG_FLAG_GADGET_RUNNING;
+ } else {
+ if (!(otg->flags & OTG_FLAG_GADGET_RUNNING))
+ return 0;
+
+ ret = otg->gadget_ops->stop(otg->gadget);
+ if (ret) {
+ dev_err(otg->dev, "otg: gadget stop failed: %d\n",
+ ret);
+ return ret;
+ }
+ otg->flags &= ~OTG_FLAG_GADGET_RUNNING;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_otg_start_gadget);
+
+/**
+ * drd_set_protocol() - Set USB protocol if possible
+ * @fsm: DRD FSM instance
+ * @protocol: USB protocol to set the state machine to
+ *
+ * Sets the OTG FSM protocol to @protocol if it changed.
+ * fsm->lock must be held.
+ *
+ * Return: 0 on success, error value otherwise.
+ */
+static int drd_set_protocol(struct otg_fsm *fsm, int protocol)
+{
+ struct usb_otg *otg = container_of(fsm, struct usb_otg, fsm);
+ int ret = 0;
+
+ if (fsm->protocol != protocol) {
+ dev_dbg(otg->dev, "otg: changing role fsm->protocol= %d; new protocol= %d\n",
+ fsm->protocol, protocol);
+ /* stop old protocol */
+ if (fsm->protocol == PROTO_HOST) {
+ ret = otg_start_host(otg, 0);
+ } else if (fsm->protocol == PROTO_GADGET) {
+ otg->gadget_ops->connect_control(otg->gadget, false);
+ ret = otg_start_gadget(otg, 0);
+ }
+
+ if (ret)
+ return ret;
+
+ /* start new protocol */
+ if (protocol == PROTO_HOST) {
+ ret = otg_start_host(otg, 1);
+ } else if (protocol == PROTO_GADGET) {
+ ret = otg_start_gadget(otg, 1);
+ otg->gadget_ops->connect_control(otg->gadget, true);
+ }
+
+ if (ret)
+ return ret;
+
+ fsm->protocol = protocol;
+ return 0;
+ }
+
+ return 0;
+}
+
+/**
+ * drd_set_state() - Set the DRD state machine state.
+ * @fsm: DRD FSM instance
+ * @new_state: the new state the DRD FSM must be set to
+ *
+ * Sets the state of the DRD state machine.
+ * fsm->lock must be held.
+ */
+static void drd_set_state(struct otg_fsm *fsm, enum usb_otg_state new_state)
+{
+ struct usb_otg *otg = container_of(fsm, struct usb_otg, fsm);
+
+ if (otg->state == new_state)
+ return;
+
+ fsm->state_changed = 1;
+ dev_dbg(otg->dev, "otg: set state: %s\n",
+ usb_otg_state_string(new_state));
+ switch (new_state) {
+ case OTG_STATE_B_IDLE:
+ drd_set_protocol(fsm, PROTO_UNDEF);
+ otg_drv_vbus(otg, 0);
+ break;
+ case OTG_STATE_B_PERIPHERAL:
+ drd_set_protocol(fsm, PROTO_GADGET);
+ otg_drv_vbus(otg, 0);
+ break;
+ case OTG_STATE_A_HOST:
+ drd_set_protocol(fsm, PROTO_HOST);
+ otg_drv_vbus(otg, 1);
+ break;
+ default:
+ dev_warn(otg->dev, "%s: otg: invalid state: %s\n",
+ __func__, usb_otg_state_string(new_state));
+ break;
+ }
+
+ otg->state = new_state;
+}
+
+/**
+ * drd_statemachine() - DRD state change judgement
+ * @otg: usb_otg instance
+ *
+ * Checks the state machine inputs and state and makes a state change
+ * if required.
+ *
+ * For DRD we're only interested in some of the OTG states
+ * i.e. OTG_STATE_B_IDLE: both peripheral and host are stopped
+ * OTG_STATE_B_PERIPHERAL: peripheral active
+ * OTG_STATE_A_HOST: host active
+ * we're only interested in the following inputs
+ * fsm->id, fsm->b_sess_vld
+ *
+ * Return: 0 if state wasn't changed, 1 if state changed.
+ */
+int drd_statemachine(struct usb_otg *otg)
+{
+ struct otg_fsm *fsm = &otg->fsm;
+ enum usb_otg_state state;
+ int ret;
+
+ mutex_lock(&fsm->lock);
+
+ fsm->state_changed = 0;
+ state = otg->state;
+
+ switch (state) {
+ case OTG_STATE_UNDEFINED:
+ if (!fsm->id)
+ drd_set_state(fsm, OTG_STATE_A_HOST);
+ else if (fsm->id && fsm->b_sess_vld)
+ drd_set_state(fsm, OTG_STATE_B_PERIPHERAL);
+ else
+ drd_set_state(fsm, OTG_STATE_B_IDLE);
+ break;
+ case OTG_STATE_B_IDLE:
+ if (!fsm->id)
+ drd_set_state(fsm, OTG_STATE_A_HOST);
+ else if (fsm->b_sess_vld)
+ drd_set_state(fsm, OTG_STATE_B_PERIPHERAL);
+ break;
+ case OTG_STATE_B_PERIPHERAL:
+ if (!fsm->id)
+ drd_set_state(fsm, OTG_STATE_A_HOST);
+ else if (!fsm->b_sess_vld)
+ drd_set_state(fsm, OTG_STATE_B_IDLE);
+ break;
+ case OTG_STATE_A_HOST:
+ if (fsm->id && fsm->b_sess_vld)
+ drd_set_state(fsm, OTG_STATE_B_PERIPHERAL);
+ else if (fsm->id && !fsm->b_sess_vld)
+ drd_set_state(fsm, OTG_STATE_B_IDLE);
+ break;
+
+ default:
+ dev_err(otg->dev, "%s: otg: invalid usb-drd state: %s\n",
+ __func__, usb_otg_state_string(state));
+ break;
+ }
+
+ ret = fsm->state_changed;
+ mutex_unlock(&fsm->lock);
+ dev_dbg(otg->dev, "otg: quit statemachine, changed %d\n",
+ fsm->state_changed);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(drd_statemachine);
+
+/**
+ * usb_drd_work() - Dual-role state machine work function
+ * @work: work_struct context
+ *
+ * Runs the DRD state machine. Scheduled whenever there is a change
+ * in FSM inputs.
+ */
+static void usb_drd_work(struct work_struct *work)
+{
+ struct usb_otg *otg = container_of(work, struct usb_otg, work);
