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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 Bießmann <andreas.devel@googlemail.com>
This commit is contained in:
Josh Wu 2014-11-10 15:24:00 +08:00 committed by Tom Rini
parent 5b15fd980b
commit 7df4486d04
2 changed files with 78 additions and 1 deletions
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75
drivers/mtd/nand/atmel_nand.c
View File

@ -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;

4
drivers/mtd/nand/atmel_nand_ecc.h
View File

@ -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