drivers/usb/musb/musb_gadget_ep0.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * MUSB OTG peripheral driver ep0 handling
   4  *
   5  * Copyright 2005 Mentor Graphics Corporation
   6  * Copyright (C) 2005-2006 by Texas Instruments
   7  * Copyright (C) 2006-2007 Nokia Corporation
   8  * Copyright (C) 2008-2009 MontaVista Software, Inc. <source@mvista.com>
   9  */
  10
  11 #include <linux/kernel.h>
  12 #include <linux/list.h>
  13 #include <linux/timer.h>
  14 #include <linux/spinlock.h>
  15 #include <linux/device.h>
  16 #include <linux/interrupt.h>
  17
  18 #include "musb_core.h"
  19
  20 /* ep0 is always musb->endpoints[0].ep_in */
  21 #define next_ep0_request(musb)  next_in_request(&(musb)->endpoints[0])
  22
  23 /*
  24  * locking note:  we use only the controller lock, for simpler correctness.
  25  * It's always held with IRQs blocked.
  26  *
  27  * It protects the ep0 request queue as well as ep0_state, not just the
  28  * controller and indexed registers.  And that lock stays held unless it
  29  * needs to be dropped to allow reentering this driver ... like upcalls to
  30  * the gadget driver, or adjusting endpoint halt status.
  31  */
  32
  33 static char *decode_ep0stage(u8 stage)
  34 {
  35         switch (stage) {
  36         case MUSB_EP0_STAGE_IDLE:       return "idle";
  37         case MUSB_EP0_STAGE_SETUP:      return "setup";
  38         case MUSB_EP0_STAGE_TX:         return "in";
  39         case MUSB_EP0_STAGE_RX:         return "out";
  40         case MUSB_EP0_STAGE_ACKWAIT:    return "wait";
  41         case MUSB_EP0_STAGE_STATUSIN:   return "in/status";
  42         case MUSB_EP0_STAGE_STATUSOUT:  return "out/status";
  43         default:                        return "?";
  44         }
  45 }
  46
  47 /* handle a standard GET_STATUS request
  48  * Context:  caller holds controller lock
  49  */
  50 static int service_tx_status_request(
  51         struct musb *musb,
  52         const struct usb_ctrlrequest *ctrlrequest)
  53 {
  54         void __iomem    *mbase = musb->mregs;
  55         int handled = 1;
  56         u8 result[2], epnum = 0;
  57         const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;
  58
  59         result[1] = 0;
  60
  61         switch (recip) {
  62         case USB_RECIP_DEVICE:
  63                 result[0] = musb->g.is_selfpowered << USB_DEVICE_SELF_POWERED;
  64                 result[0] |= musb->may_wakeup << USB_DEVICE_REMOTE_WAKEUP;
  65                 if (musb->g.is_otg) {
  66                         result[0] |= musb->g.b_hnp_enable
  67                                 << USB_DEVICE_B_HNP_ENABLE;
  68                         result[0] |= musb->g.a_alt_hnp_support
  69                                 << USB_DEVICE_A_ALT_HNP_SUPPORT;
  70                         result[0] |= musb->g.a_hnp_support
  71                                 << USB_DEVICE_A_HNP_SUPPORT;
  72                 }
  73                 break;
  74
  75         case USB_RECIP_INTERFACE:
  76                 result[0] = 0;
  77                 break;
  78
  79         case USB_RECIP_ENDPOINT: {
  80                 int             is_in;
  81                 struct musb_ep  *ep;
  82                 u16             tmp;
  83                 void __iomem    *regs;
  84
  85                 epnum = (u8) ctrlrequest->wIndex;
  86                 if (!epnum) {
  87                         result[0] = 0;
  88                         break;
  89                 }
  90
  91                 is_in = epnum & USB_DIR_IN;
  92                 epnum &= 0x0f;
  93                 if (epnum >= MUSB_C_NUM_EPS) {
  94                         handled = -EINVAL;
  95                         break;
  96                 }
  97
  98                 if (is_in)
  99                         ep = &musb->endpoints[epnum].ep_in;
 100                 else
 101                         ep = &musb->endpoints[epnum].ep_out;
 102                 regs = musb->endpoints[epnum].regs;
 103
 104                 if (!ep->desc) {
 105                         handled = -EINVAL;
 106                         break;
 107                 }
 108
 109                 musb_ep_select(mbase, epnum);
 110                 if (is_in)
 111                         tmp = musb_readw(regs, MUSB_TXCSR)
 112                                                 & MUSB_TXCSR_P_SENDSTALL;
 113                 else
 114                         tmp = musb_readw(regs, MUSB_RXCSR)
 115                                                 & MUSB_RXCSR_P_SENDSTALL;
 116                 musb_ep_select(mbase, 0);
 117
 118                 result[0] = tmp ? 1 : 0;
 119                 } break;
 120
 121         default:
 122                 /* class, vendor, etc ... delegate */
 123                 handled = 0;
 124                 break;
 125         }
 126
 127         /* fill up the fifo; caller updates csr0 */
 128         if (handled > 0) {
 129                 u16     len = le16_to_cpu(ctrlrequest->wLength);
 130
 131                 if (len > 2)
 132                         len = 2;
 133                 musb_write_fifo(&musb->endpoints[0], len, result);
 134         }
 135
 136         return handled;
 137 }
 138
 139 /*
 140  * handle a control-IN request, the end0 buffer contains the current request
 141  * that is supposed to be a standard control request. Assumes the fifo to
 142  * be at least 2 bytes long.
