drivers/usb/musb/musb_gadget_ep0.c

   1 /*
   2  * MUSB OTG peripheral driver ep0 handling
   3  *
   4  * Copyright 2005 Mentor Graphics Corporation
   5  * Copyright (C) 2005-2006 by Texas Instruments
   6  * Copyright (C) 2006-2007 Nokia Corporation
   7  * Copyright (C) 2008-2009 MontaVista Software, Inc. <source@mvista.com>
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License
  11  * version 2 as published by the Free Software Foundation.
  12  *
  13  * This program is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
  21  * 02110-1301 USA
  22  *
  23  * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
  24  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  25  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN
  26  * NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  28  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
  29  * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
  30  * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  31  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  32  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  33  *
  34  */
  35
  36 #include <linux/kernel.h>
  37 #include <linux/list.h>
  38 #include <linux/timer.h>
  39 #include <linux/spinlock.h>
  40 #include <linux/init.h>
  41 #include <linux/device.h>
  42 #include <linux/interrupt.h>
  43
  44 #include "musb_core.h"
  45
  46 /* ep0 is always musb->endpoints[0].ep_in */
  47 #define next_ep0_request(musb)  next_in_request(&(musb)->endpoints[0])
  48
  49 /*
  50  * locking note:  we use only the controller lock, for simpler correctness.
  51  * It's always held with IRQs blocked.
  52  *
  53  * It protects the ep0 request queue as well as ep0_state, not just the
  54  * controller and indexed registers.  And that lock stays held unless it
  55  * needs to be dropped to allow reentering this driver ... like upcalls to
  56  * the gadget driver, or adjusting endpoint halt status.
  57  */
  58
  59 static char *decode_ep0stage(u8 stage)
  60 {
  61         switch (stage) {
  62         case MUSB_EP0_STAGE_IDLE:       return "idle";
  63         case MUSB_EP0_STAGE_SETUP:      return "setup";
  64         case MUSB_EP0_STAGE_TX:         return "in";
  65         case MUSB_EP0_STAGE_RX:         return "out";
  66         case MUSB_EP0_STAGE_ACKWAIT:    return "wait";
  67         case MUSB_EP0_STAGE_STATUSIN:   return "in/status";
  68         case MUSB_EP0_STAGE_STATUSOUT:  return "out/status";
  69         default:                        return "?";
  70         }
  71 }
  72
  73 /* handle a standard GET_STATUS request
  74  * Context:  caller holds controller lock
  75  */
  76 static int service_tx_status_request(
  77         struct musb *musb,
  78         const struct usb_ctrlrequest *ctrlrequest)
  79 {
  80         void __iomem    *mbase = musb->mregs;
  81         int handled = 1;
  82         u8 result[2], epnum = 0;
  83         const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;
  84
  85         result[1] = 0;
  86
  87         switch (recip) {
  88         case USB_RECIP_DEVICE:
  89                 result[0] = musb->is_self_powered << USB_DEVICE_SELF_POWERED;
  90                 result[0] |= musb->may_wakeup << USB_DEVICE_REMOTE_WAKEUP;
  91 #ifdef CONFIG_USB_MUSB_OTG
  92                 if (musb->g.is_otg) {
  93                         result[0] |= musb->g.b_hnp_enable
  94                                 << USB_DEVICE_B_HNP_ENABLE;
  95                         result[0] |= musb->g.a_alt_hnp_support
  96                                 << USB_DEVICE_A_ALT_HNP_SUPPORT;
  97                         result[0] |= musb->g.a_hnp_support
  98                                 << USB_DEVICE_A_HNP_SUPPORT;
  99                 }
 100 #endif
 101                 break;
 102
 103         case USB_RECIP_INTERFACE:
 104                 result[0] = 0;
 105                 break;
 106
 107         case USB_RECIP_ENDPOINT: {
 108                 int             is_in;
 109                 struct musb_ep  *ep;
 110                 u16             tmp;
 111                 void __iomem    *regs;
 112
 113                 epnum = (u8) ctrlrequest->wIndex;
 114                 if (!epnum) {
 115                         result[0] = 0;
 116                         break;
 117                 }
 118
 119                 is_in = epnum & USB_DIR_IN;
 120                 if (is_in) {
 121                         epnum &= 0x0f;
 122                         ep = &musb->endpoints[epnum].ep_in;
 123                 } else {
 124                         ep = &musb->endpoints[epnum].ep_out;
 125                 }
 126                 regs = musb->endpoints[epnum].regs;
 127
 128                 if (epnum >= MUSB_C_NUM_EPS || !ep->desc) {
 129                         handled = -EINVAL;
 130                         break;
 131                 }
 132
 133                 musb_ep_select(mbase, epnum);
 134                 if (is_in)
 135                         tmp = musb_readw(regs, MUSB_TXCSR)
 136                                                 & MUSB_TXCSR_P_SENDSTALL;
 137                 else
 138                         tmp = musb_readw(regs, MUSB_RXCSR)
 139                                                 & MUSB_RXCSR_P_SENDSTALL;
 140                 musb_ep_select(mbase, 0);
 141
 142                 result[0] = tmp ? 1 : 0;
 143                 } break;
 144
 145         default:
 146                 /* class, vendor, etc ... delegate */
 147                 handled = 0;
 148                 break;
 149         }
 150
 151         /* fill up the fifo; caller updates csr0 */
 152         if (handled > 0) {
 153                 u16     len = le16_to_cpu(ctrlrequest->wLength);
 154
 155                 if (len > 2)
 156                         len = 2;
 157                 musb_write_fifo(&musb->endpoints[0], len, result);
 158         }
 159
 160         return handled;
 161 }
 162
 163 /*
 164  * handle a control-IN request, the end0 buffer contains the current request
 165  * that is supposed to be a standard control request. Assumes the fifo to
 166  * be at least 2 bytes long.
