mirror of
https://github.com/apache/nuttx.git
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Gregory Nutt
22cd0d47fa
This makes the user interface a little hostile. People thing of an MTU of 1500 bytes, but the corresponding packet is really 1514 bytes (including the 14 byte Ethernet header). A more friendly solution would configure the MTU (as before), but then derive the packet buffer size by adding the MAC header length. Instead, we define the packet buffer size then derive the MTU.
The MTU is not common currency in networking. On the wire, the only real issue is the MSS which is derived from MTU by subtracting the IP header and TCP header sizes (for the case of TCP). Now it is derived for the PKTSIZE by subtracting the IP header, the TCP header, and the MAC header sizes. So we should be all good and without the recurring 14 byte error in MTU's and MSS's.
Squashed commit of the following:
Trivial update to fix some spacing issues.
net/: Rename several macros containing _MTU to _PKTSIZE.
net/: Rename CONFIG_NET_SLIP_MTU to CONFIG_NET_SLIP_PKTSIZE and similarly for CONFIG_NET_TUN_MTU. These are not the MTU which does not include the size of the link layer header. These are the full size of the packet buffer memory (minus any GUARD bytes).
net/: Rename CONFIG_NET_6LOWPAN_MTU to CONFIG_NET_6LOWPAN_PKTSIZE and similarly for CONFIG_NET_TUN_MTU. These are not the MTU which does not include the size of the link layer header. These are the full size of the packet buffer memory (minus any GUARD bytes).
net/: Rename CONFIG_NET_ETH_MTU to CONFIG_NET_ETH_PKTSIZE. This is not the MTU which does not include the size of the link layer header. This is the full size of the packet buffer memory (minus any GUARD bytes).
net/: Rename the file d_mtu in the network driver structure to d_pktsize. That value saved there is not the MTU. The packetsize is the memory large enough to hold the maximum packet PLUS the size of the link layer header. The MTU does not include the link layer header.
Architecture-Specific Code
^^^^^^^^^^^^^^^^^^^^^^^^^^
Table of Contents
^^^^^^^^^^^^^^^^^
o Architecture-Specific Code
o Summary of Files
o Supported Architectures
o Configuring NuttX
Architecture-Specific Code
^^^^^^^^^^^^^^^^^^^^^^^^^^
The NuttX configuration consists of:
o Processor architecture specific files. These are the files contained
in the arch/<arch-name>/ directory discussed in this README.
o Chip/SoC specific files. Each processor processor architecture
is embedded in chip or System-on-a-Chip (SoC) architecture. The
full chip architecture includes the processor architecture plus
chip-specific interrupt logic, general purpose I/O (GIO) logic, and
specialized, internal peripherals (such as UARTs, USB, etc.).
These chip-specific files are contained within chip-specific
sub-directories in the arch/<arch-name>/ directory and are selected
via the CONFIG_ARCH_name selection
o Board specific files. In order to be usable, the chip must be
contained in a board environment. The board configuration defines
additional properties of the board including such things as
peripheral LEDs, external peripherals (such as network, USB, etc.).
These board-specific configuration files can be found in the
configs/<board-name>/ sub-directories.
This README will address the processor architecture specific files
that are contained in the arch/<arch-name>/ directory. The file
include/nuttx/arch.h identifies all of the APIs that must
be provided by this architecture specific logic. (It also includes
arch/<arch-name>/arch.h as described below).
Directory Structure
^^^^^^^^^^^^^^^^^^^
The arch directory contains architecture specific logic. The complete
board port in is defined by the architecture-specific code in this
directory (plus the board-specific configurations in the config/
subdirectory). Each architecture must provide a subdirectory <arch-name>
under arch/ with the following characteristics:
<arch-name>/
|-- include/
| |--<chip-name>/
| | `-- (chip-specific header files)
| |--<other-chips>/
| |-- arch.h
| |-- irq.h
| `-- types.h
`-- src/
|--<chip-name>/
| `-- (chip-specific source files)
|--<other-chips>/
|-- Makefile
`-- (architecture-specific source files)
Summary of Files
^^^^^^^^^^^^^^^^
include/<chip-name>/
This sub-directory contains chip-specific header files.
include/arch.h
This is a hook for any architecture specific definitions that may
be needed by the system. It is included by include/nuttx/arch.h
include/types.h
This provides architecture/toolchain-specific definitions for
standard types. This file should typedef:
_int8_t, _uint8_t, _int16_t, _uint16_t, _int32_t, _uint32_t
and if the architecture supports 64-bit integers.
