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path: root/drivers/mtd/nand/atmel_nand.c
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Diffstat (limited to 'drivers/mtd/nand/atmel_nand.c')
-rw-r--r--drivers/mtd/nand/atmel_nand.c265
1 files changed, 265 insertions, 0 deletions
diff --git a/drivers/mtd/nand/atmel_nand.c b/drivers/mtd/nand/atmel_nand.c
index 40002be41..d5eb54ad8 100644
--- a/drivers/mtd/nand/atmel_nand.c
+++ b/drivers/mtd/nand/atmel_nand.c
@@ -31,6 +31,209 @@
#include <nand.h>
+#ifdef CONFIG_ATMEL_NAND_HWECC
+
+/* Register access macros */
+#define ecc_readl(add, reg) \
+ readl(AT91_BASE_SYS + add + ATMEL_ECC_##reg)
+#define ecc_writel(add, reg, value) \
+ writel((value), AT91_BASE_SYS + add + ATMEL_ECC_##reg)
+
+#include "atmel_nand_ecc.h" /* Hardware ECC registers */
+
+/* oob layout for large page size
+ * bad block info is on bytes 0 and 1
+ * the bytes have to be consecutives to avoid
+ * several NAND_CMD_RNDOUT during read
+ */
+static struct nand_ecclayout atmel_oobinfo_large = {
+ .eccbytes = 4,
+ .eccpos = {60, 61, 62, 63},
+ .oobfree = {
+ {2, 58}
+ },
+};
+
+/* oob layout for small page size
+ * bad block info is on bytes 4 and 5
+ * the bytes have to be consecutives to avoid
+ * several NAND_CMD_RNDOUT during read
+ */
+static struct nand_ecclayout atmel_oobinfo_small = {
+ .eccbytes = 4,
+ .eccpos = {0, 1, 2, 3},
+ .oobfree = {
+ {6, 10}
+ },
+};
+
+/*
+ * Calculate HW ECC
+ *
+ * function called after a write
+ *
+ * mtd: MTD block structure
+ * dat: raw data (unused)
+ * ecc_code: buffer for ECC
+ */
+static int atmel_nand_calculate(struct mtd_info *mtd,
+ const u_char *dat, unsigned char *ecc_code)
+{
+ struct nand_chip *nand_chip = mtd->priv;
+ unsigned int ecc_value;
+
+ /* get the first 2 ECC bytes */
+ ecc_value = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, PR);
+
+ ecc_code[0] = ecc_value & 0xFF;
+ ecc_code[1] = (ecc_value >> 8) & 0xFF;
+
+ /* get the last 2 ECC bytes */
+ ecc_value = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, NPR) & ATMEL_ECC_NPARITY;
+
+ ecc_code[2] = ecc_value & 0xFF;
+ ecc_code[3] = (ecc_value >> 8) & 0xFF;
+
+ return 0;
+}
+
+/*
+ * HW ECC read page function
+ *
+ * mtd: mtd info structure
+ * chip: nand chip info structure
+ * buf: buffer to store read data
+ */
+static int atmel_nand_read_page(struct mtd_info *mtd,
+ struct nand_chip *chip, uint8_t *buf, int page)
+{
+ int eccsize = chip->ecc.size;
+ int eccbytes = chip->ecc.bytes;
+ uint32_t *eccpos = chip->ecc.layout->eccpos;
+ uint8_t *p = buf;
+ uint8_t *oob = chip->oob_poi;
+ uint8_t *ecc_pos;
+ int stat;
+
+ /* read the page */
+ chip->read_buf(mtd, p, eccsize);
+
+ /* move to ECC position if needed */
+ if (eccpos[0] != 0) {
+ /* This only works on large pages
+ * because the ECC controller waits for
+ * NAND_CMD_RNDOUTSTART after the
+ * NAND_CMD_RNDOUT.
+ * anyway, for small pages, the eccpos[0] == 0
+ */
+ chip->cmdfunc(mtd, NAND_CMD_RNDOUT,
+ mtd->writesize + eccpos[0], -1);
+ }
+
+ /* the ECC controller needs to read the ECC just after the data */
+ ecc_pos = oob + eccpos[0];
+ chip->read_buf(mtd, ecc_pos, eccbytes);
+
+ /* check if there's an error */
+ stat = chip->ecc.correct(mtd, p, oob, NULL);
+
+ if (stat < 0)
+ mtd->ecc_stats.failed++;
+ else
+ mtd->ecc_stats.corrected += stat;
+
+ /* get back to oob start (end of page) */
+ chip->cmdfunc(mtd, NAND_CMD_RNDOUT, mtd->writesize, -1);
+
+ /* read the oob */
+ chip->read_buf(mtd, oob, mtd->oobsize);
+
+ return 0;
+}
+
+/*
+ * HW ECC Correction
+ *
+ * function called after a read
+ *
+ * mtd: MTD block structure
+ * dat: raw data read from the chip
+ * read_ecc: ECC from the chip (unused)
+ * isnull: unused
+ *
+ * Detect and correct a 1 bit error for a page
+ */
+static int atmel_nand_correct(struct mtd_info *mtd, u_char *dat,
+ u_char *read_ecc, u_char *isnull)
+{
+ struct nand_chip *nand_chip = mtd->priv;
+ unsigned int ecc_status, ecc_parity, ecc_mode;
+ unsigned int ecc_word, ecc_bit;
+
+ /* get the status from the Status Register */
+ ecc_status = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, SR);
+
+ /* if there's no error */
+ if (likely(!(ecc_status & ATMEL_ECC_RECERR)))
+ return 0;
+
+ /* get error bit offset (4 bits) */
+ ecc_bit = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, PR) & ATMEL_ECC_BITADDR;
+ /* get word address (12 bits) */
+ ecc_word = ecc_readl(CONFIG_SYS_NAND_ECC_BASE, PR) & ATMEL_ECC_WORDADDR;
+ ecc_word >>= 4;
+
+ /* if there are multiple errors */
+ if (ecc_status & ATMEL_ECC_MULERR) {
+ /* check if it is a freshly erased block
+ * (filled with 0xff) */
+ if ((ecc_bit == ATMEL_ECC_BITADDR)
+ && (ecc_word == (ATMEL_ECC_WORDADDR >> 4))) {
+ /* the block has just been erased, return OK */
+ return 0;
+ }
+ /* it doesn't seems to be a freshly
+ * erased block.
