===============================================================================
|
===============================================================================
|
-- OpenRISC Debug Proxy --
|
-- OpenRISC Debug Proxy --
|
===============================================================================
|
===============================================================================
|
|
|
===============================================================================
|
===============================================================================
|
-- Description --
|
-- Description --
|
===============================================================================
|
===============================================================================
|
A console application implementing a GDB stub and and communication with an
|
A console application implementing a GDB stub and and communication with an
|
OpenRISC processor system via a USB debug cable.
|
OpenRISC processor system via a USB debug cable.
|
===============================================================================
|
===============================================================================
|
-- Versions --
|
-- Versions --
|
===============================================================================
|
===============================================================================
|
0.1.0 090201 jb@orsoc.se
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0.1.0 090201 jb@orsoc.se
|
0.1.1 090304 jb@orsoc.se
|
0.1.1 090304 jb@orsoc.se
|
0.1.2 090511 jb@orsoc.se
|
0.1.2 090511 jb@orsoc.se
|
0.1.3 090604 jb@orsoc.se
|
0.1.3 090604 jb@orsoc.se
|
0.1.4 090828 jb@orsoc.se
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0.1.4 090828 jb@orsoc.se
|
|
0.1.5 090903 jb@orsoc.se
|
===============================================================================
|
===============================================================================
|
-- Installation --
|
-- Installation --
|
===============================================================================
|
===============================================================================
|
|
|
The OR debug proxy application runs on multiple platforms only requiring
|
The OR debug proxy application runs on multiple platforms only requiring
|
slightly different driver configurations on each. Currently, Cygwin Windows,
|
slightly different driver configurations on each. Currently, Cygwin Windows,
|
several Linux distros and Mac OS X (10.4 and above) are supported.
|
several Linux distros and Mac OS X (10.4 and above) are supported.
|
Use with the ORSoC debug cable requires installation of some form of the FTDI
|
Use with the ORSoC debug cable requires installation of some form of the FTDI
|
Chip FTD2XX driver. Instructions for each platform follow.
|
Chip FTD2XX driver. Instructions for each platform follow.
|
|
|
-------------------------------------------------------------------------------
|
-------------------------------------------------------------------------------
|
-- Installation on Cygwin Windows --
|
-- Installation on Cygwin Windows --
|
-------------------------------------------------------------------------------
|
-------------------------------------------------------------------------------
|
|
|
-- Compilation of the OpenRISC Debug Proxy application --
|
-- Compilation of the OpenRISC Debug Proxy application --
|
|
|
While in the same directory which this file is located in, run a simple
|
While in the same directory which this file is located in, run a simple
|
"make" command.
|
"make" command.
|
|
|
user@cygwin-host ~/or_debug_proxy
|
user@cygwin-host ~/or_debug_proxy
|
$ make
|
$ make
|
|
|
Run the resulting executable (or_debug_proxy.exe) for usage details.
|
Run the resulting executable (or_debug_proxy.exe) for usage details.
|
|
|
|
|
-- ORSoC OpenRISC USB debug cable driver installation --
|
-- ORSoC OpenRISC USB debug cable driver installation --
|
|
|
As per the installation instructions included in FTDI Chip's D2XX Windows
|
As per the installation instructions included in FTDI Chip's D2XX Windows
|
driver. http://www.ftdichip.com/Drivers/D2XX.htm
|
driver. http://www.ftdichip.com/Drivers/D2XX.htm
|
|
|
-------------------------------------------------------------------------------
|
-------------------------------------------------------------------------------
|
-- Installation on Linux
|
-- Installation on Linux
|
-------------------------------------------------------------------------------
|
-------------------------------------------------------------------------------
|
|
|
-- Compilation of the OpenRISC Debug Proxy application --
|
-- Compilation of the OpenRISC Debug Proxy application --
|
|
|
There are two options for compilation. One results in a dynamically linked
|
There are two options for compilation. One results in a dynamically linked
|
executable, the other links against a static library. See details on
|
executable, the other links against a static library. See details on
|
installing the desired library in the following section.
