USB: xhci: Make endpoint interval debugging clearer.

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / drivers / usb / host / xhci-mem.c

/*
 * xHCI host controller driver
 *
 * Copyright (C) 2008 Intel Corp.
 *
 * Author: Sarah Sharp
 * Some code borrowed from the Linux EHCI driver.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/usb.h>
#include <linux/pci.h>
#include <linux/dmapool.h>

#include "xhci.h"

/*
 * Allocates a generic ring segment from the ring pool, sets the dma address,
 * initializes the segment to zero, and sets the private next pointer to NULL.
 *
 * Section 4.11.1.1:
 * "All components of all Command and Transfer TRBs shall be initialized to '0'"
 */
static struct xhci_segment *xhci_segment_alloc(struct xhci_hcd *xhci, gfp_t flags)
{
        struct xhci_segment *seg;
        dma_addr_t      dma;

        seg = kzalloc(sizeof *seg, flags);
        if (!seg)
                return 0;
        xhci_dbg(xhci, "Allocating priv segment structure at %p\n", seg);

        seg->trbs = dma_pool_alloc(xhci->segment_pool, flags, &dma);
        if (!seg->trbs) {
                kfree(seg);
                return 0;
        }
        xhci_dbg(xhci, "// Allocating segment at %p (virtual) 0x%llx (DMA)\n",
                        seg->trbs, (unsigned long long)dma);

        memset(seg->trbs, 0, SEGMENT_SIZE);
        seg->dma = dma;
        seg->next = NULL;

        return seg;
}

static void xhci_segment_free(struct xhci_hcd *xhci, struct xhci_segment *seg)
{
        if (!seg)
                return;
        if (seg->trbs) {
                xhci_dbg(xhci, "Freeing DMA segment at %p (virtual) 0x%llx (DMA)\n",
                                seg->trbs, (unsigned long long)seg->dma);
                dma_pool_free(xhci->segment_pool, seg->trbs, seg->dma);
                seg->trbs = NULL;
        }
        xhci_dbg(xhci, "Freeing priv segment structure at %p\n", seg);
        kfree(seg);
}

/*
 * Make the prev segment point to the next segment.
 *
 * Change the last TRB in the prev segment to be a Link TRB which points to the
 * DMA address of the next segment.  The caller needs to set any Link TRB
 * related flags, such as End TRB, Toggle Cycle, and no snoop.
 */
static void xhci_link_segments(struct xhci_hcd *xhci, struct xhci_segment *prev,
                struct xhci_segment *next, bool link_trbs)
{
        u32 val;

        if (!prev || !next)
                return;
        prev->next = next;
        if (link_trbs) {
                prev->trbs[TRBS_PER_SEGMENT-1].link.segment_ptr = next->dma;

                /* Set the last TRB in the segment to have a TRB type ID of Link TRB */
                val = prev->trbs[TRBS_PER_SEGMENT-1].link.control;
                val &= ~TRB_TYPE_BITMASK;
                val |= TRB_TYPE(TRB_LINK);
                /* Always set the chain bit with 0.95 hardware */
                if (xhci_link_trb_quirk(xhci))
                        val |= TRB_CHAIN;
                prev->trbs[TRBS_PER_SEGMENT-1].link.control = val;
        }
        xhci_dbg(xhci, "Linking segment 0x%llx to segment 0x%llx (DMA)\n",
                        (unsigned long long)prev->dma,
                        (unsigned long long)next->dma);
}

/* XXX: Do we need the hcd structure in all these functions? */
void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring)
{
        struct xhci_segment *seg;
        struct xhci_segment *first_seg;

        if (!ring || !ring->first_seg)
                return;
        first_seg = ring->first_seg;
        seg = first_seg->next;
        xhci_dbg(xhci, "Freeing ring at %p\n", ring);
        while (seg != first_seg) {
                struct xhci_segment *next = seg->next;
                xhci_segment_free(xhci, seg);
                seg = next;
        }
        xhci_segment_free(xhci, first_seg);
        ring->first_seg = NULL;
        kfree(ring);
}

static void xhci_initialize_ring_info(struct xhci_ring *ring)
{
        /* The ring is empty, so the enqueue pointer == dequeue pointer */
        ring->enqueue = ring->first_seg->trbs;
        ring->enq_seg = ring->first_seg;
        ring->dequeue = ring->enqueue;
        ring->deq_seg = ring->first_seg;
        /* The ring is initialized to 0. The producer must write 1 to the cycle
         * bit to handover ownership of the TRB, so PCS = 1.  The consumer must
         * compare CCS to the cycle bit to check ownership, so CCS = 1.
         */
        ring->cycle_state = 1;
        /* Not necessary for new rings, but needed for re-initialized rings */
        ring->enq_updates = 0;
        ring->deq_updates = 0;
}

/**
 * Create a new ring with zero or more segments.
 *
 * Link each segment together into a ring.
 * Set the end flag and the cycle toggle bit on the last segment.
 * See section 4.9.1 and figures 15 and 16.
 */
static struct xhci_ring *xhci_ring_alloc(struct xhci_hcd *xhci,
                unsigned int num_segs, bool link_trbs, gfp_t flags)
{
        struct xhci_ring        *ring;
        struct xhci_segment     *prev;

        ring = kzalloc(sizeof *(ring), flags);
        xhci_dbg(xhci, "Allocating ring at %p\n", ring);
        if (!ring)
                return 0;

