Add qemu 2.4.0
[kvmfornfv.git] / qemu / roms / u-boot / drivers / usb / musb-new / musb_gadget_ep0.c
diff --git a/qemu/roms/u-boot/drivers/usb/musb-new/musb_gadget_ep0.c b/qemu/roms/u-boot/drivers/usb/musb-new/musb_gadget_ep0.c
new file mode 100644 (file)
index 0000000..6599d38
--- /dev/null
@@ -0,0 +1,1089 @@
+/*
+ * MUSB OTG peripheral driver ep0 handling
+ *
+ * Copyright 2005 Mentor Graphics Corporation
+ * Copyright (C) 2005-2006 by Texas Instruments
+ * Copyright (C) 2006-2007 Nokia Corporation
+ * Copyright (C) 2008-2009 MontaVista Software, Inc. <source@mvista.com>
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ *
+ * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+ * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
+ * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+ * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#define __UBOOT__
+#ifndef __UBOOT__
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/timer.h>
+#include <linux/spinlock.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#else
+#include <common.h>
+#include "linux-compat.h"
+#endif
+
+#include "musb_core.h"
+
+/* ep0 is always musb->endpoints[0].ep_in */
+#define        next_ep0_request(musb)  next_in_request(&(musb)->endpoints[0])
+
+/*
+ * locking note:  we use only the controller lock, for simpler correctness.
+ * It's always held with IRQs blocked.
+ *
+ * It protects the ep0 request queue as well as ep0_state, not just the
+ * controller and indexed registers.  And that lock stays held unless it
+ * needs to be dropped to allow reentering this driver ... like upcalls to
+ * the gadget driver, or adjusting endpoint halt status.
+ */
+
+static char *decode_ep0stage(u8 stage)
+{
+       switch (stage) {
+       case MUSB_EP0_STAGE_IDLE:       return "idle";
+       case MUSB_EP0_STAGE_SETUP:      return "setup";
+       case MUSB_EP0_STAGE_TX:         return "in";
+       case MUSB_EP0_STAGE_RX:         return "out";
+       case MUSB_EP0_STAGE_ACKWAIT:    return "wait";
+       case MUSB_EP0_STAGE_STATUSIN:   return "in/status";
+       case MUSB_EP0_STAGE_STATUSOUT:  return "out/status";
+       default:                        return "?";
+       }
+}
+
+/* handle a standard GET_STATUS request
+ * Context:  caller holds controller lock
+ */
+static int service_tx_status_request(
+       struct musb *musb,
+       const struct usb_ctrlrequest *ctrlrequest)
+{
+       void __iomem    *mbase = musb->mregs;
+       int handled = 1;
+       u8 result[2], epnum = 0;
+       const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;
+
+       result[1] = 0;
+
+       switch (recip) {
+       case USB_RECIP_DEVICE:
+               result[0] = musb->is_self_powered << USB_DEVICE_SELF_POWERED;
+               result[0] |= musb->may_wakeup << USB_DEVICE_REMOTE_WAKEUP;
+               if (musb->g.is_otg) {
+                       result[0] |= musb->g.b_hnp_enable
+                               << USB_DEVICE_B_HNP_ENABLE;
+                       result[0] |= musb->g.a_alt_hnp_support
+                               << USB_DEVICE_A_ALT_HNP_SUPPORT;
+                       result[0] |= musb->g.a_hnp_support
+                               << USB_DEVICE_A_HNP_SUPPORT;
+               }
+               break;
+
+       case USB_RECIP_INTERFACE:
+               result[0] = 0;
+               break;
+
+       case USB_RECIP_ENDPOINT: {
+               int             is_in;
+               struct musb_ep  *ep;
+               u16             tmp;
+               void __iomem    *regs;
+
+               epnum = (u8) ctrlrequest->wIndex;
+               if (!epnum) {
+                       result[0] = 0;
+                       break;
+               }
+
+               is_in = epnum & USB_DIR_IN;
+               if (is_in) {
+                       epnum &= 0x0f;
+                       ep = &musb->endpoints[epnum].ep_in;
+               } else {
+                       ep = &musb->endpoints[epnum].ep_out;
+               }
+               regs = musb->endpoints[epnum].regs;
+
+               if (epnum >= MUSB_C_NUM_EPS || !ep->desc) {
+                       handled = -EINVAL;
+                       break;
+               }
+
+               musb_ep_select(mbase, epnum);
+               if (is_in)
+                       tmp = musb_readw(regs, MUSB_TXCSR)
+                                               & MUSB_TXCSR_P_SENDSTALL;
+               else
+                       tmp = musb_readw(regs, MUSB_RXCSR)
+                                               & MUSB_RXCSR_P_SENDSTALL;
+               musb_ep_select(mbase, 0);
+
+               result[0] = tmp ? 1 : 0;
+               } break;
+
+       default:
+               /* class, vendor, etc ... delegate */
+               handled = 0;
+               break;
+       }
+
+       /* fill up the fifo; caller updates csr0 */
+       if (handled > 0) {
+               u16     len = le16_to_cpu(ctrlrequest->wLength);
+
+               if (len > 2)
+                       len = 2;
+               musb_write_fifo(&musb->endpoints[0], len, result);
+       }
+
+       return handled;
+}
+
+/*
+ * handle a control-IN request, the end0 buffer contains the current request
+ * that is supposed to be a standard control request. Assumes the fifo to
+ * be at least 2 bytes long.
