Code lineage:
osdebug() is based loosely on the version in esp8266, but there didn't
seem to be an obvious way of choosing a particular UART. The basic
behavior is the same, though: provide None, and logging is disabled;
provide an integer and logging is restored to the default level.
To build on that, and because the IDF provides more functionality, a
second parameter has now been implemented which allows the active log
level to be set:
esp.osdebug(uart[, level])
The module has a corresponding set of LOG_ values to set this accordingly.
When configuring a static set of values with ifconfig() the DNS was not
being set. This patch fixes that, and additionally uses the tcpip_adapter
API to ensure it is thread safe.
Further discussion is here:
https://github.com/micropython/micropython-esp32/issues/210/
This commit is a combination of 216 commits from the initial stages of
development of this port, up to and including the point where the code was
moved to the ports/esp32 directory. These commits were mostly concerned
with setting up the build system and getting a reliable port working with
basic features. The following is a digest of the original commits in their
original order (most recent listed first), grouped where possible per
author. The list is here to give credit for the work and provide some
level of traceability and accountability. For the full history of
development please consult the original repository.
All code is MIT licensed and the relevant copyright holders are listed in
the comment-header of each file.
Damien George <damien.p.george@gmail.com>
esp32: Update to latest ESP IDF.
esp32: Update module symlinks now that code lives under the ports dir.
esp32: Update to compile with new ports/esp32 directory structure.
esp32: Move it to the ports/ directory.
esp32/machine_uart: Don't save baudrate but compute it instead.
esp32/modsocket: Add socket.readinto() method.
esp32/modesp: Add esp.gpio_matrix_in and esp.gpio_matrix_out functions.
esp32/machine_uart: Wait for all data to be tx'd before changing config.
NyxCode <moritz.bischof1@gmail.com>
esp32: Add note to README.md about updating the submodules of ESP IDF.
Anthony Briggs <anthony.briggs@gmail.com>
esp32: Update README.md installation and flashing instructions.
Javier Candeira <javier@candeira.com>
esp32: Raise error when setting input-only pin to output.
With help from Adrian Smith (fon@thefon.net)
Javier Candeira <javier@candeira.com>
esp32: Replace exception raising with corresponding mp_raise_XXX funcs.
Tisham Dhar <whatnickd@gmail.com>
esp32: Add some specific notes about building on Windows using WSL.
Ben Gamari <ben@smart-cactus.org>
esp32: Provide machine.Signal class.
Damien George <damien.p.george@gmail.com>
esp32/modnetwork: Implement AP version of network.isconnected().
Eric Poulsen <eric@zyxod.com>
esp32/README.md: Add note about btree submodule initialization.
Damien George <damien.p.george@gmail.com>
esp32: Make firmware.bin start at 0x1000 to allow flash size autodetect.
esp32: Changes to follow latest version of upstream uPy.
esp32/Makefile: Separate ESP-specific inc dirs to avoid header clashes.
esp32: Enable "btree" database module.
esp32: Update to latest ESP IDF.
Roosted7 <thomasroos@live.nl>
esp32: Update to latest ESP-IDF.
Alex King <alex_w_king@yahoo.com>
esp32/machine_timer: Add support for esp32 hardware timer.
Code lineage:
Timer() is based loosely on the version in esp8266, although the
implementation is differs significantly because of the change in
the underlying platform.
Damien George <damien.p.george@gmail.com>
esp32/machine_uart: Increase UART TX buffer size to 64.
esp32/modules: Update dht symlink.
esp32/mpconfigport.h: Enable utimeq module, needed for uasyncio.
esp32: Changes to follow latest version of upstream uPy.
esp32: Update to latest ESP-IDF.
esp32/machine_uart: Add uart.any() method.
esp32/machine_uart: Uninstall the UART driver before installing it.
Thomas Roos <mail@thomasroos.nl>
esp32: Update to latest ESP-IDF.
Eric Poulsen <eric@zyxod.com>
esp32/modsocket: Make read/write return None when in non-blocking mode.
esp32/modsocket.c: Fix send/sendto/write for non-blocking sockets.
Odd Stråbø <oddstr13@openshell.no>
esp32: Initial working implementation of machine.UART.
Code lineage (as seen by previous commits): I copied the ESP8266 code,
renamed pyb -> machine, and used esp-idf as a reference while implementing
minimal functionality. I provide all of my changes under the MIT license.
