target/linux/bcm27xx/patches-5.4/950-0393-dwc_otg-constrain-endpoint-max-packet-and-transfer-s.patch

   1 From b7944a79716c115d881898e6a95705b262e7c1c9 Mon Sep 17 00:00:00 2001
   2 From: Jonathan Bell <jonathan@raspberrypi.org>
   3 Date: Tue, 7 Jan 2020 10:08:19 +0000
   4 Subject: [PATCH] dwc_otg: constrain endpoint max packet and transfer
   5  size on split IN
   6
   7 The hcd would unconditionally set the transfer length to the endpoint
   8 packet size for non-isoc IN transfers. If the remaining buffer length
   9 was less than the length of returned data, random memory would get
  10 scribbled over, with bad effects if it crossed a page boundary.
  11
  12 Force a babble error if this happens by limiting the max transfer size
  13 to the available buffer space. DMA will stop writing to memory on a
  14 babble condition.
  15
  16 The hardware expects xfersize to be an integer multiple of maxpacket
  17 size, so override hcchar.b.mps as well.
  18
  19 Signed-off-by: Jonathan Bell <jonathan@raspberrypi.org>
  20 ---
  21  drivers/usb/host/dwc_otg/dwc_otg_hcd.c | 4 ++--
  22  1 file changed, 2 insertions(+), 2 deletions(-)
  23
  24 --- a/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
  25 +++ b/drivers/usb/host/dwc_otg/dwc_otg_hcd.c
  26 @@ -1811,7 +1811,7 @@ int fiq_fsm_queue_split_transaction(dwc_
  27         st->nr_errors = 0;
  28
  29         st->hcchar_copy.d32 = 0;
  30 -       st->hcchar_copy.b.mps = hc->max_packet;
  31 +       st->hcchar_copy.b.mps = min_t(uint32_t, hc->xfer_len, hc->max_packet);
  32         st->hcchar_copy.b.epdir = hc->ep_is_in;
  33         st->hcchar_copy.b.devaddr = hc->dev_addr;
  34         st->hcchar_copy.b.epnum = hc->ep_num;
  35 @@ -1856,7 +1856,7 @@ int fiq_fsm_queue_split_transaction(dwc_
  36         st->hctsiz_copy.b.pid = hc->data_pid_start;
  37
  38         if (hc->ep_is_in || (hc->xfer_len > hc->max_packet)) {
  39 -               hc->xfer_len = hc->max_packet;
  40 +               hc->xfer_len = min_t(uint32_t, hc->xfer_len, hc->max_packet);
  41         } else if (!hc->ep_is_in && (hc->xfer_len > 188)) {
  42                 hc->xfer_len = 188;
  43         }