 167  *
 168  * @return 0 if the request was NOT HANDLED,
 169  * < 0 when error
 170  * > 0 when the request is processed
 171  *
 172  * Context:  caller holds controller lock
 173  */
 174 static int
 175 service_in_request(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
 176 {
 177         int handled = 0;        /* not handled */
 178
 179         if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
 180                         == USB_TYPE_STANDARD) {
 181                 switch (ctrlrequest->bRequest) {
 182                 case USB_REQ_GET_STATUS:
 183                         handled = service_tx_status_request(musb,
 184                                         ctrlrequest);
 185                         break;
 186
 187                 /* case USB_REQ_SYNC_FRAME: */
 188
 189                 default:
 190                         break;
 191                 }
 192         }
 193         return handled;
 194 }
 195
 196 /*
 197  * Context:  caller holds controller lock
 198  */
 199 static void musb_g_ep0_giveback(struct musb *musb, struct usb_request *req)
 200 {
 201         musb_g_giveback(&musb->endpoints[0].ep_in, req, 0);
 202         musb->ep0_state = MUSB_EP0_STAGE_SETUP;
 203 }
 204
 205 /*
 206  * Tries to start B-device HNP negotiation if enabled via sysfs
 207  */
 208 static inline void musb_try_b_hnp_enable(struct musb *musb)
 209 {
 210         void __iomem    *mbase = musb->mregs;
 211         u8              devctl;
 212
 213         DBG(1, "HNP: Setting HR\n");
 214         devctl = musb_readb(mbase, MUSB_DEVCTL);
 215         musb_writeb(mbase, MUSB_DEVCTL, devctl | MUSB_DEVCTL_HR);
 216 }
 217
 218 /*
 219  * Handle all control requests with no DATA stage, including standard
 220  * requests such as:
 221  * USB_REQ_SET_CONFIGURATION, USB_REQ_SET_INTERFACE, unrecognized
 222  *      always delegated to the gadget driver
 223  * USB_REQ_SET_ADDRESS, USB_REQ_CLEAR_FEATURE, USB_REQ_SET_FEATURE
 224  *      always handled here, except for class/vendor/... features
 225  *
 226  * Context:  caller holds controller lock
 227  */
 228 static int
 229 service_zero_data_request(struct musb *musb,
 230                 struct usb_ctrlrequest *ctrlrequest)
 231 __releases(musb->lock)
 232 __acquires(musb->lock)
 233 {
 234         int handled = -EINVAL;
 235         void __iomem *mbase = musb->mregs;
 236         const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;
 237
 238         /* the gadget driver handles everything except what we MUST handle */
 239         if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
 240                         == USB_TYPE_STANDARD) {
 241                 switch (ctrlrequest->bRequest) {
 242                 case USB_REQ_SET_ADDRESS:
 243                         /* change it after the status stage */
 244                         musb->set_address = true;
 245                         musb->address = (u8) (ctrlrequest->wValue & 0x7f);
 246                         handled = 1;
 247                         break;
 248
 249                 case USB_REQ_CLEAR_FEATURE:
 250                         switch (recip) {
 251                         case USB_RECIP_DEVICE:
 252                                 if (ctrlrequest->wValue
 253                                                 != USB_DEVICE_REMOTE_WAKEUP)
 254                                         break;
 255                                 musb->may_wakeup = 0;
 256                                 handled = 1;
 257                                 break;
 258                         case USB_RECIP_INTERFACE:
 259                                 break;
 260                         case USB_RECIP_ENDPOINT:{
 261                                 const u8 num = ctrlrequest->wIndex & 0x0f;
 262                                 struct musb_ep *musb_ep;
 263
 264                                 if (num == 0
 265                                                 || num >= MUSB_C_NUM_EPS
 266                                                 || ctrlrequest->wValue
 267                                                         != USB_ENDPOINT_HALT)
 268                                         break;
 269
 270                                 if (ctrlrequest->wIndex & USB_DIR_IN)
 271                                         musb_ep = &musb->endpoints[num].ep_in;
 272                                 else
 273                                         musb_ep = &musb->endpoints[num].ep_out;
 274                                 if (!musb_ep->desc)
 275                                         break;
 276
 277                                 /* REVISIT do it directly, no locking games */
 278                                 spin_unlock(&musb->lock);
 279                                 musb_gadget_set_halt(&musb_ep->end_point, 0);
 280                                 spin_lock(&musb->lock);
 281
 282                                 /* select ep0 again */
 283                                 musb_ep_select(mbase, 0);
 284                                 handled = 1;
 285                                 } break;
 286                         default:
 287                                 /* class, vendor, etc ... delegate */
 288                                 handled = 0;
 289                                 break;
 290                         }
 291                         break;
 292
 293                 case USB_REQ_SET_FEATURE:
 294                         switch (recip) {
 295                         case USB_RECIP_DEVICE:
 296                                 handled = 1;
 297                                 switch (ctrlrequest->wValue) {
 298                                 case USB_DEVICE_REMOTE_WAKEUP:
 299                                         musb->may_wakeup = 1;
 300                                         break;
 301                                 case USB_DEVICE_TEST_MODE:
 302                                         if (musb->g.speed != USB_SPEED_HIGH)
 303                                                 goto stall;
 304                                         if (ctrlrequest->wIndex & 0xff)
 305                                                 goto stall;
 306
 307                                         switch (ctrlrequest->wIndex >> 8) {
 308                                         case 1:
 309                                                 pr_debug("TEST_J\n");
 310                                                 /* TEST_J */
 311                                                 musb->test_mode_nr =
 312                                                         MUSB_TEST_J;
 313                                                 break;
 314                                         case 2:
 315                                                 /* TEST_K */
 316                                                 pr_debug("TEST_K\n");
 317                                                 musb->test_mode_nr =
 318                                                         MUSB_TEST_K;
 319                                                 break;
 320                                         case 3:
 321                                                 /* TEST_SE0_NAK */
 322                                                 pr_debug("TEST_SE0_NAK\n");
 323                                                 musb->test_mode_nr =
 324                                                         MUSB_TEST_SE0_NAK;
 325                                                 break;
 326                                         case 4:
 327                                                 /* TEST_PACKET */
 328                                                 pr_debug("TEST_PACKET\n");
 329                                                 musb->test_mode_nr =
 330                                                         MUSB_TEST_PACKET;
 331                                                 break;
 332                                         default:
 333                                                 goto stall;
 334                                         }
 335
 336                                         /* enter test mode after irq */
 337                                         if (handled > 0)
 338                                                 musb->test_mode = true;
 339                                         break;
 340 #ifdef CONFIG_USB_MUSB_OTG
 341                                 case USB_DEVICE_B_HNP_ENABLE:
 342                                         if (!musb->g.is_otg)
 343                                                 goto stall;
 344                                         musb->g.b_hnp_enable = 1;
 345                                         musb_try_b_hnp_enable(musb);
 346                                         break;
 347                                 case USB_DEVICE_A_HNP_SUPPORT:
 348                                         if (!musb->g.is_otg)
 349                                                 goto stall;
 350                                         musb->g.a_hnp_support = 1;
 351                                         break;
 352                                 case USB_DEVICE_A_ALT_HNP_SUPPORT:
 353                                         if (!musb->g.is_otg)
 354                                                 goto stall;
 355                                         musb->g.a_alt_hnp_support = 1;
 356                                         break;
 357 #endif
 358 stall:
 359                                 default:
 360                                         handled = -EINVAL;
 361                                         break;
 362                                 }
 363                                 break;
 364
 365                         case USB_RECIP_INTERFACE:
 366                                 break;
 367
 368                         case USB_RECIP_ENDPOINT:{
 369                                 const u8                epnum =
 370                                         ctrlrequest->wIndex & 0x0f;
 371                                 struct musb_ep          *musb_ep;
 372                                 struct musb_hw_ep       *ep;
 373                                 void __iomem            *regs;
 374                                 int                     is_in;
 375                                 u16                     csr;
 376
 377                                 if (epnum == 0
 378                                                 || epnum >= MUSB_C_NUM_EPS
 379                                                 || ctrlrequest->wValue
 380                                                         != USB_ENDPOINT_HALT)
 381                                         break;
 382
 383                                 ep = musb->endpoints + epnum;
 384                                 regs = ep->regs;
 385                                 is_in = ctrlrequest->wIndex & USB_DIR_IN;
 386                                 if (is_in)
 387                                         musb_ep = &ep->ep_in;
 388                                 else
 389                                         musb_ep = &ep->ep_out;
 390                                 if (!musb_ep->desc)
 391                                         break;
 392
 393                                 musb_ep_select(mbase, epnum);
 394                                 if (is_in) {
 395                                         csr = musb_readw(regs,
 396                                                         MUSB_TXCSR);