+
+ pm_runtime_get_sync(otg->dev);
+ while (drd_statemachine(otg))
+ ;
+ pm_runtime_put_sync(otg->dev);
+}
+
+/**
+ * usb_otg_register() - Register the OTG/dual-role device to OTG core
+ * @dev: OTG/dual-role controller device.
+ * @config: OTG configuration.
+ *
+ * Registers the OTG/dual-role controller device with the USB OTG core.
+ *
+ * Return: struct usb_otg * if success, ERR_PTR() otherwise.
+ */
+struct usb_otg *usb_otg_register(struct device *dev,
+ struct usb_otg_config *config)
+{
+ struct usb_otg *otg;
+ int ret = 0;
+
+ if (!dev || !config || !config->fsm_ops)
+ return ERR_PTR(-EINVAL);
+
+ /* already in list? */
+ mutex_lock(&otg_list_mutex);
+ if (usb_otg_get_data(dev)) {
+ dev_err(dev, "otg: %s: device already in otg list\n",
+ __func__);
+ ret = -EINVAL;
+ goto unlock;
+ }
+
+ /* allocate and add to list */
+ otg = kzalloc(sizeof(*otg), GFP_KERNEL);
+ if (!otg) {
+ ret = -ENOMEM;
+ goto unlock;
+ }
+
+ otg->dev = dev;
+ /* otg->caps is controller caps + DT overrides */
+ otg->caps = *config->otg_caps;
+ ret = of_usb_update_otg_caps(dev->of_node, &otg->caps);
+ if (ret)
+ goto err_wq;
+
+ if ((otg->caps.hnp_support || otg->caps.srp_support ||
+ otg->caps.adp_support) && !config->otg_work) {
+ dev_err(dev,
+ "otg: otg_work must be provided for OTG support\n");
+ ret = -EINVAL;
+ goto err_wq;
+ }
+
+ if (config->otg_work) /* custom otg_work ? */
+ INIT_WORK(&otg->work, config->otg_work);
+ else
+ INIT_WORK(&otg->work, usb_drd_work);
+
+ otg->wq = create_freezable_workqueue("usb_otg");
+ if (!otg->wq) {
+ dev_err(dev, "otg: %s: can't create workqueue\n",
+ __func__);
+ ret = -ENOMEM;
+ goto err_wq;
+ }
+
+ /* set otg ops */
+ otg->fsm.ops = config->fsm_ops;
+
+ mutex_init(&otg->fsm.lock);
+
+ list_add_tail(&otg->list, &otg_list);
+ mutex_unlock(&otg_list_mutex);
+
+ return otg;
+
+err_wq:
+ kfree(otg);
+unlock:
+ mutex_unlock(&otg_list_mutex);
+ return ERR_PTR(ret);
+}
+EXPORT_SYMBOL_GPL(usb_otg_register);
+
+/**
+ * usb_otg_unregister() - Unregister the OTG/dual-role device from USB OTG core
+ * @dev: OTG controller device.
+ *
+ * Unregisters the OTG/dual-role controller device from USB OTG core.
+ * Prevents unregistering till both the associated Host and Gadget controllers
+ * have unregistered from the OTG core.
+ *
+ * Return: 0 on success, error value otherwise.
+ */
+int usb_otg_unregister(struct device *dev)
+{
+ struct usb_otg *otg;
+
+ mutex_lock(&otg_list_mutex);
+ otg = usb_otg_get_data(dev);
+ if (!otg) {
+ dev_err(dev, "otg: %s: device not in otg list\n",
+ __func__);
+ mutex_unlock(&otg_list_mutex);
+ return -EINVAL;
+ }
+
+ /* prevent unregister till both host & gadget have unregistered */
+ if (otg->host || otg->gadget) {
+ dev_err(dev, "otg: %s: host/gadget still registered\n",
+ __func__);
+ mutex_unlock(&otg_list_mutex);
+ return -EBUSY;
+ }
+
+ /* OTG FSM is halted when host/gadget unregistered */
+ destroy_workqueue(otg->wq);
+
+ /* remove from otg list */
+ list_del(&otg->list);
+ kfree(otg);
+ mutex_unlock(&otg_list_mutex);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_otg_unregister);
+
+/**
+ * usb_otg_start_fsm() - Start the OTG FSM
+ * @otg: usb_otg instance
+ *
+ * Start the OTG FSM if we can. The HCD, UDC and gadget function driver
+ * must be ready for the OTG FSM to start.
+ *
+ * fsm->lock must be held.
+ */
+static void usb_otg_start_fsm(struct usb_otg *otg)
+{
+ struct otg_fsm *fsm = &otg->fsm;
+
+ if (fsm->running)
+ goto kick_fsm;
+
+ if (!otg->host) {
+ dev_info(otg->dev, "otg: can't start till host registers\n");
+ return;
+ }
+
+ if (!otg->gadget) {
+ dev_info(otg->dev,
+ "otg: can't start till gadget UDC registers\n");
+ return;
+ }
+
+ if (!otg->gadget_ready) {
+ dev_info(otg->dev,
+ "otg: can't start till gadget function registers\n");
+ return;
+ }
+
+ fsm->running = true;
+kick_fsm:
+ queue_work(otg->wq, &otg->work);
+}
+
+/**
+ * usb_otg_stop_fsm() - Stop the OTG FSM
+ * @otg: usb_otg instance
+ *
+ * Stops the HCD, UDC and the OTG FSM.
+ *
+ * fsm->lock must be held.
+ */
+static void usb_otg_stop_fsm(struct usb_otg *otg)
+{
+ struct otg_fsm *fsm = &otg->fsm;
+
+ if (!fsm->running)
+ return;
+
+ /* no more new events queued */
+ fsm->running = false;
+
+ flush_workqueue(otg->wq);
+ otg->state = OTG_STATE_UNDEFINED;
+
+ /* stop host/gadget immediately */
+ if (fsm->protocol == PROTO_HOST) {
+ otg_start_host(otg, 0);
+ } else if (fsm->protocol == PROTO_GADGET) {
+ otg->gadget_ops->connect_control(otg->gadget, false);
+ otg_start_gadget(otg, 0);
+ }
+ fsm->protocol = PROTO_UNDEF;
+}
+
+/**
+ * usb_otg_sync_inputs() - Sync OTG inputs with the OTG state machine