        INIT_LIST_HEAD(&ring->td_list);
        if (num_segs == 0)
                return ring;

        ring->first_seg = xhci_segment_alloc(xhci, flags);
        if (!ring->first_seg)
                goto fail;
        num_segs--;

        prev = ring->first_seg;
        while (num_segs > 0) {
                struct xhci_segment     *next;

                next = xhci_segment_alloc(xhci, flags);
                if (!next)
                        goto fail;
                xhci_link_segments(xhci, prev, next, link_trbs);

                prev = next;
                num_segs--;
        }
        xhci_link_segments(xhci, prev, ring->first_seg, link_trbs);

        if (link_trbs) {
                /* See section 4.9.2.1 and 6.4.4.1 */
                prev->trbs[TRBS_PER_SEGMENT-1].link.control |= (LINK_TOGGLE);
                xhci_dbg(xhci, "Wrote link toggle flag to"
                                " segment %p (virtual), 0x%llx (DMA)\n",
                                prev, (unsigned long long)prev->dma);
        }
        xhci_initialize_ring_info(ring);
        return ring;

fail:
        xhci_ring_free(xhci, ring);
        return 0;
}

void xhci_free_or_cache_endpoint_ring(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                unsigned int ep_index)
{
        int rings_cached;

        rings_cached = virt_dev->num_rings_cached;
        if (rings_cached < XHCI_MAX_RINGS_CACHED) {
                virt_dev->num_rings_cached++;
                rings_cached = virt_dev->num_rings_cached;
                virt_dev->ring_cache[rings_cached] =
                        virt_dev->eps[ep_index].ring;
                xhci_dbg(xhci, "Cached old ring, "
                                "%d ring%s cached\n",
                                rings_cached,
                                (rings_cached > 1) ? "s" : "");
        } else {
                xhci_ring_free(xhci, virt_dev->eps[ep_index].ring);
                xhci_dbg(xhci, "Ring cache full (%d rings), "
                                "freeing ring\n",
                                virt_dev->num_rings_cached);
        }
        virt_dev->eps[ep_index].ring = NULL;
}

/* Zero an endpoint ring (except for link TRBs) and move the enqueue and dequeue
 * pointers to the beginning of the ring.
 */
static void xhci_reinit_cached_ring(struct xhci_hcd *xhci,
                struct xhci_ring *ring)
{
        struct xhci_segment     *seg = ring->first_seg;
        do {
                memset(seg->trbs, 0,
                                sizeof(union xhci_trb)*TRBS_PER_SEGMENT);
                /* All endpoint rings have link TRBs */
                xhci_link_segments(xhci, seg, seg->next, 1);
                seg = seg->next;
        } while (seg != ring->first_seg);
        xhci_initialize_ring_info(ring);
        /* td list should be empty since all URBs have been cancelled,
         * but just in case...
         */
        INIT_LIST_HEAD(&ring->td_list);
}

#define CTX_SIZE(_hcc) (HCC_64BYTE_CONTEXT(_hcc) ? 64 : 32)

struct xhci_container_ctx *xhci_alloc_container_ctx(struct xhci_hcd *xhci,
                                                    int type, gfp_t flags)
{
        struct xhci_container_ctx *ctx = kzalloc(sizeof(*ctx), flags);
        if (!ctx)
                return NULL;

        BUG_ON((type != XHCI_CTX_TYPE_DEVICE) && (type != XHCI_CTX_TYPE_INPUT));
        ctx->type = type;
        ctx->size = HCC_64BYTE_CONTEXT(xhci->hcc_params) ? 2048 : 1024;
        if (type == XHCI_CTX_TYPE_INPUT)
                ctx->size += CTX_SIZE(xhci->hcc_params);

        ctx->bytes = dma_pool_alloc(xhci->device_pool, flags, &ctx->dma);
        memset(ctx->bytes, 0, ctx->size);
        return ctx;
}

void xhci_free_container_ctx(struct xhci_hcd *xhci,
                             struct xhci_container_ctx *ctx)
{
        if (!ctx)
                return;
        dma_pool_free(xhci->device_pool, ctx->bytes, ctx->dma);
        kfree(ctx);
}

struct xhci_input_control_ctx *xhci_get_input_control_ctx(struct xhci_hcd *xhci,
                                              struct xhci_container_ctx *ctx)
{
        BUG_ON(ctx->type != XHCI_CTX_TYPE_INPUT);
        return (struct xhci_input_control_ctx *)ctx->bytes;
}

struct xhci_slot_ctx *xhci_get_slot_ctx(struct xhci_hcd *xhci,
                                        struct xhci_container_ctx *ctx)
{
        if (ctx->type == XHCI_CTX_TYPE_DEVICE)
                return (struct xhci_slot_ctx *)ctx->bytes;

        return (struct xhci_slot_ctx *)
                (ctx->bytes + CTX_SIZE(xhci->hcc_params));
}

struct xhci_ep_ctx *xhci_get_ep_ctx(struct xhci_hcd *xhci,
                                    struct xhci_container_ctx *ctx,
                                    unsigned int ep_index)
{
        /* increment ep index by offset of start of ep ctx array */
        ep_index++;
        if (ctx->type == XHCI_CTX_TYPE_INPUT)
                ep_index++;

        return (struct xhci_ep_ctx *)
                (ctx->bytes + (ep_index * CTX_SIZE(xhci->hcc_params)));
}

static void xhci_init_endpoint_timer(struct xhci_hcd *xhci,
                struct xhci_virt_ep *ep)
{
        init_timer(&ep->stop_cmd_timer);
        ep->stop_cmd_timer.data = (unsigned long) ep;
        ep->stop_cmd_timer.function = xhci_stop_endpoint_command_watchdog;
        ep->xhci = xhci;
}

/* All the xhci_tds in the ring's TD list should be freed at this point */
void xhci_free_virt_device(struct xhci_hcd *xhci, int slot_id)
{
        struct xhci_virt_device *dev;
        int i;

        /* Slot ID 0 is reserved */
        if (slot_id == 0 || !xhci->devs[slot_id])
                return;

        dev = xhci->devs[slot_id];
        xhci->dcbaa->dev_context_ptrs[slot_id] = 0;
        if (!dev)
                return;

        for (i = 0; i < 31; ++i)
                if (dev->eps[i].ring)
                        xhci_ring_free(xhci, dev->eps[i].ring);

        if (dev->ring_cache) {
                for (i = 0; i < dev->num_rings_cached; i++)
                        xhci_ring_free(xhci, dev->ring_cache[i]);
                kfree(dev->ring_cache);
        }

        if (dev->in_ctx)
                xhci_free_container_ctx(xhci, dev->in_ctx);
        if (dev->out_ctx)
                xhci_free_container_ctx(xhci, dev->out_ctx);

        kfree(xhci->devs[slot_id]);
        xhci->devs[slot_id] = 0;
}

int xhci_alloc_virt_device(struct xhci_hcd *xhci, int slot_id,
                struct usb_device *udev, gfp_t flags)
{
        struct xhci_virt_device *dev;
        int i;