 397                                         if (csr & MUSB_TXCSR_FIFONOTEMPTY)
 398                                                 csr |= MUSB_TXCSR_FLUSHFIFO;
 399                                         csr |= MUSB_TXCSR_P_SENDSTALL
 400                                                 | MUSB_TXCSR_CLRDATATOG
 401                                                 | MUSB_TXCSR_P_WZC_BITS;
 402                                         musb_writew(regs, MUSB_TXCSR,
 403                                                         csr);
 404                                 } else {
 405                                         csr = musb_readw(regs,
 406                                                         MUSB_RXCSR);
 407                                         csr |= MUSB_RXCSR_P_SENDSTALL
 408                                                 | MUSB_RXCSR_FLUSHFIFO
 409                                                 | MUSB_RXCSR_CLRDATATOG
 410                                                 | MUSB_RXCSR_P_WZC_BITS;
 411                                         musb_writew(regs, MUSB_RXCSR,
 412                                                         csr);
 413                                 }
 414
 415                                 /* select ep0 again */
 416                                 musb_ep_select(mbase, 0);
 417                                 handled = 1;
 418                                 } break;
 419
 420                         default:
 421                                 /* class, vendor, etc ... delegate */
 422                                 handled = 0;
 423                                 break;
 424                         }
 425                         break;
 426                 default:
 427                         /* delegate SET_CONFIGURATION, etc */
 428                         handled = 0;
 429                 }
 430         } else
 431                 handled = 0;
 432         return handled;
 433 }
 434
 435 /* we have an ep0out data packet
 436  * Context:  caller holds controller lock
 437  */
 438 static void ep0_rxstate(struct musb *musb)
 439 {
 440         void __iomem            *regs = musb->control_ep->regs;
 441         struct usb_request      *req;
 442         u16                     count, csr;
 443
 444         req = next_ep0_request(musb);
 445
 446         /* read packet and ack; or stall because of gadget driver bug:
 447          * should have provided the rx buffer before setup() returned.
 448          */
 449         if (req) {
 450                 void            *buf = req->buf + req->actual;
 451                 unsigned        len = req->length - req->actual;
 452
 453                 /* read the buffer */
 454                 count = musb_readb(regs, MUSB_COUNT0);
 455                 if (count > len) {
 456                         req->status = -EOVERFLOW;
 457                         count = len;
 458                 }
 459                 musb_read_fifo(&musb->endpoints[0], count, buf);
 460                 req->actual += count;
 461                 csr = MUSB_CSR0_P_SVDRXPKTRDY;
 462                 if (count < 64 || req->actual == req->length) {
 463                         musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
 464                         csr |= MUSB_CSR0_P_DATAEND;
 465                 } else
 466                         req = NULL;
 467         } else
 468                 csr = MUSB_CSR0_P_SVDRXPKTRDY | MUSB_CSR0_P_SENDSTALL;
 469
 470
 471         /* Completion handler may choose to stall, e.g. because the
 472          * message just received holds invalid data.
 473          */
 474         if (req) {
 475                 musb->ackpend = csr;
 476                 musb_g_ep0_giveback(musb, req);
 477                 if (!musb->ackpend)
 478                         return;
 479                 musb->ackpend = 0;
 480         }
 481         musb_ep_select(musb->mregs, 0);
 482         musb_writew(regs, MUSB_CSR0, csr);
 483 }
 484
 485 /*
 486  * transmitting to the host (IN), this code might be called from IRQ
 487  * and from kernel thread.
 488  *
 489  * Context:  caller holds controller lock
 490  */
 491 static void ep0_txstate(struct musb *musb)
 492 {
 493         void __iomem            *regs = musb->control_ep->regs;
 494         struct usb_request      *request = next_ep0_request(musb);
 495         u16                     csr = MUSB_CSR0_TXPKTRDY;
 496         u8                      *fifo_src;
 497         u8                      fifo_count;
 498
 499         if (!request) {
 500                 /* WARN_ON(1); */
 501                 DBG(2, "odd; csr0 %04x\n", musb_readw(regs, MUSB_CSR0));
 502                 return;
 503         }
 504
 505         /* load the data */
 506         fifo_src = (u8 *) request->buf + request->actual;
 507         fifo_count = min((unsigned) MUSB_EP0_FIFOSIZE,
 508                 request->length - request->actual);
 509         musb_write_fifo(&musb->endpoints[0], fifo_count, fifo_src);
 510         request->actual += fifo_count;
 511
 512         /* update the flags */
 513         if (fifo_count < MUSB_MAX_END0_PACKET
 514                         || request->actual == request->length) {
 515                 musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
 516                 csr |= MUSB_CSR0_P_DATAEND;
 517         } else
 518                 request = NULL;
 519
 520         /* report completions as soon as the fifo's loaded; there's no
 521          * win in waiting till this last packet gets acked.  (other than
 522          * very precise fault reporting, needed by USB TMC; possible with
 523          * this hardware, but not usable from portable gadget drivers.)
