mtd: nand: omap: make am33xx/elm.c as common driver for all OMAPx and AMxxxx platforms

ELM hardware engine which is used for ECC error detection, is present on all
latest OMAP SoC (like OMAP4xxx, OMAP5xxx, DRA7xxx, AM33xx, AM43xx). Thus ELM
driver should be moved to common drivers/mtd/nand/ folder so that all SoC
having on-chip ELM hardware engine can re-use it.
This patch has following changes:
- mv arch/arm/include/asm/arch-am33xx/elm.h arch/arm/include/asm/omap_elm.h
- mv arch/arm/cpu/armv7/am33xx/elm.c drivers/mtd/nand/omap_elm.c
- update Makefiles
- update #include <asm/elm.h>
- add CONFIG_NAND_OMAP_ELM to compile driver/mtd/nand/omap_elm.c
	and include in all board configs using AM33xx SoC platform.

Signed-off-by: Pekon Gupta <pekon@ti.com>

1 files changed, 19 insertions, 0 deletions

diff --git a/doc/README.nand b/doc/README.nand
index 3a507b6c81..ce7ea5e1e9 100644
--- a/doc/README.nand
+++ b/doc/README.nand
@@ -179,6 +179,25 @@ Configuration Options:
       Please convert your driver even if you don't need the extra
       flexibility, so that one day we can eliminate the old mechanism.
 
+
+Platform specific options
+=========================
+   CONFIG_NAND_OMAP_GPMC
+	Enables omap_gpmc.c driver for OMAPx and AMxxxx platforms.
+	GPMC controller is used for parallel NAND flash devices, and can
+	do ECC calculation (not ECC error detection) for HAM1, BCH4, BCH8
+	and BCH16 ECC algorithms.
+
+   CONFIG_NAND_OMAP_ELM
+	Enables omap_elm.c driver for OMAPx and AMxxxx platforms.
+	ELM controller is used for ECC error detection (not ECC calculation)
+	of BCH4, BCH8 and BCH16 ECC algorithms.
+	Some legacy platforms like OMAP3xx do not have in-built ELM h/w engine,
+	thus such SoC platforms need to depend on software library for ECC error
+	detection. However ECC calculation on such plaforms would still be
+	done by GPMC controller.
+
+
 NOTE:
 =====