+ *
+ * @return 0 if the request was NOT HANDLED,
+ * < 0 when error
+ * > 0 when the request is processed
+ *
+ * Context:  caller holds controller lock
+ */
+static int
+service_in_request(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
+{
+       int handled = 0;        /* not handled */
+
+       if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
+                       == USB_TYPE_STANDARD) {
+               switch (ctrlrequest->bRequest) {
+               case USB_REQ_GET_STATUS:
+                       handled = service_tx_status_request(musb,
+                                       ctrlrequest);
+                       break;
+
+               /* case USB_REQ_SYNC_FRAME: */
+
+               default:
+                       break;
+               }
+       }
+       return handled;
+}
+
+/*
+ * Context:  caller holds controller lock
+ */
+static void musb_g_ep0_giveback(struct musb *musb, struct usb_request *req)
+{
+       musb_g_giveback(&musb->endpoints[0].ep_in, req, 0);
+}
+
+/*
+ * Tries to start B-device HNP negotiation if enabled via sysfs
+ */
+static inline void musb_try_b_hnp_enable(struct musb *musb)
+{
+       void __iomem    *mbase = musb->mregs;
+       u8              devctl;
+
+       dev_dbg(musb->controller, "HNP: Setting HR\n");
+       devctl = musb_readb(mbase, MUSB_DEVCTL);
+       musb_writeb(mbase, MUSB_DEVCTL, devctl | MUSB_DEVCTL_HR);
+}
+
+/*
+ * Handle all control requests with no DATA stage, including standard
+ * requests such as:
+ * USB_REQ_SET_CONFIGURATION, USB_REQ_SET_INTERFACE, unrecognized
+ *     always delegated to the gadget driver
+ * USB_REQ_SET_ADDRESS, USB_REQ_CLEAR_FEATURE, USB_REQ_SET_FEATURE
+ *     always handled here, except for class/vendor/... features
+ *
+ * Context:  caller holds controller lock
+ */
+static int
+service_zero_data_request(struct musb *musb,
+               struct usb_ctrlrequest *ctrlrequest)
+__releases(musb->lock)
+__acquires(musb->lock)
+{
+       int handled = -EINVAL;
+       void __iomem *mbase = musb->mregs;
+       const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;
+
+       /* the gadget driver handles everything except what we MUST handle */
+       if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
+                       == USB_TYPE_STANDARD) {
+               switch (ctrlrequest->bRequest) {
+               case USB_REQ_SET_ADDRESS:
+                       /* change it after the status stage */
+                       musb->set_address = true;
+                       musb->address = (u8) (ctrlrequest->wValue & 0x7f);
+                       handled = 1;
+                       break;
+
+               case USB_REQ_CLEAR_FEATURE:
+                       switch (recip) {
+                       case USB_RECIP_DEVICE:
+                               if (ctrlrequest->wValue
+                                               != USB_DEVICE_REMOTE_WAKEUP)
+                                       break;
+                               musb->may_wakeup = 0;
+                               handled = 1;
+                               break;
+                       case USB_RECIP_INTERFACE:
+                               break;
+                       case USB_RECIP_ENDPOINT:{
+                               const u8                epnum =
+                                       ctrlrequest->wIndex & 0x0f;
+                               struct musb_ep          *musb_ep;
+                               struct musb_hw_ep       *ep;
+                               struct musb_request     *request;
+                               void __iomem            *regs;
+                               int                     is_in;
+                               u16                     csr;
+
+                               if (epnum == 0 || epnum >= MUSB_C_NUM_EPS ||
+                                   ctrlrequest->wValue != USB_ENDPOINT_HALT)
+                                       break;
+
+                               ep = musb->endpoints + epnum;
+                               regs = ep->regs;
+                               is_in = ctrlrequest->wIndex & USB_DIR_IN;
+                               if (is_in)
+                                       musb_ep = &ep->ep_in;
+                               else
+                                       musb_ep = &ep->ep_out;
+                               if (!musb_ep->desc)
+                                       break;
+
+                               handled = 1;
+                               /* Ignore request if endpoint is wedged */
+                               if (musb_ep->wedged)
+                                       break;
+
+                               musb_ep_select(mbase, epnum);
+                               if (is_in) {
+                                       csr  = musb_readw(regs, MUSB_TXCSR);
+                                       csr |= MUSB_TXCSR_CLRDATATOG |
+                                              MUSB_TXCSR_P_WZC_BITS;
+                                       csr &= ~(MUSB_TXCSR_P_SENDSTALL |
+                                                MUSB_TXCSR_P_SENTSTALL |
+                                                MUSB_TXCSR_TXPKTRDY);
+                                       musb_writew(regs, MUSB_TXCSR, csr);
+                               } else {
+                                       csr  = musb_readw(regs, MUSB_RXCSR);
+                                       csr |= MUSB_RXCSR_CLRDATATOG |
+                                              MUSB_RXCSR_P_WZC_BITS;
+                                       csr &= ~(MUSB_RXCSR_P_SENDSTALL |
+                                                MUSB_RXCSR_P_SENTSTALL);
+                                       musb_writew(regs, MUSB_RXCSR, csr);
+                               }