 143  *
 144  * @return 0 if the request was NOT HANDLED,
 145  * < 0 when error
 146  * > 0 when the request is processed
 147  *
 148  * Context:  caller holds controller lock
 149  */
 150 static int
 151 service_in_request(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
 152 {
 153         int handled = 0;        /* not handled */
 154
 155         if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
 156                         == USB_TYPE_STANDARD) {
 157                 switch (ctrlrequest->bRequest) {
 158                 case USB_REQ_GET_STATUS:
 159                         handled = service_tx_status_request(musb,
 160                                         ctrlrequest);
 161                         break;
 162
 163                 /* case USB_REQ_SYNC_FRAME: */
 164
 165                 default:
 166                         break;
 167                 }
 168         }
 169         return handled;
 170 }
 171
 172 /*
 173  * Context:  caller holds controller lock
 174  */
 175 static void musb_g_ep0_giveback(struct musb *musb, struct usb_request *req)
 176 {
 177         musb_g_giveback(&musb->endpoints[0].ep_in, req, 0);
 178 }
 179
 180 /*
 181  * Tries to start B-device HNP negotiation if enabled via sysfs
 182  */
 183 static inline void musb_try_b_hnp_enable(struct musb *musb)
 184 {
 185         void __iomem    *mbase = musb->mregs;
 186         u8              devctl;
 187
 188         musb_dbg(musb, "HNP: Setting HR");
 189         devctl = musb_readb(mbase, MUSB_DEVCTL);
 190         musb_writeb(mbase, MUSB_DEVCTL, devctl | MUSB_DEVCTL_HR);
 191 }
 192
 193 /*
 194  * Handle all control requests with no DATA stage, including standard
 195  * requests such as:
 196  * USB_REQ_SET_CONFIGURATION, USB_REQ_SET_INTERFACE, unrecognized
 197  *      always delegated to the gadget driver
 198  * USB_REQ_SET_ADDRESS, USB_REQ_CLEAR_FEATURE, USB_REQ_SET_FEATURE
 199  *      always handled here, except for class/vendor/... features
 200  *
 201  * Context:  caller holds controller lock
 202  */
 203 static int
 204 service_zero_data_request(struct musb *musb,
 205                 struct usb_ctrlrequest *ctrlrequest)
 206 __releases(musb->lock)
 207 __acquires(musb->lock)
 208 {
 209         int handled = -EINVAL;
 210         void __iomem *mbase = musb->mregs;
 211         const u8 recip = ctrlrequest->bRequestType & USB_RECIP_MASK;
 212
 213         /* the gadget driver handles everything except what we MUST handle */
 214         if ((ctrlrequest->bRequestType & USB_TYPE_MASK)
 215                         == USB_TYPE_STANDARD) {
 216                 switch (ctrlrequest->bRequest) {
 217                 case USB_REQ_SET_ADDRESS:
 218                         /* change it after the status stage */
 219                         musb->set_address = true;
 220                         musb->address = (u8) (ctrlrequest->wValue & 0x7f);
 221                         handled = 1;
 222                         break;
 223
 224                 case USB_REQ_CLEAR_FEATURE:
 225                         switch (recip) {
 226                         case USB_RECIP_DEVICE:
 227                                 if (ctrlrequest->wValue
 228                                                 != USB_DEVICE_REMOTE_WAKEUP)
 229                                         break;
 230                                 musb->may_wakeup = 0;
 231                                 handled = 1;
 232                                 break;
 233                         case USB_RECIP_INTERFACE:
 234                                 break;
 235                         case USB_RECIP_ENDPOINT:{
 236                                 const u8                epnum =
 237                                         ctrlrequest->wIndex & 0x0f;
 238                                 struct musb_ep          *musb_ep;
 239                                 struct musb_hw_ep       *ep;
 240                                 struct musb_request     *request;
 241                                 void __iomem            *regs;
 242                                 int                     is_in;
 243                                 u16                     csr;
 244
 245                                 if (epnum == 0 || epnum >= MUSB_C_NUM_EPS ||
 246                                     ctrlrequest->wValue != USB_ENDPOINT_HALT)
 247                                         break;
 248
 249                                 ep = musb->endpoints + epnum;
 250                                 regs = ep->regs;
 251                                 is_in = ctrlrequest->wIndex & USB_DIR_IN;
 252                                 if (is_in)
 253                                         musb_ep = &ep->ep_in;
 254                                 else
 255                                         musb_ep = &ep->ep_out;
 256                                 if (!musb_ep->desc)
 257                                         break;
 258
 259                                 handled = 1;
 260                                 /* Ignore request if endpoint is wedged */
 261                                 if (musb_ep->wedged)
 262                                         break;
 263
 264                                 musb_ep_select(mbase, epnum);
 265                                 if (is_in) {
 266                                         csr  = musb_readw(regs, MUSB_TXCSR);
 267                                         csr |= MUSB_TXCSR_CLRDATATOG |
 268                                                MUSB_TXCSR_P_WZC_BITS;
 269                                         csr &= ~(MUSB_TXCSR_P_SENDSTALL |
 270                                                  MUSB_TXCSR_P_SENTSTALL |
 271                                                  MUSB_TXCSR_TXPKTRDY);
 272                                         musb_writew(regs, MUSB_TXCSR, csr);
 273                                 } else {
 274                                         csr  = musb_readw(regs, MUSB_RXCSR);
 275                                         csr |= MUSB_RXCSR_CLRDATATOG |
 276                                                MUSB_RXCSR_P_WZC_BITS;
 277                                         csr &= ~(MUSB_RXCSR_P_SENDSTALL |
 278                                                  MUSB_RXCSR_P_SENTSTALL);