|
installing the desired library in the following section.
|
|
|
-- Dynamically linked executable --
|
-- Dynamically linked executable --
|
|
|
This is the default build method. In the same directory this README is
|
This is the default build method. In the same directory this README is
|
located, run a simple "make" command:
|
located, run a simple "make" command:
|
|
|
user@host:~/or_debug_proxy$ make
|
user@host:~/or_debug_proxy$ make
|
|
|
Ensure the driver library is installed before attempting to build, else it
|
Ensure the driver library is installed before attempting to build, else it
|
will fail.
|
will fail.
|
|
|
-- Static linked executable --
|
-- Static linked executable --
|
|
|
To be able to use the proxy with the ORSoC USB debug cable without requiring
|
To be able to use the proxy with the ORSoC USB debug cable without requiring
|
installation of the driver libraries into system directories, a method of
|
installation of the driver libraries into system directories, a method of
|
building and linking the proxy app to static libraries is provided. Ensure
|
building and linking the proxy app to static libraries is provided. Ensure
|
the static library for your platform is located in the lib/ directory
|
the static library for your platform is located in the lib/ directory
|
underneath the path this README is located.
|
underneath the path this README is located.
|
|
|
To build, run:
|
To build, run:
|
|
|
user@host:~/or_debug_proxy$ make static
|
user@host:~/or_debug_proxy$ make static
|
|
|
|
|
-- ORSoC OpenRISC USB debug cable driver installation --
|
-- ORSoC OpenRISC USB debug cable driver installation --
|
|
|
Before we begin:
|
Before we begin:
|
|
|
It is required that the Linux distribution have a version 2.4 kernel, or
|
It is required that the Linux distribution have a version 2.4 kernel, or
|
above. This is due to the USB driver libraries by FTDI Chip used to interface
|
above. This is due to the USB driver libraries by FTDI Chip used to interface
|
with the USB debug device.
|
with the USB debug device.
|
|
|
The ORSoC USB debugger cable uses a FTDI dual UART/FIFO chip.
|
The ORSoC USB debugger cable uses a FTDI dual UART/FIFO chip.
|
|
|
An aside: These USB to serial devices typically trigger the loading of another
|
An aside: These USB to serial devices typically trigger the loading of another
|
FTDI driver when they're attached to the system. This is the ftdi_sio driver
|
FTDI driver when they're attached to the system. This is the ftdi_sio driver
|
and now comes standard in newer kernels. This is of use to us, as one of the
|
and now comes standard in newer kernels. This is of use to us, as one of the
|
two serial devices will remain is a standard UART under /dev/ttyUSBx. However,
|
two serial devices will remain is a standard UART under /dev/ttyUSBx. However,
|
to enable a high-speed JTAG interface with our hardware we require newer,
|
to enable a high-speed JTAG interface with our hardware we require newer,
|
specialised drivers from FTDI called the D2XX drivers.
|
specialised drivers from FTDI called the D2XX drivers.
|
|
|
The Linux driver can be obtained from FTDI Chip's website,
|
The Linux driver can be obtained from FTDI Chip's website,
|
http://www.ftdichip.com, and is found under the links to "Drivers" and then
|
http://www.ftdichip.com, and is found under the links to "Drivers" and then
|
"D2XX". At the time of writing, the latest version was libftd2xx 0.4.16 and
|
"D2XX". At the time of writing, the latest version was libftd2xx 0.4.16 and
|
could be downloaded directly off their site from
|
could be downloaded directly off their site from
|
http://www.ftdichip.com/Drivers/D2XX/Linux/libftd2xx0.4.16.tar.gz
|
http://www.ftdichip.com/Drivers/D2XX/Linux/libftd2xx0.4.16.tar.gz
|
|
|
Statically linked driver:
|
Statically linked driver:
|
|
|
The simplest way to enable these drivers is to link the application
|
The simplest way to enable these drivers is to link the application
|
statically - that is, have a copy of the driver along with the debugging
|
statically - that is, have a copy of the driver along with the debugging
|
application. This is much simpler than the following driver installation
|
application. This is much simpler than the following driver installation
|
instructions. Typically in the FTDI drivers there is also a directory called
|
instructions. Typically in the FTDI drivers there is also a directory called
|
static_lib/ and this contains a driver that can be statically linked against
|
static_lib/ and this contains a driver that can be statically linked against
|
when compiling. To compile the OpenRISC debug proxy like this, copy the file in
|
when compiling. To compile the OpenRISC debug proxy like this, copy the file in
|
that static_lib/ path into the lib/ directory under the or_debug_proxy/
|
that static_lib/ path into the lib/ directory under the or_debug_proxy/
|
build directory, and do:
|
build directory, and do:
|
|
|
user@host:~/or_debug_proxy$ make static
|
user@host:~/or_debug_proxy$ make static
|
|
|
This will result in the executable being statically linked to the driver file
|
This will result in the executable being statically linked to the driver file
|
in the the lib/ folder.
