For better compatibility copy most of cortexm_base.ld
and use the same section names.
Only interrupt stacks and the two additional (currently unused)
heap sections are different between the two now.
lpc23xx has 2k of battery RAM that is retained in Deep Power Down mode.
To not overwrite that data it must only be initialized on Power On Reset.
However, RSIR looks the same when waking up from Deep Power Down as it does
on the power-on case.
So use 4 bytes of the backup RAM to keep a signature that is only valid if
memory was retained (no power-on Reset).
A small change to the linker script is required so two sections can be
placed into flash.
puf_sram only relies on an uninitialized chunk of memory.
This means to enable it we just have to hook up puf_sram_init().
All memory after __bss_end should be uninitialized at startup, so
just use that.
Enable IDLE and Deep Powerdown mode.
IDLE is pretty straightforward - insteady of busy waiting, the CPU will
enter an idle state from which it will resume on any event.
Deep Power Down shuts off the entite system except for the battery backup
power domain.
That means the CPU will reset on resume and can be woken by e.g. RTC.
SLEEP and POWERDOWN disable the PLL and the PLL and Flash respectively.
This requires some proper wake-up handling.
Since this turned out to be a major time sink and those modes are never
currently never used in RIOT outside of tests, I left this as an exercise
for a future reader.
- Moved compiler & linker flags from boards/common/msba2 to cpu/arm7_common
- Moved dependency to newlib nano to cpu/arm7_common
- Moved config to link in cpu/startup.o to cpu/arm7_common
- split up interrupt vector code from bootloader.c to vectors.c
- moved bootloader.c to arm7_init.c
- Use consistent naming:
- use lower case for everything but preprocessor stuff
- ISRs now named isr_foo()
- Functions bl_uart_init(), bl_blink(), bl_config_init() declared but never
implemented
--> Removed declarations
- Check for c preprocessor macro CPU_MC1322X is obsolete, as CPU_MC1322X is
nowhere defined in RIOT's code base
- IRQ_Routine() is never used, nor is it ever configured as ISR
- DEBUG_Routine() is never used, nor is it ever configured as ISR
- Moved VIC.c to irq_arch.c for consistent naming scheme
- Removed unused functions IRQenabled, disableFIQ, restoreFIQ, enableFIQ
- There is not header for those functions, so they *cannot* be used
- These is obviously no user, as they *cannot* be used
- There is absolutely no documentation what they would be used for
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.
- removed ISR_STACKSIZE define where unused (set to 0)
- removed thread_arch_isr_stack_usage(), thread_arch_isr_stack_start(),
and/or thread_arch_isr_stack_pointer() where not implemented