 279                                         musb_writew(regs, MUSB_RXCSR, csr);
 280                                 }
 281
 282                                 /* Maybe start the first request in the queue */
 283                                 request = next_request(musb_ep);
 284                                 if (!musb_ep->busy && request) {
 285                                         musb_dbg(musb, "restarting the request");
 286                                         musb_ep_restart(musb, request);
 287                                 }
 288
 289                                 /* select ep0 again */
 290                                 musb_ep_select(mbase, 0);
 291                                 } break;
 292                         default:
 293                                 /* class, vendor, etc ... delegate */
 294                                 handled = 0;
 295                                 break;
 296                         }
 297                         break;
 298
 299                 case USB_REQ_SET_FEATURE:
 300                         switch (recip) {
 301                         case USB_RECIP_DEVICE:
 302                                 handled = 1;
 303                                 switch (ctrlrequest->wValue) {
 304                                 case USB_DEVICE_REMOTE_WAKEUP:
 305                                         musb->may_wakeup = 1;
 306                                         break;
 307                                 case USB_DEVICE_TEST_MODE:
 308                                         if (musb->g.speed != USB_SPEED_HIGH)
 309                                                 goto stall;
 310                                         if (ctrlrequest->wIndex & 0xff)
 311                                                 goto stall;
 312
 313                                         switch (ctrlrequest->wIndex >> 8) {
 314                                         case USB_TEST_J:
 315                                                 pr_debug("USB_TEST_J\n");
 316                                                 musb->test_mode_nr =
 317                                                         MUSB_TEST_J;
 318                                                 break;
 319                                         case USB_TEST_K:
 320                                                 pr_debug("USB_TEST_K\n");
 321                                                 musb->test_mode_nr =
 322                                                         MUSB_TEST_K;
 323                                                 break;
 324                                         case USB_TEST_SE0_NAK:
 325                                                 pr_debug("USB_TEST_SE0_NAK\n");
 326                                                 musb->test_mode_nr =
 327                                                         MUSB_TEST_SE0_NAK;
 328                                                 break;
 329                                         case USB_TEST_PACKET:
 330                                                 pr_debug("USB_TEST_PACKET\n");
 331                                                 musb->test_mode_nr =
 332                                                         MUSB_TEST_PACKET;
 333                                                 break;
 334
 335                                         case 0xc0:
 336                                                 /* TEST_FORCE_HS */
 337                                                 pr_debug("TEST_FORCE_HS\n");
 338                                                 musb->test_mode_nr =
 339                                                         MUSB_TEST_FORCE_HS;
 340                                                 break;
 341                                         case 0xc1:
 342                                                 /* TEST_FORCE_FS */
 343                                                 pr_debug("TEST_FORCE_FS\n");
 344                                                 musb->test_mode_nr =
 345                                                         MUSB_TEST_FORCE_FS;
 346                                                 break;
 347                                         case 0xc2:
 348                                                 /* TEST_FIFO_ACCESS */
 349                                                 pr_debug("TEST_FIFO_ACCESS\n");
 350                                                 musb->test_mode_nr =
 351                                                         MUSB_TEST_FIFO_ACCESS;
 352                                                 break;
 353                                         case 0xc3:
 354                                                 /* TEST_FORCE_HOST */
 355                                                 pr_debug("TEST_FORCE_HOST\n");
 356                                                 musb->test_mode_nr =
 357                                                         MUSB_TEST_FORCE_HOST;
 358                                                 break;
 359                                         default:
 360                                                 goto stall;
 361                                         }
 362
 363                                         /* enter test mode after irq */
 364                                         if (handled > 0)
 365                                                 musb->test_mode = true;
 366                                         break;
 367                                 case USB_DEVICE_B_HNP_ENABLE:
 368                                         if (!musb->g.is_otg)
 369                                                 goto stall;
 370                                         musb->g.b_hnp_enable = 1;
 371                                         musb_try_b_hnp_enable(musb);
 372                                         break;
 373                                 case USB_DEVICE_A_HNP_SUPPORT:
 374                                         if (!musb->g.is_otg)
 375                                                 goto stall;
 376                                         musb->g.a_hnp_support = 1;
 377                                         break;
 378                                 case USB_DEVICE_A_ALT_HNP_SUPPORT:
 379                                         if (!musb->g.is_otg)
