[U-Boot] [PATCH v8 3/5] mtd: nand: omap: optimize chip->ecc.calculate() for H/W ECC schemes
Pekon Gupta
pekon at ti.com
Thu Oct 10 13:00:12 CEST 2013
chip->ecc.calculate() is used for calculating and fetching of ECC syndrome by
processing the data passed during Read/Write accesses.
All H/W based ECC schemes use GPMC controller to calculate ECC syndrome.
But each BCHx_ECC scheme has its own implemetation of post-processing and
fetching ECC syndrome from GPMC controller.
This patch updates OMAP_ECC_BCH8_CODE_HW ECC scheme in following way:
- merges multiple chip->calculate API for different ECC schemes
omap_calculate_ecc() + omap_calculate_ecc_bch() + omap_calculate_ecc_bch_sw()
==> omap_calculate_ecc()
- removes omap_ecc_disable() and instead uses it as inline.
Signed-off-by: Pekon Gupta <pekon at ti.com>
---
drivers/mtd/nand/omap_gpmc.c | 223 ++++++++++++-------------------------------
1 file changed, 62 insertions(+), 161 deletions(-)
diff --git a/drivers/mtd/nand/omap_gpmc.c b/drivers/mtd/nand/omap_gpmc.c
index e7687c7..af2f149 100644
--- a/drivers/mtd/nand/omap_gpmc.c
+++ b/drivers/mtd/nand/omap_gpmc.c
@@ -21,7 +21,10 @@
#define SECTOR_BYTES 512
#define ECCCLEAR (0x1 << 8)
#define ECCRESULTREG1 (0x1 << 0)
-
+#ifdef CONFIG_BCH
+static u8 bch8_polynomial[] = {0xef, 0x51, 0x2e, 0x09, 0xed, 0x93, 0x9a, 0xc2,
+ 0x97, 0x79, 0xe5, 0x24, 0xb5};
+#endif
static uint8_t cs;
static __maybe_unused struct nand_ecclayout omap_ecclayout;
@@ -143,42 +146,6 @@ static int __maybe_unused omap_correct_data(struct mtd_info *mtd, uint8_t *dat,
}
/*
- * omap_calculate_ecc - Generate non-inverted ECC bytes.
- *
- * Using noninverted ECC can be considered ugly since writing a blank
- * page ie. padding will clear the ECC bytes. This is no problem as
- * long nobody is trying to write data on the seemingly unused page.
- * Reading an erased page will produce an ECC mismatch between
- * generated and read ECC bytes that has to be dealt with separately.
- * E.g. if page is 0xFF (fresh erased), and if HW ECC engine within GPMC
- * is used, the result of read will be 0x0 while the ECC offsets of the
- * spare area will be 0xFF which will result in an ECC mismatch.
- * @mtd: MTD structure
- * @dat: unused
- * @ecc_code: ecc_code buffer
- */
-static int __maybe_unused omap_calculate_ecc(struct mtd_info *mtd,
- const uint8_t *dat, uint8_t *ecc_code)
-{
- u_int32_t val;
-
- /* Start Reading from HW ECC1_Result = 0x200 */
- val = readl(&gpmc_cfg->ecc1_result);
-
- ecc_code[0] = val & 0xFF;
- ecc_code[1] = (val >> 16) & 0xFF;
- ecc_code[2] = ((val >> 8) & 0x0F) | ((val >> 20) & 0xF0);
-
- /*
- * Stop reading anymore ECC vals and clear old results
- * enable will be called if more reads are required
- */
- writel(0x000, &gpmc_cfg->ecc_config);
-
- return 0;
-}
-
-/*
* Generic BCH interface
*/
struct nand_bch_priv {
@@ -194,12 +161,7 @@ struct nand_bch_priv {
#define ECC_BCH8 1
#define ECC_BCH16 2
-/* GPMC ecc engine settings */
-#define BCH_WRAPMODE_1 1 /* BCH wrap mode 1 */
-#define BCH_WRAPMODE_6 6 /* BCH wrap mode 6 */
-
/* BCH nibbles for diff bch levels */
-#define NAND_ECC_HW_BCH ((uint8_t)(NAND_ECC_HW_OOB_FIRST) + 1)
#define ECC_BCH4_NIBBLES 13
#define ECC_BCH8_NIBBLES 26
#define ECC_BCH16_NIBBLES 52
@@ -211,7 +173,6 @@ struct nand_bch_priv {
* When some users with other BCH strength will exists this have to change!