Odd Stråbø <oddstr13@openshell.no>
esp32/machine_uart: Rename pyb to machine.
esp32: Copy machine_uart.c from esp8266 port.
Damien George <damien.p.george@gmail.com>
esp32/moduos: Add uos.ilistdir() function.
esp32: Mount filesystem at the root of the VFS, following esp8266.
Andy Valencia <vandyswa@gmail.com>
esp32: Add hardware SHA1/SHA256 support via mbedtls API.
Code lineage: a copy of extmod/moduhashlib with the API invocation details
edited. Total derivative work.
Andy Valencia <vandyswa@gmail.com>
esp32: Add PWM support via machine.PWM class.
Code lineage:
I started by copying the esp8266 machine_pwm.c. I used information from the
ESP32 Technical Reference Manual, the esp-idf documentation, and the SDK's
sample ledc example code (but I did not copy that code, just studied it to
understand the SDK's API for PWM). So aside from the code copied from the
esp8266 PWM support, everything else you see is just new code I wrote.
I wasn't an employee of anybody when I wrote it, and I wrote it with the
understanding and intention that it's simply a derivative work of the
existing micropython code. I freely and willingly contribute it to the
project and intend that it not change the legal status of the micropython
code base in any way, even if it is included in that base in whole or part.
Damien George <damien.p.george@gmail.com>
esp32/modules: Add symlinks for upysh and upip.
Eric Poulsen <eric@zyxod.com>
esp32/modmachine: Add unique_id() function to machine module.
Damien George <damien.p.george@gmail.com>
esp32: Change dac_out_voltage to dac_output_voltage for new IDF API.
esp32: Update esp32.custom_common.ld to align with changes in ESP IDF.
Eric Poulsen <eric@zyxod.com>
esp32: Update to latest ESP IDF.
Damien George <damien.p.george@gmail.com>
esp32/modsocket: When resolving IP addr handle the case of host=''.
esp32: Update to latest ESP IDF.
Eric Poulsen <eric@zyxod.com>
esp32/Makefile: Change default FLASH_MODE to dio for WROOM-32 module.
esp32: Move FAT FS to start at 0x200000 and increase size to 2MiB.
Damien George <damien.p.george@gmail.com>
esp32: Remove enable_irq/disable_irq and use ATOMIC_SECTION instead.
esp32/mpconfigport.h: Provide ATOMIC_SECTION macros.
esp32/main: Restart the MCU if there is a failed NLR jump.
Daniel Campora <daniel@pycom.io>
esp32: Enable threading; be sure to exit GIL when a thread will block.
esp32: Trace the registers when doing a gc collect. Also make it thread ready.
esp32: Add threading implementation, disabled for the time being.
Damien George <damien.p.george@gmail.com>
esp32: Update to latest ESP IDF.
esp32/uart: Use high-level function to install UART0 RX ISR handler.
esp32/Makefile: Make FreeRTOS private include dir really private.
Eric Poulsen <eric@zyxod.com>
esp32: Add support for hardware SPI peripheral (block 1 and 2).
Sergio Conde Gómez <skgsergio@gmail.com>
esp32/modules/inisetup.py: Mount filesystem at /flash like ESP8266
Damien George <damien.p.george@gmail.com>
esp32: Convert to use core-provided KeyboardInterrupt exception.
esp32: Pump the event loop while waiting for rx-chr or delay_ms.
esp32: Implement Pin.irq() using "soft" scheduled interrupts.
esp32: Update to latest ESP IDF version.
Eric Poulsen <eric@zyxod.com>
esp32/README: Add troubleshooting section to the end.
tyggerjai <tyggerjai@gmail.com>
esp32: Add support for WS2812 and APA106 RGB LEDs.
Damien George <damien.p.george@gmail.com>
esp32: Add makeimg.py script to build full firmware; use it in Makefile.
esp32/modsocket: Make socket.read return when socket closes.
esp32/modsocket: Initialise the timeout on an accepted socket.
esp32/mphalport: Provide proper implementations of disable_/enable_irq.
esp32/modmachine: Add disable_irq/enable_irq functions.