 524          */
 525         if (request) {
 526                 musb->ackpend = csr;
 527                 musb_g_ep0_giveback(musb, request);
 528                 if (!musb->ackpend)
 529                         return;
 530                 musb->ackpend = 0;
 531         }
 532
 533         /* send it out, triggering a "txpktrdy cleared" irq */
 534         musb_ep_select(musb->mregs, 0);
 535         musb_writew(regs, MUSB_CSR0, csr);
 536 }
 537
 538 /*
 539  * Read a SETUP packet (struct usb_ctrlrequest) from the hardware.
 540  * Fields are left in USB byte-order.
 541  *
 542  * Context:  caller holds controller lock.
 543  */
 544 static void
 545 musb_read_setup(struct musb *musb, struct usb_ctrlrequest *req)
 546 {
 547         struct usb_request      *r;
 548         void __iomem            *regs = musb->control_ep->regs;
 549
 550         musb_read_fifo(&musb->endpoints[0], sizeof *req, (u8 *)req);
 551
 552         /* NOTE:  earlier 2.6 versions changed setup packets to host
 553          * order, but now USB packets always stay in USB byte order.
 554          */
 555         DBG(3, "SETUP req%02x.%02x v%04x i%04x l%d\n",
 556                 req->bRequestType,
 557                 req->bRequest,
 558                 le16_to_cpu(req->wValue),
 559                 le16_to_cpu(req->wIndex),
 560                 le16_to_cpu(req->wLength));
 561
 562         /* clean up any leftover transfers */
 563         r = next_ep0_request(musb);
 564         if (r)
 565                 musb_g_ep0_giveback(musb, r);
 566
 567         /* For zero-data requests we want to delay the STATUS stage to
 568          * avoid SETUPEND errors.  If we read data (OUT), delay accepting
 569          * packets until there's a buffer to store them in.
 570          *
 571          * If we write data, the controller acts happier if we enable
 572          * the TX FIFO right away, and give the controller a moment
 573          * to switch modes...
 574          */
 575         musb->set_address = false;
 576         musb->ackpend = MUSB_CSR0_P_SVDRXPKTRDY;
 577         if (req->wLength == 0) {
 578                 if (req->bRequestType & USB_DIR_IN)
 579                         musb->ackpend |= MUSB_CSR0_TXPKTRDY;
 580                 musb->ep0_state = MUSB_EP0_STAGE_ACKWAIT;
 581         } else if (req->bRequestType & USB_DIR_IN) {
 582                 musb->ep0_state = MUSB_EP0_STAGE_TX;
 583                 musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDRXPKTRDY);
 584                 while ((musb_readw(regs, MUSB_CSR0)
 585                                 & MUSB_CSR0_RXPKTRDY) != 0)
 586                         cpu_relax();
 587                 musb->ackpend = 0;
 588         } else
 589                 musb->ep0_state = MUSB_EP0_STAGE_RX;
 590 }
 591
 592 static int
 593 forward_to_driver(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
 594 __releases(musb->lock)
 595 __acquires(musb->lock)
 596 {
 597         int retval;
 598         if (!musb->gadget_driver)
 599                 return -EOPNOTSUPP;
 600         spin_unlock(&musb->lock);
 601         retval = musb->gadget_driver->setup(&musb->g, ctrlrequest);
 602         spin_lock(&musb->lock);
 603         return retval;
 604 }
 605
 606 /*
 607  * Handle peripheral ep0 interrupt
 608  *
 609  * Context: irq handler; we won't re-enter the driver that way.