|
in the the lib/ folder.
|
|
|
Dynamically linked driver install directions:
|
Dynamically linked driver install directions:
|
|
|
Uncompress the driver package (tar xzvf libftd2xx0.4.16.tar.gz) and read the
|
Uncompress the driver package (tar xzvf libftd2xx0.4.16.tar.gz) and read the
|
file "readme.dat" located inside, but don't complete their way of installing
|
file "readme.dat" located inside, but don't complete their way of installing
|
yet. Their installation method should be modified slightly to allow easier use
|
yet. Their installation method should be modified slightly to allow easier use
|
of the USB device by users. Read the following before performing the install
|
of the USB device by users. Read the following before performing the install
|
as per the instructions in "readme.dat", and amend their installation process
|
as per the instructions in "readme.dat", and amend their installation process
|
as you go.
|
as you go.
|
|
|
* In step 4, create an additional symbolic link, however this time with only a
|
* In step 4, create an additional symbolic link, however this time with only a
|
trailing zero, like so:
|
trailing zero, like so:
|
|
|
user@host:/usr/local/lib$ ln -s libftd2xx.so.x.x.xx libftd2xx.so.0
|
user@host:/usr/local/lib$ ln -s libftd2xx.so.x.x.xx libftd2xx.so.0
|
|
|
* Again, in step 6, create an additional symbolic link with only a trailing
|
* Again, in step 6, create an additional symbolic link with only a trailing
|
zero:
|
zero:
|
|
|
user@host:/usr/lib$ ln -s /usr/local/lib/libftd2xx.so.x.x.xx libftd2xx.so.0
|
user@host:/usr/lib$ ln -s /usr/local/lib/libftd2xx.so.x.x.xx libftd2xx.so.0
|
|
|
* In step 7 (the following may vary depending on your distribution, however in
|
* In step 7 (the following may vary depending on your distribution, however in
|
the most recent Ubuntu our suggested modification was required) instead of
|
the most recent Ubuntu our suggested modification was required) instead of
|
the line provided in "readme.dat", use the following in your /etc/fstab file
|
the line provided in "readme.dat", use the following in your /etc/fstab file
|
(note the difference is a change from "usbdevfs" to "usbfs")
|
(note the difference is a change from "usbdevfs" to "usbfs")
|
|
|
none /proc/bus/usb usbfs defaults,devmode=0666 0 0
|
none /proc/bus/usb usbfs defaults,devmode=0666 0 0
|
|
|
* The last step (mount -a) outlined in "readme.dat" can then be performed.
|
* The last step (mount -a) outlined in "readme.dat" can then be performed.
|
|
|
-- Setting USB device permissions --
|
-- Setting USB device permissions --
|
|
|
Depending on the Linux distribution and how recent it is, the method for
|
Depending on the Linux distribution and how recent it is, the method for
|
defining the permissions of the USB device when it's loaded by the kernel can
|
defining the permissions of the USB device when it's loaded by the kernel can
|
vary.
|
vary.
