Close inspection shows that xhci_queue_isoc_tx() can only fail if
prepare_transfer() gets an error from usb_hcd_link_urb_to_ep() for
the first TD. The call to prepare_ring() cannot fail because an initial
check is made to ensure the ring has enough space for all the TD.
The check for 'num_tds' being negative is pointless here, and the
check of the 'running_total' is looking for a simple coding error,
both can be deleted.
Isoc setup is the only code path that calls prepare_transfer() with
ts_index != 0 so there is no point calling prepare_ring() again.
prepare_ring() is still called twice for the first TD.
However since prepare_tranfser() doesn't depend on the number of TD
the initial prepare_ring() can be replaced by prepare_transfer()
and the existing prepare_transfer() call only made for subsequent TD.
This all means that xhci_queue_isoc_tx() can no longer fail.
Delete the (possibly dubious) 'cleanup' code and change the return
type to void.
Signed-off-by: David Laight <david.lai...@aculab.com>
---
This is compile tested only because I don't have an isoc device.
However it should be ok.
I've just ordered a cheap USB 'sound card' - presumably that
will let me test isochronous transfers.
Note: This patch will only apply cleanly if my earlier patches are applied
first.
---
drivers/usb/host/xhci-ring.c | 90 +++++++++++++-------------------------------
drivers/usb/host/xhci.h | 1 -
2 files changed, 27 insertions(+), 64 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index d0ef8b8..5480215 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2991,7 +2991,7 @@ static int prepare_transfer(struct xhci_hcd *xhci,
struct urb_priv *urb_priv;
struct xhci_td *td;
struct xhci_ring *ep_ring;
- struct xhci_ep_ctx *ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx,
ep_index);
+ struct xhci_ep_ctx *ep_ctx;
ep_ring = xhci_stream_id_to_ring(xdev, ep_index, stream_id);
if (!ep_ring) {
@@ -3000,24 +3000,26 @@ static int prepare_transfer(struct xhci_hcd *xhci,
return -EINVAL;
}
- ret = prepare_ring(xhci, ep_ring,
- le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK,
- num_trbs, mem_flags);
- if (ret)
- return ret;
-
- urb_priv = urb->hcpriv;
- td = &urb_priv->td[td_index];
+ if (td_index == 0) {
+ ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
- INIT_LIST_HEAD(&td->td_list);
- INIT_LIST_HEAD(&td->cancelled_td_list);
+ ret = prepare_ring(xhci, ep_ring,
+ le32_to_cpu(ep_ctx->ep_info) & EP_STATE_MASK,
+ num_trbs, mem_flags);
+ if (unlikely(ret))
+ return ret;
- if (td_index == 0) {
ret = usb_hcd_link_urb_to_ep(bus_to_hcd(urb->dev->bus), urb);
if (unlikely(ret))
return ret;
}
+ urb_priv = urb->hcpriv;
+ td = &urb_priv->td[td_index];
+
+ INIT_LIST_HEAD(&td->td_list);
+ INIT_LIST_HEAD(&td->cancelled_td_list);
+
td->urb = urb;
/* Add this TD to the tail of the endpoint ring's TD list */
list_add_tail(&td->td_list, &ep_ring->td_list);
@@ -3647,7 +3649,7 @@ static unsigned int
xhci_get_last_burst_packet_count(struct xhci_hcd *xhci,
}
/* This is for isoc transfer */
-static int xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
+static void xhci_queue_isoc_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
struct urb *urb, int slot_id, unsigned int ep_index)
{
struct xhci_ring *ep_ring;
@@ -3657,7 +3659,7 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci,
gfp_t mem_flags,
struct xhci_generic_trb *start_trb;
bool first_trb;
u32 field, length_field;
- int running_total, trb_buff_len, td_len, td_remain_len, ret;
+ int running_total, trb_buff_len, td_len, td_remain_len;
u64 start_addr, addr;
int i, j;
bool more_trbs_coming;
@@ -3665,10 +3667,6 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci,
gfp_t mem_flags,
ep_ring = xhci->devs[slot_id]->eps[ep_index].ring;
num_tds = urb->number_of_packets;
- if (num_tds < 1) {
- xhci_dbg(xhci, "Isoc URB with zero packets?\n");
- return -EINVAL;
- }
start_addr = (u64) urb->transfer_dma;
start_trb = &ep_ring->enqueue->generic;
@@ -3698,13 +3696,13 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci,
gfp_t mem_flags,
trbs_per_td = count_isoc_trbs_needed(xhci, urb, i);
- ret = prepare_transfer(xhci, xhci->devs[slot_id], ep_index,
- urb->stream_id, trbs_per_td, urb, i, mem_flags);
- if (ret < 0) {
- if (i == 0)
- return ret;
- goto cleanup;
- }
+ /* prepare_transfer() was called earlier for the first TRB.
