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SPI memory devices from different manufacturers have widely different configurations for Status, Control and Configuration registers. JEDEC 216C defines a new map for these common register bits and their functions, and describes how the individual bits may be accessed for a specific device. For the JEDEC 216B compliant flashes, we can partially deduce Status and Configuration registers functions by inspecting the 16th DWORD of BFPT. Older flashes that don't declare the SFDP tables (SPANSION FL512SAIFG1 311QQ063 A ©11 SPANSION) let the software decide how to interact with these registers. The commitdcb4b22eea("spi-nor: s25fl512s supports region locking") uncovered a probe error for s25fl512s, when the Quad Enable bit CR[1] was set to one in the bootloader. When this bit is one, only the Write Status (01h) command with two data byts may be used, the 01h command with one data byte is not recognized and hence the error when trying to clear the block protection bits. Fix the above by using the Write Status (01h) command with two data bytes when the Quad Enable bit is one. Backward compatibility should be fine. The newly introduced spi_nor_spansion_clear_sr_bp() is tightly coupled with the spansion_quad_enable() function. Both assume that the Write Register with 16 bits, together with the Read Configuration Register (35h) instructions are supported. Fixes:dcb4b22eea("spi-nor: s25fl512s supports region locking") Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Tested-by: Jonas Bonn <jonas@norrbonn.se> Tested-by: Geert Uytterhoeven <geert+renesas@glider.be> Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com> Tested-by: Vignesh Raghavendra <vigneshr@ti.com> Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.