Merge tag 'for-linus-20140610' of git://git.infradead.org/linux-mtd

Pull MTD updates from Brian Norris:
 - refactor m25p80.c driver for use as a general SPI NOR framework for
   other drivers which may speak to SPI NOR flash without providing full
   SPI support (i.e., not part of drivers/spi/)
 - new Freescale QuadSPI driver (utilizing new SPI NOR framework)
 - updates for the STMicro "FSM" SPI NOR driver
 - fix sync/flush behavior on mtd_blkdevs
 - fixup subpage write support on a few NAND drivers
 - correct the MTD OOB test for odd-sized OOB areas
 - add BCH-16 support for OMAP NAND
 - fix warnings and trivial refactoring
 - utilize new ECC DT bindings in pxa3xx NAND driver
 - new LPDDR NVM driver
 - address a few assorted bugs caught by Coverity
 - add new imx6sx support for GPMI NAND
 - use a bounce buffer for NAND when non-DMA-able buffers are used

* tag 'for-linus-20140610' of git://git.infradead.org/linux-mtd: (77 commits)
  mtd: gpmi: add gpmi support for imx6sx
  mtd: maps: remove check for CONFIG_MTD_SUPERH_RESERVE
  mtd: bf5xx_nand: use the managed version of kzalloc
  mtd: pxa3xx_nand: make the driver work on big-endian systems
  mtd: nand: omap: fix omap_calculate_ecc_bch() for-loop error
  mtd: nand: r852: correct write_buf loop bounds
  mtd: nand_bbt: handle error case for nand_create_badblock_pattern()
  mtd: nand_bbt: remove unused variable
  mtd: maps: sc520cdp: fix warnings
  mtd: slram: fix unused variable warning
  mtd: pfow: remove unused variable
  mtd: lpddr: fix Kconfig dependency, for I/O accessors
  mtd: nand: pxa3xx: Add supported ECC strength and step size to the DT binding
  mtd: nand: pxa3xx: Use ECC strength and step size devicetree binding
  mtd: nand: pxa3xx: Clean pxa_ecc_init() error handling
  mtd: nand: Warn the user if the selected ECC strength is too weak
  mtd: nand: omap: Documentation: How to select correct ECC scheme for your device ?
  mtd: nand: omap: add support for BCH16_ECC - NAND driver updates
  mtd: nand: omap: add support for BCH16_ECC - ELM driver updates
  mtd: nand: omap: add support for BCH16_ECC - GPMC driver updates
  ...

1 files changed, 62 insertions, 0 deletions

diff --git a/Documentation/mtd/spi-nor.txt b/Documentation/mtd/spi-nor.txt
new file mode 100644
index 000000000000..548d6306ebca
--- /dev/null
+++ b/Documentation/mtd/spi-nor.txt
@@ -0,0 +1,62 @@
+                          SPI NOR framework
+               ============================================
+
+Part I - Why do we need this framework?
+---------------------------------------
+
+SPI bus controllers (drivers/spi/) only deal with streams of bytes; the bus
+controller operates agnostic of the specific device attached. However, some
+controllers (such as Freescale's QuadSPI controller) cannot easily handle
+arbitrary streams of bytes, but rather are designed specifically for SPI NOR.
+
+In particular, Freescale's QuadSPI controller must know the NOR commands to
+find the right LUT sequence. Unfortunately, the SPI subsystem has no notion of
+opcodes, addresses, or data payloads; a SPI controller simply knows to send or
+receive bytes (Tx and Rx). Therefore, we must define a new layering scheme under
+which the controller driver is aware of the opcodes, addressing, and other
+details of the SPI NOR protocol.
+
+Part II - How does the framework work?
+--------------------------------------
+
+This framework just adds a new layer between the MTD and the SPI bus driver.
+With this new layer, the SPI NOR controller driver does not depend on the
+m25p80 code anymore.
+
+   Before this framework, the layer is like:
+
+                   MTD
+         ------------------------
+                  m25p80
+         ------------------------
+               SPI bus driver
+         ------------------------
+                SPI NOR chip
+
+   After this framework, the layer is like:
+                   MTD
+         ------------------------
+              SPI NOR framework
+         ------------------------
+                  m25p80
+         ------------------------
+               SPI bus driver
+         ------------------------
+               SPI NOR chip
+
+  With the SPI NOR controller driver (Freescale QuadSPI), it looks like:
+                   MTD
+         ------------------------
+              SPI NOR framework
+         ------------------------
+                fsl-quadSPI
+         ------------------------
+               SPI NOR chip
+
+Part III - How can drivers use the framework?
+---------------------------------------------
+
+The main API is spi_nor_scan(). Before you call the hook, a driver should
+initialize the necessary fields for spi_nor{}. Please see
+drivers/mtd/spi-nor/spi-nor.c for detail. Please also refer to fsl-quadspi.c
+when you want to write a new driver for a SPI NOR controller.