 380                                                 goto stall;
 381                                         musb->g.a_alt_hnp_support = 1;
 382                                         break;
 383                                 case USB_DEVICE_DEBUG_MODE:
 384                                         handled = 0;
 385                                         break;
 386 stall:
 387                                 default:
 388                                         handled = -EINVAL;
 389                                         break;
 390                                 }
 391                                 break;
 392
 393                         case USB_RECIP_INTERFACE:
 394                                 break;
 395
 396                         case USB_RECIP_ENDPOINT:{
 397                                 const u8                epnum =
 398                                         ctrlrequest->wIndex & 0x0f;
 399                                 struct musb_ep          *musb_ep;
 400                                 struct musb_hw_ep       *ep;
 401                                 void __iomem            *regs;
 402                                 int                     is_in;
 403                                 u16                     csr;
 404
 405                                 if (epnum == 0 || epnum >= MUSB_C_NUM_EPS ||
 406                                     ctrlrequest->wValue != USB_ENDPOINT_HALT)
 407                                         break;
 408
 409                                 ep = musb->endpoints + epnum;
 410                                 regs = ep->regs;
 411                                 is_in = ctrlrequest->wIndex & USB_DIR_IN;
 412                                 if (is_in)
 413                                         musb_ep = &ep->ep_in;
 414                                 else
 415                                         musb_ep = &ep->ep_out;
 416                                 if (!musb_ep->desc)
 417                                         break;
 418
 419                                 musb_ep_select(mbase, epnum);
 420                                 if (is_in) {
 421                                         csr = musb_readw(regs, MUSB_TXCSR);
 422                                         if (csr & MUSB_TXCSR_FIFONOTEMPTY)
 423                                                 csr |= MUSB_TXCSR_FLUSHFIFO;
 424                                         csr |= MUSB_TXCSR_P_SENDSTALL
 425                                                 | MUSB_TXCSR_CLRDATATOG
 426                                                 | MUSB_TXCSR_P_WZC_BITS;
 427                                         musb_writew(regs, MUSB_TXCSR, csr);
 428                                 } else {
 429                                         csr = musb_readw(regs, MUSB_RXCSR);
 430                                         csr |= MUSB_RXCSR_P_SENDSTALL
 431                                                 | MUSB_RXCSR_FLUSHFIFO
 432                                                 | MUSB_RXCSR_CLRDATATOG
 433                                                 | MUSB_RXCSR_P_WZC_BITS;
 434                                         musb_writew(regs, MUSB_RXCSR, csr);
 435                                 }
 436
 437                                 /* select ep0 again */
 438                                 musb_ep_select(mbase, 0);
 439                                 handled = 1;
 440                                 } break;
 441
 442                         default:
 443                                 /* class, vendor, etc ... delegate */
 444                                 handled = 0;
 445                                 break;
 446                         }
 447                         break;
 448                 default:
 449                         /* delegate SET_CONFIGURATION, etc */
 450                         handled = 0;
 451                 }
 452         } else
 453                 handled = 0;
 454         return handled;
 455 }
 456
 457 /* we have an ep0out data packet
 458  * Context:  caller holds controller lock
 459  */
 460 static void ep0_rxstate(struct musb *musb)
 461 {
 462         void __iomem            *regs = musb->control_ep->regs;
 463         struct musb_request     *request;
 464         struct usb_request      *req;
 465         u16                     count, csr;
 466
 467         request = next_ep0_request(musb);
 468         req = &request->request;
 469
 470         /* read packet and ack; or stall because of gadget driver bug:
 471          * should have provided the rx buffer before setup() returned.
 472          */
 473         if (req) {
 474                 void            *buf = req->buf + req->actual;
 475                 unsigned        len = req->length - req->actual;
 476
 477                 /* read the buffer */
 478                 count = musb_readb(regs, MUSB_COUNT0);
 479                 if (count > len) {
 480                         req->status = -EOVERFLOW;
 481                         count = len;
 482                 }
 483                 if (count > 0) {
 484                         musb_read_fifo(&musb->endpoints[0], count, buf);
 485                         req->actual += count;
 486                 }
 487                 csr = MUSB_CSR0_P_SVDRXPKTRDY;
 488                 if (count < 64 || req->actual == req->length) {
 489                         musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
 490                         csr |= MUSB_CSR0_P_DATAEND;
 491                 } else
 492                         req = NULL;
 493         } else
 494                 csr = MUSB_CSR0_P_SVDRXPKTRDY | MUSB_CSR0_P_SENDSTALL;
 495
 496
 497         /* Completion handler may choose to stall, e.g. because the
 498          * message just received holds invalid data.
 499          */
 500         if (req) {
 501                 musb->ackpend = csr;
 502                 musb_g_ep0_giveback(musb, req);
 503                 if (!musb->ackpend)
 504                         return;
 505                 musb->ackpend = 0;
 506         }
 507         musb_ep_select(musb->mregs, 0);
 508         musb_writew(regs, MUSB_CSR0, csr);
 509 }
 510
 511 /*
 512  * transmitting to the host (IN), this code might be called from IRQ
 513  * and from kernel thread.