 610  */
 611 irqreturn_t musb_g_ep0_irq(struct musb *musb)
 612 {
 613         u16             csr;
 614         u16             len;
 615         void __iomem    *mbase = musb->mregs;
 616         void __iomem    *regs = musb->endpoints[0].regs;
 617         irqreturn_t     retval = IRQ_NONE;
 618
 619         musb_ep_select(mbase, 0);       /* select ep0 */
 620         csr = musb_readw(regs, MUSB_CSR0);
 621         len = musb_readb(regs, MUSB_COUNT0);
 622
 623         DBG(4, "csr %04x, count %d, myaddr %d, ep0stage %s\n",
 624                         csr, len,
 625                         musb_readb(mbase, MUSB_FADDR),
 626                         decode_ep0stage(musb->ep0_state));
 627
 628         /* I sent a stall.. need to acknowledge it now.. */
 629         if (csr & MUSB_CSR0_P_SENTSTALL) {
 630                 musb_writew(regs, MUSB_CSR0,
 631                                 csr & ~MUSB_CSR0_P_SENTSTALL);
 632                 retval = IRQ_HANDLED;
 633                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
 634                 csr = musb_readw(regs, MUSB_CSR0);
 635         }
 636
 637         /* request ended "early" */
 638         if (csr & MUSB_CSR0_P_SETUPEND) {
 639                 musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDSETUPEND);
 640                 retval = IRQ_HANDLED;
 641                 /* Transition into the early status phase */
 642                 switch (musb->ep0_state) {
 643                 case MUSB_EP0_STAGE_TX:
 644                         musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
 645                         break;
 646                 case MUSB_EP0_STAGE_RX:
 647                         musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
 648                         break;
 649                 default:
 650                         ERR("SetupEnd came in a wrong ep0stage %s",
 651                             decode_ep0stage(musb->ep0_state));
 652                 }
 653                 csr = musb_readw(regs, MUSB_CSR0);
 654                 /* NOTE:  request may need completion */
 655         }
 656
 657         /* docs from Mentor only describe tx, rx, and idle/setup states.
 658          * we need to handle nuances around status stages, and also the
 659          * case where status and setup stages come back-to-back ...
 660          */
 661         switch (musb->ep0_state) {
 662
 663         case MUSB_EP0_STAGE_TX:
 664                 /* irq on clearing txpktrdy */
 665                 if ((csr & MUSB_CSR0_TXPKTRDY) == 0) {
 666                         ep0_txstate(musb);
 667                         retval = IRQ_HANDLED;
 668                 }
 669                 break;
 670
 671         case MUSB_EP0_STAGE_RX:
 672                 /* irq on set rxpktrdy */
 673                 if (csr & MUSB_CSR0_RXPKTRDY) {
 674                         ep0_rxstate(musb);
 675                         retval = IRQ_HANDLED;
 676                 }
 677                 break;
 678
 679         case MUSB_EP0_STAGE_STATUSIN:
 680                 /* end of sequence #2 (OUT/RX state) or #3 (no data) */
 681
 682                 /* update address (if needed) only @ the end of the
 683                  * status phase per usb spec, which also guarantees
 684                  * we get 10 msec to receive this irq... until this
 685                  * is done we won't see the next packet.
 686                  */
 687                 if (musb->set_address) {
 688                         musb->set_address = false;
 689                         musb_writeb(mbase, MUSB_FADDR, musb->address);
 690                 }
 691
 692                 /* enter test mode if needed (exit by reset) */
 693                 else if (musb->test_mode) {
 694                         DBG(1, "entering TESTMODE\n");
 695
 696                         if (MUSB_TEST_PACKET == musb->test_mode_nr)
 697                                 musb_load_testpacket(musb);
 698
 699                         musb_writeb(mbase, MUSB_TESTMODE,
 700                                         musb->test_mode_nr);
 701                 }
 702                 /* FALLTHROUGH */
 703
 704         case MUSB_EP0_STAGE_STATUSOUT:
 705                 /* end of sequence #1: write to host (TX state) */
 706                 {
 707                         struct usb_request      *req;
 708
 709                         req = next_ep0_request(musb);
 710                         if (req)
 711                                 musb_g_ep0_giveback(musb, req);
 712                 }
 713
 714                 /*
 715                  * In case when several interrupts can get coalesced,
 716                  * check to see if we've already received a SETUP packet...
 717                  */
 718                 if (csr & MUSB_CSR0_RXPKTRDY)
 719                         goto setup;
 720
 721                 retval = IRQ_HANDLED;
 722                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
 723                 break;
 724
 725         case MUSB_EP0_STAGE_IDLE:
 726                 /*
 727                  * This state is typically (but not always) indiscernible
 728                  * from the status states since the corresponding interrupts
 729                  * tend to happen within too little period of time (with only
 730                  * a zero-length packet in between) and so get coalesced...