+
+                               /* Maybe start the first request in the queue */
+                               request = next_request(musb_ep);
+                               if (!musb_ep->busy && request) {
+                                       dev_dbg(musb->controller, "restarting the request\n");
+                                       musb_ep_restart(musb, request);
+                               }
+
+                               /* select ep0 again */
+                               musb_ep_select(mbase, 0);
+                               } break;
+                       default:
+                               /* class, vendor, etc ... delegate */
+                               handled = 0;
+                               break;
+                       }
+                       break;
+
+               case USB_REQ_SET_FEATURE:
+                       switch (recip) {
+                       case USB_RECIP_DEVICE:
+                               handled = 1;
+                               switch (ctrlrequest->wValue) {
+                               case USB_DEVICE_REMOTE_WAKEUP:
+                                       musb->may_wakeup = 1;
+                                       break;
+                               case USB_DEVICE_TEST_MODE:
+                                       if (musb->g.speed != USB_SPEED_HIGH)
+                                               goto stall;
+                                       if (ctrlrequest->wIndex & 0xff)
+                                               goto stall;
+
+                                       switch (ctrlrequest->wIndex >> 8) {
+                                       case 1:
+                                               pr_debug("TEST_J\n");
+                                               /* TEST_J */
+                                               musb->test_mode_nr =
+                                                       MUSB_TEST_J;
+                                               break;
+                                       case 2:
+                                               /* TEST_K */
+                                               pr_debug("TEST_K\n");
+                                               musb->test_mode_nr =
+                                                       MUSB_TEST_K;
+                                               break;
+                                       case 3:
+                                               /* TEST_SE0_NAK */
+                                               pr_debug("TEST_SE0_NAK\n");
+                                               musb->test_mode_nr =
+                                                       MUSB_TEST_SE0_NAK;
+                                               break;
+                                       case 4:
+                                               /* TEST_PACKET */
+                                               pr_debug("TEST_PACKET\n");
+                                               musb->test_mode_nr =
+                                                       MUSB_TEST_PACKET;
+                                               break;
+
+                                       case 0xc0:
+                                               /* TEST_FORCE_HS */
+                                               pr_debug("TEST_FORCE_HS\n");
+                                               musb->test_mode_nr =
+                                                       MUSB_TEST_FORCE_HS;
+                                               break;
+                                       case 0xc1:
+                                               /* TEST_FORCE_FS */
+                                               pr_debug("TEST_FORCE_FS\n");
+                                               musb->test_mode_nr =
+                                                       MUSB_TEST_FORCE_FS;
+                                               break;
+                                       case 0xc2:
+                                               /* TEST_FIFO_ACCESS */
+                                               pr_debug("TEST_FIFO_ACCESS\n");
+                                               musb->test_mode_nr =
+                                                       MUSB_TEST_FIFO_ACCESS;
+                                               break;
+                                       case 0xc3:
+                                               /* TEST_FORCE_HOST */
+                                               pr_debug("TEST_FORCE_HOST\n");
+                                               musb->test_mode_nr =
+                                                       MUSB_TEST_FORCE_HOST;
+                                               break;
+                                       default:
+                                               goto stall;
+                                       }
+
+                                       /* enter test mode after irq */
+                                       if (handled > 0)
+                                               musb->test_mode = true;
+                                       break;
+                               case USB_DEVICE_B_HNP_ENABLE:
+                                       if (!musb->g.is_otg)
+                                               goto stall;
+                                       musb->g.b_hnp_enable = 1;
+                                       musb_try_b_hnp_enable(musb);
+                                       break;
+                               case USB_DEVICE_A_HNP_SUPPORT:
+                                       if (!musb->g.is_otg)
+                                               goto stall;
+                                       musb->g.a_hnp_support = 1;
