Previously the compiler was allowed to reorder access to the interrupt control
registers in regard to memory access not marked as `volatile` (at least some
people - most notably some compiler developers - read the C standard this way).
In practise this did not happen as irq_disable(), irq_restore(), irq_enable()
are part of a separate compilation unit: Calls to external functions unknown to
the compiler are treated as if they were memory barriers. But if link time
optimization (LTO) is enabled, this no longer would work: The compiler could
inline the code accessing the interrupt control registers and reorder the memory
accesses wrapped in irq_disable() and irq_restore() outside of their protection.
This commit adds the "memory" clobber to the inline assembly accessing the
interrupt control registers. This makes those accesses explicit compiler memory
barriers. The machine code generated without LTO enabled should not differ in
any way by this commit. But the use of irq_*() should now be safe with LTO.
During the flash step esptool.py gives the following warning:
WARNING: Flash size arguments in megabits like '16m' are deprecated.
Please use the equivalent size '2MB'.
Megabit arguments may be removed in a future release.
esptool.py v2.7-dev
This patch replaces '16m' with '2MB' to enable future compatibility.
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
The currently supported SAM0 MCUs (samd21, saml21, saml1x) share the
same RTC peripheral, yet each of them carries it's own copy of the RTC
driver.
Unify the drivers and move them to sam0_common.
Usually, the access to the IROM (flash) memory requires 32-bit word aligned reads. Attempts to access data in the IROM (flash) memory less than 32 bits in size triggers a LoadStoreError exception. With the exception handler from esp-open-rtos it becomes possible to access data in IROM (flash) with a size of less than 32 bits and thus to place .rodata sections in the IROM (flash).
Fix of #11354: Function '_write_r' of ESP32's newlibc does not write the output of function 'write(STDIO_FILENO, ...)' to the UART interface. To fix this problem, module 'newlib_syscalls_default' is now used by default. Function '_write_r' of module 'newlib_syscalls_default' uses 'stdio_write' which in turn uses 'uart_write' if module 'stdio_uart' is used which is now the default case for ESP32.
Moving atmega_stdio_init() to cpu_init() just before periph_init() guarantees
that stdio is available to allow DEBUG() in periph_init(). This also helps to
unify the boot up process of ATmega boards and de-duplicates the stdio init from
board_init().
This commit cleans up magic number and defines bitfields.
Adds error codes for ADDR/DATA NACK and ARBLOSS
Adds error handling, it corrects when an error occurs
Protects from flags that could lockup the bus
For this purpose, adapted AVR libc functions are used. When used, malloc and free functions require 304 additional bytes of code compared to the oneway_malloc module.
This driver is compliant with the candev interface. It has been tested
with STM32F0 and STM32F2 and STM32F413 ONLY at this time but should be
compliant with other STM32Fx devices