        /* Slot ID 0 is reserved */
        if (slot_id == 0 || xhci->devs[slot_id]) {
                xhci_warn(xhci, "Bad Slot ID %d\n", slot_id);
                return 0;
        }

        xhci->devs[slot_id] = kzalloc(sizeof(*xhci->devs[slot_id]), flags);
        if (!xhci->devs[slot_id])
                return 0;
        dev = xhci->devs[slot_id];

        /* Allocate the (output) device context that will be used in the HC. */
        dev->out_ctx = xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_DEVICE, flags);
        if (!dev->out_ctx)
                goto fail;

        xhci_dbg(xhci, "Slot %d output ctx = 0x%llx (dma)\n", slot_id,
                        (unsigned long long)dev->out_ctx->dma);

        /* Allocate the (input) device context for address device command */
        dev->in_ctx = xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_INPUT, flags);
        if (!dev->in_ctx)
                goto fail;

        xhci_dbg(xhci, "Slot %d input ctx = 0x%llx (dma)\n", slot_id,
                        (unsigned long long)dev->in_ctx->dma);

        /* Initialize the cancellation list and watchdog timers for each ep */
        for (i = 0; i < 31; i++) {
                xhci_init_endpoint_timer(xhci, &dev->eps[i]);
                INIT_LIST_HEAD(&dev->eps[i].cancelled_td_list);
        }

        /* Allocate endpoint 0 ring */
        dev->eps[0].ring = xhci_ring_alloc(xhci, 1, true, flags);
        if (!dev->eps[0].ring)
                goto fail;

        /* Allocate pointers to the ring cache */
        dev->ring_cache = kzalloc(
                        sizeof(struct xhci_ring *)*XHCI_MAX_RINGS_CACHED,
                        flags);
        if (!dev->ring_cache)
                goto fail;
        dev->num_rings_cached = 0;

        init_completion(&dev->cmd_completion);
        INIT_LIST_HEAD(&dev->cmd_list);

        /* Point to output device context in dcbaa. */
        xhci->dcbaa->dev_context_ptrs[slot_id] = dev->out_ctx->dma;
        xhci_dbg(xhci, "Set slot id %d dcbaa entry %p to 0x%llx\n",
                        slot_id,
                        &xhci->dcbaa->dev_context_ptrs[slot_id],
                        (unsigned long long) xhci->dcbaa->dev_context_ptrs[slot_id]);

        return 1;
fail:
        xhci_free_virt_device(xhci, slot_id);
        return 0;
}

/* Setup an xHCI virtual device for a Set Address command */
int xhci_setup_addressable_virt_dev(struct xhci_hcd *xhci, struct usb_device *udev)
{
        struct xhci_virt_device *dev;
        struct xhci_ep_ctx      *ep0_ctx;
        struct usb_device       *top_dev;
        struct xhci_slot_ctx    *slot_ctx;
        struct xhci_input_control_ctx *ctrl_ctx;

        dev = xhci->devs[udev->slot_id];
        /* Slot ID 0 is reserved */
        if (udev->slot_id == 0 || !dev) {
                xhci_warn(xhci, "Slot ID %d is not assigned to this device\n",
                                udev->slot_id);
                return -EINVAL;
        }
        ep0_ctx = xhci_get_ep_ctx(xhci, dev->in_ctx, 0);
        ctrl_ctx = xhci_get_input_control_ctx(xhci, dev->in_ctx);
        slot_ctx = xhci_get_slot_ctx(xhci, dev->in_ctx);

        /* 2) New slot context and endpoint 0 context are valid*/
        ctrl_ctx->add_flags = SLOT_FLAG | EP0_FLAG;

        /* 3) Only the control endpoint is valid - one endpoint context */
        slot_ctx->dev_info |= LAST_CTX(1);

        slot_ctx->dev_info |= (u32) udev->route;
        switch (udev->speed) {
        case USB_SPEED_SUPER:
                slot_ctx->dev_info |= (u32) SLOT_SPEED_SS;
                break;
        case USB_SPEED_HIGH:
                slot_ctx->dev_info |= (u32) SLOT_SPEED_HS;
                break;
        case USB_SPEED_FULL:
                slot_ctx->dev_info |= (u32) SLOT_SPEED_FS;
                break;
        case USB_SPEED_LOW:
                slot_ctx->dev_info |= (u32) SLOT_SPEED_LS;
                break;
        case USB_SPEED_WIRELESS:
                xhci_dbg(xhci, "FIXME xHCI doesn't support wireless speeds\n");
                return -EINVAL;
                break;
        default:
                /* Speed was set earlier, this shouldn't happen. */
                BUG();
        }
        /* Find the root hub port this device is under */
        for (top_dev = udev; top_dev->parent && top_dev->parent->parent;
                        top_dev = top_dev->parent)
                /* Found device below root hub */;
        slot_ctx->dev_info2 |= (u32) ROOT_HUB_PORT(top_dev->portnum);
        xhci_dbg(xhci, "Set root hub portnum to %d\n", top_dev->portnum);

        /* Is this a LS/FS device under a HS hub? */
        if ((udev->speed == USB_SPEED_LOW || udev->speed == USB_SPEED_FULL) &&
                        udev->tt) {
                slot_ctx->tt_info = udev->tt->hub->slot_id;
                slot_ctx->tt_info |= udev->ttport << 8;
                if (udev->tt->multi)
                        slot_ctx->dev_info |= DEV_MTT;
        }
        xhci_dbg(xhci, "udev->tt = %p\n", udev->tt);
        xhci_dbg(xhci, "udev->ttport = 0x%x\n", udev->ttport);

        /* Step 4 - ring already allocated */
        /* Step 5 */
        ep0_ctx->ep_info2 = EP_TYPE(CTRL_EP);
        /*
         * XXX: Not sure about wireless USB devices.
         */
        switch (udev->speed) {
        case USB_SPEED_SUPER:
                ep0_ctx->ep_info2 |= MAX_PACKET(512);
                break;
        case USB_SPEED_HIGH:
        /* USB core guesses at a 64-byte max packet first for FS devices */
        case USB_SPEED_FULL:
                ep0_ctx->ep_info2 |= MAX_PACKET(64);
                break;
        case USB_SPEED_LOW:
                ep0_ctx->ep_info2 |= MAX_PACKET(8);
                break;
        case USB_SPEED_WIRELESS:
                xhci_dbg(xhci, "FIXME xHCI doesn't support wireless speeds\n");
                return -EINVAL;
                break;
        default:
                /* New speed? */
                BUG();
        }
        /* EP 0 can handle "burst" sizes of 1, so Max Burst Size field is 0 */
        ep0_ctx->ep_info2 |= MAX_BURST(0);
        ep0_ctx->ep_info2 |= ERROR_COUNT(3);

        ep0_ctx->deq =
                dev->eps[0].ring->first_seg->dma;
        ep0_ctx->deq |= dev->eps[0].ring->cycle_state;

