USB: xhci: Control transfer support.

Allow device drivers to enqueue URBs to control endpoints on devices under
an xHCI host controller.  Each control transfer is represented by a
series of Transfer Descriptors (TDs) written to an endpoint ring.  There
is one TD for the Setup phase, (optionally) one TD for the Data phase, and
one TD for the Status phase.

Enqueue these TDs onto the endpoint ring that represents the control
endpoint.  The host controller hardware will return an event on the event
ring that points to the (DMA) address of one of the TDs on the endpoint
ring.  If the transfer was successful, the transfer event TRB will have a
completion code of success, and it will point to the Status phase TD.
Anything else is considered an error.

This should work for control endpoints besides the default endpoint, but
that hasn't been tested.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 383 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 901ce70b30b8..f04162ae4374 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -321,6 +321,199 @@ static void handle_port_status(struct xhci_hcd *xhci,
 }
 
 /*
+ * This TD is defined by the TRBs starting at start_trb in start_seg and ending
+ * at end_trb, which may be in another segment.  If the suspect DMA address is a
+ * TRB in this TD, this function returns that TRB's segment.  Otherwise it
+ * returns 0.
+ */
+static struct xhci_segment *trb_in_td(
+                struct xhci_segment *start_seg,
+                union xhci_trb  *start_trb,
+                union xhci_trb  *end_trb,
+                dma_addr_t      suspect_dma)
+{
+        dma_addr_t start_dma;
+        dma_addr_t end_seg_dma;
+        dma_addr_t end_trb_dma;
+        struct xhci_segment *cur_seg;
+
+        start_dma = trb_virt_to_dma(start_seg, start_trb);
+        cur_seg = start_seg;
+
+        do {
+                /*
+                 * Last TRB is a link TRB (unless we start inserting links in
+                 * the middle, FIXME if you do)
+                 */
+                end_seg_dma = trb_virt_to_dma(cur_seg, &start_seg->trbs[TRBS_PER_SEGMENT - 2]);
+                /* If the end TRB isn't in this segment, this is set to 0 */
+                end_trb_dma = trb_virt_to_dma(cur_seg, end_trb);
+
+                if (end_trb_dma > 0) {
+                        /* The end TRB is in this segment, so suspect should be here */
+                        if (start_dma <= end_trb_dma) {
+                                if (suspect_dma >= start_dma && suspect_dma <= end_trb_dma)
+                                        return cur_seg;
+                        } else {
+                                /* Case for one segment with
+                                 * a TD wrapped around to the top
+                                 */
+                                if ((suspect_dma >= start_dma &&
+                                                        suspect_dma <= end_seg_dma) ||
+                                                (suspect_dma >= cur_seg->dma &&
+                                                 suspect_dma <= end_trb_dma))
+                                        return cur_seg;
+                        }
+                        return 0;
+                } else {
+                        /* Might still be somewhere in this segment */
+                        if (suspect_dma >= start_dma && suspect_dma <= end_seg_dma)
+                                return cur_seg;
+                }
+                cur_seg = cur_seg->next;
+                start_dma = trb_virt_to_dma(cur_seg, &cur_seg->trbs[0]);
+        } while (1);
+
+}
+
+/*
+ * If this function returns an error condition, it means it got a Transfer
+ * event with a corrupted Slot ID, Endpoint ID, or TRB DMA address.
+ * At this point, the host controller is probably hosed and should be reset.
+ */
+static int handle_tx_event(struct xhci_hcd *xhci,
+                struct xhci_transfer_event *event)
+{
+        struct xhci_virt_device *xdev;
+        struct xhci_ring *ep_ring;
+        int ep_index;
+        struct xhci_td *td = 0;
+        dma_addr_t event_dma;
+        struct xhci_segment *event_seg;
+        union xhci_trb *event_trb;
+        struct urb *urb = NULL;
+        int status = -EINPROGRESS;
+
+        xdev = xhci->devs[TRB_TO_SLOT_ID(event->flags)];
+        if (!xdev) {
+                xhci_err(xhci, "ERROR Transfer event pointed to bad slot\n");
+                return -ENODEV;
+        }
+
+        /* Endpoint ID is 1 based, our index is zero based */
+        ep_index = TRB_TO_EP_ID(event->flags) - 1;
+        ep_ring = xdev->ep_rings[ep_index];
+        if (!ep_ring || (xdev->out_ctx->ep[ep_index].ep_info & EP_STATE_MASK) == EP_STATE_DISABLED) {
+                xhci_err(xhci, "ERROR Transfer event pointed to disabled endpoint\n");
+                return -ENODEV;
+        }
+
+        event_dma = event->buffer[0];
+        if (event->buffer[1] != 0)
+                xhci_warn(xhci, "WARN ignoring upper 32-bits of 64-bit TRB dma address\n");
+
+        /* This TRB should be in the TD at the head of this ring's TD list */
