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mtd: nand: omap: optimize chip->ecc.hwctl() for H/W ECC schemes 

chip->ecc.hwctl() is used for preparing the H/W controller before read/write
NAND accesses (like assigning data-buf, enabling ECC scheme configs, etc.)

Though all ECC schemes in OMAP NAND driver use GPMC controller for generating
ECC syndrome (for both Read/Write accesses). But but in current code
HAM1_ECC and BCHx_ECC schemes implement individual function to achieve this.
This patch
(1) removes omap_hwecc_init() and omap_hwecc_init_bch()
as chip->ecc.hwctl will re-initializeGPMC before every read/write call.
omap_hwecc_init_bch() -> omap_enable_ecc_bch()

(2) merges the GPMC configuration code for all ECC schemes into
single omap_enable_hwecc(), thus adding scalability for future ECC schemes.
omap_enable_hwecc() + omap_enable_ecc_bch() -> omap_enable_hwecc()

Signed-off-by: Pekon Gupta <pekon@ti.com>
This commit is contained in:
pekon gupta 2013-11-19 11:02:15 +05:30 committed by Scott Wood
parent eeb72e6761
commit f5f1f614bd
2 changed files with 54 additions and 147 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
arch/arm/include/asm/omap_gpmc.h
View File

@ -14,13 +14,6 @@
#define GPMC_BUF_EMPTY 0
#define GPMC_BUF_FULL 1
#define ECCCLEAR (0x1 << 8)
#define ECCRESULTREG1 (0x1 << 0)
#define ECCSIZE512BYTE 0xFF
#define ECCSIZE1 (ECCSIZE512BYTE << 22)
#define ECCSIZE0 (ECCSIZE512BYTE << 12)
#define ECCSIZE0SEL (0x000 << 0)
/* Generic ECC Layouts */
/* Large Page x8 NAND device Layout */
#ifdef GPMC_NAND_ECC_LP_x8_LAYOUT