+                                       break;
+                               case USB_DEVICE_A_ALT_HNP_SUPPORT:
+                                       if (!musb->g.is_otg)
+                                               goto stall;
+                                       musb->g.a_alt_hnp_support = 1;
+                                       break;
+                               case USB_DEVICE_DEBUG_MODE:
+                                       handled = 0;
+                                       break;
+stall:
+                               default:
+                                       handled = -EINVAL;
+                                       break;
+                               }
+                               break;
+
+                       case USB_RECIP_INTERFACE:
+                               break;
+
+                       case USB_RECIP_ENDPOINT:{
+                               const u8                epnum =
+                                       ctrlrequest->wIndex & 0x0f;
+                               struct musb_ep          *musb_ep;
+                               struct musb_hw_ep       *ep;
+                               void __iomem            *regs;
+                               int                     is_in;
+                               u16                     csr;
+
+                               if (epnum == 0 || epnum >= MUSB_C_NUM_EPS ||
+                                   ctrlrequest->wValue != USB_ENDPOINT_HALT)
+                                       break;
+
+                               ep = musb->endpoints + epnum;
+                               regs = ep->regs;
+                               is_in = ctrlrequest->wIndex & USB_DIR_IN;
+                               if (is_in)
+                                       musb_ep = &ep->ep_in;
+                               else
+                                       musb_ep = &ep->ep_out;
+                               if (!musb_ep->desc)
+                                       break;
+
+                               musb_ep_select(mbase, epnum);
+                               if (is_in) {
+                                       csr = musb_readw(regs, MUSB_TXCSR);
+                                       if (csr & MUSB_TXCSR_FIFONOTEMPTY)
+                                               csr |= MUSB_TXCSR_FLUSHFIFO;
+                                       csr |= MUSB_TXCSR_P_SENDSTALL
+                                               | MUSB_TXCSR_CLRDATATOG
+                                               | MUSB_TXCSR_P_WZC_BITS;
+                                       musb_writew(regs, MUSB_TXCSR, csr);
+                               } else {
+                                       csr = musb_readw(regs, MUSB_RXCSR);
+                                       csr |= MUSB_RXCSR_P_SENDSTALL
+                                               | MUSB_RXCSR_FLUSHFIFO
+                                               | MUSB_RXCSR_CLRDATATOG
+                                               | MUSB_RXCSR_P_WZC_BITS;
+                                       musb_writew(regs, MUSB_RXCSR, csr);
+                               }
+
+                               /* select ep0 again */
+                               musb_ep_select(mbase, 0);
+                               handled = 1;
+                               } break;
+
+                       default:
+                               /* class, vendor, etc ... delegate */
+                               handled = 0;
+                               break;
+                       }
+                       break;
+               default:
+                       /* delegate SET_CONFIGURATION, etc */
+                       handled = 0;
+               }
+       } else
+               handled = 0;
+       return handled;
+}
+
+/* we have an ep0out data packet
+ * Context:  caller holds controller lock
+ */
+static void ep0_rxstate(struct musb *musb)
+{
+       void __iomem            *regs = musb->control_ep->regs;
+       struct musb_request     *request;
+       struct usb_request      *req;
+       u16                     count, csr;
+
+       request = next_ep0_request(musb);
+       req = &request->request;
+
+       /* read packet and ack; or stall because of gadget driver bug:
+        * should have provided the rx buffer before setup() returned.
+        */
+       if (req) {
+               void            *buf = req->buf + req->actual;
+               unsigned        len = req->length - req->actual;
+
+               /* read the buffer */
+               count = musb_readb(regs, MUSB_COUNT0);
+               if (count > len) {
+                       req->status = -EOVERFLOW;
+                       count = len;
+               }
+               musb_read_fifo(&musb->endpoints[0], count, buf);
+               req->actual += count;
+               csr = MUSB_CSR0_P_SVDRXPKTRDY;
+               if (count < 64 || req->actual == req->length) {
+                       musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
+                       csr |= MUSB_CSR0_P_DATAEND;
+               } else
+                       req = NULL;
+       } else
+               csr = MUSB_CSR0_P_SVDRXPKTRDY | MUSB_CSR0_P_SENDSTALL;
+
+
+       /* Completion handler may choose to stall, e.g. because the
+        * message just received holds invalid data.
+        */
+       if (req) {
+               musb->ackpend = csr;
+               musb_g_ep0_giveback(musb, req);
+               if (!musb->ackpend)
+                       return;
+               musb->ackpend = 0;
+       }
+       musb_ep_select(musb->mregs, 0);
+       musb_writew(regs, MUSB_CSR0, csr);
+}
+
+/*
+ * transmitting to the host (IN), this code might be called from IRQ
+ * and from kernel thread.