+ * It cannot fail for later TRBs.
+ */
+ if (i != 0)
+ prepare_transfer(xhci, xhci->devs[slot_id], ep_index,
+ urb->stream_id, trbs_per_td, urb, i,
+ mem_flags);
td = &urb_priv->td[i];
for (j = 0; j < trbs_per_td; j++) {
@@ -3782,13 +3780,6 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci,
gfp_t mem_flags,
addr += trb_buff_len;
td_remain_len -= trb_buff_len;
}
-
- /* Check TD length */
- if (running_total != td_len) {
- xhci_err(xhci, "ISOC TD length unmatch\n");
- ret = -EINVAL;
- goto cleanup;
- }
}
if (xhci_to_hcd(xhci)->self.bandwidth_isoc_reqs == 0) {
@@ -3798,31 +3789,6 @@ static int xhci_queue_isoc_tx(struct xhci_hcd *xhci,
gfp_t mem_flags,
xhci_to_hcd(xhci)->self.bandwidth_isoc_reqs++;
giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id, start_trb);
- return 0;
-cleanup:
- /* Clean up a partially enqueued isoc transfer. */
-
- for (i--; i >= 0; i--)
- list_del_init(&urb_priv->td[i].td_list);
-
- /* Use the first TD as a temporary variable to turn the TDs we've queued
- * into No-ops with a software-owned cycle bit. That way the hardware
- * won't accidentally start executing bogus TDs when we partially
- * overwrite them. td->first_trb and td->start_seg are already set.
- */
- urb_priv->td[0].last_trb = ep_ring->enqueue;
- /* Every TRB except the first & last will have its cycle bit flipped. */
- td_to_noop(xhci, ep_ring, &urb_priv->td[0], true);
-
- /* Reset the ring enqueue back to the first TRB and its cycle bit. */
- ep_ring->enqueue = urb_priv->td[0].first_trb;
- ep_ring->enq_seg = urb_priv->td[0].start_seg;
- /* The cycle bit in the first TRB won't be modified, get its inverse. */
- ep_ring->cycle_state = (ep_ring->enqueue->generic.field[3] &
- TRB_CYCLE) ^ TRB_CYCLE;
- ep_ring->num_trbs_free = ep_ring->num_trbs_free_temp;
- usb_hcd_unlink_urb_from_ep(bus_to_hcd(urb->dev->bus), urb);
- return ret;
}
/*
@@ -3836,7 +3802,6 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci,
gfp_t mem_flags,
struct urb *urb, int slot_id, unsigned int ep_index)
{
struct xhci_virt_device *xdev;
- struct xhci_ring *ep_ring;
struct xhci_ep_ctx *ep_ctx;
int start_frame;
int xhci_interval;
@@ -3845,7 +3810,6 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci,
gfp_t mem_flags,
int ret;
xdev = xhci->devs[slot_id];
- ep_ring = xdev->eps[ep_index].ring;
ep_ctx = xhci_get_ep_ctx(xhci, xdev->out_ctx, ep_index);
num_trbs = 0;
@@ -3856,8 +3820,8 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci,
gfp_t mem_flags,
/* Check the ring to guarantee there is enough room for the whole urb.
* Do not insert any td of the urb to the ring if the check failed.
*/
- ret = prepare_ring(xhci, ep_ring, le32_to_cpu(ep_ctx->ep_info) &
EP_STATE_MASK,
- num_trbs, mem_flags);
+ ret = prepare_transfer(xhci, xdev, ep_index,
+ urb->stream_id, num_trbs, urb, 0, mem_flags);
if (ret)
return ret;
@@ -3889,9 +3853,9 @@ int xhci_queue_isoc_tx_prepare(struct xhci_hcd *xhci,
gfp_t mem_flags,
urb->dev->speed == USB_SPEED_FULL)
urb->interval /= 8;
}
- ep_ring->num_trbs_free_temp = ep_ring->num_trbs_free;
- return xhci_queue_isoc_tx(xhci, mem_flags, urb, slot_id, ep_index);
+ xhci_queue_isoc_tx(xhci, mem_flags, urb, slot_id, ep_index);
+ return 0;
}
/**** Command Ring Operations ****/
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index a7d8fdd..118f90b 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1331,7 +1331,6 @@ struct xhci_ring {
unsigned int stream_id;
unsigned int num_segs;
unsigned int num_trbs_free;
- unsigned int num_trbs_free_temp;
enum xhci_ring_type type;
bool last_td_was_short;
};
--
1.8.1.2
--
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