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Message-ID: <CA+BWVURbWoJQ+NbOXyKLrtm5Hq2JwB_UyPhaKQtCxj0df3chxA@mail.gmail.com>
Date: Thu, 2 Jul 2015 14:00:13 -0500
From: Reyad Attiyat <reyad.attiyat@...il.com>
To: Mathias Nyman <mathias.nyman@...el.com>
Cc: linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
Reyad Attiyat <reyad.attiyat@...il.com>
Subject: Re: [PATCH v3] usb: xhci: Add support for URB_ZERO_PACKET to bulk/sg transfers
This version of the patch changes last_trb varible name to
last_trb_num and fixes code style. I have also added a td to the urb
td array. This now gets prepared properl,y with prepare_transfer(),
and is handled correctly when transferred and completed. It only calls
the urb completion callback once as there is a check in finish_td() to
ensure that all td's have been received.
If you think I should change anything else please let me know.
Thank you,
Reyad Attiyat
On Thu, Jul 2, 2015 at 1:54 PM, Reyad Attiyat <reyad.attiyat@...il.com> wrote:
> This commit checks for the URB_ZERO_PACKET flag and creates an extra
> zero-length td if the urb transfer length is a multiple of the endpoint's
> max packet length.
>
> Signed-off-by: Reyad Attiyat <reyad.attiyat@...il.com>
> ---
> drivers/usb/host/xhci-ring.c | 66 ++++++++++++++++++++++++++++++++++----------
> drivers/usb/host/xhci.c | 5 ++++
> 2 files changed, 57 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
> index 7d34cbf..31ea1b9 100644
> --- a/drivers/usb/host/xhci-ring.c
> +++ b/drivers/usb/host/xhci-ring.c
> @@ -3038,9 +3038,11 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> struct xhci_td *td;
> struct scatterlist *sg;
> int num_sgs;
> - int trb_buff_len, this_sg_len, running_total;
> + int trb_buff_len, this_sg_len, running_total, ret;
> unsigned int total_packet_count;
> + bool zero_length_needed;
> bool first_trb;
> + int last_trb_num;
> u64 addr;
> bool more_trbs_coming;
>
> @@ -3056,13 +3058,27 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> total_packet_count = DIV_ROUND_UP(urb->transfer_buffer_length,
> usb_endpoint_maxp(&urb->ep->desc));
>
> - trb_buff_len = prepare_transfer(xhci, xhci->devs[slot_id],
> + ret = prepare_transfer(xhci, xhci->devs[slot_id],
> ep_index, urb->stream_id,
> num_trbs, urb, 0, mem_flags);
> - if (trb_buff_len < 0)
> - return trb_buff_len;
> + if (ret < 0)
> + return ret;
>
> urb_priv = urb->hcpriv;
> +
> + /* Deal with URB_ZERO_PACKET - need one more td/trb */
> + zero_length_needed = urb->transfer_flags & URB_ZERO_PACKET &&
> + urb_priv->length == 2;
> + if (zero_length_needed) {
> + num_trbs++;
> + xhci_dbg(xhci, "Creating zero length td.\n");
> + ret = prepare_transfer(xhci, xhci->devs[slot_id],
> + ep_index, urb->stream_id,
> + 1, urb, 1, mem_flags);
> + if (ret < 0)
> + return ret;
> + }
> +
> td = urb_priv->td[0];
>
> /*
> @@ -3092,6 +3108,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> trb_buff_len = urb->transfer_buffer_length;
>
> first_trb = true;
> + last_trb_num = zero_length_needed ? 2 : 1;
> /* Queue the first TRB, even if it's zero-length */
> do {
> u32 field = 0;
> @@ -3109,12 +3126,15 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> /* Chain all the TRBs together; clear the chain bit in the last
> * TRB to indicate it's the last TRB in the chain.