+ * @otg: usb_otg instance
+ *
+ * Used by the OTG driver to update the inputs to the OTG
+ * state machine.
+ *
+ * Can be called in IRQ context.
+ */
+void usb_otg_sync_inputs(struct usb_otg *otg)
+{
+ /* Don't kick FSM till it has started */
+ if (!otg->fsm.running)
+ return;
+
+ /* Kick FSM */
+ queue_work(otg->wq, &otg->work);
+}
+EXPORT_SYMBOL_GPL(usb_otg_sync_inputs);
+
+/**
+ * usb_otg_register_hcd() - Register the host controller to OTG core
+ * @hcd: host controller
+ * @irqnum: interrupt number
+ * @irqflags: interrupt flags
+ * @ops: HCD ops to interface with the HCD
+ *
+ * This is used by the USB Host stack to register the host controller
+ * to the OTG core. Host controller must not be started by the
+ * caller as it is left up to the OTG state machine to do so.
+ * hcd->otg_dev must contain the related otg controller device.
+ *
+ * Return: 0 on success, error value otherwise.
+ */
+int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
+ unsigned long irqflags, struct otg_hcd_ops *ops)
+{
+ struct usb_otg *otg;
+ struct device *hcd_dev = hcd->self.controller;
+ struct device *otg_dev = hcd->otg_dev;
+
+ if (!otg_dev)
+ return -EINVAL;
+
+ /* we're otg but otg controller might not yet be registered */
+ mutex_lock(&otg_list_mutex);
+ otg = usb_otg_get_data(otg_dev);
+ mutex_unlock(&otg_list_mutex);
+ if (!otg) {
+ dev_dbg(hcd_dev,
+ "otg: controller not yet registered. deferring.\n");
+ return -EPROBE_DEFER;
+ }
+
+ /* HCD will be started by OTG fsm when needed */
+ mutex_lock(&otg->fsm.lock);
+ if (otg->primary_hcd.hcd) {
+ /* probably a shared HCD ? */
+ if (usb_otg_hcd_is_primary_hcd(hcd)) {
+ dev_err(otg_dev, "otg: primary host already registered\n");
+ goto err;
+ }
+
+ if (hcd->shared_hcd == otg->primary_hcd.hcd) {
+ if (otg->shared_hcd.hcd) {
+ dev_err(otg_dev, "otg: shared host already registered\n");
+ goto err;
+ }
+
+ otg->shared_hcd.hcd = hcd;
+ otg->shared_hcd.irqnum = irqnum;
+ otg->shared_hcd.irqflags = irqflags;
+ otg->shared_hcd.ops = ops;
+ dev_info(otg_dev, "otg: shared host %s registered\n",
+ dev_name(hcd->self.controller));
+ } else {
+ dev_err(otg_dev, "otg: invalid shared host %s\n",
+ dev_name(hcd->self.controller));
+ goto err;
+ }
+ } else {
+ if (!usb_otg_hcd_is_primary_hcd(hcd)) {
+ dev_err(otg_dev, "otg: primary host must be registered first\n");
+ goto err;
+ }
+
+ otg->primary_hcd.hcd = hcd;
+ otg->primary_hcd.irqnum = irqnum;
+ otg->primary_hcd.irqflags = irqflags;
+ otg->primary_hcd.ops = ops;
+ otg->hcd_ops = ops;
+ dev_info(otg_dev, "otg: primary host %s registered\n",
+ dev_name(hcd->self.controller));
+ }
+
+ /*
+ * we're ready only if we have shared HCD
+ * or we don't need shared HCD.
+ */
+ if (otg->shared_hcd.hcd || !otg->primary_hcd.hcd->shared_hcd) {
+ otg->host = hcd_to_bus(hcd);
+ /* FIXME: set bus->otg_port if this is true OTG port with HNP */
+
+ /* start FSM */
+ usb_otg_start_fsm(otg);
+ } else {
+ dev_dbg(otg_dev, "otg: can't start till shared host registers\n");
+ }
+
+ mutex_unlock(&otg->fsm.lock);
+
+ return 0;
+
+err:
+ mutex_unlock(&otg->fsm.lock);
+ return -EINVAL;
+}
+EXPORT_SYMBOL_GPL(usb_otg_register_hcd);
+
+/**
+ * usb_otg_unregister_hcd() - Unregister the host controller from OTG core
+ * @hcd: host controller device
+ *
+ * This is used by the USB Host stack to unregister the host controller
+ * from the OTG core. Ensures that host controller is not running
+ * on successful return.
+ *
+ * Returns: 0 on success, error value otherwise.
+ */
+int usb_otg_unregister_hcd(struct usb_hcd *hcd)
+{
+ struct usb_otg *otg;
+ struct device *hcd_dev = hcd_to_bus(hcd)->controller;
+ struct device *otg_dev = hcd->otg_dev;
+
+ if (!otg_dev)
+ return -EINVAL; /* we're definitely not OTG */
+
+ mutex_lock(&otg_list_mutex);
+ otg = usb_otg_get_data(otg_dev);
+ mutex_unlock(&otg_list_mutex);
+ if (!otg) {
+ dev_err(hcd_dev, "otg: host %s wasn't registered with otg\n",
+ dev_name(hcd_dev));
+ return -EINVAL;
+ }
+
+ mutex_lock(&otg->fsm.lock);
+ if (hcd == otg->primary_hcd.hcd) {
+ otg->primary_hcd.hcd = NULL;
+ dev_info(otg_dev, "otg: primary host %s unregistered\n",
+ dev_name(hcd_dev));
+ } else if (hcd == otg->shared_hcd.hcd) {
+ otg->shared_hcd.hcd = NULL;
+ dev_info(otg_dev, "otg: shared host %s unregistered\n",
+ dev_name(hcd_dev));
+ } else {
+ mutex_unlock(&otg->fsm.lock);
+ dev_err(otg_dev, "otg: host %s wasn't registered with otg\n",
+ dev_name(hcd_dev));
+ return -EINVAL;
+ }
+
+ /* stop FSM & Host */
+ usb_otg_stop_fsm(otg);
+ otg->host = NULL;
+
+ mutex_unlock(&otg->fsm.lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_otg_unregister_hcd);
+
+/**