 731                  */
 732                 retval = IRQ_HANDLED;
 733                 musb->ep0_state = MUSB_EP0_STAGE_SETUP;
 734                 /* FALLTHROUGH */
 735
 736         case MUSB_EP0_STAGE_SETUP:
 737 setup:
 738                 if (csr & MUSB_CSR0_RXPKTRDY) {
 739                         struct usb_ctrlrequest  setup;
 740                         int                     handled = 0;
 741
 742                         if (len != 8) {
 743                                 ERR("SETUP packet len %d != 8 ?\n", len);
 744                                 break;
 745                         }
 746                         musb_read_setup(musb, &setup);
 747                         retval = IRQ_HANDLED;
 748
 749                         /* sometimes the RESET won't be reported */
 750                         if (unlikely(musb->g.speed == USB_SPEED_UNKNOWN)) {
 751                                 u8      power;
 752
 753                                 printk(KERN_NOTICE "%s: peripheral reset "
 754                                                 "irq lost!\n",
 755                                                 musb_driver_name);
 756                                 power = musb_readb(mbase, MUSB_POWER);
 757                                 musb->g.speed = (power & MUSB_POWER_HSMODE)
 758                                         ? USB_SPEED_HIGH : USB_SPEED_FULL;
 759
 760                         }
 761
 762                         switch (musb->ep0_state) {
 763
 764                         /* sequence #3 (no data stage), includes requests
 765                          * we can't forward (notably SET_ADDRESS and the
 766                          * device/endpoint feature set/clear operations)
 767                          * plus SET_CONFIGURATION and others we must
 768                          */
 769                         case MUSB_EP0_STAGE_ACKWAIT:
 770                                 handled = service_zero_data_request(
 771                                                 musb, &setup);
 772
 773                                 /* status stage might be immediate */
 774                                 if (handled > 0) {
 775                                         musb->ackpend |= MUSB_CSR0_P_DATAEND;
 776                                         musb->ep0_state =
 777                                                 MUSB_EP0_STAGE_STATUSIN;
 778                                 }
 779                                 break;
 780
 781                         /* sequence #1 (IN to host), includes GET_STATUS
 782                          * requests that we can't forward, GET_DESCRIPTOR
 783                          * and others that we must
 784                          */
 785                         case MUSB_EP0_STAGE_TX:
 786                                 handled = service_in_request(musb, &setup);
 787                                 if (handled > 0) {
 788                                         musb->ackpend = MUSB_CSR0_TXPKTRDY
 789                                                 | MUSB_CSR0_P_DATAEND;
 790                                         musb->ep0_state =
 791                                                 MUSB_EP0_STAGE_STATUSOUT;
 792                                 }
 793                                 break;
 794
 795                         /* sequence #2 (OUT from host), always forward */
 796                         default:                /* MUSB_EP0_STAGE_RX */
 797                                 break;
 798                         }
 799
 800                         DBG(3, "handled %d, csr %04x, ep0stage %s\n",
 801                                 handled, csr,
 802                                 decode_ep0stage(musb->ep0_state));
 803
 804                         /* unless we need to delegate this to the gadget
 805                          * driver, we know how to wrap this up:  csr0 has
 806                          * not yet been written.
 807                          */
 808                         if (handled < 0)
 809                                 goto stall;
 810                         else if (handled > 0)
 811                                 goto finish;
 812
 813                         handled = forward_to_driver(musb, &setup);
 814                         if (handled < 0) {
 815                                 musb_ep_select(mbase, 0);
 816 stall:
 817                                 DBG(3, "stall (%d)\n", handled);
 818                                 musb->ackpend |= MUSB_CSR0_P_SENDSTALL;
 819                                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
 820 finish:
 821                                 musb_writew(regs, MUSB_CSR0,
 822                                                 musb->ackpend);
 823                                 musb->ackpend = 0;
 824                         }
 825                 }
 826                 break;
 827
 828         case MUSB_EP0_STAGE_ACKWAIT:
 829                 /* This should not happen. But happens with tusb6010 with
 830                  * g_file_storage and high speed. Do nothing.
 831                  */
 832                 retval = IRQ_HANDLED;
 833                 break;
 834
 835         default:
 836                 /* "can't happen" */
 837                 WARN_ON(1);
 838                 musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SENDSTALL);
 839                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
 840                 break;
 841         }
 842
 843         return retval;
 844 }
 845
 846
 847 static int
 848 musb_g_ep0_enable(struct usb_ep *ep, const struct usb_endpoint_descriptor *desc)
 849 {
 850         /* always enabled */
 851         return -EINVAL;
 852 }
 853
 854 static int musb_g_ep0_disable(struct usb_ep *e)
 855 {
 856         /* always enabled */
 857         return -EINVAL;
 858 }
 859