 514  *
 515  * Context:  caller holds controller lock
 516  */
 517 static void ep0_txstate(struct musb *musb)
 518 {
 519         void __iomem            *regs = musb->control_ep->regs;
 520         struct musb_request     *req = next_ep0_request(musb);
 521         struct usb_request      *request;
 522         u16                     csr = MUSB_CSR0_TXPKTRDY;
 523         u8                      *fifo_src;
 524         u8                      fifo_count;
 525
 526         if (!req) {
 527                 /* WARN_ON(1); */
 528                 musb_dbg(musb, "odd; csr0 %04x", musb_readw(regs, MUSB_CSR0));
 529                 return;
 530         }
 531
 532         request = &req->request;
 533
 534         /* load the data */
 535         fifo_src = (u8 *) request->buf + request->actual;
 536         fifo_count = min((unsigned) MUSB_EP0_FIFOSIZE,
 537                 request->length - request->actual);
 538         musb_write_fifo(&musb->endpoints[0], fifo_count, fifo_src);
 539         request->actual += fifo_count;
 540
 541         /* update the flags */
 542         if (fifo_count < MUSB_MAX_END0_PACKET
 543                         || (request->actual == request->length
 544                                 && !request->zero)) {
 545                 musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
 546                 csr |= MUSB_CSR0_P_DATAEND;
 547         } else
 548                 request = NULL;
 549
 550         /* report completions as soon as the fifo's loaded; there's no
 551          * win in waiting till this last packet gets acked.  (other than
 552          * very precise fault reporting, needed by USB TMC; possible with
 553          * this hardware, but not usable from portable gadget drivers.)
 554          */
 555         if (request) {
 556                 musb->ackpend = csr;
 557                 musb_g_ep0_giveback(musb, request);
 558                 if (!musb->ackpend)
 559                         return;
 560                 musb->ackpend = 0;
 561         }
 562
 563         /* send it out, triggering a "txpktrdy cleared" irq */
 564         musb_ep_select(musb->mregs, 0);
 565         musb_writew(regs, MUSB_CSR0, csr);
 566 }
 567
 568 /*
 569  * Read a SETUP packet (struct usb_ctrlrequest) from the hardware.
 570  * Fields are left in USB byte-order.
 571  *
 572  * Context:  caller holds controller lock.
 573  */
 574 static void
 575 musb_read_setup(struct musb *musb, struct usb_ctrlrequest *req)
 576 {
 577         struct musb_request     *r;
 578         void __iomem            *regs = musb->control_ep->regs;
 579
 580         musb_read_fifo(&musb->endpoints[0], sizeof *req, (u8 *)req);
 581
 582         /* NOTE:  earlier 2.6 versions changed setup packets to host
 583          * order, but now USB packets always stay in USB byte order.
 584          */
 585         musb_dbg(musb, "SETUP req%02x.%02x v%04x i%04x l%d",
 586                 req->bRequestType,
 587                 req->bRequest,
 588                 le16_to_cpu(req->wValue),
 589                 le16_to_cpu(req->wIndex),
 590                 le16_to_cpu(req->wLength));
 591
 592         /* clean up any leftover transfers */
 593         r = next_ep0_request(musb);
 594         if (r)
 595                 musb_g_ep0_giveback(musb, &r->request);
 596
 597         /* For zero-data requests we want to delay the STATUS stage to
 598          * avoid SETUPEND errors.  If we read data (OUT), delay accepting
 599          * packets until there's a buffer to store them in.
 600          *
 601          * If we write data, the controller acts happier if we enable
 602          * the TX FIFO right away, and give the controller a moment
 603          * to switch modes...
 604          */
 605         musb->set_address = false;
 606         musb->ackpend = MUSB_CSR0_P_SVDRXPKTRDY;
 607         if (req->wLength == 0) {
 608                 if (req->bRequestType & USB_DIR_IN)
 609                         musb->ackpend |= MUSB_CSR0_TXPKTRDY;
 610                 musb->ep0_state = MUSB_EP0_STAGE_ACKWAIT;
 611         } else if (req->bRequestType & USB_DIR_IN) {
 612                 musb->ep0_state = MUSB_EP0_STAGE_TX;
 613                 musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDRXPKTRDY);
 614                 while ((musb_readw(regs, MUSB_CSR0)
 615                                 & MUSB_CSR0_RXPKTRDY) != 0)
 616                         cpu_relax();
 617                 musb->ackpend = 0;
 618         } else
 619                 musb->ep0_state = MUSB_EP0_STAGE_RX;
 620 }
 621
 622 static int
 623 forward_to_driver(struct musb *musb, const struct usb_ctrlrequest *ctrlrequest)
 624 __releases(musb->lock)
 625 __acquires(musb->lock)
 626 {
 627         int retval;
 628         if (!musb->gadget_driver)
 629                 return -EOPNOTSUPP;
 630         spin_unlock(&musb->lock);
 631         retval = musb->gadget_driver->setup(&musb->g, ctrlrequest);
 632         spin_lock(&musb->lock);
 633         return retval;
 634 }
 635
 636 /*
 637  * Handle peripheral ep0 interrupt
 638  *
 639  * Context: irq handler; we won't re-enter the driver that way.
 640  */
 641 irqreturn_t musb_g_ep0_irq(struct musb *musb)
 642 {
 643         u16             csr;
 644         u16             len;
 645         void __iomem    *mbase = musb->mregs;
 646         void __iomem    *regs = musb->endpoints[0].regs;
 647         irqreturn_t     retval = IRQ_NONE;
 648
 649         musb_ep_select(mbase, 0);       /* select ep0 */
 650         csr = musb_readw(regs, MUSB_CSR0);
 651         len = musb_readb(regs, MUSB_COUNT0);
 652
 653         musb_dbg(musb, "csr %04x, count %d, ep0stage %s",
 654                         csr, len, decode_ep0stage(musb->ep0_state));
 655
 656         if (csr & MUSB_CSR0_P_DATAEND) {
 657                 /*
 658                  * If DATAEND is set we should not call the callback,
 659                  * hence the status stage is not complete.
