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Based on Cyrille Pitchen's patch https://lkml.org/lkml/2017/3/22/935. This patch is a transitional patch in introducing the support of SFDP SPI memories with non-uniform erase sizes like Spansion s25fs512s. Non-uniform erase maps will be used later when initialized based on the SFDP data. Introduce the memory erase map which splits the memory array into one or many erase regions. Each erase region supports up to 4 erase types, as defined by the JEDEC JESD216B (SFDP) specification. To be backward compatible, the erase map of uniform SPI NOR flash memories is initialized so it contains only one erase region and this erase region supports only one erase command. Hence a single size is used to erase any sector/block of the memory. Besides, since the algorithm used to erase sectors on non-uniform SPI NOR flash memories is quite expensive, when possible, the erase map is tuned to come back to the uniform case. The 'erase with the best command, move forward and repeat' approach was suggested by Cristian Birsan in a brainstorm session, so: Suggested-by: Cristian Birsan <cristian.birsan@microchip.com> Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com> Reviewed-by: Marek Vasut <marek.vasut@gmail.com> Signed-off-by: Boris Brezillon <boris.brezillon@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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.