NuttX TODO List (Last updated November 17, 2008)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(7) Task/Scheduler (sched/)
(1) Dynamic loader (N/A)
(2) Memory Managment (mm/)
(1) Signals (sched/, arch/)
(1) pthreads (sched/)
(1) C++ Support
(12) Network (net/, netutils/)
(1) USB (drivers/usbdev)
(4) Libraries (lib/)
(6) File system/Generic drivers (fs/, drivers/)
(1) Pascal add-on (pcode/)
(2) Documentation (Documentation/)
(3) Build system
(2) NuttShell (NSH) (examples/nsh)
(1) Other Applications & Tests (examples/)
(2) Linux/Cywgin simulation (arch/sim)
(2) ARM (arch/arm/)
(1) ARM/C5471 (arch/arm/src/c5471/)
(1) ARM/DM320 (arch/arm/src/dm320/)
(6) ARM/LPC214x (arch/arm/src/lpc214x/)
(3) ARM/STR71x (arch/arm/src/str71x/)
(4) pjrc-8052 / MCS51 (arch/pjrc-8051/)
(1) SH-1 (arch/sh)
(8) z80/z8/ez80 (arch/z80/)
(8) z16 (arch/z16/)
o Task/Scheduler (sched/)
^^^^^^^^^^^^^^^^^^^^^^^
Description: When a tasks exits, shouldn't all of its child pthreads also be
terminated?
Status: Open
Priority: Medium, required for good emulation of process/pthread model.
Description: atexit() supports registration of one function called on exit().
Should task_delete() also cause atexit() function to be called?
Status: Open
Priority: Low, task_delete() is non-standard and its behavior is
unspecified.
Description: Implement sys/mman.h and functions
Status: Open
Priority: Low
Description: Implement sys/wait.h and functions. Consider implementing wait,
waitpid, waitid. At present, a parent has no information about
child tasks.
Status: Open
Priority: Low
Description: Implement priority inheritance
Status: Open
Priority: Medium, this is a good feature for realtime systems.
Description: Several APIs do not set errno. Need to review all APIs.
Status: Open
Priority: Medium, required for standard compliance (but makes the
code bigger)
Description: socket descriptors are not cloned as are file descriptors
by task_create().
Status: Open
Priority: Medium-to-High
o Dynamic Loader
^^^^^^^^^^^^^^
Description: At some point in the future, I intend to port the XFLAT
dynamic loader into NuttX (see http://xflat.sourceforge.net/).
That would allow NuttX to dynamically load and link
external code in a mounted filesystem.
Status: Open
Priority: Low, Nice feature and I might do it someday
o Memory Managment (mm/)
^^^^^^^^^^^^^^^^^^^^^^
Description: Add an option to free all memory allocated by a task when the
task exits. This is probably not be worth the overhead for a
deeply embedded system.
Status: Open
Priority: Medium/Low, a good feature to prevent memory leaks but would
have negative impact on memory usage and code size.
Description: Current logic adapts size_t for 16-bit address machines vs.
32-bit address machines. But a small memory option should also
be provided so that the small offset option can be used with
32-bit machines that have small RAM memories (like the lpc2148)
Status: Open
Priority: High, a good feature enhancement.
o Signals (sched/, arch/)
^^^^^^^^^^^^^^^^^^^^^^^
Description: 'Standard' signals and signal actions are not supported.
(e.g., SIGINT, SIGCHLD, SIGSEGV, etc).
Status: Open
Priority: Low, required by standards but not so critical for an
embedded system.
o pthreads (sched/)
^^^^^^^^^^^^^^^^^
Description: pthread_cancel(): Should implement cancellation points and
pthread_testcancel()
Status: Open
Priority: Low, probably not that useful
o C++ Support
^^^^^^^^^^^
Description: Need to call static constructors
Status: Open
Priority: Low, depends on toolchain. Call to gcc's built-in static
constructor logic will probably have to be performed by
user logic in user_start().
o Network (net/, netutils/)
^^^^^^^^^^^^^^^^^^^^^^^^^
Description: Several of the netutils/ apps are untested. These include
uIP's netutils/smtp, dhcpd, resolv, webclient. Only minimal
testing of the others has been performed.
Status: Open
Priority: Medium, Important but not core NuttX functionality
Description: Should implement SOCK_RAW, SOCK_PACKET
Status: Open
Priority: Low
Description: uIP polling issues / Multiple network interface support:
(1) Current logic will not support multiple ethernet drivers.
