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#  README,v 1.6 2000/08/11 19:26:31 joel Exp

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This is a README file for the MVME167 port of RTEMS 4.5.0.

Please send any comments, improvements, or bug reports to:

Charles-Antoine Gauthier

charles.gauthier@nrc.ca

or

Darlene Stewart

Darlene.Stewart@nrc.ca

Software Engineering Group

Institute for Information Technology

National Research Council of Canada

Ottawa, ON, K1A 0R6

Canada

Disclaimer

----------

The National Research Council of Canada is distributing this RTEMS

board support package for the Motorola MVME167 as free software; you

can redistribute it and/or modify it under terms of the GNU General

Public License as published by the Free Software Foundation; either

version 2, or (at your option) any later version.  This software is

distributed in the hope that it will be useful, but WITHOUT ANY

WARRANTY; without even the implied warranty of MERCHANTABILITY or

FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License

for more details. You should have received a copy of the GNU General

Public License along with RTEMS; see file COPYING. If not, write to

the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.

Under no circumstances will the National Research Council of Canada

nor Her Majesty the Queen in right of Canada assume any liablility

for the use this software, nor any responsibility for its quality or

its support.

Installation

------------

Nothing unique to the MVME167. It uses the standard build process for

m68k targets. You will need to edit linkcmds to put in the start address

of your board. We do TFTP transfers to our target. The mvme167.cfg file

builds only the ELF images, which we download to the target, skipping

over the first 0x54 bytes; Motorola S-records are not generated. Edit

this file if you want S-records.

Port Description

Console driver

---------------

This BSP includes an termios-capable interrupt-driven I/O console driver

that supports all four serial ports on the MVME167 model. The port labelled

Serial Port 1/Console on the MVME712 is normally used by 167Bug; do not open

/dev/tty00 if you are debugging using 167Bug.

Limited support is provided for polled terminal I/O. This is used when

running the timing tests, and by the printk() debug output function.

Polled I/O may use termios, or it may bypass those services. The printk()

function does not use termios. When polled I/O is used, the terminal settings

must be set through 167-Bug; trying to change the line settings through RTEMS

has no effect.

Three is no support for using interrupt-driven I/O without termios support.

The default configuration is to use polled I/O and to bypass termios. This

is done so the test can be built at the same time as the rest of the system.

It is highly recommended that the defaults be changed in the mvme167.cfg file

to reflect the desired defaults, or that the appropriate parameters be set up

in NVRAM to select the appropriate I/O modes at boot time.

When configured for interrupt-driven I/O, the console is initialized with

whatever parameters are set up in termios before it calls the firtOpen driver

callback, EXCEPT THAT HARDWARE HANDSHAKING IS TURNED OFF, i.e. CLOCAL is set

in the struct termios c_cflag field. We use 3-wire cables for I/O, and find

hardware handshaking a pain. If you enable hardware handshaking, you must drive

CTS* low on the CD2401 for output to occur. If the port is in the DTE

configuration, you must drive the RS-232 CTS line to space; if the port is

in the DCE configuration, you must drive the RS-232 RTS line to space.

To use interrupt-driven I/O, set the CD2401_IO_MODE manifest constant to 1 in

rtems/make/custom/mvme167.cfg, or configure the appropriate parameter in

User Area Non-volatile RAM. See the Configuration Parameters section below

for instructions on setting up NVRAM.

To use termios, set the CD2401_USE_TERMIOS manifest constant to 1 in

rtems/make/custom/mvme167.cfg, or configure the appropriate parameter in

User Area Non-volatile RAM. See the Configuration Parameters section

below for instructions on setting up NVRAM.

The RTEMS console, i.e. the port used by stdin, stdout and stderr (do not

confuse it with the port labelled Console on the MVME712), must be

specified in the rtems/make/custom/mvme167.cfg file, or in the NVRAM

parameters. Set the value of CONSOLE_MINOR appropriately. See below for a

list of choices. See the Configuration Parameters section below for

instructions on setting up NVRAM.

The RTEMS printk port, i.e. the port where printk sends it debugging output

text, must be specified in the rtems/make/custom/mvme167.cfg file, or in the

NVRAM parameters. Set the value of PRINTK_MINOR appropriately. See below for a

list of choices. See the Configuration Parameters section below for

instructions on setting up NVRAM.