194
drivers/mtd/nand/omap_gpmc.c
View File

@ -19,6 +19,8 @@
#define BADBLOCK_MARKER_LENGTH 2
#define SECTOR_BYTES 512
#define ECCCLEAR (0x1 << 8)
#define ECCRESULTREG1 (0x1 << 0)
static uint8_t cs;
static __maybe_unused struct nand_ecclayout omap_ecclayout;
@ -60,21 +62,6 @@ int omap_spl_dev_ready(struct mtd_info *mtd)
}
#endif
/*
* omap_hwecc_init - Initialize the Hardware ECC for NAND flash in
* GPMC controller
* @mtd: MTD device structure
*
*/
static void __maybe_unused omap_hwecc_init(struct nand_chip *chip)
{
/*
* Init ECC Control Register
* Clear all ECC | Enable Reg1
*/
writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
writel(ECCSIZE1 | ECCSIZE0 | ECCSIZE0SEL, &gpmc_cfg->ecc_size_config);
}
/*
* gen_true_ecc - This function will generate true ECC value, which
@ -191,38 +178,6 @@ static int __maybe_unused omap_calculate_ecc(struct mtd_info *mtd,
return 0;
}
/*
* omap_enable_ecc - This function enables the hardware ecc functionality
* @mtd: MTD device structure
* @mode: Read/Write mode
*/
static void __maybe_unused omap_enable_hwecc(struct mtd_info *mtd, int32_t mode)
{
struct nand_chip *chip = mtd->priv;
uint32_t val, dev_width = (chip->options & NAND_BUSWIDTH_16) >> 1;
switch (mode) {
case NAND_ECC_READ:
case NAND_ECC_WRITE:
/* Clear the ecc result registers, select ecc reg as 1 */
writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
/*
* Size 0 = 0xFF, Size1 is 0xFF - both are 512 bytes
* tell all regs to generate size0 sized regs
* we just have a single ECC engine for all CS
*/
writel(ECCSIZE1 | ECCSIZE0 | ECCSIZE0SEL,
&gpmc_cfg->ecc_size_config);
val = (dev_width << 7) | (cs << 1) | (0x1);
writel(val, &gpmc_cfg->ecc_config);
break;
default:
printf("Error: Unrecognized Mode[%d]!\n", mode);
break;
}
}
/*
* Generic BCH interface
*/
@ -263,105 +218,65 @@ static __maybe_unused struct nand_bch_priv bch_priv = {
};
/*
* omap_hwecc_init_bch - Initialize the BCH Hardware ECC for NAND flash in
* GPMC controller
* omap_enable_hwecc - configures GPMC as per ECC scheme before read/write
* @mtd: MTD device structure
* @mode: Read/Write mode
*/
__maybe_unused
static void omap_hwecc_init_bch(struct nand_chip *chip, int32_t mode)
static void omap_enable_hwecc(struct mtd_info *mtd, int32_t mode)
{
uint32_t val;
uint32_t dev_width = (chip->options & NAND_BUSWIDTH_16) >> 1;
uint32_t unused_length = 0;
uint32_t wr_mode = BCH_WRAPMODE_6;
struct nand_bch_priv *bch = chip->priv;
struct nand_chip *nand = mtd->priv;
struct nand_bch_priv *bch = nand->priv;
unsigned int dev_width = (nand->options & NAND_BUSWIDTH_16) ? 1 : 0;
unsigned int ecc_algo = 0;
unsigned int bch_type = 0;
unsigned int eccsize1 = 0x00, eccsize0 = 0x00, bch_wrapmode = 0x00;
u32 ecc_size_config_val = 0;
u32 ecc_config_val = 0;
/* Clear the ecc result registers, select ecc reg as 1 */
writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
if (bch->ecc_scheme == OMAP_ECC_BCH8_CODE_HW) {
wr_mode = BCH_WRAPMODE_1;
switch (bch->nibbles) {
case ECC_BCH4_NIBBLES:
unused_length = 3;
break;
case ECC_BCH8_NIBBLES:
unused_length = 2;
break;
case ECC_BCH16_NIBBLES:
unused_length = 0;
break;
/* configure GPMC for specific ecc-scheme */
switch (bch->ecc_scheme) {
case OMAP_ECC_HAM1_CODE_SW:
return;
case OMAP_ECC_HAM1_CODE_HW:
ecc_algo = 0x0;
bch_type = 0x0;
bch_wrapmode = 0x00;
eccsize0 = 0xFF;
eccsize1 = 0xFF;
break;
case OMAP_ECC_BCH8_CODE_HW_DETECTION_SW:
case OMAP_ECC_BCH8_CODE_HW:
ecc_algo = 0x1;
bch_type = 0x1;
if (mode == NAND_ECC_WRITE) {
bch_wrapmode = 0x01;
eccsize0 = 0; /* extra bits in nibbles per sector */
eccsize1 = 28; /* OOB bits in nibbles per sector */