 660                  */
 661                 return IRQ_HANDLED;
 662         }
 663
 664         /* I sent a stall.. need to acknowledge it now.. */
 665         if (csr & MUSB_CSR0_P_SENTSTALL) {
 666                 musb_writew(regs, MUSB_CSR0,
 667                                 csr & ~MUSB_CSR0_P_SENTSTALL);
 668                 retval = IRQ_HANDLED;
 669                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
 670                 csr = musb_readw(regs, MUSB_CSR0);
 671         }
 672
 673         /* request ended "early" */
 674         if (csr & MUSB_CSR0_P_SETUPEND) {
 675                 musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SVDSETUPEND);
 676                 retval = IRQ_HANDLED;
 677                 /* Transition into the early status phase */
 678                 switch (musb->ep0_state) {
 679                 case MUSB_EP0_STAGE_TX:
 680                         musb->ep0_state = MUSB_EP0_STAGE_STATUSOUT;
 681                         break;
 682                 case MUSB_EP0_STAGE_RX:
 683                         musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
 684                         break;
 685                 default:
 686                         ERR("SetupEnd came in a wrong ep0stage %s\n",
 687                             decode_ep0stage(musb->ep0_state));
 688                 }
 689                 csr = musb_readw(regs, MUSB_CSR0);
 690                 /* NOTE:  request may need completion */
 691         }
 692
 693         /* docs from Mentor only describe tx, rx, and idle/setup states.
 694          * we need to handle nuances around status stages, and also the
 695          * case where status and setup stages come back-to-back ...
 696          */
 697         switch (musb->ep0_state) {
 698
 699         case MUSB_EP0_STAGE_TX:
 700                 /* irq on clearing txpktrdy */
 701                 if ((csr & MUSB_CSR0_TXPKTRDY) == 0) {
 702                         ep0_txstate(musb);
 703                         retval = IRQ_HANDLED;
 704                 }
 705                 break;
 706
 707         case MUSB_EP0_STAGE_RX:
 708                 /* irq on set rxpktrdy */
 709                 if (csr & MUSB_CSR0_RXPKTRDY) {
 710                         ep0_rxstate(musb);
 711                         retval = IRQ_HANDLED;
 712                 }
 713                 break;
 714
 715         case MUSB_EP0_STAGE_STATUSIN:
 716                 /* end of sequence #2 (OUT/RX state) or #3 (no data) */
 717
 718                 /* update address (if needed) only @ the end of the
 719                  * status phase per usb spec, which also guarantees
 720                  * we get 10 msec to receive this irq... until this
 721                  * is done we won't see the next packet.
 722                  */
 723                 if (musb->set_address) {
 724                         musb->set_address = false;
 725                         musb_writeb(mbase, MUSB_FADDR, musb->address);
 726                 }
 727
 728                 /* enter test mode if needed (exit by reset) */
 729                 else if (musb->test_mode) {
 730                         musb_dbg(musb, "entering TESTMODE");
 731
 732                         if (MUSB_TEST_PACKET == musb->test_mode_nr)
 733                                 musb_load_testpacket(musb);
 734
 735                         musb_writeb(mbase, MUSB_TESTMODE,
 736                                         musb->test_mode_nr);
 737                 }
 738                 fallthrough;
 739
 740         case MUSB_EP0_STAGE_STATUSOUT:
 741                 /* end of sequence #1: write to host (TX state) */
 742                 {
 743                         struct musb_request     *req;
 744
 745                         req = next_ep0_request(musb);
 746                         if (req)
 747                                 musb_g_ep0_giveback(musb, &req->request);
 748                 }
 749
 750                 /*
 751                  * In case when several interrupts can get coalesced,
 752                  * check to see if we've already received a SETUP packet...
 753                  */
 754                 if (csr & MUSB_CSR0_RXPKTRDY)
 755                         goto setup;
 756
 757                 retval = IRQ_HANDLED;
 758                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
 759                 break;
 760
 761         case MUSB_EP0_STAGE_IDLE:
 762                 /*
 763                  * This state is typically (but not always) indiscernible
 764                  * from the status states since the corresponding interrupts
 765                  * tend to happen within too little period of time (with only
 766                  * a zero-length packet in between) and so get coalesced...