Each driver should poll on TCP connections connect on the
network supported by the driver; UDP polling should respond
with TX data only if the UDP packet is intended for the
the network supported by the driver.
(2) If there were multiple drivers, polling would occur at
double the rate. Fix by using bound IP address in TCP
connection (lipaddr) and verifying that it is in the subnet
served by the driver.
Status: Open
Priority: Medium, The feature is not important, but it is important
for NuttX to resolve the architectural issues.
Description: Sendoto() and multiple network interface support:
When polled, would have to assure that the destination IP
is on the subnet served by the polling driver.
Status: Open
Priority: Medium, The feature is not important, but it is important
for NuttX to resolve the architectural issues.
Description: IPv6 support is incomplete. Adam Dunkels has recently announced
IPv6 support for uIP (currently only as part of Contiki). Those
changes need to be ported to NuttX.
Status: Open
Priority: Medium
Description: Incoming UDP broadcast should only be accepted if listening on
INADDR_ANY(?)
Status: Open
Priority: Low
Description: Read-ahead buffers capture incoming TCP data when no user
thread is recv-ing the data. Should add some driver call to
support throttling; when there is no listener for new data, the
driver should be throttled. Perhaps the driver should disable
RX interrupts when throttled and re-anable on each poll time.
recvfrom would, of course, have to un-throttle.
Status: Open
Priority: Medium
Description: Need to standardize collection of statistics from network
drivers. examples/nsh ifconfig command should present
statistics.
Status: Open
Priority: Low
Description: Outgoing packets are dropped and overwritten by ARP packets
if the destination IP has not been mapped to a MAC. Could
improve send() performance by explicitly performing ARP before
sending the packet.
Status: Open
Priority: Medium
Description: Port PPP support from http://contiki.cvs.sourceforge.net/contiki/contiki-2.x/backyard/core/net/ppp/
Status: Open
Priority: Low
Description: At present, there cannot be two concurrent active TCP send
operations in progress. This is because the uIP ACK logic will
support only one transfer at a time. The solution is simple:
A mutex will be needed to make sure that each send that is
started is able to be the exclusive sender until all of the
data to be sent has been ACKed.
Status: Open. There is some temporary logic to examples/nsh that does
this same fix and that temporary logic should be removed when
send() is fixed.
Priority: Medium-Low. This is an important issue for applications that
send on the same TCP socket from multiple threads.
Description: Some application-level interface to the ICMP logic is needed
to support ping from the target.
Status: Open
Priority: Low
o USB (drivers/usbdev)
^^^^^^^^^^^^^^^^^^^^
Description: The USB bulk storage class driver configuration (examples/usbstorage)
does not work reliably when debug is disabled (CONFIG_DEBUG+CONFIG_DEBUG_VERBOSE
+CONFIG_DEBUG_USB) on WinXP (Linux appears to be fine). A race condition would
would be a possibility. The symptom is that that WinXP sends a MODE SENSE (6)
command with an unsupported mode page (0x1c/0x00)
Status: Open
Priority: High
o Libraries (lib/)
^^^^^^^^^^^^^^^^
Description: sscanf() and lib_vsprintf() do not support floating point
values.
Status: Open
Priority: Low
Description: The definition of environ in stdlib.h is bogus and will not
work as it should. This is because the underlying
representation of the environment is not an arry of pointers.
Status: Open
Priority: Medium
Description: fgets implementation does not use C-buffered I/O, but rather
talks to serial driver directly via read(). It includes VT-100
specific editting commands. This gets should be renamed readlin()
and a more generic fgets() should be implemented.
Status: Open
Priority: Low (unless you are using mixed C-buffered I/O with fgets and
fgetc, for example).
Description: Need some minimal termios support... at a minimum, enough to
switch between raw and "normal" modes to support behavior like
that needed for readline().
Status: Open
Priority: Low
o File system / Generic drivers (fs/, drivers/)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: Implement chmod(), truncate().
Status: Open
Priority: Low
Description: FAT: long file names
Status: Open
Priority: Medium
Description: The CAN driver is untested. Add a test for the CAN driver.
Status: Open
Priority: Medium
Description: At present, the CAN driver does not support the poll() method.
Status: Open
Priority: Low
Description: There is no way to remove a FIFO or PIPE created in the
psuedo filesystem. Once created, they persist indefinitely
and cannot be unlinked. This is actually a more generic
issue: unlink does not work for anything in the psuedo-
filesystem.
