src/devices/usb/drivers/mt-musb-host/usb-request-queue.cc

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "usb-request-queue.h"

#include <lib/zx/time.h>
#include <zircon/hw/usb.h>
#include <zircon/status.h>

#include <ddk/debug.h>
#include <fbl/auto_lock.h>

#include "trace.h"
#include "usb-spew.h"

namespace mt_usb_hci {

zx_status_t TransactionQueue::QueueRequest(usb::BorrowedRequest<> req) {
  fbl::AutoLock _(&pending_lock_);

  // To prevent a race condition by which a request is enqueued after having stopped the
  // processing thread (thus orphaning the request), this check must be made with the lock held.
  if (halted_.load()) {
    req.Complete(ZX_ERR_IO_NOT_PRESENT, 0);
    return ZX_OK;
  }

  pending_.push(std::move(req));
  pending_cond_.Signal();
  return ZX_OK;
}

zx_status_t TransactionQueue::StartQueueThread() {
  auto go = [](void* arg) { return static_cast<TransactionQueue*>(arg)->QueueThread(); };
  auto rc = thrd_create_with_name(&pending_thread_, go, this, "usb-endpoint-thread");
  if (rc != thrd_success) {
    return ZX_ERR_INTERNAL;
  }
  return ZX_OK;
}

zx_status_t TransactionQueue::CancelAll() {
  fbl::AutoLock _(&pending_lock_);
  if (transaction_) {
    transaction_->Cancel();
  }

  while (!pending_.is_empty()) {
    std::optional<usb::BorrowedRequest<>> req = pending_.pop();
    req->Complete(ZX_ERR_CANCELED, 0);
  }

  return ZX_OK;
}

size_t TransactionQueue::GetMaxTransferSize() { return static_cast<size_t>(max_pkt_sz_); }

zx_status_t TransactionQueue::Halt() {
  {
    fbl::AutoLock _(&pending_lock_);
    if (transaction_) {
      transaction_->Cancel();
    }

    halted_ = true;
    pending_cond_.Signal();
  }

  if (pending_thread_) {
    int rc;
    int status = thrd_join(pending_thread_, &rc);
    if (status != thrd_success) {
      zxlogf(ERROR, "could not join pending_thread");
      return ZX_ERR_INTERNAL;
    } else if (rc != 0) {
      zxlogf(ERROR, "pending_thread returned nonzero status: %d", rc);
      return ZX_ERR_INTERNAL;
    }
  }

  return ZX_OK;
}

int TransactionQueue::QueueThread() {
  zx_status_t status;
  std::optional<usb::BorrowedRequest<>> req;

  for (;;) {
    {
      fbl::AutoLock _(&pending_lock_);
      if (pending_.is_empty()) {
        if (halted_.load()) {
          return 0;
        }

        // To prevent deadlock, the halted check must be made both before and after waiting.
        // The first check ensures that Halt() requests issued as a transaction was being
        // processed by the body of this loop are serviced.  The second check ensures that
        // Halt() requests issued while waiting are serviced.
        pending_cond_.Wait(&pending_lock_);

        if (halted_.load()) {
          return 0;
        }
      }
      req = pending_.pop();
    }

    // Popping an empty queue is something that should never really happen.
    ZX_ASSERT(req.has_value());

    status = DispatchRequest(std::move(req.value()));
    if (status != ZX_OK) {
      zxlogf(ERROR, "could not process usb request: %s", zx_status_get_string(status));
    }
  }
  return 0;
}

zx_status_t ControlQueue::GetDeviceDescriptor(usb_device_descriptor_t* out) {
  TRACE();
  usb_setup_t req = {
      // GET_DESCRIPTOR request, see: USB 2.0 spec. section 9.4.3.
      .bmRequestType = 0x80, .bRequest = 0x6,         .wValue = 0x0100,
      .wIndex = 0,           .wLength = sizeof(*out),
  };

  transaction_ = std::make_unique<Control>(ControlType::READ, usb_.View(0), req, out, sizeof(*out),
                                           max_pkt_sz_, faddr_);
  transaction_->Advance();
  transaction_->Wait();

  if (!transaction_->Ok()) {
    zxlogf(ERROR, "usb transaction did not complete successfully");
    return ZX_ERR_INTERNAL;
  }

  max_pkt_sz_ = static_cast<size_t>(out->bMaxPacketSize0);
  return ZX_OK;
}

zx_status_t ControlQueue::SetAddress(uint8_t addr) {
  usb_setup_t req = {
      // SET_ADDRESS request, see: USB 2.0 spec. section 9.4.6.
      .bmRequestType = 0, .bRequest = 0x5, .wValue = addr, .wIndex = 0, .wLength = 0,
  };

  transaction_ = std::make_unique<Control>(ControlType::ZERO, usb_.View(0), req, nullptr, 0,
                                           max_pkt_sz_, faddr_);
  transaction_->Advance();
  transaction_->Wait();

  if (!transaction_->Ok()) {
    zxlogf(ERROR, "usb transaction did not complete successfully");
    return ZX_ERR_INTERNAL;
  }

