Since c80e7c14e6 changed the GC heap to use
all unused RAM, there is no longer any RAM available for the traditional C
heap (which is not used by default in MicroPython but may be used by C
extensions). This commit adds a provision for a board to reserve RAM for
the C heap, by defining MICROPY_C_HEAP_SIZE.
Signed-off-by: Damien George <damien@micropython.org>
Borrowing an idea from the mimxrt port (also stm32 port): in the loader
input file memmap_mp.ld calculate __GcHeapStart and __GcHeapEnd as the
unused RAM. Then in main.c use these addresses as arguments to gc_init().
The benefits of this change are:
1) When libraries are added or removed in the future changing BSS usage,
main.c's sizing of the GC heap does not need to be changed.
2) Currently these changes make the GC area about 30 KBytes larger, eg on
PICO_W the GC heap increases from 166016 to 192448 bytes. Without that
change this RAM would never get used.
3) If someone wants to disable one or more SRAM blocks on the RP2040 to
reduce power consumption it will be easy: just change the MEMORY section
in memmap_mp.ld. For instance to not use SRAM2 and SRAM3 change it to:
MEMORY
{
FLASH(rx) : ORIGIN = 0x10000000, LENGTH = 2048k
RAM(rwx) : ORIGIN = 0x21000000, LENGTH = 128k
SCRATCH_X(rwx) : ORIGIN = 0x20040000, LENGTH = 4k
SCRATCH_Y(rwx) : ORIGIN = 0x20041000, LENGTH = 4k
}
Then to turn off clocks for SRAM2 and SRAM3 from MicroPython, set the
appropriate bits in WAKE_EN0 and SLEEP_EN0.
Tested by running the firmware.uf2 file on PICO_W and displaying
micropython.mem_info(). Confirmed GC total size approximately matched the
size calculated by the loader.
Signed-off-by: cpottle9 <cpottle9@outlook.com>
Create a new linker section .unitialized_bss for bss that does not need
zero-initialising.
Move gc_heap to this section, which saves ~30ms from rising edge of RESET
to setting a pin HIGH in MicroPython.
Zero fill happens in Pico SDK crt0.S before ROSC is configured. It's very,
very slow.
Signed-off-by: Phil Howard <phil@gadgetoid.com>
This commit adds a new port "rp2" which targets the new Raspberry Pi RP2040
microcontroller.
The build system uses pure cmake (with a small Makefile wrapper for
convenience). The USB driver is TinyUSB, and there is a machine module
with most of the standard classes implemented. Some examples are provided
in the examples/rp2/ directory.
Work done in collaboration with Graham Sanderson.
Signed-off-by: Damien George <damien@micropython.org>
