usb: dwc3: Introduce OTG driver for dwc3
This is first release of otg driver for the dwc3 Synopsys USB3 core.
The otg driver implements the otg final state machine and control the
activation of the device controller or host controller.
In this first implementation, only simple DRD mode is implemented,
determine if A or B device according to the ID pin as reflected in the
OSTS.ConIDSts field.
Change-Id: I6533490aa2adfe3641ffa926666867c19a979217
Signed-off-by: Ido Shayevitz <idos@codeaurora.org>
diff --git a/drivers/usb/dwc3/dwc3_otg.c b/drivers/usb/dwc3/dwc3_otg.c
new file mode 100644
index 0000000..4449187
--- /dev/null
+++ b/drivers/usb/dwc3/dwc3_otg.c
@@ -0,0 +1,512 @@
+/**
+ * dwc3_otg.c - DesignWare USB3 DRD Controller OTG
+ *
+ * Copyright (c) 2012, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only 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/usb.h>
+#include <linux/usb/hcd.h>
+#include <linux/platform_device.h>
+
+#include "core.h"
+#include "dwc3_otg.h"
+#include "io.h"
+#include "xhci.h"
+
+
+/**
+ * dwc3_otg_set_host_regs - reset dwc3 otg registers to host operation.
+ *
+ * This function sets the OTG registers to work in A-Device host mode.
+ * This function should be called just before entering to A-Device mode.
+ *
+ * @w: Pointer to the dwc3 otg workqueue.
+ */
+static void dwc3_otg_set_host_regs(struct dwc3_otg *dotg)
+{
+ u32 octl;
+
+ /* Set OCTL[6](PeriMode) to 0 (host) */
+ octl = dwc3_readl(dotg->regs, DWC3_OCTL);
+ octl &= ~DWC3_OTG_OCTL_PERIMODE;
+ dwc3_writel(dotg->regs, DWC3_OCTL, octl);
+
+ /*
+ * TODO: add more OTG registers writes for HOST mode here,
+ * see figure 12-10 A-device flow in dwc3 Synopsis spec
+ */
+}
+
+/**
+ * dwc3_otg_set_peripheral_regs - reset dwc3 otg registers to peripheral operation.
+ *
+ * This function sets the OTG registers to work in B-Device peripheral mode.
+ * This function should be called just before entering to B-Device mode.
+ *
+ * @w: Pointer to the dwc3 otg workqueue.
+ */
+static void dwc3_otg_set_peripheral_regs(struct dwc3_otg *dotg)
+{
+ u32 octl;
+
+ /* Set OCTL[6](PeriMode) to 1 (peripheral) */
+ octl = dwc3_readl(dotg->regs, DWC3_OCTL);
+ octl |= DWC3_OTG_OCTL_PERIMODE;
+ dwc3_writel(dotg->regs, DWC3_OCTL, octl);
+
+ /*
+ * TODO: add more OTG registers writes for PERIPHERAL mode here,
+ * see figure 12-19 B-device flow in dwc3 Synopsis spec
+ */
+}
+
+/**
+ * dwc3_otg_start_host - helper function for starting/stoping the host controller driver.
+ *
+ * @otg: Pointer to the otg_transceiver structure.
+ * @on: start / stop the host controller driver.
+ *
+ * Returns 0 on success otherwise negative errno.
+ */
+static int dwc3_otg_start_host(struct usb_otg *otg, int on)
+{
+ struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);
+ struct usb_hcd *hcd;
+ struct xhci_hcd *xhci;
+ int ret = 0;
+
+ if (!otg->host)
+ return -EINVAL;
+
+ hcd = bus_to_hcd(otg->host);
+ xhci = hcd_to_xhci(hcd);
+ if (on) {
+ dev_dbg(otg->phy->dev, "%s: turn on host %s\n",
+ __func__, otg->host->bus_name);
+ dwc3_otg_set_host_regs(dotg);
+
+ /*
+ * This should be revisited for more testing post-silicon.
+ * In worst case we may need to disconnect the root hub
+ * before stopping the controller so that it does not
+ * interfere with runtime pm/system pm.
+ * We can also consider registering and unregistering xhci
+ * platform device. It is almost similar to add_hcd and
+ * remove_hcd, But we may not use standard set_host method
+ * anymore.
+ */
+ ret = hcd->driver->start(hcd);
+ if (ret) {
+ dev_err(otg->phy->dev,
+ "%s: failed to start primary hcd, ret=%d\n",
+ __func__, ret);
+ return ret;
+ }
+
+ ret = xhci->shared_hcd->driver->start(xhci->shared_hcd);
+ if (ret) {
+ dev_err(otg->phy->dev,
+ "%s: failed to start secondary hcd, ret=%d\n",
+ __func__, ret);
+ return ret;
+ }
+ } else {
+ dev_dbg(otg->phy->dev, "%s: turn off host %s\n",
+ __func__, otg->host->bus_name);
+ hcd->driver->stop(hcd);
+ }
+
+ return 0;
+}
+
+/**
+ * dwc3_otg_set_host - bind/unbind the host controller driver.
