u-boot.git/arch/arc, branch v2016.07

arc: make global_data.h usable in assembly files

2016-07-04T08:43:41+00:00

Currently on attempt to use global_data.h in an assembly file following
will happen:
-------------------->8-----------------
./arch/arc/include/asm/global_data.h: Assembler messages:
./arch/arc/include/asm/global_data.h:11: Error: bad instruction 'struct arch_global_data{'
./arch/arc/include/asm/global_data.h:12: Error: junk at end of line, first unrecognized character is `}'
scripts/Makefile.build:316: recipe for target 'arch/arc/lib/start.o' failed
-------------------->8-----------------

In this change we disable struct arch_global_data in ASM which fixes
the issue above.

Signed-off-by: Alexey Brodkin

arc: Use "-mcpu=archs" instead of deprecated "-marchs" for ARC HS

2016-07-04T08:43:40+00:00

Newer ARC toolchains don't support "-marchs" option any longer.
Instead "-mcpu=archs" should be used. What's also important older
toiolchains that support ARC HS cores will also happily accept
"-mcpu=archs" so that's a very safe move.

Signed-off-by: Alexey Brodkin

arc: Update data accessors with use of memory barriers

2016-06-13T12:38:05+00:00

Memory barriers are proven to be a requirement for both compiler and
real hardware to properly serialize access to critical data.

For example if CPU or data bus it uses may do reordering of data
accesses absence of memory barriers might easily lead to very subtle and
hard to debug data corruptions.

This implementation was heavily borrowed from up to date Linux kernel.

Signed-off-by: Alexey Brodkin

arc/cache: Flush & invalidate all caches right before enabling IOC

2016-06-13T12:38:05+00:00

According to ARC HS databook it is required to flush and disable
caches prior programming IOC registers. Otherwise ongoing coherent
memory operations may not observe the coherency protocols as
expected.

But since in ARC HS v2.1 there's no way to disable SLC (AKA L2 cache)
we're doing our best flushing and invalidating it.

Signed-off-by: Alexey Brodkin

arc/cache: really do invalidate_dcache_all() even if IOC exists

2016-06-13T12:38:05+00:00

invalidate_dcache_all() could be used in different use-cases
and what is especially important most of those cases won't be
related to DMAed data to or from peripherals, i.e. we'll be doing
invalidation of data used purely by CPU cores.

Given that IOC engine only snoops data that goes through DMA
we need to care ourselves about data used only by CPU cores
and so remove dependency on IOC from invalidate_dcache_all()
and always do real invalidation.

Signed-off-by: Alexey Brodkin

arc/cache: really do flush_dcache_all() even if IOC exists

2016-04-21T17:09:59+00:00

flush_dcache_all() is used in the very end of U-Boot self relocation
to write back all copied and then patched code and data to their
new location in the very end of available memory space.

Since that has nothing to do with IO (i.e. no external DMA happens
here) IOC won't help here and we need to write back data cache contents
manually.

Signed-off-by: Alexey Brodkin

arc: Add virt_to_phys() stub

2016-04-11T17:20:38+00:00

Commit cf7c93cdd755 "usb: ehci: Implement V2P mapping"
introduced usage of virt_to_phys() in ehci-hcd.

Since there was no implementation of virt_to_phys() for ARC
compilation of the ehci-generic driver failed.

This change adds virt_to_phys() stub for ARC so now
USB driver for AXS101 board could be built again.

Signed-off-by: Alexey Brodkin 
Cc: Daniel Schwierzeck 
Cc: Hans de Goede 
Acked-by: Marek Vasut

arc: get rid of running_on_hw

2016-04-11T17:20:30+00:00

ISS is obsolete now and nSIM is used for simulation instead.
In its turn nSIM properly handles baud-rate settings so get rid
of now useless check.

Signed-off-by: Alexey Brodkin

arc: cache - utilize IO coherency (AKA IOC) engine

2016-02-20T08:20:05+00:00

With release of ARC HS38 v2.1 new IO coherency engine could be built-in
ARC core. This hardware module ensures coherency between DMA-ed data
from peripherals and L2 cache.

With L2 and IOC enabled there's no overhead for L2 cache manual
maintenance which results in significantly improved IO bandwidth.

Signed-off-by: Alexey Brodkin

arc: cache - accommodate different L1 cache line lengths

2016-02-20T08:19:53+00:00

ARC core could be configured with different L1 and L2 (AKA SLC) cache
line lengths. At least these values are possible and were really used:
32, 64 or 128 bytes.

Current implementation requires cache line to be selected upon U-Boot
configuration and then it will only work on matching hardware. Indeed
this is quite efficient because cache line length gets hardcoded during
code compilation. But OTOH it makes binary less portable.

With this commit we allow U-Boot to determine real L1 cache line length
early in runtime and use this value later on. This extends portability
of U-Boot binary a lot.

Signed-off-by: Alexey Brodkin