+ *
+ * Context:  caller holds controller lock
+ */
+static void ep0_txstate(struct musb *musb)
+{
+       void __iomem            *regs = musb->control_ep->regs;
+       struct musb_request     *req = next_ep0_request(musb);
+       struct usb_request      *request;
+       u16                     csr = MUSB_CSR0_TXPKTRDY;
+       u8                      *fifo_src;
+       u8                      fifo_count;
+
+       if (!req) {
+               /* WARN_ON(1); */
+               dev_dbg(musb->controller, "odd; csr0 %04x\n", musb_readw(regs, MUSB_CSR0));
+               return;
+       }
+
+       request = &req->request;
+
+       /* load the data */
+       fifo_src = (u8 *) request->buf + request->actual;
+       fifo_count = min((unsigned) MUSB_EP0_FIFOSIZE,
+               request->length - request->actual);
+       musb_write_fifo(&musb->endpoints[0], fifo_count, fifo_src);
+       request->actual += fifo_count;
+
+       /* update the flags */
+       if (fifo_count < MUSB_MAX_END0_PACKET
+                       || (request->actual == request->length
+                               && !request->zero)) {
+               musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
+               csr |= MUSB_CSR0_P_DATAEND;
+       } else
+               request = NULL;
+
+       /* report completions as soon as the fifo's loaded; there's no
+        * win in waiting till this last packet gets acked.  (other than
+        * very precise fault reporting, needed by USB TMC; possible with
+        * this hardware, but not usable from portable gadget drivers.)
+        */
+       if (request) {
+               musb->ackpend = csr;
+               musb_g_ep0_giveback(musb, request);
+               if (!musb->ackpend)
+                       return;
+               musb->ackpend = 0;
+       }
+
+       /* send it out, triggering a "txpktrdy cleared" irq */
+       musb_ep_select(musb->mregs, 0);
+       musb_writew(regs, MUSB_CSR0, csr);
+}
+
+/*
+ * Read a SETUP packet (struct usb_ctrlrequest) from the hardware.
+ * Fields are left in USB byte-order.
+ *
+ * Context:  caller holds controller lock.
+ */
+static void
+musb_read_setup(struct musb *musb, struct usb_ctrlrequest *req)
+{
+       struct musb_request     *r;
+       void __iomem            *regs = musb->control_ep->regs;
+
+       musb_read_fifo(&musb->endpoints[0], sizeof *req, (u8 *)req);
+
+       /* NOTE:  earlier 2.6 versions changed setup packets to host
+        * order, but now USB packets always stay in USB byte order.
+        */
+       dev_dbg(musb->controller, "SETUP req%02x.%02x v%04x i%04x l%d\n",
+               req->bRequestType,
+               req->bRequest,
+               le16_to_cpu(req->wValue),
+               le16_to_cpu(req->wIndex),
+               le16_to_cpu(req->wLength));
+
+       /* clean up any leftover transfers */
+       r = next_ep0_request(musb);
+       if (r)
+               musb_g_ep0_giveback(musb, &r->request);
+
+       /* For zero-data requests we want to delay the STATUS stage to
+        * avoid SETUPEND errors.  If we read data (OUT), delay accepting
+        * packets until there's a buffer to store them in.
+        *
+        * If we write data, the controller acts happier if we enable
+        * the TX FIFO right away, and give the controller a moment
+        * to switch modes...
+        */
+       musb->set_address = false;
+       musb->ackpend = MUSB_CSR0_P_SVDRXPKTRDY;
+       if (req->wLength == 0) {
+               if (req->bRequestType & USB_DIR_IN)
+                       musb->ackpend |= MUSB_CSR0_TXPKTRDY;
+               musb->ep0_state = MUSB_EP0_STAGE_ACKWAIT;
+       } else if (req->bRequestType & USB_DIR_IN) {
+               musb->ep0_state = MUSB_EP0_STAGE_TX;
+               musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDRXPKTRDY);
+               while ((musb_readw(regs, MUSB_CSR0)
+                               & MUSB_CSR0_RXPKTRDY) != 0)
+                       cpu_relax();
+               musb->ackpend = 0;
+       } else
+               musb->ep0_state = MUSB_EP0_STAGE_RX;
+}
+
+static int
+forward_to_driver(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
+__releases(musb->lock)
+__acquires(musb->lock)
+{
+       int retval;
+       if (!musb->gadget_driver)
+               return -EOPNOTSUPP;
+       spin_unlock(&musb->lock);
+       retval = musb->gadget_driver->setup(&musb->g, ctrlrequest);
+       spin_lock(&musb->lock);
+       return retval;
+}
+
+/*
+ * Handle peripheral ep0 interrupt
+ *
+ * Context: irq handler; we won't re-enter the driver that way.
+ */
+irqreturn_t musb_g_ep0_irq(struct musb *musb)
+{
+       u16             csr;
+       u16             len;
+       void __iomem    *mbase = musb->mregs;
+       void __iomem    *regs = musb->endpoints[0].regs;
+       irqreturn_t     retval = IRQ_NONE;
+
+       musb_ep_select(mbase, 0);       /* select ep0 */
+       csr = musb_readw(regs, MUSB_CSR0);
+       len = musb_readb(regs, MUSB_COUNT0);
+
+       dev_dbg(musb->controller, "csr %04x, count %d, myaddr %d, ep0stage %s\n",
+                       csr, len,
+                       musb_readb(mbase, MUSB_FADDR),
+                       decode_ep0stage(musb->ep0_state));
+
+       if (csr & MUSB_CSR0_P_DATAEND) {
+               /*
+                * If DATAEND is set we should not call the callback,
+                * hence the status stage is not complete.