_int24_t, _uint24_t, int64_t, uint64_t
NOTE that these type names have a leading underscore character. This
file will be included(indirectly) by include/stdint.h and typedef'ed to
the final name without the underscore character. This roundabout way of
doings things allows the stdint.h to be removed from the include/
directory in the event that the user prefers to use the definitions
provided by their toolchain header files
irqstate_t
Must be defined to the be the size required to hold the interrupt
enable/disable state.
This file will be included by include/sys/types.h and be made
available to all files.
include/irq.h
This file needs to define some architecture specific functions (usually
inline if the compiler supports inlining) and structure. These include:
- struct xcptcontext. This structures represents the saved context
of a thread.
- irqstate_t up_irq_save(void) -- Used to disable all interrupts.
- void upirq_restore(irqstate_t flags) -- Used to restore interrupt
enables to the same state as before up_irq_save was called.
NOTE: These interfaces are not available to application code but can
only be used withint the operating system code. And, in general,
these functions should *never* be called directly, not unless you
know absolutely well what you are doing. Rather you shoudl typically
use the wrapper functions enter_critical_section() and leave_critical_section()
as prototyped in include/nuttx/irq.h.
This file must also define NR_IRQS, the total number of IRQs supported
by the board.
src/<chip-name>/
This sub-directory contains chip-specific source files.
src/Makefile
This makefile will be executed to build the targets src/libup.a and
src/up_head.o. The up_head.o file holds the entry point into the system
(power-on reset entry point, for example). It will be used in
the final link with libup.a and other system archives to generate the
final executable.
Supported Architectures
^^^^^^^^^^^^^^^^^^^^^^^
NOTE: nuttx/Documentation/NuttX.html for current information about the
state of these MCU ports.
arch/sim - Linux/Cygwin simulation
A user-mode port of NuttX to the x86 Linux platform is available.
The purpose of this port is primarily to support OS feature development.
This port does not support interrupts or a real timer (and hence no
round robin scheduler) Otherwise, it is complete.
arch/arm - ARM-based micro-controllers
This directory holds common ARM architectures. At present, this includes
the following subdirectories:
Architecture Support
arch/arm/include and arch/arm/src/common
arch/arm/src/arm and arch/arm/include/arm
arch/arm/src/armv7-a and arch/arm/include/armv6-m
arch/arm/src/armv7-a and arch/arm/include/armv7-a
arch/arm/src/armv7-m and arch/arm/include/armv7-m
arch/arm/src/armv7-r and arch/arm/include/armv7-r
MCU support
arch/arm/include/a1x and arch/arm/src/a1x
arch/arm/include/c5471 and arch/arm/src/c5471
arch/arm/include/dm320 and arch/arm/src/dm320
arch/arm/include/efm32 and arch/arm/src/efm32
arch/arm/include/imx1 and arch/arm/src/imx1
arch/arm/include/imx6 and arch/arm/src/imx6
arch/arm/include/kinetis and arch/arm/src/kinetis
arch/arm/include/kl and arch/arm/src/kl
arch/arm/include/lpc11xx and arch/arm/src/lpc11xx
arch/arm/include/lpc17xx and arch/arm/src/lpc17xx
arch/arm/include/lpc214x and arch/arm/src/lpc214x
arch/arm/include/lpc2378 and arch/arm/src/lpc2378.