+ * usb_otg_register_gadget() - Register the gadget controller to OTG core
+ * @gadget: gadget controller instance
+ * @ops: gadget interface ops
+ *
+ * This is used by the USB gadget stack to register the gadget controller
+ * to the OTG core. Gadget controller must not be started by the
+ * caller as it is left up to the OTG state machine to do so.
+ *
+ * Returns: 0 on success, error value otherwise.
+ */
+int usb_otg_register_gadget(struct usb_gadget *gadget,
+ struct otg_gadget_ops *ops)
+{
+ struct usb_otg *otg;
+ struct device *gadget_dev = &gadget->dev;
+ struct device *otg_dev = gadget->otg_dev;
+
+ if (!otg_dev)
+ return -EINVAL; /* we're definitely not OTG */
+
+ /* we're otg but otg controller might not yet be registered */
+ mutex_lock(&otg_list_mutex);
+ otg = usb_otg_get_data(otg_dev);
+ mutex_unlock(&otg_list_mutex);
+ if (!otg) {
+ dev_dbg(gadget_dev,
+ "otg: controller not yet registered, deferring.\n");
+ return -EPROBE_DEFER;
+ }
+
+ mutex_lock(&otg->fsm.lock);
+ if (otg->gadget) {
+ dev_err(otg_dev, "otg: gadget already registered with otg\n");
+ mutex_unlock(&otg->fsm.lock);
+ return -EINVAL;
+ }
+
+ otg->gadget = gadget;
+ otg->gadget_ops = ops;
+ dev_info(otg_dev, "otg: gadget %s registered\n",
+ dev_name(&gadget->dev));
+
+ /* FSM will be started in usb_otg_gadget_ready() */
+ mutex_unlock(&otg->fsm.lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_otg_register_gadget);
+
+/**
+ * usb_otg_unregister_gadget() - Unregister the gadget controller from OTG core
+ * @gadget: gadget controller
+ *
+ * This is used by the USB gadget stack to unregister the gadget controller
+ * from the OTG core. Ensures that gadget controller is not running
+ * on successful return.
+ *
+ * Returns: 0 on success, error value otherwise.
+ */
+int usb_otg_unregister_gadget(struct usb_gadget *gadget)
+{
+ struct usb_otg *otg;
+ struct device *gadget_dev = &gadget->dev;
+ struct device *otg_dev = gadget->otg_dev;
+
+ if (!otg_dev)
+ return -EINVAL;
+
+ mutex_lock(&otg_list_mutex);
+ otg = usb_otg_get_data(otg_dev);
+ mutex_unlock(&otg_list_mutex);
+ if (!otg) {
+ dev_err(gadget_dev,
+ "otg: gadget %s wasn't registered with otg\n",
+ dev_name(&gadget->dev));
+ return -EINVAL;
+ }
+
+ mutex_lock(&otg->fsm.lock);
+ if (otg->gadget != gadget) {
+ mutex_unlock(&otg->fsm.lock);
+ dev_err(otg_dev, "otg: gadget %s wasn't registered with otg\n",
+ dev_name(&gadget->dev));
+ return -EINVAL;
+ }
+
+ /* FSM must be stopped in usb_otg_gadget_ready() */
+ if (otg->gadget_ready) {
+ dev_err(otg_dev,
+ "otg: gadget %s unregistered before being unready, forcing stop\n",
+ dev_name(&gadget->dev));
+ usb_otg_stop_fsm(otg);
+ }
+
+ otg->gadget = NULL;
+ mutex_unlock(&otg->fsm.lock);
+
+ dev_info(otg_dev, "otg: gadget %s unregistered\n",
+ dev_name(&gadget->dev));
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_otg_unregister_gadget);
+
+/**
+ * usb_otg_gadget_ready() - Notify gadget function driver ready status
+ * @gadget: gadget controller
+ * @ready: 0: function driver ready, 1: function driver not ready
+ *
+ * Notify the OTG core about status of the gadget function driver.
+ * As OTG core is responsible to start/stop the gadget controller, it
+ * must be aware when the gadget function driver is available or not.
+ * This function is used by the Gadget core to inform the OTG core
+ * about the gadget function driver readyness.
+ *
+ * Return: 0 on sucess, error value otherwise.
+ */
+int usb_otg_gadget_ready(struct usb_gadget *gadget, bool ready)
+{
+ struct usb_otg *otg;
+ struct device *gadget_dev = &gadget->dev;
+ struct device *otg_dev = gadget->otg_dev;
+
+ if (!otg_dev)
+ return -EINVAL;
+
+ mutex_lock(&otg_list_mutex);
+ otg = usb_otg_get_data(otg_dev);
+ mutex_unlock(&otg_list_mutex);
+ if (!otg) {
+ dev_err(gadget_dev,
+ "otg: gadget %s wasn't registered with otg\n",
+ dev_name(&gadget->dev));
+ return -EINVAL;
+ }
+
+ mutex_lock(&otg->fsm.lock);
+ if (otg->gadget != gadget) {
+ mutex_unlock(&otg->fsm.lock);
+ dev_err(otg_dev, "otg: gadget %s wasn't registered with otg\n",
+ dev_name(&gadget->dev));
+ return -EINVAL;
+ }
+
+ /* Start/stop FSM & gadget */
+ otg->gadget_ready = ready;
+ if (ready)
+ usb_otg_start_fsm(otg);
+ else
+ usb_otg_stop_fsm(otg);
+
+ dev_dbg(otg_dev, "otg: gadget %s %sready\n", dev_name(&gadget->dev),
+ ready ? "" : "not ");
+
+ mutex_unlock(&otg->fsm.lock);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(usb_otg_gadget_ready);
+
+MODULE_LICENSE("GPL");
diff --git a/drivers/usb/core/Kconfig b/drivers/usb/core/Kconfig
index ae228d0..37f8c54 100644
--- a/drivers/usb/core/Kconfig
+++ b/drivers/usb/core/Kconfig
@@ -41,20 +41,6 @@ config USB_DYNAMIC_MINORS