Interrupt-driven and polled I/O cannot be mixed in the MVME167, except that

printk always used polled I/O without termios. If interrupt-driven I/O is

used and printk is used, do not open the device that printk uses from an

RTEMS application.

Console and printk port choices:

  1 - /dev/tty1, Serial Port 2/TTY01 on the MVME712M.

  2 - /dev/tty2, Serial Port 3 on the MVME712M.

  3 - /dev/tty3, Serial Port 4 on the MVME712M.

Setting the RTEMS console to port 0 when interrupt-driven I/O is specified

will prevent 167-Bug from using that port.

To use polled I/O on port 2 or 3, the port must be configured in 167-Bug. See

the "PF" command in the "Debugging Package for Motorola 68K CISC CPUs User's

Manual", part number 68KBUG.

Floating-point

--------------

The MC68040 has a built-in FPU. This FPU does not implement all the

instruction of the MC68881/MC68882 floating-point coprocessors in

hardware. The -m68040 compilation options instructs gcc to not generate

the missing instructions. All of the RTEMS code is built this way. Some

of the missing functionality must be supplied by external libraries. The

required functions are part of libgcc.a.

The issue gets complicated because libc, libm and libgcc do not come as

m68040-specific variants. The default variants of these libraries are for the

MC68020 and MC68030. There are specific variants for the MC68000 (which has

limited addressing modes with respect to later family members), and specific

variants for systems without a floating-point unit, either a built-in FPU or

a coprocessor. These latter variants will be referred to as the msoft-float

variants. There is a msoft-float variant for the MC68000, and one for the

other family members.

The default variants of libc, libm and libgcc appear to work just fine for the

MC68040, AS LONG AS NO FLOATING POINT FUNCTIONS ARE CALLED. In particular,

printf() and scanf() raise unimplemented floating-point instruction exceptions

at run time. Expect almost every function that must compute a floating-point

result to also raise unimplemented floating-point instruction exceptions. Do

not use these variants if your application does any floating-point operations,

unless you use the Motorola FPSP package (described further down).

The msoft-float variants do print out floating-point numbers properly, but we

have not tested them extensively, so use them with caution. In particular,

the Paranoia test fails when linked with the msoft-float variants of the

libraries; it goes into an infinite loop after milestone 40.

MSOFT_FLOAT VARIANTS MUST BE USED TOGETHER. If you use the msoft-float variant

of libc and libm, you must also linked with the msoft-float variant of libgcc,

otherwise calls such as printf() print out floating-point values incorrectly.

RTEMS comes with the Motorola FPSP (Floating-Point Support Package) for the

MC68040 (rtems/c/src/lib/libcp/m68k/m68040/fpsp). This package emulates the

missing floating-point instructions. It is built automatically for the

MVME167 and installed in bsp_start().

The FPSP allows the use of the default variants of libc, libm and libgcc.

It also runs the paranoia test properly, and prints out the correct results.

It should probably be used in preference to the msoft-float libraries, as it

appears to work better. The disadvantage of the FPSP is that it increases the

size of the executable by about 60KB and that it relies on run time

exceptions.

If your application does not do any floating-point operations at all, you

should consider disabling the FPSP. In bsp_start(), emove the call to

M68KFPSPInstallExceptionHandlers(), and uncomment the three lines in

mvme167.cfg that redefine which variants of libc, libm and libgcc to link

against.

Configuration Parameters

------------------------

If Jumper J1-4 is installed, certain configuration parameters may be read from

the first 31 bytes of User Area NVRAM starting at 0xFFFC0000. In this case, the

remaining J1-[5-7] jumpers are ignored, and the user is responsible for writing

the appropriate values in NVRAM (via 167-Bug) in order to alter the default

behaviour. A zero value in NVRAM results in the default behaviour. The paramaters

that are configurable and their default settings are described below.

