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authorpekon gupta <pekon@ti.com>2013-11-19 11:02:15 +0530
committerScott Wood <scottwood@freescale.com>2014-03-03 20:09:03 -0600
commitf5f1f614bda83fae868d5634f86e0098162ceb3b (patch)
tree2ff7fa042001df8660f8245c2fb3efc108694613 /drivers
parenteeb72e67619b98d2502fe634a3a5d9953de92ad0 (diff)
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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>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/mtd/nand/omap_gpmc.c198
1 files changed, 56 insertions, 142 deletions
diff --git a/drivers/mtd/nand/omap_gpmc.c b/drivers/mtd/nand/omap_gpmc.c
index 389c4de..48b2f75 100644
--- a/drivers/mtd/nand/omap_gpmc.c
+++ b/drivers/mtd/nand/omap_gpmc.c
@@ -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
@@ -192,38 +179,6 @@ static int __maybe_unused omap_calculate_ecc(struct mtd_info *mtd,
}
/*
- * 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
*/
struct nand_bch_priv {
@@ -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;
-
- /* 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;
- }
-
- /*
- * 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;
+ 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;
+
+ /* 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 */
}
- } 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);
-
- /*
- * 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);
+ /* 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 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;