mtd: nand: sunxi: introduce sunxi_nfc_hw_ecc_read/write_chunk()

The logic behind normal and syndrome ECC handling is pretty much the same,
the only difference is the ECC bytes placement.
Create two functions to read/write ECC chunks. Those functions will later
be used by the sunxi_nfc_hw_ecc_read/write_page() and
sunxi_nfc_hw_syndrome_ecc_read/write_page() functions.

Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

drivers/mtd/nand/sunxi_nand.c

@@ -567,6 +567,98 @@ static void sunxi_nfc_hw_ecc_disable(struct mtd_info *mtd)
 	       nfc->regs + NFC_REG_ECC_CTL);
 }
 
+static int sunxi_nfc_hw_ecc_read_chunk(struct mtd_info *mtd,
+				       u8 *data, int data_off,
+				       u8 *oob, int oob_off,
+				       int *cur_off,
+				       unsigned int *max_bitflips)
+{
+	struct nand_chip *nand = mtd->priv;
+	struct sunxi_nfc *nfc = to_sunxi_nfc(nand->controller);
+	struct nand_ecc_ctrl *ecc = &nand->ecc;
+	u32 status;
+	int ret;
+
+	if (*cur_off != data_off)
+		nand->cmdfunc(mtd, NAND_CMD_RNDOUT, data_off, -1);
+
+	sunxi_nfc_read_buf(mtd, data, ecc->size);
+
+	if (data_off + ecc->bytes != oob_off)
+		nand->cmdfunc(mtd, NAND_CMD_RNDOUT, oob_off, -1);
+
+	ret = sunxi_nfc_wait_cmd_fifo_empty(nfc);
+	if (ret)
+		return ret;
+
+	writel(NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD | NFC_ECC_OP,
+	       nfc->regs + NFC_REG_CMD);
+
+	ret = sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
+	if (ret)
+		return ret;
+
+	status = readl(nfc->regs + NFC_REG_ECC_ST);
+	ret = NFC_ECC_ERR_CNT(0, readl(nfc->regs + NFC_REG_ECC_ERR_CNT(0)));
+
+	memcpy_fromio(data, nfc->regs + NFC_RAM0_BASE, ecc->size);
+
+	nand->cmdfunc(mtd, NAND_CMD_RNDOUT, oob_off, -1);
+	sunxi_nfc_read_buf(mtd, oob, ecc->bytes + 4);
+
+	if (status & NFC_ECC_ERR(0))
+		ret = -EIO;
+
+	if (ret < 0) {
+		mtd->ecc_stats.failed++;
+	} else {
+		mtd->ecc_stats.corrected += ret;
+		*max_bitflips = max_t(unsigned int, *max_bitflips, ret);
+	}
+
+	*cur_off = oob_off + ecc->bytes + 4;
+
+	return 0;
+}
+
+static int sunxi_nfc_hw_ecc_write_chunk(struct mtd_info *mtd,
+					const u8 *data, int data_off,
+					const u8 *oob, int oob_off,
+					int *cur_off)
+{
+	struct nand_chip *nand = mtd->priv;
+	struct sunxi_nfc *nfc = to_sunxi_nfc(nand->controller);
+	struct nand_ecc_ctrl *ecc = &nand->ecc;
+	int ret;
+
+	if (data_off != *cur_off)
+		nand->cmdfunc(mtd, NAND_CMD_RNDIN, data_off, -1);
+
+	sunxi_nfc_write_buf(mtd, data, ecc->size);
+
+	/* Fill OOB data in */
+	writel(NFC_BUF_TO_USER_DATA(oob), nfc->regs + NFC_REG_USER_DATA(0));
+
+	if (data_off + ecc->bytes != oob_off)
+		nand->cmdfunc(mtd, NAND_CMD_RNDIN, oob_off, -1);
+
+	ret = sunxi_nfc_wait_cmd_fifo_empty(nfc);
+	if (ret)
+		return ret;
+
+	writel(NFC_DATA_TRANS | NFC_DATA_SWAP_METHOD |
+	       NFC_ACCESS_DIR | NFC_ECC_OP,
+	       nfc->regs + NFC_REG_CMD);
+
+	ret = sunxi_nfc_wait_int(nfc, NFC_CMD_INT_FLAG, 0);
+	if (ret)
+		return ret;
+
+	*cur_off = oob_off + ecc->bytes + 4;
+
+	return 0;
+}
+
 static int sunxi_nfc_hw_ecc_read_page(struct mtd_info *mtd,
 				      struct nand_chip *chip, uint8_t *buf,
 				      int oob_required, int page)