Status: Open, but partially resolved: pipe buffer is at least freed
when there are not open references to the pipe/FIFO.
Priority: Medium
Description: The ROMFS file system does not verify checksums on either
volume header on on the individual files.
Status: Open
Priority: Low. I have mixed feelings about if NuttX should pay a
performance penalty for better data integrity.
Description: FAT: FAT32 is untested -- because I don't have any large
enough devices yet to support a FAT32 FS.
Status: Open
Priority: Medium
Description: The simple SPI based MMCS/SD driver in fs/mmcsd does not
yet handle multiple block transfers.
Status: Open
Priority: Medium-Low
o Pascal Add-On (pcode/)
^^^^^^^^^^^^^^^^^^^^^^
Description: Need APIs to verify execution of P-Code from memory buffer.
Status: Open
Priority: Low
Description: Loader and object format may be too large for some small
memory systems. Consider ways to reduce memory footprint.
Status: Open
Priority: Medium
o Documentation (Documentation/)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: Document driver/ logic
Status: Open
Priority: Low
Description: Document C-library APIs
Status: Open
Priority: Low
o Build system
^^^^^^^^^^^^
Description: Some names under arch are still incorrect. These should be
processor architecture names: pjrc-8051 should be 805x
Status: Open
Priority: Low
Description: configs/pjrc-8051 should be configs/pjrc-87c52
Status: Open
Priority: Low
Description: Dependencies do not work correctly under configs/<board>/src
(same as arch/<arch>/src/board).
Status: Open
Priority: Medium (maybe higher for z80 target)
Description: It would be nice to de-couple some of the behaviors enabled by
CONFIG_DEBUG. For example, CONFIG_DEBUG turns on debug output,
but also disables optimization make the binary much bigger.
Status: Open
Priority: Low. There workaround is easy.. just edit the configuration's
Make.def file to control the behavior that you want.
Description: Need a NuttX configuration tool. The number of configuration
settings has become quite large and difficult to manage manually.
Status: Open
Priority: Medium-low
o NuttShell (NSH) (examples/nsh)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: When the telnetd front end is received, each TCP packet
received causes a prompt (nsh >) to be presented. The
prompt should only be presented when the user enters a
carriage return.
Status: Open
Priority: Low
Description: Here are some commands that would be good to have in NSH:
ping
Status: Open
Priority: Low
o Other Applications & Tests (examples/)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: The redirection test (part of examples/pipe) terminates
incorrectly on the Cywgin-based simulation platform (but works
fine on the Linux-based simulation platform).
o Linux/Cywgin simulation (arch/sim)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: Need to implement timing. Use system timing resources to fake
a NuttX real time clock. At present, the timer is driven in
non-realtime (like 1000x realtime) and causes some behavior
differences from real platforms.
Status: Open
Priority: Low (because the simulator is only a test/development platform)
Description: The simulated serial driver also has some odd behavior. It
will stall for a long time on reads when the C stdio buffers are
being refilled. This only effects the behavior of things like
fgetc(). Workaround: Set CONFIG_STDIO_BUFFER_SIZE=0, suppressing
all C buffered I/O.
Status: Open
Priority: Low (because the simulator is only a test/development platform)
o ARM (arch/arm/)
^^^^^^^^^^^^^^^
Description: ARM interrupt handling performance could be improved in many
ways. One easy way is to use a pointer to the context save
area in current_regs instead of using up_copystate so much.
see handling of 'current_regs" in arch/sh/src/common/* for
examples of how this might be done.
Status: Open
Priority: Low
Description: The ARM interrupt handler restores all regisers upon return.
This could be improved as well: If there is not context
switch, then the static registers need not be restored
because they will not be modified by the called C code.
(see arch/sh/src/sh1/sh1_vector.S for example)
Status: Open
Priority: Low
o ARM/C5471 (arch/arm/src/c5471/)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: UART re-configuration is untested and conditionally compiled out.
Status: Open
Priority: Medium. ttyS1 is not configured, but not used; ttyS0 is configured
by the bootloader
o ARM/DM320 (arch/arm/src/dm320/)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: config/ntos-dm320: It seems that when a lot of debug statements
are added, the system no longer boots. This is suspected to be
a stack problem: Making the stack bigger or removing arrays on
the stack seems to fix the problem (might also be the
bootloader overwriting memory)
Status: Open
Priority: Medium
Description: A USB device controller driver was added but has never been tested.