        /* Steps 7 and 8 were done in xhci_alloc_virt_device() */

        return 0;
}

/* Return the polling or NAK interval.
 *
 * The polling interval is expressed in "microframes".  If xHCI's Interval field
 * is set to N, it will service the endpoint every 2^(Interval)*125us.
 *
 * The NAK interval is one NAK per 1 to 255 microframes, or no NAKs if interval
 * is set to 0.
 */
static inline unsigned int xhci_get_endpoint_interval(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        unsigned int interval = 0;

        switch (udev->speed) {
        case USB_SPEED_HIGH:
                /* Max NAK rate */
                if (usb_endpoint_xfer_control(&ep->desc) ||
                                usb_endpoint_xfer_bulk(&ep->desc))
                        interval = ep->desc.bInterval;
                /* Fall through - SS and HS isoc/int have same decoding */
        case USB_SPEED_SUPER:
                if (usb_endpoint_xfer_int(&ep->desc) ||
                                usb_endpoint_xfer_isoc(&ep->desc)) {
                        if (ep->desc.bInterval == 0)
                                interval = 0;
                        else
                                interval = ep->desc.bInterval - 1;
                        if (interval > 15)
                                interval = 15;
                        if (interval != ep->desc.bInterval + 1)
                                dev_warn(&udev->dev, "ep %#x - rounding interval to %d microframes\n",
                                                ep->desc.bEndpointAddress, 1 << interval);
                }
                break;
        /* Convert bInterval (in 1-255 frames) to microframes and round down to
         * nearest power of 2.
         */
        case USB_SPEED_FULL:
        case USB_SPEED_LOW:
                if (usb_endpoint_xfer_int(&ep->desc) ||
                                usb_endpoint_xfer_isoc(&ep->desc)) {
                        interval = fls(8*ep->desc.bInterval) - 1;
                        if (interval > 10)
                                interval = 10;
                        if (interval < 3)
                                interval = 3;
                        if ((1 << interval) != 8*ep->desc.bInterval)
                                dev_warn(&udev->dev,
                                                "ep %#x - rounding interval"
                                                " to %d microframes, "
                                                "ep desc says %d microframes\n",
                                                ep->desc.bEndpointAddress,
                                                1 << interval,
                                                8*ep->desc.bInterval);
                }
                break;
        default:
                BUG();
        }
        return EP_INTERVAL(interval);
}

static inline u32 xhci_get_endpoint_type(struct usb_device *udev,
                struct usb_host_endpoint *ep)
{
        int in;
        u32 type;

        in = usb_endpoint_dir_in(&ep->desc);
        if (usb_endpoint_xfer_control(&ep->desc)) {
                type = EP_TYPE(CTRL_EP);
        } else if (usb_endpoint_xfer_bulk(&ep->desc)) {
                if (in)
                        type = EP_TYPE(BULK_IN_EP);
                else
                        type = EP_TYPE(BULK_OUT_EP);
        } else if (usb_endpoint_xfer_isoc(&ep->desc)) {
                if (in)
                        type = EP_TYPE(ISOC_IN_EP);
                else
                        type = EP_TYPE(ISOC_OUT_EP);
        } else if (usb_endpoint_xfer_int(&ep->desc)) {
                if (in)
                        type = EP_TYPE(INT_IN_EP);
                else
                        type = EP_TYPE(INT_OUT_EP);
        } else {
                BUG();
        }
        return type;
}

int xhci_endpoint_init(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                struct usb_device *udev,
                struct usb_host_endpoint *ep,
                gfp_t mem_flags)
{
        unsigned int ep_index;
        struct xhci_ep_ctx *ep_ctx;
        struct xhci_ring *ep_ring;
        unsigned int max_packet;
        unsigned int max_burst;

        ep_index = xhci_get_endpoint_index(&ep->desc);
        ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);

        /* Set up the endpoint ring */
        virt_dev->eps[ep_index].new_ring =
                xhci_ring_alloc(xhci, 1, true, mem_flags);
        if (!virt_dev->eps[ep_index].new_ring) {
                /* Attempt to use the ring cache */
                if (virt_dev->num_rings_cached == 0)
                        return -ENOMEM;
                virt_dev->eps[ep_index].new_ring =
                        virt_dev->ring_cache[virt_dev->num_rings_cached];
                virt_dev->ring_cache[virt_dev->num_rings_cached] = NULL;
                virt_dev->num_rings_cached--;
                xhci_reinit_cached_ring(xhci, virt_dev->eps[ep_index].new_ring);
        }
        ep_ring = virt_dev->eps[ep_index].new_ring;
        ep_ctx->deq = ep_ring->first_seg->dma | ep_ring->cycle_state;

        ep_ctx->ep_info = xhci_get_endpoint_interval(udev, ep);

        /* FIXME dig Mult and streams info out of ep companion desc */

        /* Allow 3 retries for everything but isoc;
         * error count = 0 means infinite retries.
         */
        if (!usb_endpoint_xfer_isoc(&ep->desc))
                ep_ctx->ep_info2 = ERROR_COUNT(3);
        else
                ep_ctx->ep_info2 = ERROR_COUNT(1);

        ep_ctx->ep_info2 |= xhci_get_endpoint_type(udev, ep);