+                */
+               return IRQ_HANDLED;
+       }
+
+       /* I sent a stall.. need to acknowledge it now.. */
+       if (csr & MUSB_CSR0_P_SENTSTALL) {
+               musb_writew(regs, MUSB_CSR0,
+                               csr & ~MUSB_CSR0_P_SENTSTALL);
+               retval = IRQ_HANDLED;
+               musb->ep0_state = MUSB_EP0_STAGE_IDLE;
+               csr = musb_readw(regs, MUSB_CSR0);
+       }
+
+       /* request ended "early" */
+       if (csr & MUSB_CSR0_P_SETUPEND) {
+               musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDSETUPEND);
+               retval = IRQ_HANDLED;
+               /* Transition into the early status phase */
+               switch (musb->ep0_state) {
+               case MUSB_EP0_STAGE_TX:
+                       musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
+                       break;
+               case MUSB_EP0_STAGE_RX:
+                       musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
+                       break;
+               default:
+                       ERR("SetupEnd came in a wrong ep0stage %s\n",
+                           decode_ep0stage(musb->ep0_state));
+               }
+               csr = musb_readw(regs, MUSB_CSR0);
+               /* NOTE:  request may need completion */
+       }
+
+       /* docs from Mentor only describe tx, rx, and idle/setup states.
+        * we need to handle nuances around status stages, and also the
+        * case where status and setup stages come back-to-back ...
+        */
+       switch (musb->ep0_state) {
+
+       case MUSB_EP0_STAGE_TX:
+               /* irq on clearing txpktrdy */
+               if ((csr & MUSB_CSR0_TXPKTRDY) == 0) {
+                       ep0_txstate(musb);
+                       retval = IRQ_HANDLED;
+               }
+               break;
+
+       case MUSB_EP0_STAGE_RX:
+               /* irq on set rxpktrdy */
+               if (csr & MUSB_CSR0_RXPKTRDY) {
+                       ep0_rxstate(musb);
+                       retval = IRQ_HANDLED;
+               }
+               break;
+
+       case MUSB_EP0_STAGE_STATUSIN:
+               /* end of sequence #2 (OUT/RX state) or #3 (no data) */
+
+               /* update address (if needed) only @ the end of the
+                * status phase per usb spec, which also guarantees
+                * we get 10 msec to receive this irq... until this
+                * is done we won't see the next packet.
+                */
+               if (musb->set_address) {
+                       musb->set_address = false;
+                       musb_writeb(mbase, MUSB_FADDR, musb->address);
+               }
+
+               /* enter test mode if needed (exit by reset) */
+               else if (musb->test_mode) {
+                       dev_dbg(musb->controller, "entering TESTMODE\n");
+
+                       if (MUSB_TEST_PACKET == musb->test_mode_nr)
+                               musb_load_testpacket(musb);
+
+                       musb_writeb(mbase, MUSB_TESTMODE,
+                                       musb->test_mode_nr);
+               }
+               /* FALLTHROUGH */
+
+       case MUSB_EP0_STAGE_STATUSOUT:
+               /* end of sequence #1: write to host (TX state) */
+               {
+                       struct musb_request     *req;
+
+                       req = next_ep0_request(musb);
+                       if (req)
+                               musb_g_ep0_giveback(musb, &req->request);
+               }
+
+               /*
+                * In case when several interrupts can get coalesced,
+                * check to see if we've already received a SETUP packet...
+                */
+               if (csr & MUSB_CSR0_RXPKTRDY)
+                       goto setup;
+
+               retval = IRQ_HANDLED;
+               musb->ep0_state = MUSB_EP0_STAGE_IDLE;
+               break;
+
+       case MUSB_EP0_STAGE_IDLE:
+               /*
+                * This state is typically (but not always) indiscernible
+                * from the status states since the corresponding interrupts
+                * tend to happen within too little period of time (with only
+                * a zero-length packet in between) and so get coalesced...