If you are unsure about this, say N here.

-config USB_OTG
- bool "OTG support"
- depends on PM
- default n
- help
- The most notable feature of USB OTG is support for a
- "Dual-Role" device, which can act as either a device
- or a host. The initial role is decided by the type of
- plug inserted and can be changed later when two dual
- role devices talk to each other.
-
- Select this only if your board has Mini-AB/Micro-AB
- connector.
-
config USB_OTG_WHITELIST
bool "Rely on OTG and EH Targeted Peripherals List"
depends on USB
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 3c3f31c..5fc9095 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -16,6 +16,7 @@
menuconfig USB_GADGET
tristate "USB Gadget Support"
select USB_COMMON
+ select USB_OTG_CORE
select NLS
help
USB is a master/slave protocol, organized with one master
diff --git a/include/linux/usb/gadget.h b/include/linux/usb/gadget.h
index f4fc0aa..1d74fb8 100644
--- a/include/linux/usb/gadget.h
+++ b/include/linux/usb/gadget.h
@@ -328,6 +328,7 @@ struct usb_gadget_ops {
* @in_epnum: last used in ep number
* @mA: last set mA value
* @otg_caps: OTG capabilities of this gadget.
+ * @otg_dev: OTG controller device, if needs to be used with OTG core.
* @sg_supported: true if we can handle scatter-gather
* @is_otg: True if the USB device port uses a Mini-AB jack, so that the
* gadget driver must provide a USB OTG descriptor.
@@ -385,6 +386,7 @@ struct usb_gadget {
unsigned in_epnum;
unsigned mA;
struct usb_otg_caps *otg_caps;
+ struct device *otg_dev;