Nick Moore <nick@zoic.org>
esp32/modsocket.c: add comment explaining timeout behaviour
esp32/modsocket.c: clean up send methods for retries too
esp32/modsocket.c: sockets always nonblocking, accept timeout in modsocket
esp32: Update to latest ESP IDF version.
esp32/modsocket.c: remove MSG_PEEK workaround on select ioctl.
esp32/modsocket.c: Initialize tcp when modsocket loads.
Damien George <damien.p.george@gmail.com>
esp32/main: Bump heap size from 64k to 96k.
esp32/modutime: Add time.time() function.
esp32/modsocket: Convert lwip errnos to uPy ones.
esp32/modules: Provide symlink to ds18x20 module.
esp32: Add support for onewire protocol via OneWire module.
esp32: Add support for DHT11 and DHT22 sensors.
esp32/mphalport: Improve delay and ticks functions.
esp32: Update to latest ESP IDF.
esp32/modules: Provide symlink to urequests from micropython-lib.
esp32: Populate sys.path.
Nick Moore <nick@zoic.org>
esp32/machine_dac.c: implement DAC pins as well
esp32/machine_adc.c: also machine.ADC
esp32/machine_touchpad.c: add support for touchpad
Damien George <damien.p.george@gmail.com>
esp32/README: Add hint about using GNUmakefile on case-insensitive FS.
esp32/mpconfigport.h: Enable maximum speed software SPI.
esp32: Provide improved version of mp_hal_delay_us_fast.
esp32/mpconfigport.h: Enable MICROPY_PY_BUILTINS_POW3 option.
esp32: Update to latest ESP IDF.
esp32: Convert to use new oofatfs library and generic VFS sub-system.
esp32: Enable help('modules') to list builtin modules.
esp32: Convert to use new builtin help function.
Aaron Kelly <AaronKelly@email.com>
esp32/README: Add comment about ESP-IDF version
Damien George <damien.p.george@gmail.com>
esp32: Consistently use size_t instead of mp_uint_t.
esp32: Change "Micro Python" to "MicroPython" in license comments.
esp32/Makefile: Use -C argument to git instead of cd'ing.
esp32/help: Add section to help about using the network module.
esp32/README: Add section about configuring and using an ESP32 board.
esp32/README: Remove paragraph about buggy toolchain, it's now fixed.
esp32/modnetwork: Change network init logging from info to debug.
esp32/modnetwork: Don't start AP automatically when init'ing wifi.
esp32/modsocket: Implement socket.setsockopt, to support SO_REUSEADDR.
esp32: Update to latest ESP IDF.
esp32/sdkconfig.h: Remove unused CONFIG_ESPTOOLPY_xxx config settings.
esp32/modsocket: Add support for DGRAM and RAW, and sendto/recvfrom.
esp32/modsocket: Fix return value of "port" in socket.accept.
esp32/modsocket: Make socket.recv take exactly 2 args.
esp32: Enable ussl module, using mbedtls component from ESP IDF.
esp32/modsocket: Rename "socket" module to "usocket".
esp32/sdkconfig: Increase max number of open sockets from 4 to 8.
esp32/modsocket: Add error checking for creating and closing sockets.
esp32/modsocket: Use _r (re-entrant) versions of LWIP socket API funcs.
esp32/modsocket: Raise an exception if socket.connect did not succeed.
esp32/modsocket: Make socket.accept return a tuple: (client, addr).
esp32/modsocket: Use m_new_obj_with_finaliser instead of calloc.
esp32/Makefile: Add check for IDF version, and warn if not supported.
esp32/esp32.custom_common.ld: Update to follow changes in IDF.
esp32: Update to latest ESP IDF.
nubcore <x@nubcore.com>
esp32: add #define CONFIG_ESP32_WIFI_RX_BUFFER_NUM 25
Nick Moore <nick@zoic.org>
esp32/modsocket.c: add in sendall and makefile methods #10
esp32/modsocket.c: fixups for #10
esp32/modsocket.c: fix copyright, socket_recv gets param and exception
esp32/modnetwork.c: fix copyright, network.active param to bool
Damien George <damien.p.george@gmail.com>
esp32/modnetwork: Implement wlan.isconnected() method.
esp32/modnetwork: Add initial implementation of wlan.config().
esp32/modnetwork: Simplify event_handler messages.