*/
static __maybe_unused struct nand_bch_priv bch_priv = {
- .mode = NAND_ECC_HW_BCH,
.type = ECC_BCH8,
.nibbles = ECC_BCH8_NIBBLES,
.control = NULL
@@ -280,54 +241,74 @@ static void omap_enable_hwecc(struct mtd_info *mtd, int32_t mode)
}
/*
- * omap_ecc_disable - Disable H/W ECC calculation
- *
- * @mtd: MTD device structure
- */
-static void __maybe_unused omap_ecc_disable(struct mtd_info *mtd)
-{
- writel((readl(&gpmc_cfg->ecc_config) & ~0x1), &gpmc_cfg->ecc_config);
-}
-
-/*
- * BCH support using ELM module
- */
-/*
- * omap_read_bch8_result - Read BCH result for BCH8 level
+ * omap_calculate_ecc - Read ECC result
+ * @mtd: MTD structure
+ * @dat: unused
+ * @ecc_code: ecc_code buffer
*
- * @mtd: MTD device structure
- * @big_endian: When set read register 3 first
- * @ecc_code: Read syndrome from BCH result registers
+ * Using noninverted ECC can be considered ugly since writing a blank
+ * page ie. padding will clear the ECC bytes. This is no problem as
+ * long nobody is trying to write data on the seemingly unused page.
+ * Reading an erased page will produce an ECC mismatch between
+ * generated and read ECC bytes that has to be dealt with separately.
+ * E.g. if page is 0xFF (fresh erased), and if HW ECC engine within GPMC
+ * is used, the result of read will be 0x0 while the ECC offsets of the
+ * spare area will be 0xFF which will result in an ECC mismatch.
*/
-static void omap_read_bch8_result(struct mtd_info *mtd, uint8_t big_endian,
+static int omap_calculate_ecc(struct mtd_info *mtd, const uint8_t *dat,
uint8_t *ecc_code)
{
- uint32_t *ptr;
+ struct nand_chip *chip = mtd->priv;
+ struct nand_bch_priv *bch = chip->priv;
+ uint32_t *ptr, val = 0;
int8_t i = 0, j;
- if (big_endian) {
+ switch (bch->ecc_scheme) {
+ case OMAP_ECC_HAM1_CODE_HW:
+ val = readl(&gpmc_cfg->ecc1_result);
+ ecc_code[0] = val & 0xFF;
+ ecc_code[1] = (val >> 16) & 0xFF;
+ ecc_code[2] = ((val >> 8) & 0x0F) | ((val >> 20) & 0xF0);
+ break;
+#ifdef CONFIG_BCH
+ case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+#endif
+ case OMAP_ECC_BCH8_CODE_HW:
ptr = &gpmc_cfg->bch_result_0_3[0].bch_result_x[3];
- ecc_code[i++] = readl(ptr) & 0xFF;
+ val = readl(ptr);
+ ecc_code[i++] = (val >> 0) & 0xFF;
ptr--;
for (j = 0; j < 3; j++) {
- ecc_code[i++] = (readl(ptr) >> 24) & 0xFF;
- ecc_code[i++] = (readl(ptr) >> 16) & 0xFF;
- ecc_code[i++] = (readl(ptr) >> 8) & 0xFF;
- ecc_code[i++] = readl(ptr) & 0xFF;
+ val = readl(ptr);
+ ecc_code[i++] = (val >> 24) & 0xFF;
+ ecc_code[i++] = (val >> 16) & 0xFF;
+ ecc_code[i++] = (val >> 8) & 0xFF;
+ ecc_code[i++] = (val >> 0) & 0xFF;
ptr--;
}
- } else {
- ptr = &gpmc_cfg->bch_result_0_3[0].bch_result_x[0];
- for (j = 0; j < 3; j++) {
- ecc_code[i++] = readl(ptr) & 0xFF;
- ecc_code[i++] = (readl(ptr) >> 8) & 0xFF;
- ecc_code[i++] = (readl(ptr) >> 16) & 0xFF;
- ecc_code[i++] = (readl(ptr) >> 24) & 0xFF;
- ptr++;
- }
- ecc_code[i++] = readl(ptr) & 0xFF;
- ecc_code[i++] = 0; /* 14th byte is always zero */
+ break;
+ default:
+ return -EINVAL;
}
+ /* ECC scheme specific syndrome customizations */
+ switch (bch->ecc_scheme) {
+ case OMAP_ECC_HAM1_CODE_HW:
+ break;
+#ifdef CONFIG_BCH
+ case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
+
+ for (i = 0; i < chip->ecc.bytes; i++)
+ *(ecc_code + i) = *(ecc_code + i) ^
+ bch8_polynomial[i];
+ break;
+#endif
+ case OMAP_ECC_BCH8_CODE_HW:
+ ecc_code[chip->ecc.bytes - 1] = 0x00;
+ break;
+ default:
+ return -EINVAL;
+ }
+ return 0;
}
/*
