[U-Boot] [PATCH v2 2/7] mtd: nand: omap_elm: use bch_type instead of nibble count to differentiate between BCH4/BCH8/BCH16

Pekon Gupta
2014-04-11T07:25:30Z

ELM hardware engine support ECC error detection for multiple ECC strengths like
+------+------------------------+
|Type | ECC syndrome length |
+------+------------------------+
|BCH4 | 6.5 bytes = 13 nibbles |
|BCH8 | 13 byte = 26 nibbles |
|BCH16 | 26 bytes = 52 nibbles |
+------+------------------------+

Current implementation of omap_elm driver uses ECC syndrom length (in 'nibbles')
to differentiate between BCH4/BCH8/BCH16. This patch replaces it with 'bch_type'

Signed-off-by: Pekon Gupta <pekon@ti.com>
Reviewed-by: Stefan Roese <sr@denx.de>
---
drivers/mtd/nand/omap_elm.c | 20 ++++++++------------
drivers/mtd/nand/omap_gpmc.c | 10 ++--------
include/linux/mtd/omap_elm.h | 2 +-
3 files changed, 11 insertions(+), 21 deletions(-)

diff --git a/drivers/mtd/nand/omap_elm.c b/drivers/mtd/nand/omap_elm.c
index 4c65f3b..afa629a 100644
--- a/drivers/mtd/nand/omap_elm.c
+++ b/drivers/mtd/nand/omap_elm.c
@@ -24,14 +24,12 @@
struct elm *elm_cfg;

/**
- * elm_load_syndromes - Load BCH syndromes based on nibble selection
+ * elm_load_syndromes - Load BCH syndromes based on bch_type selection
* @syndrome: BCH syndrome
- * @nibbles:
+ * @bch_type: BCH4/BCH8/BCH16
* @poly: Syndrome Polynomial set to use
- *
- * Load BCH syndromes based on nibble selection
*/
-static void elm_load_syndromes(u8 *syndrome, u32 nibbles, u8 poly)
+static void elm_load_syndromes(u8 *syndrome, enum bch_level bch_type, u8 poly)
{
u32 *ptr;
u32 val;
@@ -47,8 +45,7 @@ static void elm_load_syndromes(u8 *syndrome, u32 nibbles, u8 poly)
(syndrome[7] << 24);
writel(val, ptr);

- /* BCH 8-bit with 26 nibbles (4*8=32) */
- if (nibbles > 13) {
+ if (bch_type == BCH_8_BIT || bch_type == BCH_16_BIT) {
/* reg 2 */
ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[2];
val = syndrome[8] | (syndrome[9] << 8) | (syndrome[10] << 16) |
@@ -61,8 +58,7 @@ static void elm_load_syndromes(u8 *syndrome, u32 nibbles, u8 poly)
writel(val, ptr);
}

- /* BCH 16-bit with 52 nibbles (7*8=56) */
- if (nibbles > 26) {
+ if (bch_type == BCH_16_BIT) {
/* reg 4 */
ptr = &elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[4];
val = syndrome[16] | (syndrome[17] << 8) |
@@ -86,7 +82,7 @@ static void elm_load_syndromes(u8 *syndrome, u32 nibbles, u8 poly)
/**
* elm_check_errors - Check for BCH errors and return error locations
* @syndrome: BCH syndrome
- * @nibbles:
+ * @bch_type: BCH4/BCH8/BCH16
* @error_count: Returns number of errrors in the syndrome
* @error_locations: Returns error locations (in decimal) in this array
*
@@ -94,14 +90,14 @@ static void elm_load_syndromes(u8 *syndrome, u32 nibbles, u8 poly)
* and locations in the array passed. Returns -1 if error is not correctable,
* else returns 0
*/
-int elm_check_error(u8 *syndrome, u32 nibbles, u32 *error_count,
+int elm_check_error(u8 *syndrome, enum bch_level bch_type, u32 *error_count,
u32 *error_locations)
{
u8 poly = ELM_DEFAULT_POLY;
s8 i;
u32 location_status;

- elm_load_syndromes(syndrome, nibbles, poly);
+ elm_load_syndromes(syndrome, bch_type, poly);

/* start processing */
writel((readl(&elm_cfg->syndrome_fragments[poly].syndrome_fragment_x[6])
diff --git a/drivers/mtd/nand/omap_gpmc.c b/drivers/mtd/nand/omap_gpmc.c
index 881a636..af38f00 100644
--- a/drivers/mtd/nand/omap_gpmc.c
+++ b/drivers/mtd/nand/omap_gpmc.c
@@ -153,7 +153,6 @@ static int __maybe_unused omap_correct_data(struct mtd_info *mtd, uint8_t *dat,
struct nand_bch_priv {
uint8_t mode;
uint8_t type;
- uint8_t nibbles;
struct bch_control *control;
enum omap_ecc ecc_scheme;
};
@@ -163,11 +162,6 @@ struct nand_bch_priv {
#define ECC_BCH8 1
#define ECC_BCH16 2

-/* BCH nibbles for diff bch levels */
-#define ECC_BCH4_NIBBLES 13
-#define ECC_BCH8_NIBBLES 26
-#define ECC_BCH16_NIBBLES 52
-
/*
* This can be a single instance cause all current users have only one NAND
* with nearly the same setup (BCH8, some with ELM and others with sw BCH
@@ -176,7 +170,6 @@ struct nand_bch_priv {
*/
static __maybe_unused struct nand_bch_priv bch_priv = {
.type = ECC_BCH8,
- .nibbles = ECC_BCH8_NIBBLES,
.control = NULL
};

@@ -383,7 +376,8 @@ static int omap_correct_data_bch(struct mtd_info *mtd, uint8_t *dat,
}
/* use elm module to check for errors */
elm_config((enum bch_level)(bch->type));
- if (elm_check_error(calc_ecc, bch->nibbles, &error_count, error_loc)) {
+ if (elm_check_error(calc_ecc, (enum bch_level)bch->type,
+ &error_count, error_loc)) {
printf("nand: error: uncorrectable ECC errors\n");
return -EINVAL;
}
diff --git a/include/linux/mtd/omap_elm.h b/include/linux/mtd/omap_elm.h
index 45454ea..a6e9591 100644
--- a/include/linux/mtd/omap_elm.h
+++ b/include/linux/mtd/omap_elm.h
@@ -68,7 +68,7 @@ struct elm {
struct location error_location[8]; /* 0x800 */
};

-int elm_check_error(u8 *syndrome, u32 nibbles, u32 *error_count,
+int elm_check_error(u8 *syndrome, enum bch_level bch_type, u32 *error_count,
u32 *error_locations);
int elm_config(enum bch_level level);
void elm_reset(void);
--
1.8.5.1.163.gd7aced9