MACH-S3C2440: Speed up NAND controller for this CPU

The S3C2440 provides 32 bit access to the NAND's data. Add specific read
routines to speed up data reading and writing.

These routines are stolen from the Linux kernel.

Signed-off-by: Juergen Beisert <juergen@kreuzholzen.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>

1 files changed, 55 insertions, 0 deletions

diff --git a/drivers/mtd/nand/nand_s3c2410.c b/drivers/mtd/nand/nand_s3c2410.c
index 76ea9db46e..df0b7c18a9 100644
--- a/drivers/mtd/nand/nand_s3c2410.c
+++ b/drivers/mtd/nand/nand_s3c2410.c
@@ -194,6 +194,57 @@ static void __nand_boot_init disable_nand_controller(void __iomem *host)
 
 /* ----------------------------------------------------------------------- */
 
+#ifdef CONFIG_CPU_S3C2440
+/**
+ * Read one block of data from the NAND port
+ * @param[in] mtd Instance data
+ * @param[out] buf buffer to write data to
+ * @param[in] len byte count
+ *
+ * This is a special block read variant for the S3C2440 CPU.
+ */
+static void s3c2440_nand_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+	struct nand_chip *nand_chip = mtd->priv;
+	struct s3c24x0_nand_host *host = nand_chip->priv;
+
+	readsl(host->base + NFDATA, buf, len >> 2);
+
+	/* cleanup any fractional read */
+	if (len & 3) {
+		buf += len & ~3;
+
+		for (; len & 3; len--)
+			*buf++ = readb(host->base + NFDATA);
+	}
+}
+
+/**
+ * Write one block of data to the NAND port
+ * @param[in] mtd Instance data
+ * @param[out] buf buffer to read data from
+ * @param[in] len byte count
+ *
+ * This is a special block write variant for the S3C2440 CPU.
+ */
+static void s3c2440_nand_write_buf(struct mtd_info *mtd, const uint8_t *buf,
+					int len)
+{
+	struct nand_chip *nand_chip = mtd->priv;
+	struct s3c24x0_nand_host *host = nand_chip->priv;
+
+	writesl(host->base + NFDATA, buf, len >> 2);
+
+	/* cleanup any fractional write */
+	if (len & 3) {
+		buf += len & ~3;
+
+		for (; len & 3; len--, buf++)
+			writeb(*buf, host->base + NFDATA);
+	}
+}
+#endif
+
 /**
  * Check the ECC and try to repair the data if possible
  * @param[in] mtd_info FIXME
@@ -390,6 +441,10 @@ static int s3c24x0_nand_probe(struct device_d *dev)
 
 	chip->IO_ADDR_R = chip->IO_ADDR_W = IOMEM(dev->map_base + NFDATA);
 
+#ifdef CONFIG_CPU_S3C2440
+	chip->read_buf = s3c2440_nand_read_buf;
+	chip->write_buf = s3c2440_nand_write_buf;
+#endif
 	chip->cmd_ctrl = s3c24x0_nand_hwcontrol;
 	chip->dev_ready = s3c24x0_nand_devready;
 	chip->select_chip = s3c24x0_nand_select_chip;