// Copyright 2017 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 <assert.h>
#include <ddk/debug.h>
#include <zircon/assert.h>

#include <usb/usb-request.h>
#include <fbl/auto_lock.h>

#include "dwc3.h"
#include "dwc3-regs.h"
#include "dwc3-types.h"

#include <stdio.h>
#include <string.h>

#define EP_FIFO_SIZE    PAGE_SIZE

static zx_paddr_t dwc3_ep_trb_phys(dwc3_endpoint_t* ep, dwc3_trb_t* trb) {
    return io_buffer_phys(&ep->fifo.buffer) + (trb - ep->fifo.first) * sizeof(*trb);
}

static void dwc3_enable_ep(dwc3_t* dwc, unsigned ep_num, bool enable) {
    auto* mmio = dwc3_mmio(dwc);

    fbl::AutoLock lock(&dwc->lock);

    if (enable) {
        DALEPENA::Get().ReadFrom(mmio).EnableEp(ep_num).WriteTo(mmio);
    } else {
        DALEPENA::Get().ReadFrom(mmio).DisableEp(ep_num).WriteTo(mmio);
    }
}

zx_status_t dwc3_ep_fifo_init(dwc3_t* dwc, unsigned ep_num) {
    ZX_DEBUG_ASSERT(ep_num < countof(dwc->eps));
    dwc3_endpoint_t* ep = &dwc->eps[ep_num];
    dwc3_fifo_t* fifo = &ep->fifo;

    static_assert(EP_FIFO_SIZE <= PAGE_SIZE, "");
    zx_status_t status = io_buffer_init(&fifo->buffer, dwc->bti_handle.get(), EP_FIFO_SIZE,
                                        IO_BUFFER_RW | IO_BUFFER_CONTIG);
    if (status != ZX_OK) {
        return status;
    }

    fifo->first = static_cast<dwc3_trb_t*>(io_buffer_virt(&fifo->buffer));
    fifo->next = fifo->first;
    fifo->current = nullptr;
    fifo->last = fifo->first + (EP_FIFO_SIZE / sizeof(dwc3_trb_t)) - 1;

    // set up link TRB pointing back to the start of the fifo
    dwc3_trb_t* trb = fifo->last;
    zx_paddr_t trb_phys = io_buffer_phys(&fifo->buffer);
    trb->ptr_low = (uint32_t)trb_phys;
    trb->ptr_high = (uint32_t)(trb_phys >> 32);
    trb->status = 0;
    trb->control = TRB_TRBCTL_LINK | TRB_HWO;
    io_buffer_cache_flush(&ep->fifo.buffer, (trb - ep->fifo.first) * sizeof(*trb), sizeof(*trb));

    return ZX_OK;
}

void dwc3_ep_fifo_release(dwc3_t* dwc, unsigned ep_num) {
    ZX_DEBUG_ASSERT(ep_num < countof(dwc->eps));
    dwc3_endpoint_t* ep = &dwc->eps[ep_num];

    io_buffer_release(&ep->fifo.buffer);
}

void dwc3_ep_start_transfer(dwc3_t* dwc, unsigned ep_num, unsigned type, zx_paddr_t buffer,
                            size_t length, bool send_zlp) {
    zxlogf(LTRACE, "dwc3_ep_start_transfer ep %u type %u length %zu\n", ep_num, type, length);

    // special case: EP0_OUT and EP0_IN use the same fifo
    dwc3_endpoint_t* ep = (ep_num == EP0_IN ? &dwc->eps[EP0_OUT] : &dwc->eps[ep_num]);

    dwc3_trb_t* trb = ep->fifo.next++;
    if (ep->fifo.next == ep->fifo.last) {
        ep->fifo.next = ep->fifo.first;
    }
    if (ep->fifo.current == nullptr) {
        ep->fifo.current = trb;
    }

