[U-Boot] Regressions in MTD / SPI FLASH

[Eugeniy Paltsev]

We faced with regressions caused by
commit c4e8862308d4 (mtd: spi: Switch to new SPI NOR framework)
This switch was performed by removing entire u-boot spi-flash
core implementation and copying it from another project.
However the switch is performed without proper testing and 
investigations about fixes/improvements were made in u-boot
spi-flash core. This results in regressions.

One of regression we faced with is related to SST26 flash series which
is used on HSDK board. The cause is that SST26 protection ops
implementation was dropped. The fix of this regression is send
as a patch in this series.

However there are another regressions. I.E: we also faced with broken
SPI flash on another SNPS boards - AXS101 and AXS103. They use different
flash IC (n25q512ax3) and I didn't investigate the cause yet.

I can also expect regressions among other u-boot users
and I believe that subsystem changes mustn't be done such harmful way.

Eugeniy Paltsev (1):
  MTD: SPI: revert removing SST26* flash IC protection ops

 drivers/mtd/spi/sf_internal.h  |   1 +
 drivers/mtd/spi/spi-nor-core.c | 181 +++++++++++++++++++++++++++++++++
 drivers/mtd/spi/spi-nor-ids.c  |   8 +-
 include/linux/mtd/spi-nor.h    |   4 +
 4 files changed, 190 insertions(+), 4 deletions(-)

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2.21.0