u-boot.git/arch/mips/lib, branch v2018.11

MIPS: cache: remove config option CONFIG_SYS_MIPS_CACHE_MODE

2018-09-22T19:04:10+00:00

Caches should be configured to mode CONF_CM_CACHABLE_NONCOHERENT
(or CONF_CM_CACHABLE_COW when a CM is available). There is no
need to make this configurable.

Signed-off-by: Daniel Schwierzeck

MIPS: cache: make index base address configurable

2018-09-22T19:02:03+00:00

The index base address used for the cache initialisation is currently
hard-coded to CKSEG0. Make this value configurable if a MIPS system
needs to have a different address (e.g. in SRAM or ScratchPad RAM).

Signed-off-by: Daniel Schwierzeck

MIPS: cache: optimise changing of k0 CCA mode

2018-09-22T19:02:03+00:00

Changing the Cache Coherency Algorithm (CCA) for kernel mode
requires executing from KSEG1. Thus do a jump from KSEG0 to KSEG1
before changing the CCA mode. Jump back to KSEG0 afterwards.

Signed-off-by: Daniel Schwierzeck

MIPS: cache: reimplement dcache_[status, enable, disable]

2018-09-22T19:02:03+00:00

Those functions are not needed during cache init and can be
implemented in C. Only support the safe disabling of caches when
this is required for booting an OS. Reenabling caches is much
harder to implement if an optional coherency manager must be
supported. As there is no real use-case anyway, dcache_enable
is implemented with an error message.

Signed-off-by: Daniel Schwierzeck

SPDX: Convert all of our single license tags to Linux Kernel style

2018-05-07T13:34:12+00:00

When U-Boot started using SPDX tags we were among the early adopters and
there weren't a lot of other examples to borrow from.  So we picked the
area of the file that usually had a full license text and replaced it
with an appropriate SPDX-License-Identifier: entry.  Since then, the
Linux Kernel has adopted SPDX tags and they place it as the very first
line in a file (except where shebangs are used, then it's second line)
and with slightly different comment styles than us.

In part due to community overlap, in part due to better tag visibility
and in part for other minor reasons, switch over to that style.

This commit changes all instances where we have a single declared
license in the tag as both the before and after are identical in tag
contents.  There's also a few places where I found we did not have a tag
and have introduced one.

Signed-off-by: Tom Rini

fdt: Implement weak arch_fixup_fdt()

2018-02-18T19:53:38+00:00

Only ARM and in some configs MIPS really implement arch_fixup_fdt().
Others just use the same boilerplate which is not good by itself,
but what's worse if we try to build with disabled CONFIG_CMD_BOOTM
and enabled CONFIG_OF_LIBFDT we'll hit an unknown symbol which was
apparently implemented in arch/xxx/lib/bootm.c.

Now with weak arch_fixup_fdt() right in image-fdt.c where it is
used we get both items highlighted above fixed.

Signed-off-by: Alexey Brodkin 
Cc: Daniel Schwierzeck 
Cc: Simon Glass 
Cc: York Sun 
Cc: Stefan Roese 
Reviewed-by: Tom Rini 
Reviewed-by: Daniel Schwierzeck

MIPS: Break out of cache loops for unimplemented caches

2017-11-28T20:59:30+00:00

If we run on a CPU which doesn't implement a particular cache then we
would previously get stuck in an infinite loop, executing a cache op on
the first "line" of the missing cache & then incrementing the address by
0. This was being avoided for the L2 caches, but not for the L1s. Fix
this by generalising the check for a zero line size & avoiding the cache
op loop when this is the case.

Signed-off-by: Paul Burton 
Cc: Daniel Schwierzeck 
Cc: u-boot@lists.denx.de

MIPS: Clear instruction hazards in flush_cache()

2017-11-28T20:59:30+00:00

When writing code, for example during relocation, we ensure that the
icache has a coherent view of the new instructions with a call to
flush_cache(). This handles the bulk of the work to ensure the new
instructions will execute as expected, however it does not ensure that
the CPU pipeline doesn't already contain instructions taken from a stale
view of the affected memory. This could theoretically be a problem for
relocation, but in practice typically isn't because we sync caches for
enough code after the entry point of the newly written code that by the
time the CPU pipeline might possibly fetch any of it we'll have long ago
written it back & invalidated any stale icache entries. This is however
a problem for shorter regions of code.

In preparation for later patches which write shorter segments of code,
ensure any instruction hazards are cleared by flush_cache() by
introducing & using a new instruction_hazard_barrier() function which
makes use of the jr.hb instruction to clear the hazard.

Signed-off-by: Paul Burton 
Cc: Daniel Schwierzeck 
Cc: u-boot@lists.denx.de

MIPS: Ensure cache ops complete in cache maintenance functions

2017-11-28T20:59:30+00:00

A typical use of cache maintenance functions is to force writeback of
data which a device is about to read using DMA - for example a
descriptor or command structure. Such users of cache maintenance
functions require that operations on the cache have completed before
they proceed to instruct a device to read memory. This requires that we
place a completion barrier (ie. sync instruction) between the cache ops
and whatever write informs the device to perform DMA.

Whilst strictly speaking this isn't all users of the cache maintenance
functions & we could instead place the barriers in the drivers that
require them, it would be much more invasive to do so than to just have
the barrier be the default by placing it in the cache functions
themselves. The cost is low enough that it shouldn't matter to us in any
rare cases that we use the cache functions when not performing DMA.

Signed-off-by: Paul Burton 
Cc: Daniel Schwierzeck 
Cc: u-boot@lists.denx.de

env: Rename getenv/_f() to env_get()

2017-08-16T12:30:24+00:00

We are now using an env_ prefix for environment functions. Rename these
two functions for consistency. Also add function comments in common.h.

Quite a few places use getenv() in a condition context, provoking a
warning from checkpatch. These are fixed up in this patch also.

Suggested-by: Wolfgang Denk 
Signed-off-by: Simon Glass