linux/drivers/usb
Anurag Kumar Vulisha b7a4fbe230 usb: dwc3: Correct the logic for checking TRB full in __dwc3_prepare_one_trb()
Availability of TRB's is calculated using dwc3_calc_trbs_left(), which
determines total available TRB's based on the HWO bit set in a TRB.

In the present code, __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 yet have
the HWO bit set before calling dwc3_calc_trbs_left(), there are chances
that dwc3_calc_trbs_left() wrongly calculates this present working TRB
as free(since the HWO bit is not yet set) and returns the total available
TRBs as greater than zero (including the present working TRB). This could
be a problem.

This patch corrects the above mentioned problem in __dwc3_prepare_one_trb()
by increementing the dep->trb_enqueue at the last (after preparing the TRB)
instead of increementing at the start and setting the IOC bit only if the
total available TRBs returned by dwc3_calc_trbs_left() is 1 . Since we are
increementing the dep->trb_enqueue at the last, the present working TRB is
also considered as available by dwc3_calc_trbs_left() and non zero value is
returned . So, according to the modified logic, when the total available
TRBs is equal to 1 that means the total available TRBs in the pool are 0.

Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xilinx.com>
Reviewed-by: Thinh Nguyen <thinhn@synopsys.com>
Tested-by: Tejas Joglekar <tejas.joglekar@synopsys.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
2018-12-05 10:44:55 +02:00
..
atm
c67x00
chipidea usb: chipidea: Fix otg event handler 2018-09-20 17:04:22 +08:00
class usb: cdc-acm: add entry for Hiro (Conexant) modem 2018-11-20 12:12:06 +01:00
common usb: roles: Take care of driver module reference counting 2018-09-20 13:20:24 +02:00
core usb: core: Fix hub port connection events lost 2018-11-14 14:28:26 -08:00
dwc2 usb: dwc2: gadget: Accept LPM token when TxFIFO is not empty 2018-11-26 09:06:32 +02:00
dwc3 usb: dwc3: Correct the logic for checking TRB full in __dwc3_prepare_one_trb() 2018-12-05 10:44:55 +02:00
early mm: remove include/linux/bootmem.h 2018-10-31 08:54:16 -07:00
gadget usb: gadget: f_fs: Allow scatter-gather buffers 2018-11-26 09:06:32 +02:00
host usb: xhci: Prevent bus suspend if a port connect change or polling state is detected 2018-11-15 09:17:40 -08:00
image
isp1760 usb: isp1760: remove redundant variable 'selector' 2018-07-13 15:41:56 +02:00
misc USB: misc: appledisplay: add 20" Apple Cinema Display 2018-11-07 13:23:18 +01:00
mon USB: mon: use ktime_get_real_ts64 instead of getnstimeofday64 2018-06-25 21:58:26 +08:00
mtu3 usb: mtu3: disable vbus rise/fall interrupts of ltssm 2018-10-02 10:39:02 +03:00
musb usb: musb: dsps: do not disable CPPI41 irq in driver teardown 2018-09-20 12:40:14 +02:00
phy usb: phy: ab8500: silence some uninitialized variable warnings 2018-10-18 19:44:39 +02:00
renesas_usbhs usb: renesas_usbhs: add support for R-Car E3 2018-10-02 10:48:08 +03:00
roles usb: roles: intel_xhci: Fix Unbalanced pm_runtime_enable 2018-10-09 16:13:42 +02:00
serial USB/PHY patches for 4.20-rc1 2018-10-26 08:14:13 -07:00
storage USB: STORAGE: ISD200 Fixed coding style issue "space required in for loop" 2018-09-20 15:10:29 +02:00
typec usb: typec: ucsi: add support for Cypress CCGx 2018-11-09 18:49:59 +01:00
usbip Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-01 19:58:52 -07:00
wusbcore USB/PHY patches for 4.20-rc1 2018-10-26 08:14:13 -07:00
Kconfig usb: select USB_COMMON for usb role switch config 2018-04-22 15:23:37 +02:00
Makefile usb: roles: Add Intel xHCI USB role switch driver 2018-03-22 13:49:27 +01:00
README
usb-skeleton.c usb: usb-skeleton: use irqsave() in USB's complete callback 2018-06-28 19:36:06 +09:00

To understand all the Linux-USB framework, you'll use these resources:

    * This source code.  This is necessarily an evolving work, and
      includes kerneldoc that should help you get a current overview.
      ("make pdfdocs", and then look at "usb.pdf" for host side and
      "gadget.pdf" for peripheral side.)  Also, Documentation/usb has
      more information.

    * The USB 2.0 specification (from www.usb.org), with supplements
      such as those for USB OTG and the various device classes.
      The USB specification has a good overview chapter, and USB
      peripherals conform to the widely known "Chapter 9".

    * Chip specifications for USB controllers.  Examples include
      host controllers (on PCs, servers, and more); peripheral
      controllers (in devices with Linux firmware, like printers or
      cell phones); and hard-wired peripherals like Ethernet adapters.

    * Specifications for other protocols implemented by USB peripheral
      functions.  Some are vendor-specific; others are vendor-neutral
      but just standardized outside of the www.usb.org team.

Here is a list of what each subdirectory here is, and what is contained in
them.

core/		- This is for the core USB host code, including the
		  usbfs files and the hub class driver ("hub_wq").

host/		- This is for USB host controller drivers.  This
		  includes UHCI, OHCI, EHCI, and others that might
		  be used with more specialized "embedded" systems.

gadget/		- This is for USB peripheral controller drivers and
		  the various gadget drivers which talk to them.


Individual USB driver directories.  A new driver should be added to the
first subdirectory in the list below that it fits into.

image/		- This is for still image drivers, like scanners or
		  digital cameras.
../input/	- This is for any driver that uses the input subsystem,
		  like keyboard, mice, touchscreens, tablets, etc.
../media/	- This is for multimedia drivers, like video cameras,
		  radios, and any other drivers that talk to the v4l
		  subsystem.
../net/		- This is for network drivers.
serial/		- This is for USB to serial drivers.
storage/	- This is for USB mass-storage drivers.
class/		- This is for all USB device drivers that do not fit
		  into any of the above categories, and work for a range
		  of USB Class specified devices. 
misc/		- This is for all USB device drivers that do not fit
		  into any of the above categories.