unsigned sg_supported:1;
unsigned is_otg:1;
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 7729c1f..36bd54f 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -185,6 +185,7 @@ struct usb_hcd {
struct mutex *bandwidth_mutex;
struct usb_hcd *shared_hcd;
struct usb_hcd *primary_hcd;
+ struct device *otg_dev; /* OTG controller device */


#define HCD_BUFFER_POOLS 4
diff --git a/include/linux/usb/otg-fsm.h b/include/linux/usb/otg-fsm.h
index 26e6531..943714a 100644
--- a/include/linux/usb/otg-fsm.h
+++ b/include/linux/usb/otg-fsm.h
@@ -60,6 +60,11 @@ enum otg_fsm_timer {
/**
* struct otg_fsm - OTG state machine according to the OTG spec
*
+ * DRD mode hardware Inputs
+ *
+ * @id: TRUE for B-device, FALSE for A-device.
+ * @b_sess_vld: VBUS voltage in regulation.
+ *
* OTG hardware Inputs
*
* Common inputs for A and B device
@@ -132,6 +137,7 @@ enum otg_fsm_timer {
* a_clr_err: Asserted (by application ?) to clear a_vbus_err due to an
* overcurrent condition and causes the A-device to transition
* to a_wait_vfall
+ * running: state machine running/stopped indicator
*/
struct otg_fsm {
/* Input */
@@ -187,6 +193,7 @@ struct otg_fsm {
int b_ase0_brst_tmout;
int a_bidl_adis_tmout;