+ *
+ * @otg: Pointer to the otg_transceiver structure.
+ * @host: Pointer to the usb_bus structure.
+ *
+ * Returns 0 on success otherwise negative errno.
+ */
+static int dwc3_otg_set_host(struct usb_otg *otg, struct usb_bus *host)
+{
+ struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);
+
+ if (host) {
+ dev_dbg(otg->phy->dev, "%s: set host %s\n",
+ __func__, host->bus_name);
+ otg->host = host;
+
+ /*
+ * Only after both peripheral and host are set then check
+ * OTG sm. This prevents unnecessary activation of the sm
+ * in case the ID is high.
+ */
+ if (otg->gadget)
+ schedule_work(&dotg->sm_work);
+ } else {
+ if (otg->phy->state == OTG_STATE_A_HOST) {
+ dwc3_otg_start_host(otg, 0);
+ otg->host = NULL;
+ otg->phy->state = OTG_STATE_UNDEFINED;
+ schedule_work(&dotg->sm_work);
+ } else {
+ otg->host = NULL;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * dwc3_otg_start_peripheral - bind/unbind the peripheral controller.
+ *
+ * @otg: Pointer to the otg_transceiver structure.
+ * @gadget: pointer to the usb_gadget structure.
+ *
+ * Returns 0 on success otherwise negative errno.
+ */
+static int dwc3_otg_start_peripheral(struct usb_otg *otg, int on)
+{
+ struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);
+
+ if (!otg->gadget)
+ return -EINVAL;
+
+ if (on) {
+ dev_dbg(otg->phy->dev, "%s: turn on gadget %s\n",
+ __func__, otg->gadget->name);
+ dwc3_otg_set_peripheral_regs(dotg);
+ usb_gadget_vbus_connect(otg->gadget);
+ } else {
+ dev_dbg(otg->phy->dev, "%s: turn off gadget %s\n",
+ __func__, otg->gadget->name);
+ usb_gadget_vbus_disconnect(otg->gadget);
+ }
+
+ return 0;
+}
+
+/**
+ * dwc3_otg_set_peripheral - bind/unbind the peripheral controller driver.
+ *
+ * @otg: Pointer to the otg_transceiver structure.
+ * @gadget: pointer to the usb_gadget structure.
+ *
+ * Returns 0 on success otherwise negative errno.
+ */
+static int dwc3_otg_set_peripheral(struct usb_otg *otg,
+ struct usb_gadget *gadget)
+{
+ struct dwc3_otg *dotg = container_of(otg, struct dwc3_otg, otg);
+
+ if (gadget) {
+ dev_dbg(otg->phy->dev, "%s: set gadget %s\n",
+ __func__, gadget->name);
+ otg->gadget = gadget;
+
+ /*
+ * Only after both peripheral and host are set then check
+ * OTG sm. This prevents unnecessary activation of the sm
+ * in case the ID is grounded.
+ */
+ if (otg->host)
+ schedule_work(&dotg->sm_work);
+ } else {
+ if (otg->phy->state == OTG_STATE_B_PERIPHERAL) {
+ dwc3_otg_start_peripheral(otg, 0);
+ otg->gadget = NULL;
+ otg->phy->state = OTG_STATE_UNDEFINED;
+ schedule_work(&dotg->sm_work);
+ } else {
+ otg->gadget = NULL;
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * dwc3_otg_interrupt - interrupt handler for dwc3 otg events.
+ * @_dotg: Pointer to out controller context structure
+ *
+ * Returns IRQ_HANDLED on success otherwise IRQ_NONE.
+ */
+static irqreturn_t dwc3_otg_interrupt(int irq, void *_dotg)
+{
+ struct dwc3_otg *dotg = (struct dwc3_otg *)_dotg;
+ u32 oevt_reg;
+ int ret = IRQ_NONE;
+ int handled_irqs = 0;
+
+ oevt_reg = dwc3_readl(dotg->regs, DWC3_OEVT);
+
+ if (oevt_reg & DWC3_OEVTEN_OTGCONIDSTSCHNGEVNT) {
+ /*
+ * ID sts has changed, read it and later, in the workqueue
+ * function, switch from A to B or from B to A.