        Cache Mode (0xFFFC0000 - 1 byte)

          Set the following bits in the byte to set the desired cache mode:

            bit 0

              1 - data cache enable

            bit 1

              1 - instruction cache enable

            bits 2 & 3:

                    00 = cachable, write-through

                    01 = cachable, copyback

                    10 = noncachable, serialized

                    11 = noncachable

        Console driver I/O mode (0xFFFC0001 - 1 byte)

          Set the following bits in the byte to set the desired I/O mode:

            bit 0

              1 - use termios

            bit 1

              1 - interrupt-driven I/O

        Console driver ports (0xFFFC0002 - 1 byte)

          Set the following bits in the byte to select the console and printk ports:

            bit 0 & 1 select the RTEMS console port

        00 - /dev/tty0, Serial Port 1/Console on the MVME712M.

        01 - /dev/tty1, Serial Port 2/TTY01 on the MVME712M.

        10 - /dev/tty2, Serial Port 3 on the MVME712M.

        11 - /dev/tty3, Serial Port 4 on the MVME712M.

            bit 4 & 5 select the RTEMS printk port

        00 - /dev/tty0, Serial Port 1/Console on the MVME712M.

        01 - /dev/tty1, Serial Port 2/TTY01 on the MVME712M.

        10 - /dev/tty2, Serial Port 3 on the MVME712M.

        11 - /dev/tty3, Serial Port 4 on the MVME712M.

    If the printk port is the same as some other port that will be opened by an

    RTEMS application, then the driver must use polled I/O, or the printk port

    must not be used.

        IP Address (0xFFFC0004 - 4 bytes)

                write the hexadecimal representation of the IP address of the board in this

                locatio, e.g. 192.168.1.2 = 0xC0A80102

                default: obtain the IP address from an rtems_bsdnet_ifconfig structure

        Netmask (0xFFFC0008 - 4 bytes)

                write the hexadecimal representation of the netmask in this location

                for example, 255.255.255.0 = 0xFFFFFF00

                default: obtain the netmask from an rtems_bsdnet_ifconfig structure

        Ethernet Address (0xFFFC000C - 6 bytes)

                write the Ethernet address of the board in this location

                default: obtain the hardware address from an rtems_bsdnet_ifconfig

                         structure

        Processor ID (0xFFFC0012 - 2 bytes)

                reserved for future use

        RMA start (0xFFFC0014 - 4 bytes)

                reserved for future use

        VMA start (0xFFFC0018 - 4 bytes)

                reserved for future use

        RamSize (0xFFFC001C - 4 bytes)

                reserved for future use

Cache Control and Memory Mapping

--------------------------------

If configuration is not obtained from non-volatile RAM (ie. J1-4 is off),

cache control is done through the remaining J1 jumpers as follows:

If Jumper J1-7 is installed, the data cache will be turned on. If Jumper

J1-6 is installed, the instruction cache will be turned on. (If a jumper

is off, its corresponding cache will remain disabled).

If Jumper J1-5 is installed, the data cache will be placed in copyback

mode. If it is removed, it will be placed in writethrough mode.

Currently, block address translation is set up to map the virtual

0x00000000--0x7FFFFFFF to the physical range 0x00000000--0x7FFFFFFF. The

port relies on the hardware to raise exceptions when addressing

non-existent memory. Caching is not controllable on a finer grain.

Networking

----------

If configuration is not obtained from non-volatile RAM (ie. J1-4 is off),

the networking parameters shown above must be specified in an initialized

rtems_bsdnet_ifconfig struct. This structure is declared and initialized to

specify any network devices and includes entries for ip_address, ip_netmask

and hardware_address. See the Network Device Configuration section of the

RTEMS Networking Supplement.

When non-default (non-zero) networking paramaters are provided in NVRAM (ie.

j1-4 is on), the user MUST ensure that the corresponding entries in the

ifconfig struct are NULL. Failing to do so is an error, because it causes

the memory allocated for the initialized struct values to be lost.

Miscellaneous

-------------

The timer and clock drivers were patterned after the MVME162 and MVME152

ports.

At this time, we do not have an MPCI layer for the MVME167. We are planning

to write one.

This port supplies its own fatal_error_handler, which attempts to print some

error message through 167Bug (on the Serial Port 1/Console on the MVME712M).

