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Tom Rini 7dbafe0634 Merge tag 'arc-last-minute-fixes-for-2020.04' of https://gitlab.denx.de/u-boot/custodians/u-boot-arc 
This last minute pull-request is intended to fix some drivers
when used on ARC boards. The problem was introduced by
07906b3dad

What happened while doing one pretty simple improvement to make
U-Boot port more flexible and portable (by switching accessors from
assembly-written to plain C version) we implicitly added 2 problems:

 1. Downgraded accessors from being volatile which signalled to
    the compiler that it's now possible to do all kinds of optimizations
    which may easily include merge of subsequent byte reads/writes into
    word operations. Which is OK for accessing mormal memory but
    breaks operation of peripherals if we access its memory-mapped regs
    in such a "creative" manner.
 2. As a part of assembly-written implementation we had compiler barriers
    in form of the following construction 'asm volatile("" : : : "memory")',
    and we dropped it in C implemntation. This in its turn enabled compiler
    to mess with instruction ordering. Guess what it gives us in the end :)

So with all that we had in some corner-cases veeery funny instruction flows
generated. And in particular it broke DW SPI functionality when we were
writing large amount of data. Funny enough our tests which were writing
small amount of data still worked and only by the chance we caught that
breakage and unrolled that quite interesting loop of unexpected
problems.

The road to hell is paved with good intentions. Amen :)
2020-03-31 15:10:54 -04:00
..
arc ARC: IO: add MB for __raw_* memory accessors 2020-03-31 18:31:53 +03:00
arm Merge branch 'master' of git://git.denx.de/u-boot-socfpga 2020-03-31 10:05:25 -04:00
m68k dma-mapping: add <asm/dma-mapping.h> for all architectures 2020-02-20 15:09:54 +08:00
microblaze dma-mapping: add <asm/dma-mapping.h> for all architectures 2020-02-20 15:09:54 +08:00
mips dma-mapping: add <asm/dma-mapping.h> for all architectures 2020-02-20 15:09:54 +08:00
nds32 dma-mapping: move dma_map_(un)single() to <linux/dma-mapping.h> 2020-02-19 21:27:30 +08:00
nios2 common: Move hang() to the same header as panic() 2020-01-24 23:06:49 +05:30
powerpc gazerbeam: add clocks property to SPI node 2020-03-31 10:06:52 -04:00
riscv riscv: Implement new SBI v0.2 extensions 2020-03-17 11:29:54 +08:00
sandbox dma-mapping: add <asm/dma-mapping.h> for all architectures 2020-02-20 15:09:54 +08:00
sh dma-mapping: add <asm/dma-mapping.h> for all architectures 2020-02-20 15:09:54 +08:00
x86 x86: apl: Use cpu_x86_get_count() for cpu_ops.get_count 2020-03-05 18:25:22 +08:00
xtensa dma-mapping: add <asm/dma-mapping.h> for all architectures 2020-02-20 15:09:54 +08:00
.gitignore
Kconfig x86: Enable pinctrl in SPL and TPL 2019-12-15 11:44:24 +08:00