lkml.org 
[lkml]   [2018]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH v2 1/8] usb: dwc3: Correct the logic for checking TRB full in __dwc3_prepare_one_trb()
Date
Availability of TRB's are calculated using dwc3_calc_trbs_left(), which
determines available TRB's based on the HWO bit set in a TRB.

__dwc3_prepare_one_trb() is called with a TRB which needs to be prepared
for transfer. This __dwc3_prepare_one_trb() calls dwc3_calc_trbs_left()
to determine total available TRBs and set IOC bit if the total available
TRBs are zero. Since the present working TRB(which is passed as an
argument to __dwc3_prepare_one_trb() ) doesn't have HWO bit already set,
there are chances where dwc3_calc_trbs_left() wrongly calculates this
present working TRB as free(since the HWO bit is not yet set). This could
be a problem. This patch correct this issue by setting HWO bit before
calling dwc3_calc_trbs_left()

Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com>
---
Changes in v2:
1. Changed the commit message
---
drivers/usb/dwc3/gadget.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 69bf137..f73d219 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -990,6 +990,8 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb,
trb->ctrl |= DWC3_TRB_CTRL_ISP_IMI;
}

+ trb->ctrl |= DWC3_TRB_CTRL_HWO;
+
if ((!no_interrupt && !chain) ||
(dwc3_calc_trbs_left(dep) == 0))
trb->ctrl |= DWC3_TRB_CTRL_IOC;
@@ -1000,8 +1002,6 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb,
if (usb_endpoint_xfer_bulk(dep->endpoint.desc) && dep->stream_capable)
trb->ctrl |= DWC3_TRB_CTRL_SID_SOFN(stream_id);

- trb->ctrl |= DWC3_TRB_CTRL_HWO;
-
trace_dwc3_prepare_trb(dep, trb);
}

--
2.1.1
\
 
 \ /
  Last update: 2018-08-17 14:26    [W:0.107 / U:0.256 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site