+        if (list_empty(&ep_ring->td_list)) {
+                xhci_warn(xhci, "WARN Event TRB for slot %d ep %d with no TDs queued?\n",
+                                TRB_TO_SLOT_ID(event->flags), ep_index);
+                xhci_dbg(xhci, "Event TRB with TRB type ID %u\n",
+                                (unsigned int) (event->flags & TRB_TYPE_BITMASK)>>10);
+                xhci_print_trb_offsets(xhci, (union xhci_trb *) event);
+                urb = NULL;
+                goto cleanup;
+        }
+        td = list_entry(ep_ring->td_list.next, struct xhci_td, td_list);
+
+        /* Is this a TRB in the currently executing TD? */
+        event_seg = trb_in_td(ep_ring->deq_seg, ep_ring->dequeue,
+                        td->last_trb, event_dma);
+        if (!event_seg) {
+                /* HC is busted, give up! */
+                xhci_err(xhci, "ERROR Transfer event TRB DMA ptr not part of current TD\n");
+                return -ESHUTDOWN;
+        }
+        event_trb = &event_seg->trbs[(event_dma - event_seg->dma) / sizeof(*event_trb)];
+
+        /* Now update the urb's actual_length and give back to the core */
+        /* Was this a control transfer? */
+        if (usb_endpoint_xfer_control(&td->urb->ep->desc)) {
+                xhci_debug_trb(xhci, xhci->event_ring->dequeue);
+                switch (GET_COMP_CODE(event->transfer_len)) {
+                case COMP_SUCCESS:
+                        if (event_trb == ep_ring->dequeue) {
+                                xhci_warn(xhci, "WARN: Success on ctrl setup TRB without IOC set??\n");
+                                status = -ESHUTDOWN;
+                        } else if (event_trb != td->last_trb) {
+                                xhci_warn(xhci, "WARN: Success on ctrl data TRB without IOC set??\n");
+                                status = -ESHUTDOWN;
+                        } else {
+                                xhci_dbg(xhci, "Successful control transfer!\n");
+                                status = 0;
+                        }
+                        break;
+                case COMP_SHORT_TX:
+                        xhci_warn(xhci, "WARN: short transfer on control ep\n");
+                        status = -EREMOTEIO;
+                        break;
+                case COMP_STALL:
+                        xhci_warn(xhci, "WARN: Stalled control ep\n");
+                        status = -EPIPE;
+                        break;
+                case COMP_TRB_ERR:
+                        xhci_warn(xhci, "WARN: TRB error on control ep\n");
+                        status = -EILSEQ;
+                        break;
+                case COMP_TX_ERR:
+                        xhci_warn(xhci, "WARN: transfer error on control ep\n");
+                        status = -EPROTO;
+                        break;
+                case COMP_DB_ERR:
+                        xhci_warn(xhci, "WARN: HC couldn't access mem fast enough on control TX\n");
+                        status = -ENOSR;
+                        break;
+                default:
+                        xhci_dbg(xhci, "ERROR Unknown event condition, HC probably busted\n");
+                        goto cleanup;
+                }
+                /*
+                 * Did we transfer any data, despite the errors that might have
+                 * happened?  I.e. did we get past the setup stage?
+                 */
+                if (event_trb != ep_ring->dequeue) {
+                        /* The event was for the status stage */
+                        if (event_trb == td->last_trb) {
+                                td->urb->actual_length = td->urb->transfer_buffer_length;
+                        } else {
+                        /* The event was for the data stage */
+                                td->urb->actual_length = td->urb->transfer_buffer_length -
+                                        TRB_LEN(event->transfer_len);
+                        }
+                }
+                while (ep_ring->dequeue != td->last_trb)
+                        inc_deq(xhci, ep_ring, false);
+                inc_deq(xhci, ep_ring, false);
+
+                /* Clean up the endpoint's TD list */
+                urb = td->urb;
+                list_del(&td->td_list);
+                kfree(td);
+        } else {
+                xhci_dbg(xhci, "FIXME do something for non-control transfers\n");
+        }
+cleanup:
+        inc_deq(xhci, xhci->event_ring, true);
+        set_hc_event_deq(xhci);
+
+        if (urb) {
+                usb_hcd_unlink_urb_from_ep(xhci_to_hcd(xhci), urb);
+                spin_unlock(&xhci->lock);
+                usb_hcd_giveback_urb(xhci_to_hcd(xhci), urb, status);
+                spin_lock(&xhci->lock);
+        }
+        return 0;
+}
+
+/*
  * This function handles all OS-owned events on the event ring.  It may drop
  * xhci->lock between event processing (e.g. to pass up port status changes).
  */
@@ -328,6 +521,7 @@ void handle_event(struct xhci_hcd *xhci)
 {
         union xhci_trb *event;
         int update_ptrs = 1;
+        int ret;
 