+ */
+ dotg->osts = dwc3_readl(dotg->regs, DWC3_OSTS);
+ if ((dotg->otg.phy->state == OTG_STATE_B_IDLE) ||
+ (dotg->otg.phy->state == OTG_STATE_A_IDLE)) {
+
+ /*
+ * OTG state is ABOUT to change to A or B device, but
+ * since ID sts was chnaged, then we return the state
+ * machine to the start point.
+ */
+ dotg->otg.phy->state = OTG_STATE_UNDEFINED;
+ }
+ schedule_work(&dotg->sm_work);
+
+ handled_irqs |= DWC3_OEVTEN_OTGCONIDSTSCHNGEVNT;
+ ret = IRQ_HANDLED;
+ }
+
+ /*
+ * Clear the interrupts we handled.
+ */
+ if (ret == IRQ_HANDLED)
+ dwc3_writel(dotg->regs, DWC3_OEVT, handled_irqs);
+
+ return ret;
+}
+
+/**
+ * dwc3_otg_sm_work - workqueue function.
+ *
+ * @w: Pointer to the dwc3 otg workqueue
+ *
+ * NOTE: After any change in phy->state,
+ * we must reschdule the state machine.
+ */
+static void dwc3_otg_sm_work(struct work_struct *w)
+{
+ struct dwc3_otg *dotg = container_of(w, struct dwc3_otg, sm_work);
+ struct usb_phy *phy = dotg->otg.phy;
+
+ dev_dbg(phy->dev, "%s state\n", otg_state_string(phy->state));
+
+ /* Check OTG state */
+ switch (phy->state) {
+ case OTG_STATE_UNDEFINED:
+ /* Switch to A or B-Device according to IDSTS */
+ if (dotg->osts & DWC3_OTG_OSTS_CONIDSTS)
+ phy->state = OTG_STATE_B_IDLE;
+ else
+ phy->state = OTG_STATE_A_IDLE;
+
+ schedule_work(&dotg->sm_work);
+ break;
+ case OTG_STATE_B_IDLE:
+ if (dwc3_otg_start_peripheral(&dotg->otg, 1)) {
+ /*
+ * Probably set_peripheral was not called yet.
+ * We will re-try as soon as it will be called
+ */
+ dev_err(phy->dev,
+ "unable to start B-device\n");
+ phy->state = OTG_STATE_UNDEFINED;
+ } else
+ phy->state = OTG_STATE_B_PERIPHERAL;
+
+ schedule_work(&dotg->sm_work);
+ break;
+ case OTG_STATE_B_PERIPHERAL:
+ if (!(dotg->osts & DWC3_OTG_OSTS_CONIDSTS)) {
+ dwc3_otg_start_peripheral(&dotg->otg, 0);
+ phy->state = OTG_STATE_A_IDLE;
+ schedule_work(&dotg->sm_work);
+ }
+ break;
+ case OTG_STATE_A_IDLE:
+ /* Switch to A-Device*/
+ if (dwc3_otg_start_host(&dotg->otg, 1)) {
+ /*
+ * Probably set_host was not called yet.
+ * We will re-try as soon as it will be called
+ */
+ dev_err(phy->dev,
+ "unable to start A-device\n");
+ phy->state = OTG_STATE_UNDEFINED;
+ } else
+ phy->state = OTG_STATE_A_HOST;
+
+ schedule_work(&dotg->sm_work);
+ break;
+ case OTG_STATE_A_HOST:
+ if (dotg->osts & DWC3_OTG_OSTS_CONIDSTS) {
+ dwc3_otg_start_host(&dotg->otg, 0);
+ phy->state = OTG_STATE_B_IDLE;
+ schedule_work(&dotg->sm_work);
+ }
+ break;
+ default:
+ dev_err(phy->dev, "%s: invalid otg-state\n", __func__);
+
+ }
+}
+
+
+/**
+ * dwc3_otg_reset - reset dwc3 otg registers.
+ *
+ * @w: Pointer to the dwc3 otg workqueue
+ */
+static void dwc3_otg_reset(struct dwc3_otg *dotg)
+{
+ /*
+ * OCFG[2] - OTG-Version = 1
+ * OCFG[1] - HNPCap = 0
+ * OCFG[0] - SRPCap = 0
+ */
+ dwc3_writel(dotg->regs, DWC3_OCFG, 0x4);
+
+ /*
+ * OCTL[6] - PeriMode = 1
+ * OCTL[5] - PrtPwrCtl = 0
+ * OCTL[4] - HNPReq = 0
+ * OCTL[3] - SesReq = 0
+ * OCTL[2] - TermSelDLPulse = 0
+ * OCTL[1] - DevSetHNPEn = 0
+ * OCTL[0] - HstSetHNPEn = 0
+ */
+ dwc3_writel(dotg->regs, DWC3_OCTL, 0x40);
+
+ /* Clear all otg events (interrupts) indications */
+ dwc3_writel(dotg->regs, DWC3_OEVT, 0xFFFF);
+
+ /* Enable only the ConIDStsChngEn event*/
+ dwc3_writel(dotg->regs, DWC3_OEVTEN,
+ DWC3_OEVTEN_OTGCONIDSTSCHNGEVNT);
+
+ /* Read OSTS */
+ dotg->osts = dwc3_readl(dotg->regs, DWC3_OSTS);
+
+}
+
+/**
+ * dwc3_otg_init - Initializes otg related registers
+ * @dwc: Pointer to out controller context structure
+ *
+ * Returns 0 on success otherwise negative errno.