|
|
|
* Recent udev systems (most 2.6 kernel systems)
|
* Recent udev systems (most 2.6 kernel systems)
|
|
|
There can be variations in the way udev organises its files for setting up
|
There can be variations in the way udev organises its files for setting up
|
rules and permissions of devices attached to the system, but the following
|
rules and permissions of devices attached to the system, but the following
|
should cover most systems.
|
should cover most systems.
|
|
|
Do a listing of the udev rules directory
|
Do a listing of the udev rules directory
|
|
|
user@host:~$ ls /etc/udev/rules.d/
|
user@host:~$ ls /etc/udev/rules.d/
|
|
|
There should be a file somewhere, with the word "permissions" in the name. On
|
There should be a file somewhere, with the word "permissions" in the name. On
|
some systems it could be called "40-permissions.rules", on others possibly
|
some systems it could be called "40-permissions.rules", on others possibly
|
"020_permissions.rules". Locate the permissions file in /etc/udev/rules.d/
|
"020_permissions.rules". Locate the permissions file in /etc/udev/rules.d/
|
and, as the super user (root), open the file to edit. The author prefers nano.
|
and, as the super user (root), open the file to edit. The author prefers nano.
|
|
|
user@host:/etc/udev/rules.d$ sudo nano 40-permissions.rules
|
user@host:/etc/udev/rules.d$ sudo nano 40-permissions.rules
|
[sudo] password for user:
|
[sudo] password for user:
|
|
|
Of course, editing as super user (sudo'ing) will require the ability to sudo.
|
Of course, editing as super user (sudo'ing) will require the ability to sudo.
|
|
|
The following can differ from system to system. In this case, a recent version
|
The following can differ from system to system. In this case, a recent version
|
of Ubuntu, the file "40-permissions.rules" was present and will be edited.
|
of Ubuntu, the file "40-permissions.rules" was present and will be edited.
|
|
|
In this particular permissions file there are different sections, some with
|
In this particular permissions file there are different sections, some with
|
labels.
|
labels.
|
|
|
Search for the lines with LABEL="usb_serial_start" and
|
Search for the lines with LABEL="usb_serial_start" and
|
LABEL="usb_serial_end". In BETWEEN these two LABEL lines, insert two new lines
|
LABEL="usb_serial_end". In BETWEEN these two LABEL lines, insert two new lines
|
containing the following:
|
containing the following:
|
|
|
# Permissions for ORSoC USB debugger FT2232 device
|
# Permissions for ORSoC USB debugger FT2232 device
|
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6010", MODE="0666", GROUP="tty"
|
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6010", MODE="0666", GROUP="tty"
|
|
|
If these LABEL="" lines cannot be found (for instance, different distros have
|
If these LABEL="" lines cannot be found (for instance, different distros have
|
their udev setup differently) insert the above line anywhere in the file. This
|
their udev setup differently) insert the above line anywhere in the file. This
|
is not a definite way of enabling these permissions, and udev exists in many
|
is not a definite way of enabling these permissions, and udev exists in many
|
forms and configurations, so if this does not work, please contact the author
|
forms and configurations, so if this does not work, please contact the author
|
regarding the issue.
|
regarding the issue.
|
|
|
* Fedora 9
|
* Fedora 9
|
|
|
As an example of a slightly different system, Fedora 9 does not have a
|
As an example of a slightly different system, Fedora 9 does not have a
|
xx-permissions.rules file. The solution is to create a new file, but in this
|
xx-permissions.rules file. The solution is to create a new file, but in this
|
case choose the name "51-permissions.rules". It can have just the rule listed
|
case choose the name "51-permissions.rules". It can have just the rule listed
|
above:
|
above:
|
|
|
# Permissions for ORSoC USB debugger FT2232 device
|
# Permissions for ORSoC USB debugger FT2232 device
|
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6010", MODE="0666", GROUP="tty"
|
ATTRS{idVendor}=="0403", ATTRS{idProduct}=="6010", MODE="0666", GROUP="tty"
|
|
|
The reason for the filename change is that the udev rules files are read in
|
The reason for the filename change is that the udev rules files are read in
|
lexical order (i.e. the order they would appear in a dictionary). With Fedora
|
lexical order (i.e. the order they would appear in a dictionary). With Fedora
|
9 the old FTDI driver is included as standard, and there is default rule in
|
9 the old FTDI driver is included as standard, and there is default rule in
|
50-udev-default.rules, which would override anything in 40-permissions.rules
|
50-udev-default.rules, which would override anything in 40-permissions.rules
|
(since it would be read first). By using the name 51-permissions.rules, our
|
(since it would be read first). By using the name 51-permissions.rules, our
|
rule will override anything set in 50-udev-default.rules.