+                */
+               retval = IRQ_HANDLED;
+               musb->ep0_state = MUSB_EP0_STAGE_SETUP;
+               /* FALLTHROUGH */
+
+       case MUSB_EP0_STAGE_SETUP:
+setup:
+               if (csr & MUSB_CSR0_RXPKTRDY) {
+                       struct usb_ctrlrequest  setup;
+                       int                     handled = 0;
+
+                       if (len != 8) {
+                               ERR("SETUP packet len %d != 8 ?\n", len);
+                               break;
+                       }
+                       musb_read_setup(musb, &setup);
+                       retval = IRQ_HANDLED;
+
+                       /* sometimes the RESET won't be reported */
+                       if (unlikely(musb->g.speed == USB_SPEED_UNKNOWN)) {
+                               u8      power;
+
+                               printk(KERN_NOTICE "%s: peripheral reset "
+                                               "irq lost!\n",
+                                               musb_driver_name);
+                               power = musb_readb(mbase, MUSB_POWER);
+                               musb->g.speed = (power & MUSB_POWER_HSMODE)
+                                       ? USB_SPEED_HIGH : USB_SPEED_FULL;
+
+                       }
+
+                       switch (musb->ep0_state) {
+
+                       /* sequence #3 (no data stage), includes requests
+                        * we can't forward (notably SET_ADDRESS and the
+                        * device/endpoint feature set/clear operations)
+                        * plus SET_CONFIGURATION and others we must
+                        */
+                       case MUSB_EP0_STAGE_ACKWAIT:
+                               handled = service_zero_data_request(
+                                               musb, &setup);
+
+                               /*
+                                * We're expecting no data in any case, so
+                                * always set the DATAEND bit -- doing this
+                                * here helps avoid SetupEnd interrupt coming
+                                * in the idle stage when we're stalling...
+                                */
+                               musb->ackpend |= MUSB_CSR0_P_DATAEND;
+
+                               /* status stage might be immediate */
+                               if (handled > 0)
+                                       musb->ep0_state =
+                                               MUSB_EP0_STAGE_STATUSIN;
+                               break;
+
+                       /* sequence #1 (IN to host), includes GET_STATUS
+                        * requests that we can't forward, GET_DESCRIPTOR
+                        * and others that we must
+                        */
+                       case MUSB_EP0_STAGE_TX:
+                               handled = service_in_request(musb, &setup);
+                               if (handled > 0) {
+                                       musb->ackpend = MUSB_CSR0_TXPKTRDY
+                                               | MUSB_CSR0_P_DATAEND;
+                                       musb->ep0_state =
+                                               MUSB_EP0_STAGE_STATUSOUT;
+                               }
+                               break;
+
+                       /* sequence #2 (OUT from host), always forward */
+                       default:                /* MUSB_EP0_STAGE_RX */
+                               break;
+                       }
+
+                       dev_dbg(musb->controller, "handled %d, csr %04x, ep0stage %s\n",
+                               handled, csr,
+                               decode_ep0stage(musb->ep0_state));
+
+                       /* unless we need to delegate this to the gadget
+                        * driver, we know how to wrap this up:  csr0 has
+                        * not yet been written.
+                        */
+                       if (handled < 0)
+                               goto stall;
+                       else if (handled > 0)
+                               goto finish;
+
+                       handled = forward_to_driver(musb, &setup);
+                       if (handled < 0) {
+                               musb_ep_select(mbase, 0);
+stall:
+                               dev_dbg(musb->controller, "stall (%d)\n", handled);
+                               musb->ackpend |= MUSB_CSR0_P_SENDSTALL;
+                               musb->ep0_state = MUSB_EP0_STAGE_IDLE;
+finish:
+                               musb_writew(regs, MUSB_CSR0,
+                                               musb->ackpend);
+                               musb->ackpend = 0;
+                       }
+               }
+               break;
+
+       case MUSB_EP0_STAGE_ACKWAIT:
+               /* This should not happen. But happens with tusb6010 with
+                * g_file_storage and high speed. Do nothing.