+ bool running;
struct otg_fsm_ops *ops;

/* Current usb protocol used: 0:undefine; 1:host; 2:client */
diff --git a/include/linux/usb/otg.h b/include/linux/usb/otg.h
index 85b8fb5..9d72951 100644
--- a/include/linux/usb/otg.h
+++ b/include/linux/usb/otg.h
@@ -10,10 +10,67 @@
#define __LINUX_USB_OTG_H

#include <linux/phy/phy.h>
-#include <linux/usb/phy.h>
-#include <linux/usb/otg-fsm.h>
+#include <linux/device.h>
+#include <linux/usb.h>
#include <linux/usb/hcd.h>
+#include <linux/usb/gadget.h>
+#include <linux/usb/otg-fsm.h>
+#include <linux/usb/phy.h>
+
+/**
+ * struct otg_hcd - host controller state and interface
+ *
+ * @hcd: host controller
+ * @irqnum: IRQ number
+ * @irqflags: IRQ flags
+ * @ops: OTG to host controller interface
+ * @otg_dev: OTG controller device
+ */
+struct otg_hcd {
+ struct usb_hcd *hcd;
+ unsigned int irqnum;
+ unsigned long irqflags;
+ struct otg_hcd_ops *ops;
+ struct device *otg_dev;
+};
+
+/**
+ * struct usb_otg_caps - describes the otg capabilities of the device
+ * @otg_rev: The OTG revision number the device is compliant with, it's
+ * in binary-coded decimal (i.e. 2.0 is 0200H).
+ * @hnp_support: Indicates if the device supports HNP.
+ * @srp_support: Indicates if the device supports SRP.
+ * @adp_support: Indicates if the device supports ADP.
+ */
+struct usb_otg_caps {
+ u16 otg_rev;
+ bool hnp_support;
+ bool srp_support;
+ bool adp_support;
+};

+/**
+ * struct usb_otg - usb otg controller state
+ *
+ * @default_a: Indicates we are an A device. i.e. Host.
+ * @phy: USB PHY interface
+ * @usb_phy: old usb_phy interface
+ * @host: host controller bus
+ * @gadget: gadget device
+ * @state: current OTG state
+ * @dev: OTG controller device
+ * @caps: OTG capabilities revision, hnp, srp, etc
+ * @fsm: OTG finite state machine
+ * @hcd_ops: host controller interface
+ * ------- internal use only -------
+ * @primary_hcd: primary host state and interface
+ * @shared_hcd: shared host state and interface
+ * @gadget_ops: gadget controller interface
+ * @list: list of OTG controllers
+ * @work: OTG state machine work
+ * @wq: OTG state machine work queue
+ * @flags: to track if host/gadget is running
+ */
struct usb_otg {
u8 default_a;

@@ -24,9 +81,25 @@ struct usb_otg {
struct usb_gadget *gadget;

enum usb_otg_state state;
+ struct device *dev;
+ struct usb_otg_caps caps;
struct otg_fsm fsm;
struct otg_hcd_ops *hcd_ops;

+ /* internal use only */
+ struct otg_hcd primary_hcd;
+ struct otg_hcd shared_hcd;
+ struct otg_gadget_ops *gadget_ops;
+ bool gadget_ready;
+ struct list_head list;
+ struct work_struct work;
+ struct workqueue_struct *wq;
+ u32 flags;
+#define OTG_FLAG_GADGET_RUNNING (1 << 0)
+#define OTG_FLAG_HOST_RUNNING (1 << 1)
+ /* use otg->fsm.lock for serializing access */
+
+/*------------- deprecated interface -----------------------------*/
/* bind/unbind the host controller */
int (*set_host)(struct usb_otg *otg, struct usb_bus *host);