Nick Moore <nick@zoic.org>
esp32/modsocket.c: support for ioctl, settimeout, setblocking, getaddrinfo
Damien George <damien.p.george@gmail.com>
esp32/README: Add comment about FLASH_MODE being dio.
esp32: Update to latest ESP IDF.
esp32/modnetwork: Remove unnecessary indirection variable for scan list.
esp32/modnetwork: Check that STA is active before trying to scan.
esp32/mphalport: Replace portTICK_RATE_MS with portTICK_PERIOD_MS.
esp32/README: Add comment about using $(HOME) in makefile.
esp32/modnetwork: Use memset instead of bzero, the latter is deprecated.
esp32/modnetwork: Improve error handling when STA is connecting to AP.
esp32/Makefile: Use tab instead of spaces, and use shorter variable.
Nick Moore <nick@zoic.org>
esp32/modsocket.c: AF_*, SOCK_* and IPPROTO_* constants
esp32/modsocket.c: socket.settimeout implementation
Damien George <damien.p.george@gmail.com>
esp32/Makefile: Update to latest ESP IDF.
Nick Moore <nick@zoic.org>
esp32/modsocket.c: use mp streams for sockets
esp32: network.WLAN.ifconfig based on esp8266 version
esp32: Fix up exception handling
esp32: sketchy modsocket ... revisit this once modnetwork is sorted
esp32: First cut at modnetwork, manually rebased from prev. version
Damien George <damien.p.george@gmail.com>
esp32/help: Update help text.
esp32: Add info about Microbric Pty Ltd being the sponsor of this port.
esp32: Add README.md file.
esp32/mpconfigport.h: Add weak links to many of the builtin modules.
esp32: Enable soft implementation of machine.SPI class.
esp32/Makefile: Simplify APP_LD_ARGS by using OBJ variable.
esp32/Makefile: Reorganise Makefile and add some comments.
esp32/Makefile: Clean up CFLAGS for ESP IDF components.
esp32/Makefile: Tidy up names of ESP IDF components, to match dir name.
esp32/Makefile: Define and use ESPCOMP variable.
esp32: Update to latest ESP IDF.
esp32/main: Enable filesystem support.
esp32: Use custom ld script to ensure correct code get placed in iram.
esp32: Update to latest ESP IDF.
esp32/main: Pin the uPy task to core 0.
esp32: Update to use latest ESP IDF.
esp32: Disable boot-up scripts, spi_flash_erase_sector no longer works.
esp32: Add scripts to init and mount filesystem.
esp32: Enable frozen bytecode, with scripts stored in "modules/" dir.
esp32/modesp: Increase flash_user_start position to 1Mbyte.
esp32/Makefile: Add "erase" target for convenient erasure.
esp32/sdkconfig: Reorder config settings to put common things together.
esp32/sdkconfig: Change to use single core only.
esp32: Add esp module.
esp32/uart.c: Make sure uart ISR handler is all in iram.
esp32/main.c: Use ESP_TASK_PRIO_MIN + 1 for mp_task's priority.
esp32/Makefile: Use only bare-minimum flags when compiling .S files.
esp32/Makefile: Rename "firmware" to "application".
esp32: Update ESP IDF version.
esp32/Makefile: Add declarations to build bootloader and partitions.
esp32/Makefile: When deploying, write the application last.
esp32/Makefile: Use $(INC) variable instead of listing include dirs.
esp32/Makefile: Use locally built versions of freertos and newlib libs.
esp32: Add low-level uart handler with ISR and ringbuf for stdin.
esp32: Add machine.idle() function.
esp32: Add machine.I2C class.
esp32: Enable machine.time_pulse_us.
esp32: Add initial implementation of machine.Pin class.
esp32: Prepare main.c for using xTaskCreateStatic.
esp32: Clean up mphalport.h.
esp32: Add initial uos module.
esp32: Clean up mpconfigport.h, enable more features.
esp32: Use new reset function.
esp32: Update to latest ESP IDF.
esp32: Add idf-version target to Makefile, to track IDF commit.
esp32: Initial port to ESP32.
This function was implemented as an experiment, and was enabled only in
unix port. To remind, it allows to access arbitrary files frozen as
source modules (vs bytecode).
However, further experimentation showed that the same functionality can
be implemented with frozen bytecode. The process requires more steps, but
with suitable toolset it doesn't matter patch. This process is:
1. Convert binary files into "Python resource module" with
tools/mpy_bin2res.py.