 767                  */
 768                 retval = IRQ_HANDLED;
 769                 musb->ep0_state = MUSB_EP0_STAGE_SETUP;
 770                 fallthrough;
 771
 772         case MUSB_EP0_STAGE_SETUP:
 773 setup:
 774                 if (csr & MUSB_CSR0_RXPKTRDY) {
 775                         struct usb_ctrlrequest  setup;
 776                         int                     handled = 0;
 777
 778                         if (len != 8) {
 779                                 ERR("SETUP packet len %d != 8 ?\n", len);
 780                                 break;
 781                         }
 782                         musb_read_setup(musb, &setup);
 783                         retval = IRQ_HANDLED;
 784
 785                         /* sometimes the RESET won't be reported */
 786                         if (unlikely(musb->g.speed == USB_SPEED_UNKNOWN)) {
 787                                 u8      power;
 788
 789                                 printk(KERN_NOTICE "%s: peripheral reset "
 790                                                 "irq lost!\n",
 791                                                 musb_driver_name);
 792                                 power = musb_readb(mbase, MUSB_POWER);
 793                                 musb->g.speed = (power & MUSB_POWER_HSMODE)
 794                                         ? USB_SPEED_HIGH : USB_SPEED_FULL;
 795
 796                         }
 797
 798                         switch (musb->ep0_state) {
 799
 800                         /* sequence #3 (no data stage), includes requests
 801                          * we can't forward (notably SET_ADDRESS and the
 802                          * device/endpoint feature set/clear operations)
 803                          * plus SET_CONFIGURATION and others we must
 804                          */
 805                         case MUSB_EP0_STAGE_ACKWAIT:
 806                                 handled = service_zero_data_request(
 807                                                 musb, &setup);
 808
 809                                 /*
 810                                  * We're expecting no data in any case, so
 811                                  * always set the DATAEND bit -- doing this
 812                                  * here helps avoid SetupEnd interrupt coming
 813                                  * in the idle stage when we're stalling...
 814                                  */
 815                                 musb->ackpend |= MUSB_CSR0_P_DATAEND;
 816
 817                                 /* status stage might be immediate */
 818                                 if (handled > 0)
 819                                         musb->ep0_state =
 820                                                 MUSB_EP0_STAGE_STATUSIN;
 821                                 break;
 822
 823                         /* sequence #1 (IN to host), includes GET_STATUS
 824                          * requests that we can't forward, GET_DESCRIPTOR
 825                          * and others that we must
 826                          */
 827                         case MUSB_EP0_STAGE_TX:
 828                                 handled = service_in_request(musb, &setup);
 829                                 if (handled > 0) {
 830                                         musb->ackpend = MUSB_CSR0_TXPKTRDY
 831                                                 | MUSB_CSR0_P_DATAEND;
 832                                         musb->ep0_state =
 833                                                 MUSB_EP0_STAGE_STATUSOUT;
 834                                 }
 835                                 break;
 836
 837                         /* sequence #2 (OUT from host), always forward */
 838                         default:                /* MUSB_EP0_STAGE_RX */
 839                                 break;
 840                         }
 841
 842                         musb_dbg(musb, "handled %d, csr %04x, ep0stage %s",
 843                                 handled, csr,
 844                                 decode_ep0stage(musb->ep0_state));
 845
 846                         /* unless we need to delegate this to the gadget
 847                          * driver, we know how to wrap this up:  csr0 has
 848                          * not yet been written.
 849                          */
 850                         if (handled < 0)
 851                                 goto stall;
 852                         else if (handled > 0)
 853                                 goto finish;
 854
 855                         handled = forward_to_driver(musb, &setup);
 856                         if (handled < 0) {
 857                                 musb_ep_select(mbase, 0);
 858 stall:
 859                                 musb_dbg(musb, "stall (%d)", handled);
 860                                 musb->ackpend |= MUSB_CSR0_P_SENDSTALL;
 861                                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
 862 finish:
 863                                 musb_writew(regs, MUSB_CSR0,
 864                                                 musb->ackpend);
 865                                 musb->ackpend = 0;
 866                         }
 867                 }
 868                 break;
 869
 870         case MUSB_EP0_STAGE_ACKWAIT:
 871                 /* This should not happen. But happens with tusb6010 with
 872                  * g_file_storage and high speed. Do nothing.
 873                  */
 874                 retval = IRQ_HANDLED;
 875                 break;
 876
 877         default:
 878                 /* "can't happen" */
 879                 WARN_ON(1);
 880                 musb_writew(regs, MUSB_CSR0, MUSB_CSR0_P_SENDSTALL);
 881                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
 882                 break;
 883         }
 884
 885         return retval;
 886 }
 887
 888
 889 static int
 890 musb_g_ep0_enable(struct usb_ep *ep, const struct usb_endpoint_descriptor *desc)
 891 {
 892         /* always enabled */