@@ -42,26 +115,95 @@ struct usb_otg {

/* start or continue HNP role switch */
int (*start_hnp)(struct usb_otg *otg);
-
+/*---------------------------------------------------------------*/
};

/**
- * struct usb_otg_caps - describes the otg capabilities of the device
- * @otg_rev: The OTG revision number the device is compliant with, it's
- * in binary-coded decimal (i.e. 2.0 is 0200H).
- * @hnp_support: Indicates if the device supports HNP.
- * @srp_support: Indicates if the device supports SRP.
- * @adp_support: Indicates if the device supports ADP.
+ * struct usb_otg_config - OTG controller configuration
+ * @caps: OTG capabilities of the controller
+ * @ops: OTG FSM operations
+ * @otg_work: optional custom OTG state machine work function
*/
-struct usb_otg_caps {
- u16 otg_rev;
- bool hnp_support;
- bool srp_support;
- bool adp_support;
+struct usb_otg_config {
+ struct usb_otg_caps *otg_caps;
+ struct otg_fsm_ops *fsm_ops;
+ void (*otg_work)(struct work_struct *work);
};

extern const char *usb_otg_state_string(enum usb_otg_state state);

+#if IS_ENABLED(CONFIG_USB_OTG)
+struct usb_otg *usb_otg_register(struct device *dev,
+ struct usb_otg_config *config);
+int usb_otg_unregister(struct device *dev);
+int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
+ unsigned long irqflags, struct otg_hcd_ops *ops);
+int usb_otg_unregister_hcd(struct usb_hcd *hcd);
+int usb_otg_register_gadget(struct usb_gadget *gadget,
+ struct otg_gadget_ops *ops);
+int usb_otg_unregister_gadget(struct usb_gadget *gadget);
+void usb_otg_sync_inputs(struct usb_otg *otg);
+int usb_otg_start_host(struct usb_otg *otg, int on);
+int usb_otg_start_gadget(struct usb_otg *otg, int on);
+int usb_otg_gadget_ready(struct usb_gadget *gadget, bool ready);
+
+#else /* CONFIG_USB_OTG */
+
+static inline struct usb_otg *usb_otg_register(struct device *dev,
+ struct usb_otg_config *config)
+{
+ return ERR_PTR(-ENOTSUPP);
+}
+
+static inline int usb_otg_unregister(struct device *dev)
+{
+ return -ENOTSUPP;
+}
+
+static inline int usb_otg_register_hcd(struct usb_hcd *hcd, unsigned int irqnum,
+ unsigned long irqflags,
+ struct otg_hcd_ops *ops)
+{
+ return -ENOTSUPP;
+}
+
+static inline int usb_otg_unregister_hcd(struct usb_hcd *hcd)
+{
+ return -ENOTSUPP;
+}
+
+static inline int usb_otg_register_gadget(struct usb_gadget *gadget,
+ struct otg_gadget_ops *ops)
+{
+ return -ENOTSUPP;
+}
+
+static inline int usb_otg_unregister_gadget(struct usb_gadget *gadget)
+{
+ return -ENOTSUPP;
+}
+
+static inline void usb_otg_sync_inputs(struct usb_otg *otg)
+{
+}
+
+static inline int usb_otg_start_host(struct usb_otg *otg, int on)
+{
+ return -ENOTSUPP;
+}
+
+static inline int usb_otg_start_gadget(struct usb_otg *otg, int on)
+{
+ return -ENOTSUPP;
+}
+
+static inline int usb_otg_gadget_ready(struct usb_gadget *gadget, bool ready)
+{
+ return -ENOTSUPP;
+}
+#endif /* CONFIG_USB_OTG */
+
+/*------------- deprecated interface -----------------------------*/
/* Context: can sleep */
static inline int
otg_start_hnp(struct usb_otg *otg)
@@ -113,6 +255,8 @@ otg_start_srp(struct usb_otg *otg)
return -ENOTSUPP;
}

+/*---------------------------------------------------------------*/
+
/* for OTG controller drivers (and maybe other stuff) */
extern int usb_bus_start_enum(struct usb_bus *bus, unsigned port_num);

@@ -237,4 +381,6 @@ static inline int otg_start_gadget(struct usb_otg *otg, int on)
return otg->fsm.ops->start_gadget(otg, on);
}

+int drd_statemachine(struct usb_otg *otg);
+
#endif /* __LINUX_USB_OTG_H */
--
2.7.4