> */
> - if (num_trbs > 1) {
> + if (num_trbs > last_trb_num) {
> field |= TRB_CHAIN;
> - } else {
> - /* FIXME - add check for ZERO_PACKET flag before this */
> + } else if (num_trbs == last_trb_num) {
> td->last_trb = ep_ring->enqueue;
> field |= TRB_IOC;
> + } else if (zero_length_needed && num_trbs == 1) {
> + trb_buff_len = 0;
> + urb_priv->td[1]->last_trb = ep_ring->enqueue;
> + field |= TRB_IOC;
> }
>
> /* Only set interrupt on short packet for IN endpoints */
> @@ -3176,7 +3196,7 @@ static int queue_bulk_sg_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> if (running_total + trb_buff_len > urb->transfer_buffer_length)
> trb_buff_len =
> urb->transfer_buffer_length - running_total;
> - } while (running_total < urb->transfer_buffer_length);
> + } while (num_trbs > 0);
>
> check_trb_math(urb, num_trbs, running_total);
> giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
> @@ -3194,7 +3214,9 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> int num_trbs;
> struct xhci_generic_trb *start_trb;
> bool first_trb;
> + int last_trb_num;
> bool more_trbs_coming;
> + bool zero_length_needed;
> int start_cycle;
> u32 field, length_field;
>
> @@ -3225,7 +3247,6 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> num_trbs++;
> running_total += TRB_MAX_BUFF_SIZE;
> }
> - /* FIXME: this doesn't deal with URB_ZERO_PACKET - need one more */
>
> ret = prepare_transfer(xhci, xhci->devs[slot_id],
> ep_index, urb->stream_id,
> @@ -3234,6 +3255,20 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> return ret;
>
> urb_priv = urb->hcpriv;
> +
> + /* Deal with URB_ZERO_PACKET - need one more td/trb */
> + zero_length_needed = urb->transfer_flags & URB_ZERO_PACKET &&
> + urb_priv->length == 2;
> + if (zero_length_needed) {
> + num_trbs++;
> + xhci_dbg(xhci, "Creating zero length td.\n");
> + ret = prepare_transfer(xhci, xhci->devs[slot_id],
> + ep_index, urb->stream_id,
> + 1, urb, 1, mem_flags);
> + if (ret < 0)
> + return ret;
> + }
> +
> td = urb_priv->td[0];
>
> /*
> @@ -3255,7 +3290,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> trb_buff_len = urb->transfer_buffer_length;
>
> first_trb = true;
> -
> + last_trb_num = zero_length_needed ? 2 : 1;
> /* Queue the first TRB, even if it's zero-length */
> do {
> u32 remainder = 0;
> @@ -3272,12 +3307,15 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> /* Chain all the TRBs together; clear the chain bit in the last
> * TRB to indicate it's the last TRB in the chain.
> */
> - if (num_trbs > 1) {
> + if (num_trbs > last_trb_num) {
> field |= TRB_CHAIN;
> - } else {
> - /* FIXME - add check for ZERO_PACKET flag before this */
> + } else if (num_trbs == last_trb_num) {
> td->last_trb = ep_ring->enqueue;
> field |= TRB_IOC;
> + } else if (zero_length_needed && num_trbs == 1) {
> + trb_buff_len = 0;
> + urb_priv->td[1]->last_trb = ep_ring->enqueue;
> + field |= TRB_IOC;
> }
>
> /* Only set interrupt on short packet for IN endpoints */
> @@ -3315,7 +3353,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
> trb_buff_len = urb->transfer_buffer_length - running_total;
> if (trb_buff_len > TRB_MAX_BUFF_SIZE)
> trb_buff_len = TRB_MAX_BUFF_SIZE;
> - } while (running_total < urb->transfer_buffer_length);
> + } while (num_trbs > 0);
>
> check_trb_math(urb, num_trbs, running_total);
> giveback_first_trb(xhci, slot_id, ep_index, urb->stream_id,
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 36bf089..40f433d 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -1340,6 +1340,11 @@ int xhci_urb_enqueue(struct usb_hcd *hcd, struct urb *urb, gfp_t mem_flags)
>
> if (usb_endpoint_xfer_isoc(&urb->ep->desc))
> size = urb->number_of_packets;
> + else if (usb_endpoint_is_bulk_out(&urb->ep->desc) &&
> + urb->transfer_buffer_length > 0 &&
> + urb->transfer_flags & URB_ZERO_PACKET &&
> + !(urb->transfer_buffer_length % usb_endpoint_maxp(&urb->ep->desc)))
> + size = 2;
> else
> size = 1;
>
> --
> 2.4.3
>
--
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