        /* Set the max packet size and max burst */
        switch (udev->speed) {
        case USB_SPEED_SUPER:
                max_packet = ep->desc.wMaxPacketSize;
                ep_ctx->ep_info2 |= MAX_PACKET(max_packet);
                /* dig out max burst from ep companion desc */
                if (!ep->ss_ep_comp) {
                        xhci_warn(xhci, "WARN no SS endpoint companion descriptor.\n");
                        max_packet = 0;
                } else {
                        max_packet = ep->ss_ep_comp->desc.bMaxBurst;
                }
                ep_ctx->ep_info2 |= MAX_BURST(max_packet);
                break;
        case USB_SPEED_HIGH:
                /* bits 11:12 specify the number of additional transaction
                 * opportunities per microframe (USB 2.0, section 9.6.6)
                 */
                if (usb_endpoint_xfer_isoc(&ep->desc) ||
                                usb_endpoint_xfer_int(&ep->desc)) {
                        max_burst = (ep->desc.wMaxPacketSize & 0x1800) >> 11;
                        ep_ctx->ep_info2 |= MAX_BURST(max_burst);
                }
                /* Fall through */
        case USB_SPEED_FULL:
        case USB_SPEED_LOW:
                max_packet = ep->desc.wMaxPacketSize & 0x3ff;
                ep_ctx->ep_info2 |= MAX_PACKET(max_packet);
                break;
        default:
                BUG();
        }
        /* FIXME Debug endpoint context */
        return 0;
}

void xhci_endpoint_zero(struct xhci_hcd *xhci,
                struct xhci_virt_device *virt_dev,
                struct usb_host_endpoint *ep)
{
        unsigned int ep_index;
        struct xhci_ep_ctx *ep_ctx;

        ep_index = xhci_get_endpoint_index(&ep->desc);
        ep_ctx = xhci_get_ep_ctx(xhci, virt_dev->in_ctx, ep_index);

        ep_ctx->ep_info = 0;
        ep_ctx->ep_info2 = 0;
        ep_ctx->deq = 0;
        ep_ctx->tx_info = 0;
        /* Don't free the endpoint ring until the set interface or configuration
         * request succeeds.
         */
}

/* Copy output xhci_ep_ctx to the input xhci_ep_ctx copy.
 * Useful when you want to change one particular aspect of the endpoint and then
 * issue a configure endpoint command.
 */
void xhci_endpoint_copy(struct xhci_hcd *xhci,
                struct xhci_container_ctx *in_ctx,
                struct xhci_container_ctx *out_ctx,
                unsigned int ep_index)
{
        struct xhci_ep_ctx *out_ep_ctx;
        struct xhci_ep_ctx *in_ep_ctx;

        out_ep_ctx = xhci_get_ep_ctx(xhci, out_ctx, ep_index);
        in_ep_ctx = xhci_get_ep_ctx(xhci, in_ctx, ep_index);

        in_ep_ctx->ep_info = out_ep_ctx->ep_info;
        in_ep_ctx->ep_info2 = out_ep_ctx->ep_info2;
        in_ep_ctx->deq = out_ep_ctx->deq;
        in_ep_ctx->tx_info = out_ep_ctx->tx_info;
}

/* Copy output xhci_slot_ctx to the input xhci_slot_ctx.
 * Useful when you want to change one particular aspect of the endpoint and then
 * issue a configure endpoint command.  Only the context entries field matters,
 * but we'll copy the whole thing anyway.
 */
void xhci_slot_copy(struct xhci_hcd *xhci,
                struct xhci_container_ctx *in_ctx,
                struct xhci_container_ctx *out_ctx)
{
        struct xhci_slot_ctx *in_slot_ctx;
        struct xhci_slot_ctx *out_slot_ctx;

        in_slot_ctx = xhci_get_slot_ctx(xhci, in_ctx);
        out_slot_ctx = xhci_get_slot_ctx(xhci, out_ctx);

        in_slot_ctx->dev_info = out_slot_ctx->dev_info;
        in_slot_ctx->dev_info2 = out_slot_ctx->dev_info2;
        in_slot_ctx->tt_info = out_slot_ctx->tt_info;
        in_slot_ctx->dev_state = out_slot_ctx->dev_state;
}

/* Set up the scratchpad buffer array and scratchpad buffers, if needed. */
static int scratchpad_alloc(struct xhci_hcd *xhci, gfp_t flags)
{
        int i;
        struct device *dev = xhci_to_hcd(xhci)->self.controller;
        int num_sp = HCS_MAX_SCRATCHPAD(xhci->hcs_params2);

        xhci_dbg(xhci, "Allocating %d scratchpad buffers\n", num_sp);

        if (!num_sp)
                return 0;

        xhci->scratchpad = kzalloc(sizeof(*xhci->scratchpad), flags);
        if (!xhci->scratchpad)
                goto fail_sp;

        xhci->scratchpad->sp_array =
                pci_alloc_consistent(to_pci_dev(dev),
                                     num_sp * sizeof(u64),
                                     &xhci->scratchpad->sp_dma);
        if (!xhci->scratchpad->sp_array)
                goto fail_sp2;

        xhci->scratchpad->sp_buffers = kzalloc(sizeof(void *) * num_sp, flags);
        if (!xhci->scratchpad->sp_buffers)
                goto fail_sp3;

        xhci->scratchpad->sp_dma_buffers =
                kzalloc(sizeof(dma_addr_t) * num_sp, flags);

        if (!xhci->scratchpad->sp_dma_buffers)
                goto fail_sp4;

        xhci->dcbaa->dev_context_ptrs[0] = xhci->scratchpad->sp_dma;
        for (i = 0; i < num_sp; i++) {
                dma_addr_t dma;
                void *buf = pci_alloc_consistent(to_pci_dev(dev),
                                                 xhci->page_size, &dma);
                if (!buf)
                        goto fail_sp5;

                xhci->scratchpad->sp_array[i] = dma;
                xhci->scratchpad->sp_buffers[i] = buf;
                xhci->scratchpad->sp_dma_buffers[i] = dma;
        }

        return 0;

 fail_sp5:
        for (i = i - 1; i >= 0; i--) {
                pci_free_consistent(to_pci_dev(dev), xhci->page_size,
                                    xhci->scratchpad->sp_buffers[i],
                                    xhci->scratchpad->sp_dma_buffers[i]);
        }
        kfree(xhci->scratchpad->sp_dma_buffers);

 fail_sp4:
        kfree(xhci->scratchpad->sp_buffers);

 fail_sp3:
        pci_free_consistent(to_pci_dev(dev), num_sp * sizeof(u64),
                            xhci->scratchpad->sp_array,
                            xhci->scratchpad->sp_dma);