+                */
+               retval = IRQ_HANDLED;
+               break;
+
+       default:
+               /* "can't happen" */
+               WARN_ON(1);
+               musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SENDSTALL);
+               musb->ep0_state = MUSB_EP0_STAGE_IDLE;
+               break;
+       }
+
+       return retval;
+}
+
+
+static int
+musb_g_ep0_enable(struct usb_ep *ep, const struct usb_endpoint_descriptor *desc)
+{
+       /* always enabled */
+       return -EINVAL;
+}
+
+static int musb_g_ep0_disable(struct usb_ep *e)
+{
+       /* always enabled */
+       return -EINVAL;
+}
+
+static int
+musb_g_ep0_queue(struct usb_ep *e, struct usb_request *r, gfp_t gfp_flags)
+{
+       struct musb_ep          *ep;
+       struct musb_request     *req;
+       struct musb             *musb;
+       int                     status;
+       unsigned long           lockflags;
+       void __iomem            *regs;
+
+       if (!e || !r)
+               return -EINVAL;
+
+       ep = to_musb_ep(e);
+       musb = ep->musb;
+       regs = musb->control_ep->regs;
+
+       req = to_musb_request(r);
+       req->musb = musb;
+       req->request.actual = 0;
+       req->request.status = -EINPROGRESS;
+       req->tx = ep->is_in;
+
+       spin_lock_irqsave(&musb->lock, lockflags);
+
+       if (!list_empty(&ep->req_list)) {
+               status = -EBUSY;
+               goto cleanup;
+       }
+
+       switch (musb->ep0_state) {
+       case MUSB_EP0_STAGE_RX:         /* control-OUT data */
+       case MUSB_EP0_STAGE_TX:         /* control-IN data */
+       case MUSB_EP0_STAGE_ACKWAIT:    /* zero-length data */
+               status = 0;
+               break;
+       default:
+               dev_dbg(musb->controller, "ep0 request queued in state %d\n",
+                               musb->ep0_state);
+               status = -EINVAL;
+               goto cleanup;
+       }
+
+       /* add request to the list */
+       list_add_tail(&req->list, &ep->req_list);
+
+       dev_dbg(musb->controller, "queue to %s (%s), length=%d\n",
+                       ep->name, ep->is_in ? "IN/TX" : "OUT/RX",
+                       req->request.length);
+
+       musb_ep_select(musb->mregs, 0);
+
+       /* sequence #1, IN ... start writing the data */
+       if (musb->ep0_state == MUSB_EP0_STAGE_TX)
+               ep0_txstate(musb);
+
+       /* sequence #3, no-data ... issue IN status */
+       else if (musb->ep0_state == MUSB_EP0_STAGE_ACKWAIT) {
+               if (req->request.length)
+                       status = -EINVAL;
+               else {
+                       musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
+                       musb_writew(regs, MUSB_CSR0,
+                                       musb->ackpend | MUSB_CSR0_P_DATAEND);
+                       musb->ackpend = 0;
+                       musb_g_ep0_giveback(ep->musb, r);
+               }
+
+       /* else for sequence #2 (OUT), caller provides a buffer
+        * before the next packet arrives.  deferred responses
+        * (after SETUP is acked) are racey.
+        */
+       } else if (musb->ackpend) {
+               musb_writew(regs, MUSB_CSR0, musb->ackpend);
+               musb->ackpend = 0;
+       }
+
+cleanup:
+       spin_unlock_irqrestore(&musb->lock, lockflags);
+       return status;
+}
+
+static int musb_g_ep0_dequeue(struct usb_ep *ep, struct usb_request *req)
+{
+       /* we just won't support this */
+       return -EINVAL;
+}
+
+static int musb_g_ep0_halt(struct usb_ep *e, int value)
+{
+       struct musb_ep          *ep;
+       struct musb             *musb;
+       void __iomem            *base, *regs;
+       unsigned long           flags;
+       int                     status;
+       u16                     csr;
+
+       if (!e || !value)
+               return -EINVAL;
+
+       ep = to_musb_ep(e);
+       musb = ep->musb;
+       base = musb->mregs;
+       regs = musb->control_ep->regs;
+       status = 0;
+
+       spin_lock_irqsave(&musb->lock, flags);
+
+       if (!list_empty(&ep->req_list)) {
+               status = -EBUSY;
+               goto cleanup;
+       }
+
+       musb_ep_select(base, 0);
+       csr = musb->ackpend;
+
+       switch (musb->ep0_state) {
+
+       /* Stalls are usually issued after parsing SETUP packet, either
+        * directly in irq context from setup() or else later.
+        */
+       case MUSB_EP0_STAGE_TX:         /* control-IN data */
+       case MUSB_EP0_STAGE_ACKWAIT:    /* STALL for zero-length data */
+       case MUSB_EP0_STAGE_RX:         /* control-OUT data */
+               csr = musb_readw(regs, MUSB_CSR0);
+               /* FALLTHROUGH */
+
+       /* It's also OK to issue stalls during callbacks when a non-empty
+        * DATA stage buffer has been read (or even written).
+        */
+       case MUSB_EP0_STAGE_STATUSIN:   /* control-OUT status */
+       case MUSB_EP0_STAGE_STATUSOUT:  /* control-IN status */
+
+               csr |= MUSB_CSR0_P_SENDSTALL;
+               musb_writew(regs, MUSB_CSR0, csr);
+               musb->ep0_state = MUSB_EP0_STAGE_IDLE;
+               musb->ackpend = 0;
+               break;
+       default:
+               dev_dbg(musb->controller, "ep0 can't halt in state %d\n", musb->ep0_state);
+               status = -EINVAL;
+       }
+
+cleanup:
+       spin_unlock_irqrestore(&musb->lock, flags);
+       return status;
+}
+
+const struct usb_ep_ops musb_g_ep0_ops = {
+       .enable         = musb_g_ep0_enable,
+       .disable        = musb_g_ep0_disable,
+       .alloc_request  = musb_alloc_request,
+       .free_request   = musb_free_request,
+       .queue          = musb_g_ep0_queue,
+       .dequeue        = musb_g_ep0_dequeue,
+       .set_halt       = musb_g_ep0_halt,
+};