Commit Graph

6 Commits

Author SHA1 Message Date
Andrew Boie 5846018d0d nios2: crt0: fix GDB debugging
When an image is sent over the wire with the GDB 'load' command,
it tries to start execution from the __start symbol, which needs to
be in RAM. Since the reset vector is in ROM, name it something else.

Change-Id: Id0bbfa76db9a8a81bd7ff20be3f2baec81eae15e
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2016-06-22 01:31:12 +00:00
Andrew Boie 0d9b755bb1 nios2: ensure stack pointer is properly aligned
Kconfig doesn't enforce any kind of alignment when specifying the
ISR stack size. Perform the assembly equivalent of STACK_ROUND_DOWN.

Change-Id: Ib7fb72ff7db8a3aa20ec6d0c59a03aa8227f6671
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2016-06-22 01:31:11 +00:00
Andrew Boie 464676510b nios2: crt0: init interrupt stack as well
CONFIG_INIT_STACKS should initialize all stack regions
with 0xaa. Make sure the initial interrupt stack gets this
as well. Take care not to exceed the bounds of the array
if it is not 4-byte aligned.

Change-Id: Ib23329ac84a5a8515272be2944f948e8faba65b3
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2016-06-22 01:31:10 +00:00
Andrew Boie 31e8030c05 nios2: set initial stack pointer to the interrupt stack
Change-Id: I5a71215dde9e7fdc7d5d9de5297f5f493de40ca8
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2016-06-10 15:22:39 +00:00
Andrew Boie 191f1df574 nios2: crt0: split into __start and __text_start
__start is the CPU's reset vector. In a typical Nios II configuration,
the exception vector is 0x20 bytes after the reset vector, severely
constraining the amount of code that can go in here.

Split this into __start and __text_start. The only thing that __start
really need to do is init the instruction cache and jump into
__text_start.

JIRA IDs placed in comments for missing items.

Change-Id: I3c6b8ed65e8fcf6b6a735b80cf007d0180599230
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2016-06-10 15:22:39 +00:00
Andrew Boie 2d5645e57a nios2: add minimal crt0.S
At the moment this just jumps into prep_c, with comments left
on other things that need to be done. Having this here ensures that
the early boot code isn't discarded by gc-sections.

vector_table.c removed, it isn't the right approach for this CPU.
Proper method for initializing reset and exception vectors still
being investigated.

Change-Id: Id7965c671f1a55c42ecfb65119497405a646bec4
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
2016-05-09 18:09:26 +00:00