 fail_sp2:
        kfree(xhci->scratchpad);
        xhci->scratchpad = NULL;

 fail_sp:
        return -ENOMEM;
}

static void scratchpad_free(struct xhci_hcd *xhci)
{
        int num_sp;
        int i;
        struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);

        if (!xhci->scratchpad)
                return;

        num_sp = HCS_MAX_SCRATCHPAD(xhci->hcs_params2);

        for (i = 0; i < num_sp; i++) {
                pci_free_consistent(pdev, xhci->page_size,
                                    xhci->scratchpad->sp_buffers[i],
                                    xhci->scratchpad->sp_dma_buffers[i]);
        }
        kfree(xhci->scratchpad->sp_dma_buffers);
        kfree(xhci->scratchpad->sp_buffers);
        pci_free_consistent(pdev, num_sp * sizeof(u64),
                            xhci->scratchpad->sp_array,
                            xhci->scratchpad->sp_dma);
        kfree(xhci->scratchpad);
        xhci->scratchpad = NULL;
}

struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
                bool allocate_in_ctx, bool allocate_completion,
                gfp_t mem_flags)
{
        struct xhci_command *command;

        command = kzalloc(sizeof(*command), mem_flags);
        if (!command)
                return NULL;

        if (allocate_in_ctx) {
                command->in_ctx =
                        xhci_alloc_container_ctx(xhci, XHCI_CTX_TYPE_INPUT,
                                        mem_flags);
                if (!command->in_ctx) {
                        kfree(command);
                        return NULL;
                }
        }

        if (allocate_completion) {
                command->completion =
                        kzalloc(sizeof(struct completion), mem_flags);
                if (!command->completion) {
                        xhci_free_container_ctx(xhci, command->in_ctx);
                        kfree(command);
                        return NULL;
                }
                init_completion(command->completion);
        }

        command->status = 0;
        INIT_LIST_HEAD(&command->cmd_list);
        return command;
}

void xhci_free_command(struct xhci_hcd *xhci,
                struct xhci_command *command)
{
        xhci_free_container_ctx(xhci,
                        command->in_ctx);
        kfree(command->completion);
        kfree(command);
}

void xhci_mem_cleanup(struct xhci_hcd *xhci)
{
        struct pci_dev  *pdev = to_pci_dev(xhci_to_hcd(xhci)->self.controller);
        int size;
        int i;

        /* Free the Event Ring Segment Table and the actual Event Ring */
        if (xhci->ir_set) {
                xhci_writel(xhci, 0, &xhci->ir_set->erst_size);
                xhci_write_64(xhci, 0, &xhci->ir_set->erst_base);
                xhci_write_64(xhci, 0, &xhci->ir_set->erst_dequeue);
        }
        size = sizeof(struct xhci_erst_entry)*(xhci->erst.num_entries);
        if (xhci->erst.entries)
                pci_free_consistent(pdev, size,
                                xhci->erst.entries, xhci->erst.erst_dma_addr);
        xhci->erst.entries = NULL;
        xhci_dbg(xhci, "Freed ERST\n");
        if (xhci->event_ring)
                xhci_ring_free(xhci, xhci->event_ring);
        xhci->event_ring = NULL;
        xhci_dbg(xhci, "Freed event ring\n");

        xhci_write_64(xhci, 0, &xhci->op_regs->cmd_ring);
        if (xhci->cmd_ring)
                xhci_ring_free(xhci, xhci->cmd_ring);
        xhci->cmd_ring = NULL;
        xhci_dbg(xhci, "Freed command ring\n");

        for (i = 1; i < MAX_HC_SLOTS; ++i)
                xhci_free_virt_device(xhci, i);

        if (xhci->segment_pool)
                dma_pool_destroy(xhci->segment_pool);
        xhci->segment_pool = NULL;
        xhci_dbg(xhci, "Freed segment pool\n");

        if (xhci->device_pool)
                dma_pool_destroy(xhci->device_pool);
        xhci->device_pool = NULL;
        xhci_dbg(xhci, "Freed device context pool\n");

        xhci_write_64(xhci, 0, &xhci->op_regs->dcbaa_ptr);
        if (xhci->dcbaa)
                pci_free_consistent(pdev, sizeof(*xhci->dcbaa),
                                xhci->dcbaa, xhci->dcbaa->dma);
        xhci->dcbaa = NULL;

        scratchpad_free(xhci);
        xhci->page_size = 0;
        xhci->page_shift = 0;
}

static int xhci_test_trb_in_td(struct xhci_hcd *xhci,
                struct xhci_segment *input_seg,
                union xhci_trb *start_trb,
                union xhci_trb *end_trb,
                dma_addr_t input_dma,
                struct xhci_segment *result_seg,
                char *test_name, int test_number)
{
        unsigned long long start_dma;
        unsigned long long end_dma;
        struct xhci_segment *seg;

        start_dma = xhci_trb_virt_to_dma(input_seg, start_trb);
        end_dma = xhci_trb_virt_to_dma(input_seg, end_trb);

        seg = trb_in_td(input_seg, start_trb, end_trb, input_dma);
        if (seg != result_seg) {
                xhci_warn(xhci, "WARN: %s TRB math test %d failed!\n",
                                test_name, test_number);
                xhci_warn(xhci, "Tested TRB math w/ seg %p and "
                                "input DMA 0x%llx\n",
                                input_seg,
                                (unsigned long long) input_dma);
                xhci_warn(xhci, "starting TRB %p (0x%llx DMA), "
                                "ending TRB %p (0x%llx DMA)\n",
                                start_trb, start_dma,
                                end_trb, end_dma);
                xhci_warn(xhci, "Expected seg %p, got seg %p\n",
                                result_seg, seg);
                return -1;
        }
        return 0;
}