|
rule will override anything set in 50-udev-default.rules.
|
|
|
If you find problems with permissions, then check that no later rules files
|
If you find problems with permissions, then check that no later rules files
|
are overriding settings.
|
are overriding settings.
|
|
|
The devices whose permissions are set are /dev/ttyUSB0 /dev/ttyUSB1, the
|
The devices whose permissions are set are /dev/ttyUSB0 /dev/ttyUSB1, the
|
/dev/usbdevnnn for the USB slot (nnn) being used, and the files in
|
/dev/usbdevnnn for the USB slot (nnn) being used, and the files in
|
/dev/bus/usb/nnn/xxx. They should all be in group tty and have permission
|
/dev/bus/usb/nnn/xxx. They should all be in group tty and have permission
|
rw-rw-rw.
|
rw-rw-rw.
|
|
|
* Older systems, (early udev, devfs)
|
* Older systems, (early udev, devfs)
|
|
|
None of these systems were tested, however it should be easy enough to locate
|
None of these systems were tested, however it should be easy enough to locate
|
the device by the vendor ID and product ID on the USB bus. See the Udev
|
the device by the vendor ID and product ID on the USB bus. See the Udev
|
instructions above for these values.
|
instructions above for these values.
|
|
|
* Reloading the ftdi_sio driver
|
* Reloading the ftdi_sio driver
|
|
|
If it is desired that the D2XX drivers be unloaded and the original ftdi_sio one
|
If it is desired that the D2XX drivers be unloaded and the original ftdi_sio one
|
reactivated (recreating the two /dev/ttyUSB devices), it is as simple as
|
reactivated (recreating the two /dev/ttyUSB devices), it is as simple as
|
removing and replacing the USB dongle from the system. However, it can also be
|
removing and replacing the USB dongle from the system. However, it can also be
|
done at the prompt by first running as root "modprobe -r ftdi_sio", and then
|
done at the prompt by first running as root "modprobe -r ftdi_sio", and then
|
"modprobe ftdi_sio vendor=0x0403 product=0x6010", which totally removes and
|
"modprobe ftdi_sio vendor=0x0403 product=0x6010", which totally removes and
|
then reloads the device.
|
then reloads the device.
|
|
|
-- Usage OpenRISC Debug Proxy application --
|
-- Usage OpenRISC Debug Proxy application --
|
|
|
The proxy application can then be run with the desired options, or for
|
The proxy application can then be run with the desired options, or for
|
usage details, run the program with no options specified.
|
usage details, run the program with no options specified.
