nuttx-bb/nuttx/TODO

NuttX TODO List (Last updated July 31, 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)
  (3)  Libraries (lib/)
  (5)  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/)
  (0)  ARM (arch/arm/)
  (1)  ARM/C5471 (arch/arm/src/c5471/)
  (1)  ARM/DM320 (arch/arm/src/dm320/)
  (3)  ARM/LPC214x (arch/arm/src/lpc214x/)
  (4)  pjrc-8052 / MCS51 (arch/pjrc-8051/)
  (7)  z80/z8 (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
  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: Implement USB bulk storage class driver
  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

o File system / Generic drivers (fs/, drivers/)
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

  Description: Implement chmod(), truncate().
  Status:      Open
  Priority:    Low

  Description: FAT32: 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: 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.

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).  Seems to be worse using SDCC.
  Status:      Open
  Priority:    Medium (maybe higher for z80 target)

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 ARM (arch/arm/)
  ^^^^^^^^^^^^^^^

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

o ARM/LPC214x (arch/arm/src/lpc214x/)
  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

  Description: Add MMC/SD support
  Status:      Open
  Priority:    Medium

  Description: Should use Vector Interrupts
  Status:      Open
  Priority:    Low

  Description: USB DMA not fully implemented
  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

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 z80/z8 (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


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