mtd: spi-nor: Move m25p80 code in spi-nor.c

The m25p80 driver is actually a generic wrapper around the spi-mem
layer. Not only the driver name is misleading, but we'd expect such a
common logic to be directly available in the core. Another reason for
moving this code is that SPI NOR controller drivers should
progressively be replaced by SPI controller drivers implementing the
spi_mem_ops interface, and when the conversion is done, we should have
a single spi-nor driver directly interfacing with the spi-mem layer.

While moving the code we also fix a longstanding issue when
non-DMA-able buffers are passed by the MTD layer.

Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Vignesh Raghavendra <vigneshr@ti.com>
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>

drivers/mtd/devices/Kconfig

@@ -79,24 +79,6 @@ config MTD_DATAFLASH_OTP
 	  other key product data.  The second half is programmed with a
 	  unique-to-each-chip bit pattern at the factory.
 
-config MTD_M25P80
-	tristate "Support most SPI Flash chips (AT26DF, M25P, W25X, ...)"
-	depends on SPI_MASTER && MTD_SPI_NOR
-	select SPI_MEM
-	help
-	  This enables access to most modern SPI flash chips, used for
-	  program and data storage.   Series supported include Atmel AT26DF,
-	  Spansion S25SL, SST 25VF, ST M25P, and Winbond W25X.  Other chips
-	  are supported as well.  See the driver source for the current list,
-	  or to add other chips.
-
-	  Note that the original DataFlash chips (AT45 series, not AT26DF),
-	  need an entirely different driver.
-
-	  Set up your spi devices with the right board-specific platform data,
-	  if you want to specify device partitioning or to use a device which
-	  doesn't support the JEDEC ID instruction.
-
 config MTD_MCHP23K256
 	tristate "Microchip 23K256 SRAM"
 	depends on SPI_MASTER

drivers/mtd/devices/Makefile

@@ -12,7 +12,6 @@ obj-$(CONFIG_MTD_MTDRAM)	+= mtdram.o
 obj-$(CONFIG_MTD_LART)		+= lart.o
 obj-$(CONFIG_MTD_BLOCK2MTD)	+= block2mtd.o
 obj-$(CONFIG_MTD_DATAFLASH)	+= mtd_dataflash.o
-obj-$(CONFIG_MTD_M25P80)	+= m25p80.o
 obj-$(CONFIG_MTD_MCHP23K256)	+= mchp23k256.o
 obj-$(CONFIG_MTD_SPEAR_SMI)	+= spear_smi.o
 obj-$(CONFIG_MTD_SST25L)	+= sst25l.o

drivers/mtd/spi-nor/Kconfig

@@ -2,6 +2,8 @@
 menuconfig MTD_SPI_NOR
 	tristate "SPI-NOR device support"
 	depends on MTD
+	depends on MTD && SPI_MASTER
+	select SPI_MEM
 	help
 	  This is the framework for the SPI NOR which can be used by the SPI
 	  device drivers and the SPI-NOR device driver.