/* TRB math checks for xhci_trb_in_td(), using the command and event rings. */
static int xhci_check_trb_in_td_math(struct xhci_hcd *xhci, gfp_t mem_flags)
{
        struct {
                dma_addr_t              input_dma;
                struct xhci_segment     *result_seg;
        } simple_test_vector [] = {
                /* A zeroed DMA field should fail */
                { 0, NULL },
                /* One TRB before the ring start should fail */
                { xhci->event_ring->first_seg->dma - 16, NULL },
                /* One byte before the ring start should fail */
                { xhci->event_ring->first_seg->dma - 1, NULL },
                /* Starting TRB should succeed */
                { xhci->event_ring->first_seg->dma, xhci->event_ring->first_seg },
                /* Ending TRB should succeed */
                { xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT - 1)*16,
                        xhci->event_ring->first_seg },
                /* One byte after the ring end should fail */
                { xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT - 1)*16 + 1, NULL },
                /* One TRB after the ring end should fail */
                { xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT)*16, NULL },
                /* An address of all ones should fail */
                { (dma_addr_t) (~0), NULL },
        };
        struct {
                struct xhci_segment     *input_seg;
                union xhci_trb          *start_trb;
                union xhci_trb          *end_trb;
                dma_addr_t              input_dma;
                struct xhci_segment     *result_seg;
        } complex_test_vector [] = {
                /* Test feeding a valid DMA address from a different ring */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = xhci->event_ring->first_seg->trbs,
                        .end_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
                        .input_dma = xhci->cmd_ring->first_seg->dma,
                        .result_seg = NULL,
                },
                /* Test feeding a valid end TRB from a different ring */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = xhci->event_ring->first_seg->trbs,
                        .end_trb = &xhci->cmd_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
                        .input_dma = xhci->cmd_ring->first_seg->dma,
                        .result_seg = NULL,
                },
                /* Test feeding a valid start and end TRB from a different ring */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = xhci->cmd_ring->first_seg->trbs,
                        .end_trb = &xhci->cmd_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
                        .input_dma = xhci->cmd_ring->first_seg->dma,
                        .result_seg = NULL,
                },
                /* TRB in this ring, but after this TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[0],
                        .end_trb = &xhci->event_ring->first_seg->trbs[3],
                        .input_dma = xhci->event_ring->first_seg->dma + 4*16,
                        .result_seg = NULL,
                },
                /* TRB in this ring, but before this TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[3],
                        .end_trb = &xhci->event_ring->first_seg->trbs[6],
                        .input_dma = xhci->event_ring->first_seg->dma + 2*16,
                        .result_seg = NULL,
                },
                /* TRB in this ring, but after this wrapped TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 3],
                        .end_trb = &xhci->event_ring->first_seg->trbs[1],
                        .input_dma = xhci->event_ring->first_seg->dma + 2*16,
                        .result_seg = NULL,
                },
                /* TRB in this ring, but before this wrapped TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 3],
                        .end_trb = &xhci->event_ring->first_seg->trbs[1],
                        .input_dma = xhci->event_ring->first_seg->dma + (TRBS_PER_SEGMENT - 4)*16,
                        .result_seg = NULL,
                },
                /* TRB not in this ring, and we have a wrapped TD */
                {       .input_seg = xhci->event_ring->first_seg,
                        .start_trb = &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 3],
                        .end_trb = &xhci->event_ring->first_seg->trbs[1],
                        .input_dma = xhci->cmd_ring->first_seg->dma + 2*16,
                        .result_seg = NULL,
                },
        };

        unsigned int num_tests;
        int i, ret;

        num_tests = sizeof(simple_test_vector) / sizeof(simple_test_vector[0]);
        for (i = 0; i < num_tests; i++) {
                ret = xhci_test_trb_in_td(xhci,
                                xhci->event_ring->first_seg,
                                xhci->event_ring->first_seg->trbs,
                                &xhci->event_ring->first_seg->trbs[TRBS_PER_SEGMENT - 1],
                                simple_test_vector[i].input_dma,
                                simple_test_vector[i].result_seg,
                                "Simple", i);
                if (ret < 0)
                        return ret;
        }

        num_tests = sizeof(complex_test_vector) / sizeof(complex_test_vector[0]);
        for (i = 0; i < num_tests; i++) {
                ret = xhci_test_trb_in_td(xhci,
                                complex_test_vector[i].input_seg,
                                complex_test_vector[i].start_trb,
                                complex_test_vector[i].end_trb,
                                complex_test_vector[i].input_dma,
                                complex_test_vector[i].result_seg,
                                "Complex", i);
                if (ret < 0)
                        return ret;
        }
        xhci_dbg(xhci, "TRB math tests passed.\n");
        return 0;
}


int xhci_mem_init(struct xhci_hcd *xhci, gfp_t flags)
{
        dma_addr_t      dma;
        struct device   *dev = xhci_to_hcd(xhci)->self.controller;
        unsigned int    val, val2;
        u64             val_64;
        struct xhci_segment     *seg;
        u32 page_size;
        int i;

        page_size = xhci_readl(xhci, &xhci->op_regs->page_size);
        xhci_dbg(xhci, "Supported page size register = 0x%x\n", page_size);
        for (i = 0; i < 16; i++) {
                if ((0x1 & page_size) != 0)
                        break;
                page_size = page_size >> 1;
        }
        if (i < 16)
                xhci_dbg(xhci, "Supported page size of %iK\n", (1 << (i+12)) / 1024);
        else
                xhci_warn(xhci, "WARN: no supported page size\n");
        /* Use 4K pages, since that's common and the minimum the HC supports */
        xhci->page_shift = 12;
        xhci->page_size = 1 << xhci->page_shift;
        xhci_dbg(xhci, "HCD page size set to %iK\n", xhci->page_size / 1024);

        /*
         * Program the Number of Device Slots Enabled field in the CONFIG
         * register with the max value of slots the HC can handle.
         */
        val = HCS_MAX_SLOTS(xhci_readl(xhci, &xhci->cap_regs->hcs_params1));
        xhci_dbg(xhci, "// xHC can handle at most %d device slots.\n",
                        (unsigned int) val);
        val2 = xhci_readl(xhci, &xhci->op_regs->config_reg);
        val |= (val2 & ~HCS_SLOTS_MASK);
        xhci_dbg(xhci, "// Setting Max device slots reg = 0x%x.\n",
                        (unsigned int) val);
        xhci_writel(xhci, val, &xhci->op_regs->config_reg);