} else {
bch_wrapmode = 0x01;
eccsize0 = 26; /* ECC bits in nibbles per sector */
eccsize1 = 2; /* non-ECC bits in nibbles per sector */
}
/*
* This is ecc_size_config for ELM mode. Here we are using
* different settings for read and write access and also
* depending on BCH strength.
*/
switch (mode) {
case NAND_ECC_WRITE:
/* write access only setup eccsize1 config */
val = ((unused_length + bch->nibbles) << 22);
break;
case NAND_ECC_READ:
default:
/*
* by default eccsize0 selected for ecc1resultsize
* eccsize0 config.
*/
val = (bch->nibbles << 12);
/* eccsize1 config */
val |= (unused_length << 22);
break;
}
} else {
/*
* This ecc_size_config setting is for BCH sw library.
*
* Note: we only support BCH8 currently with BCH sw library!
* Should be really easy to adobt to BCH4, however some omap3
* have flaws with BCH4.
*
* Here we are using wrapping mode 6 both for reading and
* writing, with:
* size0 = 0 (no additional protected byte in spare area)
* size1 = 32 (skip 32 nibbles = 16 bytes per sector in
* spare area)
*/
val = (32 << 22) | (0 << 12);
break;
default:
return;
}
/* ecc size configuration */
writel(val, &gpmc_cfg->ecc_size_config);
/* Clear ecc and enable bits */
writel(ECCCLEAR | ECCRESULTREG1, &gpmc_cfg->ecc_control);
/* Configure ecc size for BCH */
ecc_size_config_val = (eccsize1 << 22) | (eccsize0 << 12);
writel(ecc_size_config_val, &gpmc_cfg->ecc_size_config);
/*
* Configure the ecc engine in gpmc
* We assume 512 Byte sector pages for access to NAND.
*/
val = (1 << 16); /* enable BCH mode */
val |= (bch->type << 12); /* setup BCH type */
val |= (wr_mode << 8); /* setup wrapping mode */
val |= (dev_width << 7); /* setup device width (16 or 8 bit) */
val |= (cs << 1); /* setup chip select to work on */
debug("set ECC_CONFIG=0x%08x\n", val);
writel(val, &gpmc_cfg->ecc_config);
}
/*
* omap_enable_ecc_bch - This function enables the bch h/w ecc functionality
* @mtd: MTD device structure
* @mode: Read/Write mode
*/
__maybe_unused
static void omap_enable_ecc_bch(struct mtd_info *mtd, int32_t mode)
{
struct nand_chip *chip = mtd->priv;
omap_hwecc_init_bch(chip, mode);
/* enable ecc */
writel((readl(&gpmc_cfg->ecc_config) | 0x1), &gpmc_cfg->ecc_config);
/* Configure device details for BCH engine */
ecc_config_val = ((ecc_algo << 16) | /* HAM1 | BCHx */
(bch_type << 12) | /* BCH4/BCH8/BCH16 */
(bch_wrapmode << 8) | /* wrap mode */
(dev_width << 7) | /* bus width */
(0x0 << 4) | /* number of sectors */
(cs << 1) | /* ECC CS */
(0x1)); /* enable ECC */
writel(ecc_config_val, &gpmc_cfg->ecc_config);
}
/*
@ -835,7 +750,7 @@ static int omap_select_ecc_scheme(struct nand_chip *nand,
nand->ecc.strength = 8;
nand->ecc.size = SECTOR_BYTES;
nand->ecc.bytes = 13;
nand->ecc.hwctl = omap_enable_ecc_bch;
nand->ecc.hwctl = omap_enable_hwecc;
nand->ecc.correct = omap_correct_data_bch_sw;
nand->ecc.calculate = omap_calculate_ecc_bch_sw;
/* define ecc-layout */
@ -852,7 +767,6 @@ static int omap_select_ecc_scheme(struct nand_chip *nand,
ecclayout->oobfree[0].offset = i + BADBLOCK_MARKER_LENGTH;
ecclayout->oobfree[0].length = oobsize - ecclayout->eccbytes -
BADBLOCK_MARKER_LENGTH;
omap_hwecc_init_bch(nand, NAND_ECC_READ);
bch->ecc_scheme = OMAP_ECC_BCH8_CODE_HW_DETECTION_SW;
break;
#else
@ -878,7 +792,7 @@ static int omap_select_ecc_scheme(struct nand_chip *nand,
nand->ecc.strength = 8;
nand->ecc.size = SECTOR_BYTES;
nand->ecc.bytes = 14;
nand->ecc.hwctl = omap_enable_ecc_bch;
nand->ecc.hwctl = omap_enable_hwecc;
nand->ecc.correct = omap_correct_data_bch;
nand->ecc.calculate = omap_calculate_ecc_bch;
nand->ecc.read_page = omap_read_page_bch;