+ * We can't correct so many errors */
+ printk(KERN_WARNING "atmel_nand : multiple errors detected."
+ " Unable to correct.\n");
+ return -EIO;
+ }
+
+ /* if there's a single bit error : we can correct it */
+ if (ecc_status & ATMEL_ECC_ECCERR) {
+ /* there's nothing much to do here.
+ * the bit error is on the ECC itself.
+ */
+ printk(KERN_WARNING "atmel_nand : one bit error on ECC code."
+ " Nothing to correct\n");
+ return 0;
+ }
+
+ printk(KERN_WARNING "atmel_nand : one bit error on data."
+ " (word offset in the page :"
+ " 0x%x bit offset : 0x%x)\n",
+ ecc_word, ecc_bit);
+ /* correct the error */
+ if (nand_chip->options & NAND_BUSWIDTH_16) {
+ /* 16 bits words */
+ ((unsigned short *) dat)[ecc_word] ^= (1 << ecc_bit);
+ } else {
+ /* 8 bits words */
+ dat[ecc_word] ^= (1 << ecc_bit);
+ }
+ printk(KERN_WARNING "atmel_nand : error corrected\n");
+ return 1;
+}
+
+/*
+ * Enable HW ECC : unused on most chips
+ */
+static void atmel_nand_hwctl(struct mtd_info *mtd, int mode)
+{
+}
+#endif
+
static void at91_nand_hwcontrol(struct mtd_info *mtd,
int cmd, unsigned int ctrl)
{
@@ -64,6 +267,11 @@ static int at91_nand_ready(struct mtd_info *mtd)
int board_nand_init(struct nand_chip *nand)
{
+#ifdef CONFIG_ATMEL_NAND_HWECC
+ static int chip_nr = 0;
+ struct mtd_info *mtd;
+#endif
+
nand->ecc.mode = NAND_ECC_SOFT;
#ifdef CONFIG_SYS_NAND_DBW_16
nand->options = NAND_BUSWIDTH_16;
@@ -74,5 +282,62 @@ int board_nand_init(struct nand_chip *nand)
#endif
nand->chip_delay = 20;
+#ifdef CONFIG_ATMEL_NAND_HWECC
+ nand->ecc.mode = NAND_ECC_HW;
+ nand->ecc.calculate = atmel_nand_calculate;
+ nand->ecc.correct = atmel_nand_correct;
+ nand->ecc.hwctl = atmel_nand_hwctl;
+ nand->ecc.read_page = atmel_nand_read_page;
+ nand->ecc.bytes = 4;
+#endif
+
+#ifdef CONFIG_ATMEL_NAND_HWECC
+ mtd = &nand_info[chip_nr++];
+ mtd->priv = nand;
+
+ /* Detect NAND chips */
+ if (nand_scan_ident(mtd, 1)) {
+ printk(KERN_WARNING "NAND Flash not found !\n");
+ return -ENXIO;
+ }
+
+ if (nand->ecc.mode == NAND_ECC_HW) {
+ /* ECC is calculated for the whole page (1 step) */
+ nand->ecc.size = mtd->writesize;
+
+ /* set ECC page size and oob layout */
+ switch (mtd->writesize) {
+ case 512:
+ nand->ecc.layout = &atmel_oobinfo_small;
+ ecc_writel(CONFIG_SYS_NAND_ECC_BASE, MR, ATMEL_ECC_PAGESIZE_528);
+ break;
+ case 1024:
+ nand->ecc.layout = &atmel_oobinfo_large;
+ ecc_writel(CONFIG_SYS_NAND_ECC_BASE, MR, ATMEL_ECC_PAGESIZE_1056);
+ break;
+ case 2048:
+ nand->ecc.layout = &atmel_oobinfo_large;
+ ecc_writel(CONFIG_SYS_NAND_ECC_BASE, MR, ATMEL_ECC_PAGESIZE_2112);
+ break;
+ case 4096:
+ nand->ecc.layout = &atmel_oobinfo_large;
+ ecc_writel(CONFIG_SYS_NAND_ECC_BASE, MR, ATMEL_ECC_PAGESIZE_4224);
+ break;
+ default:
+ /* page size not handled by HW ECC */
+ /* switching back to soft ECC */
+ nand->ecc.mode = NAND_ECC_SOFT;
+ nand->ecc.calculate = NULL;
+ nand->ecc.correct = NULL;
+ nand->ecc.hwctl = NULL;
+ nand->ecc.read_page = NULL;
+ nand->ecc.postpad = 0;
+ nand->ecc.prepad = 0;
+ nand->ecc.bytes = 0;
+ break;
+ }
+ }
+#endif
+
return 0;
}
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