mtd: sh_flctl: Restructure the hardware ECC handling

There are multiple reasons for a rewrite:
 - a race exists: when _4ECCEND is set, _4ECCFA may become true too
   meanwhile, which is lost and a non-correctable error is treated as
   correctable.
 - the ECC statistics don't get properly propagated to the base code.
 - empty pages would get marked as corrupted

The rewrite resolves the issues and I hope it gives a more explicit
code flow structure.

Signed-off-by: Bastian Hecht <hechtb@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/include/linux/mtd/sh_flctl.h b/include/linux/mtd/sh_flctl.h
index 3feaae0..01e4b15 100644
--- a/include/linux/mtd/sh_flctl.h
+++ b/include/linux/mtd/sh_flctl.h
@@ -129,9 +129,15 @@
 #define	_4ECCEND	(0x1 << 1)	/* 4 symbols end */
 #define	_4ECCEXST	(0x1 << 0)	/* 4 symbols exist */
 
-#define INIT_FL4ECCRESULT_VAL	0x03FF03FF
 #define LOOP_TIMEOUT_MAX	0x00010000
 
+enum flctl_ecc_res_t {
+	FL_SUCCESS,
+	FL_REPAIRABLE,
+	FL_ERROR,
+	FL_TIMEOUT
+};
+
 struct sh_flctl {
 	struct mtd_info		mtd;
 	struct nand_chip	chip;
@@ -151,8 +157,6 @@
 	uint32_t flcmncr_base;	/* base value of FLCMNCR */
 	uint32_t flintdmacr_base;	/* irq enable bits */
 
-	int	hwecc_cant_correct[4];
-
 	unsigned page_size:1;	/* NAND page size (0 = 512, 1 = 2048) */
 	unsigned hwecc:1;	/* Hardware ECC (0 = disabled, 1 = enabled) */
 	unsigned holden:1;	/* Hardware has FLHOLDCR and HOLDEN is set */