Host System

-----------

The port was initially developed on an RS-6000 running AIX 4.2. The following

tools were used:

    - GNU gcc 2.8.1 configured for a powerpc-ibm-aix4.2.0.0 host and

      m68k-rtems target;

    - GNU binutils 2.9.1 configured for a powerpc-ibm-aix4.2.0.0 host and

      m68k-rtems target;

It was also tested on a Pentium II-based PC running Windows NT Workstation 4.0

and the Cygnus Cygwin32 release b20.1 environment, with the following tools:

    - EGCS 1.1.1 configured for a i586-cygwin32 host and m68k-rtems target;

    - GNU binutils 2.9.4 configured for a i586-cygwin32 host and m68k-rtems

      target;

With the latter environment, be patient; builds take a very looong time...

Current development is done on a Pentium III PC running RedHat Linux 6.1.

At the time this README was composed, the latest working compiler that was

used successfully was gcc version 2.96 20000213 (experimental). Both the C

and C++ compilers were working. Binutils 2.10 are used.

Known Problems

--------------

Polled I/O without termios may not work very well on input. The problem

is that input processing is not done: applications may get characters too

early, and may get characters that they normally would not get, such as

backspace or delete. Furthermore, input is not buffered at all. The latest

versions of rtems seem to set the count field in the rtems_libio_rw_args_t

argument to the buffer size, not to the number of characters expected on

input. Rather than wait for 1024 characters on each call, the driver

returns each character when it is received.

The cdtest will not run with interrupt-driven I/O. The reason is that the

constructors for the static objects are called at boot time when the

interrupts are still disabled. The output buffer fills up, but never empties,

and the application goes into an infinite loop waiting for buffer space. This

should have been documented in the rtems/c/src/tests/PROBLEMS file. The moral

of this story is: do not do I/O from the constructors or destructors of static

objects.

Output stops prematurely in the termios test when the console is operating in

interrupt-driven mode because the serial port is re-initialized before all

characters in the last raw output buffer are sent. Adding calls to tcdrain()

in the test task helps, but it does not solve the problem. What happens is

that the CD2401 raises a transmit interrupt when the last character in the

DMA buffer is written into the transmit FIFO, not when the last character

has been transmitted. When tcdrain() returns, there might be up to 16

characters in the output FIFO. The call to tcsetattr() causes the serial port

to re-initialize, at which point the output FIFO is cleared. We could not find

a way to detect whether characters are still in the FIFO and to wait for them

to be transmitted.

The first raw buffer to be transmitted after the console is re-initialized

with tcsetattr() is garbled. At this time, it does not seem worth while to

track this problem down.

In the stackchk test, an access fault exception is raised after the stack is

blown. This is one case were overwritting the first or last 16 bytes of the

stack does cause problems (but hey, an exception occurred, which is better

than propagating the error).

In the stackchk test, an access fault exception is raised after the stack is

blown. This is one case were overwritting the first or last 16 bytes of the

stack does cause problems (but hey, an exception occurred, which is better

than propagating the error).

When using interrupt-driven I/O, psx08 produces all the expected output, but

it does not return control to 167Bug. Is this test supposed to work with

interrupt-driven console I/O?

What is new

-----------

Support for Java is being actively worked on.

Thanks

------

- to On-Line Applications Research Corporation (OAR) for developing

RTEMS and making it available on a Technology Transfer basis;

- to FSF and Cygnus Support for great free software;

Test Configuration

------------------

Board:                Motorola MVME167

CPU:                  Motorola MC68040

Clock Speed:          25 MHz

RAM:                  4 MBytes of 32-bit DRAM with parity

Cache Configuration:  Instruction cache on; data cache on, copyback mode.

Times Reported in:    microseconds

Timer Source:         VMEchip2 Tick Timer 1

GCC Flags:            -m68040 -g -O4 -fomit-frame-pointer

Console:              Operate in polled mode. Set CD2401_POLLED_IO to 1 in

                      rtems/c/src/lib/libbsp/m68k/mvme167/console/console.c.

Test Results

------------

Single processor tests:  All tests passed, except the following ones:

  - paranoia required the FPSP and the default variants of libm (and libc and

    libgcc) for us. It may work with the msoft-float variants for you, but it

    does require the FPSP.

  - cpuuse and malloctest did not work.

  - The stackchk test got an access fault exception before the RTEMS stack

    checker had had a chance to detect the corrupted stack.

Multi-processort tests:  not applicable -- No MPCI layer yet.

Timing tests: See rtems/c/src/lib/libbsp/m68k/mvme167/times