    trb->ptr_low = (uint32_t)buffer;
    trb->ptr_high = (uint32_t)(buffer >> 32);
    trb->status = TRB_BUFSIZ(static_cast<uint32_t>(length));
    if (send_zlp) {
        trb->control = type | TRB_HWO;
    } else {
        trb->control = type | TRB_LST | TRB_IOC | TRB_HWO;
    }
    io_buffer_cache_flush(&ep->fifo.buffer, (trb - ep->fifo.first) * sizeof(*trb), sizeof(*trb));

    if (send_zlp) {
        dwc3_trb_t* zlp_trb = ep->fifo.next++;
        if (ep->fifo.next == ep->fifo.last) {
            ep->fifo.next = ep->fifo.first;
        }
        zlp_trb->ptr_low = 0;
        zlp_trb->ptr_high = 0;
        zlp_trb->status = TRB_BUFSIZ(0);
        zlp_trb->control = type | TRB_LST | TRB_IOC | TRB_HWO;
        io_buffer_cache_flush(&ep->fifo.buffer, (zlp_trb - ep->fifo.first) * sizeof(*trb),
                              sizeof(*trb));
    }

    dwc3_cmd_ep_start_transfer(dwc, ep_num, dwc3_ep_trb_phys(ep, trb));
}

static void dwc3_ep_queue_next_locked(dwc3_t* dwc, dwc3_endpoint_t* ep) {
    dwc_usb_req_internal_t* req_int;

    if (ep->current_req == nullptr && ep->got_not_ready &&
        (req_int = list_remove_head_type(&ep->queued_reqs, dwc_usb_req_internal_t, node))
            != nullptr) {
        usb_request_t* req = INTERNAL_TO_USB_REQ(req_int);
        ep->current_req = req;
        ep->got_not_ready = false;
        if (EP_IN(ep->ep_num)) {
            usb_request_cache_flush(req, 0, req->header.length);
        } else {
            usb_request_cache_flush_invalidate(req, 0, req->header.length);
        }

        // TODO(voydanoff) scatter/gather support
        phys_iter_t iter;
        zx_paddr_t phys;
        usb_request_physmap(req, dwc->bti_handle.get());
        usb_request_phys_iter_init(&iter, req, PAGE_SIZE);
        usb_request_phys_iter_next(&iter, &phys);
        bool send_zlp = req->header.send_zlp && (req->header.length % ep->max_packet_size) == 0;
        dwc3_ep_start_transfer(dwc, ep->ep_num, TRB_TRBCTL_NORMAL, phys, req->header.length,
                               send_zlp);
    }
}

zx_status_t dwc3_ep_config(dwc3_t* dwc, const usb_endpoint_descriptor_t* ep_desc,
                           const usb_ss_ep_comp_descriptor_t* ss_comp_desc) {
    // convert address to index in range 0 - 31
    // low bit is IN/OUT
    unsigned ep_num = dwc3_ep_num(ep_desc->bEndpointAddress);
    if (ep_num < 2) {
        // index 0 and 1 are for endpoint zero
        return ZX_ERR_INVALID_ARGS;
    }

    uint8_t ep_type = usb_ep_type(ep_desc);
    if (ep_type == USB_ENDPOINT_ISOCHRONOUS) {
        zxlogf(ERROR, "dwc3_ep_config: isochronous endpoints are not supported\n");
        return ZX_ERR_NOT_SUPPORTED;
    }

    dwc3_endpoint_t* ep = &dwc->eps[ep_num];

    fbl::AutoLock lock(&ep->lock);

    zx_status_t status = dwc3_ep_fifo_init(dwc, ep_num);
    if (status != ZX_OK) {
        zxlogf(ERROR, "dwc3_config_ep: dwc3_ep_fifo_init failed %d\n", status);
        return status;
    }
    ep->max_packet_size = usb_ep_max_packet(ep_desc);
    ep->type = ep_type;
    ep->interval = ep_desc->bInterval;
    // TODO(voydanoff) USB3 support

    ep->enabled = true;

