From 7df4486d04204e654b5965267bb6c645b3c13052 Mon Sep 17 00:00:00 2001
From: Josh Wu <josh.wu@atmel.com>
Date: Mon, 10 Nov 2014 15:24:00 +0800
Subject: [PATCH] mtd: atmel_nand: runtime to build gf table for pmecc
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As in SAMA5D4 SoC, the gf table in ROM code can not be seen.
So, when we try to use PMECC, we need to build it when do
initialization.
Add a macro NO_GALOIS_TABLE_IN_ROM in soc header file. If it
is defined we will build gf table runtime.
The PMECC use the BCH algorithm, so based on the build_gf_tables()
function in lib/bch.c, we can build the Galois Field lookup table.
Signed-off-by: Josh Wu <josh.wu@atmel.com>
Signed-off-by: Bo Shen <voice.shen@atmel.com>
Signed-off-by: Andreas BieÃmann <andreas.devel@googlemail.com>
---
drivers/mtd/nand/atmel_nand.c | 75 ++++++++++++++++++++++++++++++-
drivers/mtd/nand/atmel_nand_ecc.h | 4 ++
2 files changed, 78 insertions(+), 1 deletion(-)
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 3b6093a81b..620b6e8ff9 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -763,6 +763,62 @@ static int pmecc_choose_ecc(struct atmel_nand_host *host,
}
#endif
+#if defined(NO_GALOIS_TABLE_IN_ROM)
+static uint16_t *pmecc_galois_table;
+static inline int deg(unsigned int poly)
+{
+ /* polynomial degree is the most-significant bit index */
+ return fls(poly) - 1;
+}
+
+static int build_gf_tables(int mm, unsigned int poly,
+ int16_t *index_of, int16_t *alpha_to)
+{
+ unsigned int i, x = 1;
+ const unsigned int k = 1 << deg(poly);
+ unsigned int nn = (1 << mm) - 1;
+
+ /* primitive polynomial must be of degree m */
+ if (k != (1u << mm))
+ return -EINVAL;
+
+ for (i = 0; i < nn; i++) {
+ alpha_to[i] = x;
+ index_of[x] = i;
+ if (i && (x == 1))
+ /* polynomial is not primitive (a^i=1 with 0<i<2^m-1) */
+ return -EINVAL;
+ x <<= 1;
+ if (x & k)
+ x ^= poly;
+ }
+
+ alpha_to[nn] = 1;
+ index_of[0] = 0;
+
+ return 0;
+}
+
+static uint16_t *create_lookup_table(int sector_size)
+{
+ int degree = (sector_size == 512) ?
+ PMECC_GF_DIMENSION_13 :
+ PMECC_GF_DIMENSION_14;
+ unsigned int poly = (sector_size == 512) ?
+ PMECC_GF_13_PRIMITIVE_POLY :
+ PMECC_GF_14_PRIMITIVE_POLY;
+ int table_size = (sector_size == 512) ?
+ PMECC_INDEX_TABLE_SIZE_512 :
+ PMECC_INDEX_TABLE_SIZE_1024;
+
+ int16_t *addr = kzalloc(2 * table_size * sizeof(uint16_t), GFP_KERNEL);
+ if (addr && build_gf_tables(degree, poly, addr, addr + table_size))
+ return NULL;
+
+ return (uint16_t *)addr;
+}
+#endif
+
static int atmel_pmecc_nand_init_params(struct nand_chip *nand,
struct mtd_info *mtd)
{
@@ -810,11 +866,18 @@ static int atmel_pmecc_nand_init_params(struct nand_chip *nand,
sector_size = host->pmecc_sector_size;
/* TODO: need check whether cap & sector_size is validate */
-
+#if defined(NO_GALOIS_TABLE_IN_ROM)
+ /*
+ * As pmecc_rom_base is the begin of the gallois field table, So the
+ * index offset just set as 0.
+ */
+ host->pmecc_index_table_offset = 0;
+#else
if (host->pmecc_sector_size == 512)
host->pmecc_index_table_offset = ATMEL_PMECC_INDEX_OFFSET_512;
else
host->pmecc_index_table_offset = ATMEL_PMECC_INDEX_OFFSET_1024;
+#endif
MTDDEBUG(MTD_DEBUG_LEVEL1,
"Initialize PMECC params, cap: %d, sector: %d\n",
@@ -823,7 +886,17 @@ static int atmel_pmecc_nand_init_params(struct nand_chip *nand,
host->pmecc = (struct pmecc_regs __iomem *) ATMEL_BASE_PMECC;
host->pmerrloc = (struct pmecc_errloc_regs __iomem *)
ATMEL_BASE_PMERRLOC;
+#if defined(NO_GALOIS_TABLE_IN_ROM)
+ pmecc_galois_table = create_lookup_table(host->pmecc_sector_size);
+ if (!pmecc_galois_table) {
+ dev_err(host->dev, "out of memory\n");
+ return -ENOMEM;
+ }
+
+ host->pmecc_rom_base = (void __iomem *)pmecc_galois_table;
+#else
host->pmecc_rom_base = (void __iomem *) ATMEL_BASE_ROM;
+#endif
/* ECC is calculated for the whole page (1 step) */
nand->ecc.size = mtd->writesize;
diff --git a/drivers/mtd/nand/atmel_nand_ecc.h b/drivers/mtd/nand/atmel_nand_ecc.h
index 92d4ec59fd..eac860d13c 100644
--- a/drivers/mtd/nand/atmel_nand_ecc.h
+++ b/drivers/mtd/nand/atmel_nand_ecc.h
@@ -141,6 +141,10 @@ struct pmecc_errloc_regs {
#define PMECC_GF_DIMENSION_13 13
#define PMECC_GF_DIMENSION_14 14
+/* Primitive Polynomial used by PMECC */
+#define PMECC_GF_13_PRIMITIVE_POLY 0x201b
+#define PMECC_GF_14_PRIMITIVE_POLY 0x4443
+
#define PMECC_INDEX_TABLE_SIZE_512 0x2000
#define PMECC_INDEX_TABLE_SIZE_1024 0x4000
--
2.39.5