|
|
|
user@host:~/or_debug_proxy$ ./or_debug_proxy
|
user@host:~/or_debug_proxy$ ./or_debug_proxy
|
|
|
Invalid or insufficient arguments
|
Invalid or insufficient arguments
|
|
|
OpenRISC GDB proxy server usage: or_debug_proxy -server_type port
|
OpenRISC GDB proxy server usage: or_debug_proxy -server_type port
|
|
|
server_type:
|
server_type:
|
-r Start a server using RSP, connection to hadware target via
|
-r Start a server using RSP, connection to hadware target via
|
USB
|
USB
|
-j Start a server using legacy OR remote JTAG protocol, to
|
-j Start a server using legacy OR remote JTAG protocol, to
|
hardware target via USB
|
hardware target via USB
|
-v Start a server using RSP, connection to RTL sim. VPI server
|
-v Start a server using RSP, connection to RTL sim. VPI server
|
target via sockets
|
target via sockets
|
|
|
port_number:
|
port_number:
|
Any free port within the usable range of 0 - 65535
|
Any free port within the usable range of 0 - 65535
|
|
|
Example:
|
Example:
|
Start a GDB server on port 5555, using RSP, connecting to
|
Start a GDB server on port 5555, using RSP, connecting to
|
hardware target via USB
|
hardware target via USB
|
or_debug_proxy -r 5555
|
or_debug_proxy -r 5555
|
|
|
|
|
* Platforms tested, and known to be working, on:
|
* Platforms tested, and known to be working, on:
|
Ubuntu 8.04
|
Ubuntu 8.04
|
Debian
|
Debian
|
|
|
-------------------------------------------------------------------------------
|
-------------------------------------------------------------------------------
|
-- Installation on Mac OS X --
|
-- Installation on Mac OS X --
|
-------------------------------------------------------------------------------
|
-------------------------------------------------------------------------------
|
|
|
-- ORSoC OpenRISC USB debug cable driver installation --
|
-- ORSoC OpenRISC USB debug cable driver installation --
|
|
|
As per the installation instructions included in FTDI Chip's D2XX Mac OS X
|
As per the installation instructions included in FTDI Chip's D2XX Mac OS X
|
driver. http://www.ftdichip.com/Drivers/D2XX.htm
|
driver. http://www.ftdichip.com/Drivers/D2XX.htm
|
|
|
-- Compilation of the OpenRISC Debug Proxy application --
|
-- Compilation of the OpenRISC Debug Proxy application --
|
|
|
As per the Linux instructions.
|
As per the Linux instructions.
|
|
|
|
|
* Note: Tested on an Intel Mac, running OS X version 10.4
|
* Note: Tested on an Intel Mac, running OS X version 10.4
|
|
|
|
|
|
|
===============================================================================
|
===============================================================================
|
-- Usage notes --
|
-- Usage notes --
|
===============================================================================
|
===============================================================================
|
|
|
When the program initialises it sets up some form of communication with an
|
When the program initialises it sets up some form of communication with an
|
OpenRISC processor (developed and tested with a OR1k design similar to the
|
OpenRISC processor (developed and tested with a OR1k design similar to the
|
ORPSoC design found in the OR1k project archive on OpenCores), either via a
|
ORPSoC design found in the OR1k project archive on OpenCores), either via a
|
USB debug cable or via sockets interface to an RTL simulation. After this, it
|
USB debug cable or via sockets interface to an RTL simulation. After this, it
|
waits for a connection from GDB, and then the debugging session can begin.
|
waits for a connection from GDB, and then the debugging session can begin.
|
|
|
The proxy has been written to be robust, for example it will hopefully handle
|
The proxy has been written to be robust, for example it will hopefully handle
|
disruptions like processor crashes, hardware resets, and connection dropouts
|
disruptions like processor crashes, hardware resets, and connection dropouts
|
gracefully enough to not require a complete restart of the proxy and GDB.
|
gracefully enough to not require a complete restart of the proxy and GDB.
|
|
|
Some basic mechanics of the proxy are as follows:
|
Some basic mechanics of the proxy are as follows:
|
|
|
* When the program is "continued" from GDB, the proxy will poll the processors
|
* When the program is "continued" from GDB, the proxy will poll the processors
|
stall indicator. If it detects the processor is stalled it will check against
|
stall indicator. If it detects the processor is stalled it will check against
|
a list of software breakpoints to determine if this was the reason for the
|
a list of software breakpoints to determine if this was the reason for the
|
halt, otherwise it returns a signal depending on what it thinks the problem
|
halt, otherwise it returns a signal depending on what it thinks the problem
|
is.
|
is.