         if (!xhci->event_ring || !xhci->event_ring->dequeue) {
                 xhci->error_bitmask |= 1 << 1;
@@ -351,6 +545,13 @@ void handle_event(struct xhci_hcd *xhci)
                 handle_port_status(xhci, event);
                 update_ptrs = 0;
                 break;
+        case TRB_TYPE(TRB_TRANSFER):
+                ret = handle_tx_event(xhci, &event->trans_event);
+                if (ret < 0)
+                        xhci->error_bitmask |= 1 << 9;
+                else
+                        update_ptrs = 0;
+                break;
         default:
                 xhci->error_bitmask |= 1 << 3;
         }
@@ -364,6 +565,8 @@ void handle_event(struct xhci_hcd *xhci)
         handle_event(xhci);
 }
 
+/****           Endpoint Ring Operations        ****/
+
 /*
  * Generic function for queueing a TRB on a ring.
  * The caller must have checked to make sure there's room on the ring.
@@ -382,6 +585,186 @@ static void queue_trb(struct xhci_hcd *xhci, struct xhci_ring *ring,
         inc_enq(xhci, ring, consumer);
 }
 
+/*
+ * Does various checks on the endpoint ring, and makes it ready to queue num_trbs.
+ * FIXME allocate segments if the ring is full.
+ */
+static int prepare_ring(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
+                u32 ep_state, unsigned int num_trbs, gfp_t mem_flags)
+{
+        /* Make sure the endpoint has been added to xHC schedule */
+        xhci_dbg(xhci, "Endpoint state = 0x%x\n", ep_state);
+        switch (ep_state) {
+        case EP_STATE_DISABLED:
+                /*
+                 * USB core changed config/interfaces without notifying us,
+                 * or hardware is reporting the wrong state.
+                 */
+                xhci_warn(xhci, "WARN urb submitted to disabled ep\n");
+                return -ENOENT;
+        case EP_STATE_HALTED:
+        case EP_STATE_ERROR:
+                xhci_warn(xhci, "WARN waiting for halt or error on ep "
+                                "to be cleared\n");
+                /* FIXME event handling code for error needs to clear it */
+                /* XXX not sure if this should be -ENOENT or not */
+                return -EINVAL;
+        case EP_STATE_STOPPED:
+        case EP_STATE_RUNNING:
+                break;
+        default:
+                xhci_err(xhci, "ERROR unknown endpoint state for ep\n");
+                /*
+                 * FIXME issue Configure Endpoint command to try to get the HC
+                 * back into a known state.
+                 */
+                return -EINVAL;
+        }
+        if (!room_on_ring(xhci, ep_ring, num_trbs)) {
+                /* FIXME allocate more room */
+                xhci_err(xhci, "ERROR no room on ep ring\n");
+                return -ENOMEM;
+        }
+        return 0;
+}
+
+int xhci_prepare_transfer(struct xhci_hcd *xhci,
+                struct xhci_virt_device *xdev,
+                unsigned int ep_index,
+                unsigned int num_trbs,
+                struct urb *urb,
+                struct xhci_td **td,
+                gfp_t mem_flags)
+{
+        int ret;
+
+        ret = prepare_ring(xhci, xdev->ep_rings[ep_index],
+                        xdev->out_ctx->ep[ep_index].ep_info & EP_STATE_MASK,
+                        num_trbs, mem_flags);
+        if (ret)
+                return ret;
+        *td = kzalloc(sizeof(struct xhci_td), mem_flags);
+        if (!*td)
+                return -ENOMEM;
+        INIT_LIST_HEAD(&(*td)->td_list);
+
+        ret = usb_hcd_link_urb_to_ep(xhci_to_hcd(xhci), urb);
+        if (unlikely(ret)) {
+                kfree(*td);
+                return ret;
+        }
+
+        (*td)->urb = urb;
+        urb->hcpriv = (void *) (*td);
+        /* Add this TD to the tail of the endpoint ring's TD list */
+        list_add_tail(&(*td)->td_list, &xdev->ep_rings[ep_index]->td_list);
+
+        return 0;
+}
+
+/* Caller must have locked xhci->lock */
+int queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
+                struct urb *urb, int slot_id, unsigned int ep_index)
+{
+        struct xhci_ring *ep_ring;
+        int num_trbs;
+        int ret;
+        struct usb_ctrlrequest *setup;