2. Freeze as the bytecode.
3. Use micropython-lib's pkg_resources.resource_stream() to access it.
In other words, the extra step is using tools/mpy_bin2res.py (because
there would be wrapper for uio.resource_stream() anyway).
Going frozen bytecode route allows more flexibility, and same/additional
efficiency:
1. Frozen source support can be disabled altogether for additional code
savings.
2. Resources could be also accessed as a buffer, not just as a stream.
There're few caveats too:
1. It wasn't actually profiled the overhead of storing a resource in
"Python resource module" vs storing it directly, but it's assumed that
overhead is small.
2. The "efficiency" claim above applies to the case when resource
file is frozen as the bytecode. If it's not, it actually will take a
lot of RAM on loading. But in this case, the resource file should not
be used (i.e. generated) in the first place, and micropython-lib's
pkg_resources.resource_stream() implementation has the appropriate
fallback to read the raw files instead. This still poses some distribution
issues, e.g. to deployable to baremetal ports (which almost certainly
would require freezeing as the bytecode), a distribution package should
include the resource module. But for non-freezing deployment, presense
of resource module will lead to memory inefficiency.
All the discussion above reminds why uio.resource_stream() was implemented
in the first place - to address some of the issues above. However, since
then, frozen bytecode approach seems to prevail, so, while there're still
some issues to address with it, this change is being made.
This change saves 488 bytes for the unix x86_64 port.
Command-line argc and argv should be passed, and as we don't have them,
placeholders were passed, but incorrectly. As we don't have them, just
pass 0/NULL. Looking at the source, this migh lead to problems under
Windows, but this test doesn't run under Windows.
Also, use "%d" printf format consistently with the rest of the codebase.
Prior to this fix, enabling WebREPL for the first time via webrepl_setup
did not work at all because "boot.py" did not contain any lines with
"webrepl" in them that could be uncommented.
This time hopefully should work reliably, using make $(wildcard) function,
which in this case either expands to existing prj_$(BOARD).conf file, or to
an empty string for non-existing one.
This is a low-cost evaluation kit board from ST based on the STM32
Nucleo-144 form factor. It uses the STM32F746ZG MCU in the LQFP144
package. The MCU has 1MB of flash and 320kB of System RAM.
Cortex-M7 runs at up to 216MHz.
This patch simplifies the str creation API to favour the common case of
creating a str object that is not forced to be interned. To force
interning of a new str the new mp_obj_new_str_via_qstr function is added,
and should only be used if warranted.
Apart from simplifying the mp_obj_new_str function (and making it have the
same signature as mp_obj_new_bytes), this patch also reduces code size by a
bit (-16 bytes for bare-arm and roughly -40 bytes on the bare-metal archs).
Recent vendor SDKs ship libs with code in .text section, which previously
was going into .irom0.text. Adjust the linker script to route these
sections back to iROM (follows upstream change).
The SHA1 hashing functionality is provided via the "axtls" library's
implementation, and hence is unavailable when the "axtls" library is not being
used. This change provides the same SHA1 hashing functionality when using the
"mbedtls" library by using its implementation instead.
Macros to convert big-endian values to host byte order and vice-versa.
These were defined in adhoc way for some ports (e.g. esp8266), allow
reuse, provide default implementations, while allow ports to override.
In the vendor SDK 2.1.0, some of the functions which previously didn't
have prototypes, finally acquired them. Change prototypes on our side
to match those in vendor headers, to avoid warnings-as-errors.
With inplace methods now disabled by default, it makes sense to enable
reverse methods, as they allow for more useful features, e.g. allow
for datetime module to implement both 2 * HOUR and HOUR * 2 (where
HOUR is e.g. timedelta object).
Unix naming is historical, before current conventions were established.
All other ports however have it as "modusocket.c", so rename for
consistency and to avoid confusion.
The legacy function pyb.repl_uart() is still provided and retains its
original behaviour (it only accepts a UART object). uos.dupterm() will now
accept any object with write/readinto methods. At the moment there is just
1 dupterm slot.
The W5200 and W5500 can support up to 80MHz so 42MHz (the maximum the
pyboard can do in its standard configuration) should be safe.
Tested to give around 1050000 kbytes/sec TCP download speed on a W5500,
which is about 10% more than with the previous SPI speed of 21MHz.