  // The USB spec. requires at least a 2ms sleep for device to finish processing new address
  // (see: USB 2.0 spec. 9.2.6.3).
  zx::nanosleep(zx::deadline_after(zx::msec(5)));

  faddr_ = addr;
  return ZX_OK;
}

zx_status_t ControlQueue::DispatchRequest(usb::BorrowedRequest<> req) {
  zx_status_t status;
  usb_setup_t setup = req.request()->setup;

  if (setup.wLength == 0) {  // See: USB 2.0 spec. section 9.3.5.
    transaction_ = std::make_unique<Control>(ControlType::ZERO, usb_.View(0), setup, nullptr, 0,
                                             max_pkt_sz_, faddr_);
  } else {
    void* vmo_addr;
    status = req.Mmap(&vmo_addr);
    if (status != ZX_OK) {
      zxlogf(ERROR, "could not map request vmo: %s", zx_status_get_string(status));
      req.Complete(status, 0);
      return status;
    }

    size_t size = req.request()->header.length;
    if ((setup.bmRequestType & USB_DIR_MASK) == USB_DIR_IN) {
      transaction_ = std::make_unique<Control>(ControlType::READ, usb_.View(0), setup, vmo_addr,
                                               size, max_pkt_sz_, faddr_);
    } else {  // USB_DIR_OUT
      transaction_ = std::make_unique<Control>(ControlType::WRITE, usb_.View(0), setup, vmo_addr,
                                               size, max_pkt_sz_, faddr_);
    }
  }

  transaction_->Advance();
  transaction_->Wait();

  if (halted_.load()) {
    req.Complete(ZX_ERR_IO_NOT_PRESENT, 0);
    return ZX_OK;
  } else if (!transaction_->Ok()) {
    zxlogf(ERROR, "usb control transfer did not complete successfully");
    req.Complete(ZX_ERR_INTERNAL, 0);
    return ZX_ERR_INTERNAL;
  }
  req.Complete(ZX_OK, transaction_->actual());
  return ZX_OK;
}

zx_status_t BulkQueue::DispatchRequest(usb::BorrowedRequest<> req) {
  void* vmo_addr;
  auto status = req.Mmap(&vmo_addr);
  if (status != ZX_OK) {
    zxlogf(ERROR, "could not map request vmo: %s", zx_status_get_string(status));
    req.Complete(status, 0);
    return status;
  }

  size_t size = req.request()->header.length;
  transaction_ = std::make_unique<Bulk>(usb_.View(0), faddr_, vmo_addr, size, descriptor_);
  transaction_->Advance();
  transaction_->Wait();

  if (halted_.load()) {
    req.Complete(ZX_ERR_IO_NOT_PRESENT, 0);
    return ZX_OK;
  } else if (!transaction_->Ok()) {
    zxlogf(ERROR, "usb bulk transfer did not complete successfully");
    req.Complete(ZX_ERR_INTERNAL, 0);
    return ZX_ERR_INTERNAL;
  }
  req.Complete(ZX_OK, transaction_->actual());
  return ZX_OK;
}

zx_status_t InterruptQueue::DispatchRequest(usb::BorrowedRequest<> req) {
  void* vmo_addr;
  auto status = req.Mmap(&vmo_addr);
  if (status != ZX_OK) {
    zxlogf(ERROR, "could not map request vmo: %s", zx_status_get_string(status));
    req.Complete(status, 0);
    return status;
  }

  size_t size = req.request()->header.length;
  transaction_ = std::make_unique<Interrupt>(usb_.View(0), faddr_, vmo_addr, size, descriptor_);
  transaction_->Advance();
  transaction_->Wait();

  if (halted_.load()) {
    req.Complete(ZX_ERR_IO_NOT_PRESENT, 0);
    return ZX_OK;
  } else if (!transaction_->Ok()) {
    zxlogf(ERROR, "usb interrupt transfer did not complete successfully");
    req.Complete(ZX_ERR_INTERNAL, 0);
    return ZX_ERR_INTERNAL;
  }
  req.Complete(ZX_OK, transaction_->actual());
  return ZX_OK;
}

}  // namespace mt_usb_hci