 893         return -EINVAL;
 894 }
 895
 896 static int musb_g_ep0_disable(struct usb_ep *e)
 897 {
 898         /* always enabled */
 899         return -EINVAL;
 900 }
 901
 902 static int
 903 musb_g_ep0_queue(struct usb_ep *e, struct usb_request *r, gfp_t gfp_flags)
 904 {
 905         struct musb_ep          *ep;
 906         struct musb_request     *req;
 907         struct musb             *musb;
 908         int                     status;
 909         unsigned long           lockflags;
 910         void __iomem            *regs;
 911
 912         if (!e || !r)
 913                 return -EINVAL;
 914
 915         ep = to_musb_ep(e);
 916         musb = ep->musb;
 917         regs = musb->control_ep->regs;
 918
 919         req = to_musb_request(r);
 920         req->musb = musb;
 921         req->request.actual = 0;
 922         req->request.status = -EINPROGRESS;
 923         req->tx = ep->is_in;
 924
 925         spin_lock_irqsave(&musb->lock, lockflags);
 926
 927         if (!list_empty(&ep->req_list)) {
 928                 status = -EBUSY;
 929                 goto cleanup;
 930         }
 931
 932         switch (musb->ep0_state) {
 933         case MUSB_EP0_STAGE_RX:         /* control-OUT data */
 934         case MUSB_EP0_STAGE_TX:         /* control-IN data */
 935         case MUSB_EP0_STAGE_ACKWAIT:    /* zero-length data */
 936                 status = 0;
 937                 break;
 938         default:
 939                 musb_dbg(musb, "ep0 request queued in state %d",
 940                                 musb->ep0_state);
 941                 status = -EINVAL;
 942                 goto cleanup;
 943         }
 944
 945         /* add request to the list */
 946         list_add_tail(&req->list, &ep->req_list);
 947
 948         musb_dbg(musb, "queue to %s (%s), length=%d",
 949                         ep->name, ep->is_in ? "IN/TX" : "OUT/RX",
 950                         req->request.length);
 951
 952         musb_ep_select(musb->mregs, 0);
 953
 954         /* sequence #1, IN ... start writing the data */
 955         if (musb->ep0_state == MUSB_EP0_STAGE_TX)
 956                 ep0_txstate(musb);
 957
 958         /* sequence #3, no-data ... issue IN status */
 959         else if (musb->ep0_state == MUSB_EP0_STAGE_ACKWAIT) {
 960                 if (req->request.length)
 961                         status = -EINVAL;
 962                 else {
 963                         musb->ep0_state = MUSB_EP0_STAGE_STATUSIN;
 964                         musb_writew(regs, MUSB_CSR0,
 965                                         musb->ackpend | MUSB_CSR0_P_DATAEND);
 966                         musb->ackpend = 0;
 967                         musb_g_ep0_giveback(ep->musb, r);
 968                 }
 969
 970         /* else for sequence #2 (OUT), caller provides a buffer
 971          * before the next packet arrives.  deferred responses
 972          * (after SETUP is acked) are racey.
 973          */
 974         } else if (musb->ackpend) {
 975                 musb_writew(regs, MUSB_CSR0, musb->ackpend);
 976                 musb->ackpend = 0;
 977         }
 978
 979 cleanup:
 980         spin_unlock_irqrestore(&musb->lock, lockflags);
 981         return status;
 982 }
 983
 984 static int musb_g_ep0_dequeue(struct usb_ep *ep, struct usb_request *req)
 985 {
 986         /* we just won't support this */
 987         return -EINVAL;
 988 }
 989
 990 static int musb_g_ep0_halt(struct usb_ep *e, int value)
 991 {
 992         struct musb_ep          *ep;
 993         struct musb             *musb;
 994         void __iomem            *base, *regs;
 995         unsigned long           flags;
 996         int                     status;
 997         u16                     csr;
 998
 999         if (!e || !value)
1000                 return -EINVAL;
1001
1002         ep = to_musb_ep(e);
1003         musb = ep->musb;
1004         base = musb->mregs;
1005         regs = musb->control_ep->regs;
1006         status = 0;
1007
1008         spin_lock_irqsave(&musb->lock, flags);
1009
1010         if (!list_empty(&ep->req_list)) {
1011                 status = -EBUSY;
1012                 goto cleanup;
1013         }
1014
1015         musb_ep_select(base, 0);
1016         csr = musb->ackpend;
1017
1018         switch (musb->ep0_state) {
1019
1020         /* Stalls are usually issued after parsing SETUP packet, either
1021          * directly in irq context from setup() or else later.
1022          */
1023         case MUSB_EP0_STAGE_TX:         /* control-IN data */
1024         case MUSB_EP0_STAGE_ACKWAIT:    /* STALL for zero-length data */
1025         case MUSB_EP0_STAGE_RX:         /* control-OUT data */
1026                 csr = musb_readw(regs, MUSB_CSR0);
1027                 fallthrough;
1028
1029         /* It's also OK to issue stalls during callbacks when a non-empty
1030          * DATA stage buffer has been read (or even written).
1031          */
1032         case MUSB_EP0_STAGE_STATUSIN:   /* control-OUT status */
1033         case MUSB_EP0_STAGE_STATUSOUT:  /* control-IN status */
1034
1035                 csr |= MUSB_CSR0_P_SENDSTALL;
1036                 musb_writew(regs, MUSB_CSR0, csr);
1037                 musb->ep0_state = MUSB_EP0_STAGE_IDLE;
1038                 musb->ackpend = 0;
1039                 break;
1040         default:
1041                 musb_dbg(musb, "ep0 can't halt in state %d", musb->ep0_state);
1042                 status = -EINVAL;
1043         }
1044
1045 cleanup:
1046         spin_unlock_irqrestore(&musb->lock, flags);
1047         return status;
1048 }
1049
1050 const struct usb_ep_ops musb_g_ep0_ops = {
1051         .enable         = musb_g_ep0_enable,
1052         .disable        = musb_g_ep0_disable,
1053         .alloc_request  = musb_alloc_request,
1054         .free_request   = musb_free_request,
1055         .queue          = musb_g_ep0_queue,
1056         .dequeue        = musb_g_ep0_dequeue,
1057         .set_halt       = musb_g_ep0_halt,
1058 };