Which Wiznet chip to use is a compile-time option: MICROPY_PY_WIZNET5K
should be set to either 5200 or 5500 to support either one of these
Ethernet chips. The driver is called network.WIZNET5K in both cases.
Note that this commit introduces a breaking-change at the build level
because previously the valid values for MICROPY_PY_WIZNET5K were 0 and 1
but now they are 0, 5200 and 5500.
The uos.dupterm() signature and behaviour is updated to reflect the latest
enhancements in the docs. It has minor backwards incompatibility in that
it no longer accepts zero arguments.
The dupterm_rx helper function is moved from esp8266 to extmod and
generalised to support multiple dupterm slots.
A port can specify multiple slots by defining the MICROPY_PY_OS_DUPTERM
config macro to an integer, being the number of slots it wants to have;
0 means to disable the dupterm feature altogether.
The unix and esp8266 ports are updated to work with the new interface and
are otherwise unchanged with respect to functionality.
While this console API improves handling on real hardware boards
(e.g. clipboard paste is much more reliable, as well as programmatic
communication), it vice-versa poses problems under QEMU, apparently
because it doesn't emulate UART interrupt handling faithfully. That
leads to inability to run the testsuite on QEMU at all. To work that
around, we have to suuport both old and new console routines, and use
the old ones under QEMU.
Ideally, these should be configurable from Python (using network module),
but as that doesn't exist, we better off using Zephyr's native bootstrap
configuration facility.
Header files that are considered internal to the py core and should not
normally be included directly are:
py/nlr.h - internal nlr configuration and declarations
py/bc0.h - contains bytecode macro definitions
py/runtime0.h - contains basic runtime enums
Instead, the top-level header files to include are one of:
py/obj.h - includes runtime0.h and defines everything to use the
mp_obj_t type
py/runtime.h - includes mpstate.h and hence nlr.h, obj.h, runtime0.h,
and defines everything to use the general runtime support functions
Additional, specific headers (eg py/objlist.h) can be included if needed.
This adds a new configuration option to print runtime warnings and errors to
stderr. On Unix, CPython prints warnings and unhandled exceptions to stderr,
so the unix port here is configured to use this option.
The unix port already printed unhandled exceptions on the main thread to
stderr. This patch fixes unhandled exceptions on other threads and warnings
(issue #2838) not printing on stderr.
Additionally, a couple tests needed to be fixed to handle this new behavior.
This is done by also capturing stderr when running tests.
The timer prescaler is buffered by default, and this patch enables ARPE
which buffers the auto-reload register. With both of these registers
buffered it's now possible to smoothly change the timer's frequency and
have a smoothly varying PWM output.
Current users of fixed vstr buffers (building file paths) assume that there
is no overflow and do not check for overflow after building the vstr. This
has the potential to lead to NULL pointer dereferences
(when vstr_null_terminated_str returns NULL because it can't allocate RAM
for the terminating byte) and stat'ing and loading invalid path names (due
to the path being truncated). The safest and simplest thing to do in these
cases is just raise an exception if a write goes beyond the end of a fixed
vstr buffer, which is what this patch does. It also simplifies the vstr
code.
Prior to this patch calling pyb.Timer(id) would always create a new timer
instance, even if there was an existing one. This patch fixes this
behaviour to match other peripherals, like UART, such that constructing a
timer with just the id will retrieve any existing instances.
The patch also refactors the way timers are validated on construction to
simplify and reduce code size.
If, for class X, X.__add__(Y) doesn't exist (or returns NotImplemented),
try Y.__radd__(X) instead.
This patch could be simpler, but requires undoing operand swap and
operation switch to get non-confusing error message in case __radd__
doesn't exist.
connect, send, recv, sendto and recvfrom now release the GIL. accept
already releases the GIL because it calls mp_hal_delay_ms() within its
busy-wait loop.
Previous to this patch the i2c.scan() method would do up to 100 probes per
I2C address, to detect the devices on the bus. This repeated probing was a
relic from when the code was copied from the accelerometer initialisation,
which requires to do repeated probes while waiting for the accelerometer
chip to turn on.
But I2C devices shouldn't need more than 1 probe to detect their presence,
and the generic software I2C implementation uses 1 probe successfully. So
this patch changes the implementation to use 1 probe per address, which
significantly speeds up the scan operation.
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.