    if (dwc->configured) {
        dwc3_ep_queue_next_locked(dwc, ep);
    }

    return ZX_OK;
}

zx_status_t dwc3_ep_disable(dwc3_t* dwc, uint8_t ep_addr) {
    // convert address to index in range 0 - 31
    // low bit is IN/OUT
    unsigned ep_num = dwc3_ep_num(ep_addr);
    if (ep_num < 2) {
        // index 0 and 1 are for endpoint zero
        return ZX_ERR_INVALID_ARGS;
    }

    dwc3_endpoint_t* ep = &dwc->eps[ep_num];

    fbl::AutoLock lock(&ep->lock);

    dwc3_ep_fifo_release(dwc, ep_num);
    ep->enabled = false;

    return ZX_OK;
}

void dwc3_ep_queue(dwc3_t* dwc, unsigned ep_num, usb_request_t* req) {
    dwc3_endpoint_t* ep = &dwc->eps[ep_num];
    auto* req_int = USB_REQ_TO_INTERNAL(req);

    // OUT transactions must have length > 0 and multiple of max packet size
    if (EP_OUT(ep_num)) {
        if (req->header.length == 0 || req->header.length % ep->max_packet_size != 0) {
            zxlogf(ERROR, "dwc3_ep_queue: OUT transfers must be multiple of max packet size\n");
            usb_request_complete(req, ZX_ERR_INVALID_ARGS, 0, &req_int->complete_cb);
            return;
        }
    }

    fbl::AutoLock lock(&ep->lock);

    if (!ep->enabled) {
        usb_request_complete(req, ZX_ERR_BAD_STATE, 0, &req_int->complete_cb);
        return;
    }

    list_add_tail(&ep->queued_reqs, &req_int->node);

    if (dwc->configured) {
        dwc3_ep_queue_next_locked(dwc, ep);
    }
}

void dwc3_ep_set_config(dwc3_t* dwc, unsigned ep_num, bool enable) {
    zxlogf(TRACE, "dwc3_ep_set_config %u\n", ep_num);

    dwc3_endpoint_t* ep = &dwc->eps[ep_num];

    if (enable) {
        dwc3_cmd_ep_set_config(dwc, ep_num, ep->type, ep->max_packet_size, ep->interval, false);
        dwc3_cmd_ep_transfer_config(dwc, ep_num);
        dwc3_enable_ep(dwc, ep_num, true);
    } else {
        dwc3_enable_ep(dwc, ep_num, false);
    }
}

void dwc3_start_eps(dwc3_t* dwc) {
    zxlogf(TRACE, "dwc3_start_eps\n");

    dwc3_cmd_ep_set_config(dwc, EP0_IN, USB_ENDPOINT_CONTROL, dwc->eps[EP0_IN].max_packet_size, 0,
                           true);
    dwc3_cmd_start_new_config(dwc, EP0_OUT, 2);

    for (unsigned ep_num = 2; ep_num < countof(dwc->eps); ep_num++) {
        dwc3_endpoint_t* ep = &dwc->eps[ep_num];
        if (ep->enabled) {
            dwc3_ep_set_config(dwc, ep_num, true);

            fbl::AutoLock lock(&ep->lock);
            dwc3_ep_queue_next_locked(dwc, ep);
        }
    }
}

void dwc_ep_read_trb(dwc3_endpoint_t* ep, dwc3_trb_t* trb, dwc3_trb_t* out_trb) {
    if (trb >= ep->fifo.first && trb < ep->fifo.last) {
        io_buffer_cache_flush_invalidate(&ep->fifo.buffer, (trb - ep->fifo.first) * sizeof(*trb),
                                         sizeof(*trb));
        memcpy((void *)out_trb, (void *)trb, sizeof(*trb));
    } else {
        zxlogf(ERROR, "dwc_ep_read_trb: bad trb\n");
    }
}

void dwc3_ep_xfer_started(dwc3_t* dwc, unsigned ep_num, unsigned rsrc_id) {
    dwc3_endpoint_t* ep = &dwc->eps[ep_num];
    fbl::AutoLock lock(&ep->lock);