arch/arm/include/lpc31xx and arch/arm/src/lpc31xx
arch/arm/include/lpc43xx and arch/arm/src/lpc43xx
arch/arm/include/moxart and arch/arm/src/moxart
arch/arm/include/nuc1xx and arch/arm/src/nuc1xx
arch/arm/include/sam34 and arch/arm/src/sam34
arch/arm/include/sama45 and arch/arm/src/sama5
arch/arm/include/samdl and arch/arm/src/samdl
arch/arm/include/samv7 and arch/arm/src/samv7
arch/arm/include/stm32 and arch/arm/src/stm32
arch/arm/include/stm32f7 and arch/arm/src/stm32f7
arch/arm/include/stm32l4 and arch/arm/src/stm32l4
arch/arm/include/str71x and arch/arm/src/str71x
arch/arm/include/tiva and arch/arm/src/tiva
arch/arm/include/tms570 and arch/arm/src/tms570
arch/avr
This directory is dedicated to ports to the Atmel AVR (8-bit) and AVR32 (32-bit)
MCU families. STATUS: Under development.
Architecture Support
arch/avr/include/avr and arch/avr/src/avr
arch/avr/include/avr32 and arch/avr/src/avr32
MCU support
arch/avr/include/atmega and arch/avr/src/atmega
arch/avr/include/at90usb and arch/avr/src/at90usb
arch/avr/include/at32uc3 and arch/avr/src/at32uc3
arch/hc
This directory is dedicated to ports to the Freescale HC family.
arch/arm/include/m9s12 and arch/arm/src/m9s12
arch/mips
This directory is dedicated to ports to the MIPS family.
Architecture Support
arch/mips/include/mips32 and arch/mips/src/mips32
MCU support
arch/mips/include/pic32mx and arch/mips/src/pic32mx
arch/mips/include/pic32mz and arch/mips/src/pic32mz
arch/renesas - Support for Renesas and legacy Hitachi microcontrollers.
This include SuperH and M16C.
Architecture Support
arch/renesas/include and arch/renesas/src/common
MCU support
arch/renesas/include/m16c and arch/renesas/src/m16c
arch/renesas/include/sh1 and arch/renesas/src/sh1
arch/or1k
This directory is dedicated to ports to OpenRISC architectures.
arch/or1k/include/mor1k and arch/or1k/src/mor1k
arch/risc-v
This directory is dedicated to ports to the RISC-V family.
Architecture Support
arch/risc-v/include/rv32im
MCU support
arch/risc-v/include/nr5m100
arch/x86 - Intel x86 architectures
This directory holds related, 32- and 64-bit architectures from Intel.
At present, this includes the following subdirectories:
Architecture Support
arch/x86/include and arch/x86/src/common
MCU support
arch/x86/include/i486 and arch/x86/src/i486
arch/x86/include/qemu and arch/x86/src/qemu
arch/xtensa
Implementations based on the Cadence® Tensilica® Xtensa® processors,
such as the Xtensa LX6 dataplane processing units (DPUs). At
present, this includes the following subdirectories:
Common XTENSA support:
arch/xtensa/include and arch/xtensa/src/common
LX6 DPU support:
arch/xtensa/include/lx6 and arch/xtensa/xtensa/lx6
Expressif ESP32 implemenation of the LX6 DPU:
arch/xtensa/include/esp32 and arch/xtensa/xtensa/esp32
arch/z16 - ZiLOG 16-bit processors
This directory holds related, 16-bit architectures from ZiLOG. At
present, this includes the following subdirectories:
Architecture Support
arch/z16/include and arch/z16/src/common
MCU support
arch/z16/include/z16f and arch/z16/src/z16f
arch/z80 - ZiLOG 8-bit microcontrollers
This directory holds related, 8-bit architectures from ZiLOG. At
present, this includes the following subdirectories:
Architecture Support
arch/z80/include and arch/z80/src/common
MCU support
arch/z80/include/z80 and arch/z80/src/z80
arch/z80/include/z8 and arch/z80/src/z8
arch/z80/include/ez80 and arch/z80/src/ez80