+        struct xhci_generic_trb *start_trb;
+        int start_cycle;
+        u32 field;
+        struct xhci_td *td;
+
+        ep_ring = xhci->devs[slot_id]->ep_rings[ep_index];
+
+        /*
+         * Need to copy setup packet into setup TRB, so we can't use the setup
+         * DMA address.
+         */
+        if (!urb->setup_packet)
+                return -EINVAL;
+
+        if (!in_interrupt())
+                xhci_dbg(xhci, "Queueing ctrl tx for slot id %d, ep %d\n",
+                                slot_id, ep_index);
+        /* 1 TRB for setup, 1 for status */
+        num_trbs = 2;
+        /*
+         * Don't need to check if we need additional event data and normal TRBs,
+         * since data in control transfers will never get bigger than 16MB
+         * XXX: can we get a buffer that crosses 64KB boundaries?
+         */
+        if (urb->transfer_buffer_length > 0)
+                num_trbs++;
+        ret = xhci_prepare_transfer(xhci, xhci->devs[slot_id], ep_index, num_trbs,
+                        urb, &td, mem_flags);
+        if (ret < 0)
+                return ret;
+
+        /*
+         * Don't give the first TRB to the hardware (by toggling the cycle bit)
+         * until we've finished creating all the other TRBs.  The ring's cycle
+         * state may change as we enqueue the other TRBs, so save it too.
+         */
+        start_trb = &ep_ring->enqueue->generic;
+        start_cycle = ep_ring->cycle_state;
+
+        /* Queue setup TRB - see section 6.4.1.2.1 */
+        /* FIXME better way to translate setup_packet into two u32 fields? */
+        setup = (struct usb_ctrlrequest *) urb->setup_packet;
+        queue_trb(xhci, ep_ring, false,
+                        /* FIXME endianness is probably going to bite my ass here. */
+                        setup->bRequestType | setup->bRequest << 8 | setup->wValue << 16,
+                        setup->wIndex | setup->wLength << 16,
+                        TRB_LEN(8) | TRB_INTR_TARGET(0),
+                        /* Immediate data in pointer */
+                        TRB_IDT | TRB_TYPE(TRB_SETUP));
+
+        /* If there's data, queue data TRBs */
+        field = 0;
+        if (urb->transfer_buffer_length > 0) {
+                if (setup->bRequestType & USB_DIR_IN)
+                        field |= TRB_DIR_IN;
+                queue_trb(xhci, ep_ring, false,
+                                lower_32_bits(urb->transfer_dma),
+                                upper_32_bits(urb->transfer_dma),
+                                TRB_LEN(urb->transfer_buffer_length) | TRB_INTR_TARGET(0),
+                                /* Event on short tx */
+                                field | TRB_ISP | TRB_TYPE(TRB_DATA) | ep_ring->cycle_state);
+        }
+
+        /* Save the DMA address of the last TRB in the TD */
+        td->last_trb = ep_ring->enqueue;
+
+        /* Queue status TRB - see Table 7 and sections 4.11.2.2 and 6.4.1.2.3 */
+        /* If the device sent data, the status stage is an OUT transfer */
+        if (urb->transfer_buffer_length > 0 && setup->bRequestType & USB_DIR_IN)
+                field = 0;
+        else
+                field = TRB_DIR_IN;
+        queue_trb(xhci, ep_ring, false,
+                        0,
+                        0,
+                        TRB_INTR_TARGET(0),
+                        /* Event on completion */
+                        field | TRB_IOC | TRB_TYPE(TRB_STATUS) | ep_ring->cycle_state);
+
+        /*
+         * Pass all the TRBs to the hardware at once and make sure this write
+         * isn't reordered.
+         */
+        wmb();
+        start_trb->field[3] |= start_cycle;
+        field = xhci_readl(xhci, &xhci->dba->doorbell[slot_id]) & DB_MASK;
+        xhci_writel(xhci, field | EPI_TO_DB(ep_index), &xhci->dba->doorbell[slot_id]);
+        /* Flush PCI posted writes */
+        xhci_readl(xhci, &xhci->dba->doorbell[slot_id]);
+
+        return 0;
+}
+
+/****           Command Ring Operations         ****/
+
 /* Generic function for queueing a command TRB on the command ring */
 static int queue_command(struct xhci_hcd *xhci, u32 field1, u32 field2, u32 field3, u32 field4)
 {