    ep->rsrc_id = rsrc_id;
}

void dwc3_ep_xfer_not_ready(dwc3_t* dwc, unsigned ep_num, unsigned stage) {
    zxlogf(LTRACE, "dwc3_ep_xfer_not_ready ep %u state %d\n", ep_num, dwc->ep0_state);

    if (ep_num == EP0_OUT || ep_num == EP0_IN) {
        dwc3_ep0_xfer_not_ready(dwc, ep_num, stage);
    } else {
        dwc3_endpoint_t* ep = &dwc->eps[ep_num];

        fbl::AutoLock lock(&ep->lock);
        ep->got_not_ready = true;
        dwc3_ep_queue_next_locked(dwc, ep);
    }
}

void dwc3_ep_xfer_complete(dwc3_t* dwc, unsigned ep_num) {
    zxlogf(LTRACE, "dwc3_ep_xfer_complete ep %u state %d\n", ep_num, dwc->ep0_state);

    if (ep_num >= countof(dwc->eps)) {
        zxlogf(ERROR, "dwc3_ep_xfer_complete: bad ep_num %u\n", ep_num);
        return;
    }

    if (ep_num == EP0_OUT || ep_num == EP0_IN) {
        dwc3_ep0_xfer_complete(dwc, ep_num);
    } else {
        dwc3_endpoint_t* ep = &dwc->eps[ep_num];

        ep->lock.Acquire();
        usb_request_t* req = ep->current_req;
        ep->current_req = nullptr;

        if (req) {
            dwc3_trb_t  trb;
            dwc_ep_read_trb(ep, ep->fifo.current, &trb);
            ep->fifo.current = nullptr;
            if (trb.control & TRB_HWO) {
                zxlogf(ERROR, "TRB_HWO still set in dwc3_ep_xfer_complete\n");
            }

            zx_off_t actual = req->header.length - TRB_BUFSIZ(trb.status);
//            dwc3_ep_queue_next_locked(dwc, ep);

            ep->lock.Release();

            auto* req_int = USB_REQ_TO_INTERNAL(req);
            usb_request_complete(req, ZX_OK, actual, &req_int->complete_cb);
        } else {
            ep->lock.Release();
            zxlogf(ERROR, "dwc3_ep_xfer_complete: no usb request found to complete!\n");
        }
    }
}

zx_status_t dwc3_ep_set_stall(dwc3_t* dwc, unsigned ep_num, bool stall) {
    if (ep_num >= countof(dwc->eps)) {
        return ZX_ERR_INVALID_ARGS;
    }

    dwc3_endpoint_t* ep = &dwc->eps[ep_num];
    fbl::AutoLock lock(&ep->lock);

    if (!ep->enabled) {
        return ZX_ERR_BAD_STATE;
    }
    if (stall && !ep->stalled) {
        dwc3_cmd_ep_set_stall(dwc, ep_num);
    } else if (!stall && ep->stalled) {
        dwc3_cmd_ep_clear_stall(dwc, ep_num);
    }
    ep->stalled = stall;

    return ZX_OK;
}

void dwc3_ep_end_transfers(dwc3_t* dwc, unsigned ep_num, zx_status_t reason) {
    dwc3_endpoint_t* ep = &dwc->eps[ep_num];
    fbl::AutoLock lock(&ep->lock);

    if (ep->current_req) {
        dwc3_cmd_ep_end_transfer(dwc, ep_num);
        auto* req_int = USB_REQ_TO_INTERNAL(ep->current_req);
        usb_request_complete(ep->current_req, reason, 0, &req_int->complete_cb);
        ep->current_req = nullptr;
    }

    dwc_usb_req_internal_t* req_int;
    while ((req_int = list_remove_head_type(&ep->queued_reqs, dwc_usb_req_internal_t, node))
                != nullptr) {
        usb_request_t* req = INTERNAL_TO_USB_REQ(req_int);
        usb_request_complete(req, reason, 0, &req_int->complete_cb);
    }
}