 860 static int
 861 musb_g_ep0_queue(struct usb_ep *e, struct usb_request *r, gfp_t gfp_flags)
 862 {
 863         struct musb_ep          *ep;
 864         struct musb_request     *req;
 865         struct musb             *musb;
 866         int                     status;
 867         unsigned long           lockflags;
 868         void __iomem            *regs;
 869
 870         if (!e || !r)
 871                 return -EINVAL;
 872
 873         ep = to_musb_ep(e);
 874         musb = ep->musb;
 875         regs = musb->control_ep->regs;
 876
 877         req = to_musb_request(r);
 878         req->musb = musb;
 879         req->request.actual = 0;
 880         req->request.status = -EINPROGRESS;
 881         req->tx = ep->is_in;
 882
 883         spin_lock_irqsave(&musb->lock, lockflags);
 884
 885         if (!list_empty(&ep->req_list)) {
 886                 status = -EBUSY;
 887                 goto cleanup;
 888         }
 889
 890         switch (musb->ep0_state) {
 891         case MUSB_EP0_STAGE_RX:         /* control-OUT data */
 892         case MUSB_EP0_STAGE_TX:         /* control-IN data */
 893         case MUSB_EP0_STAGE_ACKWAIT:    /* zero-length data */
 894                 status = 0;
 895                 break;
 896         default:
 897                 DBG(1, "ep0 request queued in state %d\n",
 898                                 musb->ep0_state);
 899                 status = -EINVAL;
 900                 goto cleanup;
 901         }
 902
 903         /* add request to the list */
 904         list_add_tail(&(req->request.list), &(ep->req_list));
 905
 906         DBG(3, "queue to %s (%s), length=%d\n",
 907                         ep->name, ep->is_in ? "IN/TX" : "OUT/RX",
 908                         req->request.length);
 909
 910         musb_ep_select(musb->mregs, 0);
 911
 912         /* sequence #1, IN ... start writing the data */
 913         if (musb->ep0_state == MUSB_EP0_STAGE_TX)
 914                 ep0_txstate(musb);
 915
 916         /* sequence #3, no-data ... issue IN status */
 917         else if (musb->ep0_state == MUSB_EP0_STAGE_ACKWAIT) {
 918                 if (req->request.length)
 919                         status = -EINVAL;
 920                 else {
 921                         musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
 922                         musb_writew(regs, MUSB_CSR0,
 923                                         musb->ackpend | MUSB_CSR0_P_DATAEND);
 924                         musb->ackpend = 0;
 925                         musb_g_ep0_giveback(ep->musb, r);
 926                 }
 927
 928         /* else for sequence #2 (OUT), caller provides a buffer
 929          * before the next packet arrives.  deferred responses
 930          * (after SETUP is acked) are racey.
 931          */
 932         } else if (musb->ackpend) {
 933                 musb_writew(regs, MUSB_CSR0, musb->ackpend);
 934                 musb->ackpend = 0;
 935         }
 936
 937 cleanup:
 938         spin_unlock_irqrestore(&musb->lock, lockflags);
 939         return status;
 940 }
 941
 942 static int musb_g_ep0_dequeue(struct usb_ep *ep, struct usb_request *req)
 943 {
 944         /* we just won't support this */
 945         return -EINVAL;
 946 }
 947
 948 static int musb_g_ep0_halt(struct usb_ep *e, int value)
 949 {
 950         struct musb_ep          *ep;
 951         struct musb             *musb;
 952         void __iomem            *base, *regs;
 953         unsigned long           flags;
 954         int                     status;
 955         u16                     csr;
 956
 957         if (!e || !value)
 958                 return -EINVAL;
 959
 960         ep = to_musb_ep(e);
 961         musb = ep->musb;
 962         base = musb->mregs;
 963         regs = musb->control_ep->regs;
 964         status = 0;
 965
 966         spin_lock_irqsave(&musb->lock, flags);
 967
 968         if (!list_empty(&ep->req_list)) {
 969                 status = -EBUSY;
 970                 goto cleanup;
 971         }
 972
 973         musb_ep_select(base, 0);
 974         csr = musb->ackpend;
 975
 976         switch (musb->ep0_state) {
 977
 978         /* Stalls are usually issued after parsing SETUP packet, either
 979          * directly in irq context from setup() or else later.
 980          */
 981         case MUSB_EP0_STAGE_TX:         /* control-IN data */
 982         case MUSB_EP0_STAGE_ACKWAIT:    /* STALL for zero-length data */
 983         case MUSB_EP0_STAGE_RX:         /* control-OUT data */
 984                 csr = musb_readw(regs, MUSB_CSR0);
 985                 /* FALLTHROUGH */
 986
 987         /* It's also OK to issue stalls during callbacks when a non-empty
 988          * DATA stage buffer has been read (or even written).
 989          */
 990         case MUSB_EP0_STAGE_STATUSIN:   /* control-OUT status */
 991         case MUSB_EP0_STAGE_STATUSOUT:  /* control-IN status */
 992
 993                 csr |= MUSB_CSR0_P_SENDSTALL;
 994                 musb_writew(regs, MUSB_CSR0, csr);
 995                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
 996                 musb->ackpend = 0;
 997                 break;
 998         default:
 999                 DBG(1, "ep0 can't halt in state %d\n", musb->ep0_state);
1000                 status = -EINVAL;
1001         }
1002
1003 cleanup:
1004         spin_unlock_irqrestore(&musb->lock, flags);
1005         return status;
1006 }
1007
1008 const struct usb_ep_ops musb_g_ep0_ops = {
1009         .enable         = musb_g_ep0_enable,
1010         .disable        = musb_g_ep0_disable,
1011         .alloc_request  = musb_alloc_request,
1012         .free_request   = musb_free_request,
1013         .queue          = musb_g_ep0_queue,
1014         .dequeue        = musb_g_ep0_dequeue,
1015         .set_halt       = musb_g_ep0_halt,
1016 };