|
|
|
* The there is alo polling for "interrupt" (^C signals) sent from GDB,
|
* The there is alo polling for "interrupt" (^C signals) sent from GDB,
|
which will cause the processor to be stalled, wherever it is, and control
|
which will cause the processor to be stalled, wherever it is, and control
|
returned to GDB (the proxy will await further commands from GDB.) It is
|
returned to GDB (the proxy will await further commands from GDB.) It is
|
optional to implement this awareness of the interrupt signal from GDB, but
|
optional to implement this awareness of the interrupt signal from GDB, but
|
the developers have found this functionality extremely useful and thought
|
the developers have found this functionality extremely useful and thought
|
others might too.
|
others might too.
|
|
|
* Troubleshooting tip: If the proxy prints out the following line(s):
|
* Troubleshooting tip: If the proxy prints out the following line(s):
|
RSP step with signal 'S04' received
|
RSP step with signal 'S04' received
|
when attempting to continue, or single step, a program from GDB, it is
|
when attempting to continue, or single step, a program from GDB, it is
|
necessary to restart both the proxy and GDB before being continuing.
|
necessary to restart both the proxy and GDB before being continuing.
|
This bug is perhaps caused by changing the file GDB is debugging during the
|
This bug is perhaps caused by changing the file GDB is debugging during the
|
same session.
|
same session.
|
|
|
TODO List:
|
TODO List:
|
* USB<->JTAG Driver TODO: Increase speed of the proxy
|
* USB<->JTAG Driver TODO: Increase speed of the proxy
|
It appears that the current transfer rate of around 20k/s is due to
|
It appears that the current transfer rate of around 20k/s is due to
|
pauses in the driver. This was determined by profiling the proxy and
|
pauses in the driver. This was determined by profiling the proxy and
|
noticing that, over a 4-odd megabyte transfer from GDB, taking about 4
|
noticing that, over a 4-odd megabyte transfer from GDB, taking about 4
|
minutes, the proxy only executed for 2.5 seconds, and the three most
|
minutes, the proxy only executed for 2.5 seconds, and the three most
|
used functions, accounting for 50% of execution were functions in the
|
used functions, accounting for 50% of execution were functions in the
|
driver. This indicates that either better use of, or better
|
driver. This indicates that either better use of, or better
|
implementation of, the driver could dramatically increase speed.
|
implementation of, the driver could dramatically increase speed.
|
|
SOLVED: It appears increasing the packet size of the GDB transfers can
|
|
achieve a significant increase in speed. GDB queries the proxy at when
|
|
it connects about its maximum packet size. It was previously 255 bytes
|
|
and this meant larger downloads were "slow". Raising this transfer size
|
|
to around 4kB (4096 bytes) resulted in a throughput increase of almost
|
|
10-times. This is due to the fact that most of the transfer time is
|
|
spent on waiting for the driver - the overhead per call is significant
|
|
if only transferring 255 bytes, so increasing the amount per transfer
|
|
reduces the amount of time waiting for the driver to perform the trans-
|
|
action. Sizes greater than 4kB, for some reason, cause the driver to
|
|
have issues - resulting in incorrect CRC reading and bad Status returns
|
|
from the driver functions. Why this is so should be investigated.
|
* USB<->JTAG Driver TODO:
|
* USB<->JTAG Driver TODO:
|
Get the latest version of the MPSSE function code (from
|
Get the latest version of the MPSSE function code (from
|
http://ftdichip.com/Projects/MPSSE/FTCJTAG/FTCJTAG_Source.zip at last
|
http://ftdichip.com/Projects/MPSSE/FTCJTAG/FTCJTAG_Source.zip at last
|
check) and update our Linux compatible version with the ones here. This
|
check) and update our Linux compatible version with the ones here. This
|
might provide improved stability or performance, but from the list of
|
might provide improved stability or performance, but from the list of
|
improvements made to the files from our version it doesn't appear like
|
improvements made to the files from our version it doesn't appear like
|
it would result in significant improvement in the proxy app.
|
it would result in significant improvement in the proxy app.
|
* Better README
|
* Better README
|
It would be nice to provide more important documentation of nuances of
|
It would be nice to provide more important documentation of nuances of
|
the proxy operation
|
the proxy operation
|
|
|