@@ -366,35 +347,6 @@ static void omap_rotate_ecc_bch(struct mtd_info *mtd, uint8_t *calc_ecc,
}
/*
- * omap_calculate_ecc_bch - Read BCH ECC result
- *
- * @mtd: MTD structure
- * @dat: unused
- * @ecc_code: ecc_code buffer
- */
-static int omap_calculate_ecc_bch(struct mtd_info *mtd, const uint8_t *dat,
- uint8_t *ecc_code)
-{
- struct nand_chip *chip = mtd->priv;
- struct nand_bch_priv *bch = chip->priv;
- uint8_t big_endian = 1;
- int8_t ret = 0;
-
- if (bch->type == ECC_BCH8)
- omap_read_bch8_result(mtd, big_endian, ecc_code);
- else /* BCH4 and BCH16 currently not supported */
- ret = -1;
-
- /*
- * Stop reading anymore ECC vals and clear old results
- * enable will be called if more reads are required
- */
- omap_ecc_disable(mtd);
-
- return ret;
-}
-
-/*
* omap_fix_errors_bch - Correct bch error in the data
*
* @mtd: MTD device structure
@@ -549,57 +501,6 @@ static int omap_read_page_bch(struct mtd_info *mtd, struct nand_chip *chip,
* OMAP3 BCH8 support (with BCH library)
*/
#ifdef CONFIG_BCH
-/*
- * omap_calculate_ecc_bch_sw - Read BCH ECC result
- *
- * @mtd: MTD device structure
- * @dat: The pointer to data on which ecc is computed (unused here)
- * @ecc: The ECC output buffer
- */
-static int omap_calculate_ecc_bch_sw(struct mtd_info *mtd, const uint8_t *dat,
- uint8_t *ecc)
-{
- int ret = 0;
- size_t i;
- unsigned long nsectors, val1, val2, val3, val4;
-
- nsectors = ((readl(&gpmc_cfg->ecc_config) >> 4) & 0x7) + 1;
-
- for (i = 0; i < nsectors; i++) {
- /* Read hw-computed remainder */
- val1 = readl(&gpmc_cfg->bch_result_0_3[i].bch_result_x[0]);
- val2 = readl(&gpmc_cfg->bch_result_0_3[i].bch_result_x[1]);
- val3 = readl(&gpmc_cfg->bch_result_0_3[i].bch_result_x[2]);
- val4 = readl(&gpmc_cfg->bch_result_0_3[i].bch_result_x[3]);
-
- /*
- * Add constant polynomial to remainder, in order to get an ecc
- * sequence of 0xFFs for a buffer filled with 0xFFs.
- */
- *ecc++ = 0xef ^ (val4 & 0xFF);
- *ecc++ = 0x51 ^ ((val3 >> 24) & 0xFF);
- *ecc++ = 0x2e ^ ((val3 >> 16) & 0xFF);
- *ecc++ = 0x09 ^ ((val3 >> 8) & 0xFF);
- *ecc++ = 0xed ^ (val3 & 0xFF);
- *ecc++ = 0x93 ^ ((val2 >> 24) & 0xFF);
- *ecc++ = 0x9a ^ ((val2 >> 16) & 0xFF);
- *ecc++ = 0xc2 ^ ((val2 >> 8) & 0xFF);
- *ecc++ = 0x97 ^ (val2 & 0xFF);
- *ecc++ = 0x79 ^ ((val1 >> 24) & 0xFF);
- *ecc++ = 0xe5 ^ ((val1 >> 16) & 0xFF);
- *ecc++ = 0x24 ^ ((val1 >> 8) & 0xFF);
- *ecc++ = 0xb5 ^ (val1 & 0xFF);
- }
-
- /*
- * Stop reading anymore ECC vals and clear old results
- * enable will be called if more reads are required
- */
- omap_ecc_disable(mtd);
-
- return ret;
-}
-
/**
* omap_correct_data_bch_sw - Decode received data and correct errors
* @mtd: MTD device structure
@@ -748,7 +649,7 @@ static int omap_select_ecc_scheme(struct nand_chip *nand,
nand->ecc.bytes = 13;
nand->ecc.hwctl = omap_enable_hwecc;
nand->ecc.correct = omap_correct_data_bch_sw;
- nand->ecc.calculate = omap_calculate_ecc_bch_sw;
+ nand->ecc.calculate = omap_calculate_ecc;
/* define ecc-layout */
ecclayout->eccbytes = nand->ecc.bytes * eccsteps;
for (i = 0; i < ecclayout->eccbytes; i++)
@@ -778,7 +679,7 @@ static int omap_select_ecc_scheme(struct nand_chip *nand,
nand->ecc.bytes = 14;
nand->ecc.hwctl = omap_enable_hwecc;
nand->ecc.correct = omap_correct_data_bch;
- nand->ecc.calculate = omap_calculate_ecc_bch;
+ nand->ecc.calculate = omap_calculate_ecc;
nand->ecc.read_page = omap_read_page_bch;
/* define ecc-layout */
ecclayout->eccbytes = nand->ecc.bytes * eccsteps;
--
1.8.1
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