commit c3c016c "sf: Add SPI NOR protection mechanism" introduced
flash_lock()/flash_unlock()/flash_is_locked() methods for SPI flash,
but not every flash driver supplies these. We should test these
methods against NULL before actually calling them.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Fabio Estevam <fabio.estevam@freescale.com>
Reviewed-by: Jagan Teki <jteki@openedev.com>

The current error message in get_part if CONFIG_MTDPARTS is disabled is
"offset is not a number" which is confusing and doesn't help at all.

Change that for something that might give a hint on what's going on.

Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Tom Rini <trini@konsulko.com>

Add Altera Generic Quad SPI Controller support. The controller
converts SPI NOR flash to parallel flash interface. So it is
not like other SPI flash, but rather like CFI flash.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>

Convert cfi flash to driver model.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>
Reviewed-by: Simon Glass <sjg@chromium.org>

Implement a Memory Technology Device (MTD) uclass. It should
include most flash drivers in the future. Though no uclass ops
are defined yet, the MTD ops could be used.

The NAND flash driver is based on MTD. The CFI flash and SPI
flash support MTD, too. It should make sense to convert them
to MTD uclass.

Signed-off-by: Thomas Chou <thomas@wytron.com.tw>

Many SPI flashes have protection bits (BP2, BP1 and BP0) in the
status register that can protect selected regions of the SPI NOR.

Take these bits into account when performing erase operations,
making sure that the protected areas are skipped.

Tested on a mx6qsabresd:

=> sf probe
SF: Detected M25P32 with page size 256 Bytes, erase size 64 KiB, total 4 MiB
=> sf protect lock  0x3f0000 0x10000
=> sf erase 0x3f0000 0x10000
offset 0x3f0000 is protected and cannot be erased
SF: 65536 bytes @ 0x3f0000 Erased: ERROR
=> sf protect unlock  0x3f0000 0x10000
=> sf erase 0x3f0000 0x10000
SF: 65536 bytes @ 0x3f0000 Erased: OK

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
[re-worked to fit the lock common to dm and non-dm]
Signed-off-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Jagan Teki <jteki@openedev.com>

Add the SPI NOR protection mechanism from the kernel.

This code is based on the work from
Brian Norris <computersforpeace@gmail.com>
Here is the commit details:
"mtd: spi-nor: refactor block protection functions"
(sha1: 62593cf40b23b523b9fc9334ca61ba6c595ebb09)

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Jagan Teki <jteki@openedev.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Jagan Teki <jteki@openedev.com>

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>

Use the is_power_of_2() definition from log2.h to align with the
kernel implementation.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Reviewed-by: Tom Rini <trini@konsulko.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Jagan Teki <jteki@openedev.com>