+ */
+int dwc3_otg_init(struct dwc3 *dwc)
+{
+ u32 reg;
+ int ret = 0;
+ struct dwc3_otg *dotg;
+
+ dev_dbg(dwc->dev, "dwc3_otg_init\n");
+
+ /*
+ * GHWPARAMS6[10] bit is SRPSupport.
+ * This bit also reflects DWC_USB3_EN_OTG
+ */
+ reg = dwc3_readl(dwc->regs, DWC3_GHWPARAMS6);
+ if (!(reg & DWC3_GHWPARAMS6_SRP_SUPPORT)) {
+ /*
+ * No OTG support in the HW core.
+ * We return 0 to indicate no error, since this is acceptable
+ * situation, just continue probe the dwc3 driver without otg.
+ */
+ dev_dbg(dwc->dev, "dwc3_otg address space is not supported\n");
+ return 0;
+ }
+
+ /* Allocate and init otg instance */
+ dotg = kzalloc(sizeof(struct dwc3_otg), GFP_KERNEL);
+ if (!dotg) {
+ dev_err(dwc->dev, "unable to allocate dwc3_otg\n");
+ return -ENOMEM;
+ }
+
+ dotg->irq = platform_get_irq(to_platform_device(dwc->dev), 0);
+ if (dotg->irq < 0) {
+ dev_err(dwc->dev, "%s: missing IRQ\n", __func__);
+ ret = -ENODEV;
+ goto err1;
+ }
+
+ dotg->regs = dwc->regs;
+
+ dotg->otg.set_peripheral = dwc3_otg_set_peripheral;
+ dotg->otg.set_host = dwc3_otg_set_host;
+
+ /* This reference is used by dwc3 modules for checking otg existance */
+ dwc->dotg = dotg;
+
+ dotg->otg.phy = kzalloc(sizeof(struct usb_phy), GFP_KERNEL);
+ if (!dotg->otg.phy) {
+ dev_err(dwc->dev, "unable to allocate dwc3_otg.phy\n");
+ ret = -ENOMEM;
+ goto err1;
+ }
+
+ dotg->otg.phy->otg = &dotg->otg;
+ dotg->otg.phy->dev = dwc->dev;
+
+ ret = usb_set_transceiver(dotg->otg.phy);
+ if (ret) {
+ dev_err(dotg->otg.phy->dev,
+ "%s: failed to set transceiver, already exists\n",
+ __func__);
+ goto err2;
+ }
+
+ dwc3_otg_reset(dotg);
+
+ dotg->otg.phy->state = OTG_STATE_UNDEFINED;
+
+ INIT_WORK(&dotg->sm_work, dwc3_otg_sm_work);
+
+ ret = request_irq(dotg->irq, dwc3_otg_interrupt, IRQF_SHARED,
+ "dwc3_otg", dotg);
+ if (ret) {
+ dev_err(dotg->otg.phy->dev, "failed to request irq #%d --> %d\n",
+ dotg->irq, ret);
+ goto err3;
+ }
+
+ return 0;
+
+err3:
+ cancel_work_sync(&dotg->sm_work);
+ usb_set_transceiver(NULL);
+err2:
+ kfree(dotg->otg.phy);
+err1:
+ dwc->dotg = NULL;
+ kfree(dotg);
+
+ return ret;
+}
+
+/**
+ * dwc3_otg_exit
+ * @dwc: Pointer to out controller context structure
+ *
+ * Returns 0 on success otherwise negative errno.
+ */
+void dwc3_otg_exit(struct dwc3 *dwc)
+{
+ struct dwc3_otg *dotg = dwc->dotg;
+
+ /* dotg is null when GHWPARAMS6[10]=SRPSupport=0, see dwc3_otg_init */
+ if (dotg) {
+ cancel_work_sync(&dotg->sm_work);
+ usb_set_transceiver(NULL);
+ free_irq(dotg->irq, dotg);
+ kfree(dotg->otg.phy);
+ kfree(dotg);
+ dwc->dotg = NULL;
+ }
+}