Status: Open
Priority: Medium
o ARM/LPC214x (arch/arm/src/lpc214x/)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: Should use Vector Interrupts
Status: Open
Priority: Low
Description: USB DMA not fully implemented. Partial logic is in place but it is
fragmentary and bogus.
Status: Open
Priority: Low
Description: USB Serial Driver reports wrong error when opened before the
USB is connected (reports EBADF instead of ENOTCONN)
Status: Open
Priority: Low
Description: The USB bulk storage class driver configuration (examples/usbstorage)
does not work reliably when debug is disabled (CONFIG_DEBUG+CONFIG_DEBUG_VERBOSE
+CONFIG_DEBUG_USB) on WinXP (Linux appears to be fine). A race condition would
would be a possibility. The symptom is that that WinXP sends a MODE SENSE (6)
command with an unsupported mode page (0x1c/0x00)
Status: Open
Priority: High
Description: At present the SPI driver is polled. Should it be interrupt driven?
Status: Open
Priority: Medium
Description: At present the SPI driver is polled -AND- there is a rather large, arbitrary,
delay in one of the block access routines. The purpose of the delay is to
avoid a race conditions. This begs for a re-design -OR- at a minimum, some
optimiation of the delay time.
Status: Open
Priority: Medium
o ARM/STR71x (arch/arm/src/str71x/)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: Basic port is complete but untested. Complete integration
Status: Open
Priority: High
Description: Add SPI driver and integrate with MMC/SD support.
Status: Open
Priority: Medium
Description: Develop a USB driver and integrate with existing USB serial
and storage class drivers.
Status: Open
Priority: Medium
o pjrc-8052 / MCS51 (arch/pjrc-8051/)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Description: Current status:
- Basic OS task management seems OK
- Fails when interrupts enabled. The stack pointer is around
0x6e before the failure occurs. It looks like some issue
when the stack pointer moves from the directly to indirectly
addressable region (0x80 boundary).
- Work on the 8052 is temporarily on hold
Status: Open
Priority: Low, 8051 is a tough platform because of the tiny stack.
Description: Use timer 0 as system timer. Timer 2 is needed for second UART.
Logic is implemented, but there needs to be a system
configuration to change the ticks-per-second value to match the
timer interrupt rate
Status: Open
Priority: Low
Description: During build, there are several integer overflows reported:
sched/gmtime_r.c aroud lines 184 and 185
sched/clock_initialize.c at line 107
sched/pthread_create.c at 330
examples/ostest/barrier.c around lines 53 and 74
examples/ostest/sighand.c at 225 and 244
driver/serial.c in usleep calls around 347 and 354
Status: Open
Priority: Medium
Description Global data is not being initialized. Logic like that of SDCCs
crt0*.s needs to be incorporated into the system boot logic
Status: Open
Priority: Low -- only because there as so many other issues with 8051
o SH-1 (arch/sh)
^^^^^^^^^^^^^^
Description: There are instabilities that make the SH-1 port un-usable. The
nature of these is not understood; the behavior is that certain SH-1
instructions stop working as advertised. I have seen the following
examples:
412b jmp @r1 - Set a return address in PR, i.e., it behaved like
410b jsr @r1. Normally 412b works correctly, but in the failure
condition, it reliably set the PR.
69F6 mov.l @r15+,r9 - wrote the value of R1 to @r15+. This behavior
does not correspond to any known SH-1 instruction
This could be a silicon problem, some pipeline issue that is not
handled properly by the gcc 3.4.5 toolchain (which has very limit
SH-1 support to begin with), or perhaps with the CMON debugger. At
any rate, I have exhausted all of the energy that I am willing to put
into this cool old processor for the time being.
Status: Open
Priority: Low -- because the SH-1, SH7032, is very old and only of historical
interest.
o z80/z8/ez80 (arch/z80)
^^^^^^^^^^^^^^^^^^^^^^^
Description: The SDCC version the same problems with interger overflow during
compilation as described for pjrc-8051. At typical cause is code like
usleep(500*1000) which exceeds the range of a 16-bit integer
Status: See pjrc-8051
Priority: See pjrc-8051
Description: The simulated Z80 serial console (configs/z80sim/src/z80_serial.c +
driver/serial.c) does not work. This is because there are
no interrupts in the simulation so there is never any serial
traffic.
Status: Open
Priority: Low -- the simulated console is not critical path and the designs
to solve the problem are complex.
Description: ZDS-II Librarian complains that the source for the .obj file
is not in the library.