        /*
         * Section 5.4.8 - doorbell array must be
         * "physically contiguous and 64-byte (cache line) aligned".
         */
        xhci->dcbaa = pci_alloc_consistent(to_pci_dev(dev),
                        sizeof(*xhci->dcbaa), &dma);
        if (!xhci->dcbaa)
                goto fail;
        memset(xhci->dcbaa, 0, sizeof *(xhci->dcbaa));
        xhci->dcbaa->dma = dma;
        xhci_dbg(xhci, "// Device context base array address = 0x%llx (DMA), %p (virt)\n",
                        (unsigned long long)xhci->dcbaa->dma, xhci->dcbaa);
        xhci_write_64(xhci, dma, &xhci->op_regs->dcbaa_ptr);

        /*
         * Initialize the ring segment pool.  The ring must be a contiguous
         * structure comprised of TRBs.  The TRBs must be 16 byte aligned,
         * however, the command ring segment needs 64-byte aligned segments,
         * so we pick the greater alignment need.
         */
        xhci->segment_pool = dma_pool_create("xHCI ring segments", dev,
                        SEGMENT_SIZE, 64, xhci->page_size);

        /* See Table 46 and Note on Figure 55 */
        xhci->device_pool = dma_pool_create("xHCI input/output contexts", dev,
                        2112, 64, xhci->page_size);
        if (!xhci->segment_pool || !xhci->device_pool)
                goto fail;

        /* Set up the command ring to have one segments for now. */
        xhci->cmd_ring = xhci_ring_alloc(xhci, 1, true, flags);
        if (!xhci->cmd_ring)
                goto fail;
        xhci_dbg(xhci, "Allocated command ring at %p\n", xhci->cmd_ring);
        xhci_dbg(xhci, "First segment DMA is 0x%llx\n",
                        (unsigned long long)xhci->cmd_ring->first_seg->dma);

        /* Set the address in the Command Ring Control register */
        val_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
        val_64 = (val_64 & (u64) CMD_RING_RSVD_BITS) |
                (xhci->cmd_ring->first_seg->dma & (u64) ~CMD_RING_RSVD_BITS) |
                xhci->cmd_ring->cycle_state;
        xhci_dbg(xhci, "// Setting command ring address to 0x%x\n", val);
        xhci_write_64(xhci, val_64, &xhci->op_regs->cmd_ring);
        xhci_dbg_cmd_ptrs(xhci);

        val = xhci_readl(xhci, &xhci->cap_regs->db_off);
        val &= DBOFF_MASK;
        xhci_dbg(xhci, "// Doorbell array is located at offset 0x%x"
                        " from cap regs base addr\n", val);
        xhci->dba = (void *) xhci->cap_regs + val;
        xhci_dbg_regs(xhci);
        xhci_print_run_regs(xhci);
        /* Set ir_set to interrupt register set 0 */
        xhci->ir_set = (void *) xhci->run_regs->ir_set;

        /*
         * Event ring setup: Allocate a normal ring, but also setup
         * the event ring segment table (ERST).  Section 4.9.3.
         */
        xhci_dbg(xhci, "// Allocating event ring\n");
        xhci->event_ring = xhci_ring_alloc(xhci, ERST_NUM_SEGS, false, flags);
        if (!xhci->event_ring)
                goto fail;
        if (xhci_check_trb_in_td_math(xhci, flags) < 0)
                goto fail;

        xhci->erst.entries = pci_alloc_consistent(to_pci_dev(dev),
                        sizeof(struct xhci_erst_entry)*ERST_NUM_SEGS, &dma);
        if (!xhci->erst.entries)
                goto fail;
        xhci_dbg(xhci, "// Allocated event ring segment table at 0x%llx\n",
                        (unsigned long long)dma);

        memset(xhci->erst.entries, 0, sizeof(struct xhci_erst_entry)*ERST_NUM_SEGS);
        xhci->erst.num_entries = ERST_NUM_SEGS;
        xhci->erst.erst_dma_addr = dma;
        xhci_dbg(xhci, "Set ERST to 0; private num segs = %i, virt addr = %p, dma addr = 0x%llx\n",
                        xhci->erst.num_entries,
                        xhci->erst.entries,
                        (unsigned long long)xhci->erst.erst_dma_addr);

        /* set ring base address and size for each segment table entry */
        for (val = 0, seg = xhci->event_ring->first_seg; val < ERST_NUM_SEGS; val++) {
                struct xhci_erst_entry *entry = &xhci->erst.entries[val];
                entry->seg_addr = seg->dma;
                entry->seg_size = TRBS_PER_SEGMENT;
                entry->rsvd = 0;
                seg = seg->next;
        }

        /* set ERST count with the number of entries in the segment table */
        val = xhci_readl(xhci, &xhci->ir_set->erst_size);
        val &= ERST_SIZE_MASK;
        val |= ERST_NUM_SEGS;
        xhci_dbg(xhci, "// Write ERST size = %i to ir_set 0 (some bits preserved)\n",
                        val);
        xhci_writel(xhci, val, &xhci->ir_set->erst_size);

        xhci_dbg(xhci, "// Set ERST entries to point to event ring.\n");
        /* set the segment table base address */
        xhci_dbg(xhci, "// Set ERST base address for ir_set 0 = 0x%llx\n",
                        (unsigned long long)xhci->erst.erst_dma_addr);
        val_64 = xhci_read_64(xhci, &xhci->ir_set->erst_base);
        val_64 &= ERST_PTR_MASK;
        val_64 |= (xhci->erst.erst_dma_addr & (u64) ~ERST_PTR_MASK);
        xhci_write_64(xhci, val_64, &xhci->ir_set->erst_base);

        /* Set the event ring dequeue address */
        xhci_set_hc_event_deq(xhci);
        xhci_dbg(xhci, "Wrote ERST address to ir_set 0.\n");
        xhci_print_ir_set(xhci, xhci->ir_set, 0);

        /*
         * XXX: Might need to set the Interrupter Moderation Register to
         * something other than the default (~1ms minimum between interrupts).
         * See section 5.5.1.2.
         */
        init_completion(&xhci->addr_dev);
        for (i = 0; i < MAX_HC_SLOTS; ++i)
                xhci->devs[i] = 0;

        if (scratchpad_alloc(xhci, flags))
                goto fail;

        return 0;

fail:
        xhci_warn(xhci, "Couldn't initialize memory\n");
        xhci_mem_cleanup(xhci);
        return -ENOMEM;
}