jtag: drivers: xlnx-pcie-xvc: Add support for Xilinx XVC/PCIe

Add support for Xilinx Virtual Cable over PCIe JTAG controller.
It is commonly used in Xilinx based PCI Express designs with JTAG IP
in the FPGA fabric.

Access to the JTAG registers happens via the PCI Express extended
configuration space.

This can be used to debug soft-cores instantiated in the FPGA fabric.

The clang static checker doesn't find any new problems with this change.

Change-Id: Ib12ede0d1f26dacfda808d5e05b947b640c5bde7
Signed-off-by: Moritz Fischer <moritzf@google.com>
Reviewed-on: http://openocd.zylin.com/5314
Tested-by: jenkins
Reviewed-by: Antonio Borneo <borneo.antonio@gmail.com>
Reviewed-by: Marex
Reviewed-by: Oleksij Rempel <linux@rempel-privat.de>

1 files changed, 22 insertions, 0 deletions

diff --git a/doc/openocd.texi b/doc/openocd.texi
index c526a63..cb1c5b7 100644
--- a/doc/openocd.texi
+++ b/doc/openocd.texi
@@ -617,6 +617,9 @@ produced, PDF schematics are easily found and it is easy to make.
 @* A JTAG driver acting as a client for the JTAG VPI server interface.
 @* Link: @url{http://github.com/fjullien/jtag_vpi}
 
+@item @b{xlnx_pcie_xvc}
+@* A JTAG driver exposing Xilinx Virtual Cable over PCI Express to OpenOCD as JTAG interface.
+
 @end itemize
 
 @node About Jim-Tcl
@@ -3127,6 +3130,25 @@ opendous-jtag is a freely programmable USB adapter.
 This is the Keil ULINK v1 JTAG debugger.
 @end deffn
 
+@deffn {Interface Driver} {xlnx_pcie_xvc}
+This driver supports the Xilinx Virtual Cable (XVC) over PCI Express.
+It is commonly found in Xilinx based PCI Express designs. It allows debugging
+fabric based JTAG devices such as Cortex-M1/M3 microcontrollers. Access to this is
+exposed via extended capability registers in the PCI Express configuration space.
+
+For more information see Xilinx PG245 (Section on From_PCIE_to_JTAG mode).
+
+@deffn {Config Command} {xlnx_pcie_xvc_config} device
+Specifies the PCI Express device via parameter @var{device} to use.
+
+The correct value for @var{device} can be obtained by looking at the output
+of lscpi -D (first column) for the corresponding device.
+
+The string will be of the format "DDDD:BB:SS.F" such as "0000:65:00.1".
+
+@end deffn
+@end deffn
+
 @deffn {Interface Driver} {ZY1000}
 This is the Zylin ZY1000 JTAG debugger.
 @end deffn