Status: Open
Priority: Low, thought to be cosmetic. I think this is a consequence of
replacing vs. inserting the library.
Description: The ZDS-II compiler (version 4.10.1) fails with an internal error
while compiler mm/mm_initialize. This has been reported as
incident 81509.
I have found the following workaround that I use to build for the
time being:
--- mm/mm_initialize.c.SAVE 2008-02-13 08:06:46.833857700 -0600
+++ mm/mm_initialize.c 2008-02-13 08:07:26.367608900 -0600
@@ -94,8 +94,11 @@
{
int i;
+#if 0 /* DO NOT CHECK IN */
CHECK_ALLOCNODE_SIZE;
CHECK_FREENODE_SIZE;
+#endif
/* Set up global variables */
Status: Open
Priority: High
Description: Add support for prioritized ez8 interrupts. Currently logic supports
only nominal interrupt priority.
Status: Open
Priority: Low
Description: The z8Encore! port has only been verified on the ZDS-II instruction
set simulator.
Status: Open
Priority: Medium
Description: Upgrade to the ZDS-II Z8Encore! 4.11.0 toolchain
Status: Open
Priority: Low
Description: The XTRS target (configs/xtrs) has a clean problem. The clean
rule removes .asm files. This works because there are no .asm
files except in sub-directories that are provided from 'make clean' --
except for XTRS: It has a .asm file in its src/ directory that
gets removed everytime clean is performd.
Status: Open
Priority: High if you happen to be working with XTRS.
o z16 (arch/z16)
^^^^^^^^^^^^^^^^
Description: ZDS-II Librarian complains that the source for the .obj file
is not in the library.
Status: Open
Priority: Low, thought to be cosmetic. I think this is a consequence of
replacing vs. inserting the library.
Description: When the interrupt-driven serial driver is used, the system
hangs. This is because of TX ready (TRDE) interrupts that
get lost while interrupts are disabled. The existing
serial driver appears to be limited to hardware with a
latching, level-sensitive TX ready interrupt.
Status: Open
Priority: Medium. A polled, write-only serial driver is used in the
interim for system testing.
Description: The system delays do not appear to be correct with the
examples/ostest/timedmqueue.c test.
Status: Open
Priority: Medium-High
Description: At present, the z16f port does not run properly when CONFIG_DEBUG
is disabled: The obvious symptom is that there is no printf()
output. I have isolated with problem to errors in optimization.
With -reduceopt on the command line, I can get the printf output.
However, there are still errors in the compiled code -- specifically
in sched/timer_create.c.
I have submitted a bug report to ZiLOG for this (support incident
81400). You can see the status of the bug report (and lots more
technical detail) here:
http://support.zilog.com/support/incident/incident_support.asp?iIncidentId=81400&iSiteId=1&chLanguageCode=ENG
Summary of ZiLOG analysis: "This is a ZNEO compiler problem. ... [a] workaround
is to replace:
if ( !timerid || (clockid != 0) )
By:
if ((clockid != 0) || !timerid)"
Status: Open
Priority: Medium-High
Description: The pascal add-on does not work with the z16f (that is
configuration z16f2800100zcog/pashello). This appears to be
another ZDS-II error: when executing the instruction
SYSIO 0, WRITESTR a large case statement is executed. This
involves a call into the ZiLOG runtime library to __uwcase().
__uwcase is passed a pointer to a structure containing jump
information. The cause of the failure appears to be that
the referenced switch data is bad.
This is submited as ZiLOG support incident 81459.
Summary of ZiLOG analysis: "This is a ZNEO run time library problem.
One workaround is to replace the line 58 in uwcase.asm
From:
ADD R9,#4 ; Skip handler
To:
ADD R9,#2 ; Skip handler
And add uwcase.asm to the project.
If the customer does not want to modify uwcase.asm then the other
workaround is to add a dummy case and make it same as default:
case 0x8000:
default:
This will make sure that uwcase is not called but ulcase is called."
Status: Open. Due to licensing issues, I cannot include the modified
uwcase in the NuttX code base.
Priority: Medium
Description: Add support to maintain SPOV in context switching. This
improvement will provide protection against stack overflow
and make a safer system solution.
Status: Open
Priority: Low
Description: Add support for prioritized interrupts. Currently logic supports
only nominal interrupt priority.
Status: Open
Priority: Low
Description: Upgrade to the ZDS-II ZNEO 4.11.1 toolchain
Status: Open
Priority: Low
