[RFC 45/47] mtd: nand: stm_nand_bch: read and write buffers (FLEX)

Lee Jones
2014-03-25T08:22:07Z

read or write in 4 Byte chunks at a time until there is less than
8 Bytes remaining, at which point split down into reading the
reset a single Byte at a time.

Signed-off-by: Lee Jones <lee.jones@linaro.org>
---
drivers/mtd/nand/stm_nand_bch.c | 72 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 72 insertions(+)

diff --git a/drivers/mtd/nand/stm_nand_bch.c b/drivers/mtd/nand/stm_nand_bch.c
index f5b0a00..975326e 100644
--- a/drivers/mtd/nand/stm_nand_bch.c
+++ b/drivers/mtd/nand/stm_nand_bch.c
@@ -686,6 +686,75 @@ static void flex_addr(struct nandi_controller *nandi,
writel(addr, nandi->base + NANDHAM_FLEX_ADD);
}

+static void flex_read_buf(struct mtd_info *mtd, uint8_t *buf, int len)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct nandi_controller *nandi = chip->priv;
+ int aligned;
+
+ emiss_nandi_select(STM_NANDI_HAMMING);
+
+ /* Read bytes until buf is 4-byte aligned */
+ while (len && ((unsigned int)buf & 0x3)) {
+ *buf++ = (uint8_t)(readl(nandi->base + NANDHAM_FLEX_DATA)
+ & 0xff);
+ len--;
+ };
+
+ /* Use 'BEATS_4'/readsl */
+ if (len > 8) {
+ aligned = len & ~0x3;
+ writel(FLEX_DATA_CFG_BEATS_4 | FLEX_DATA_CFG_CSN,
+ nandi->base + NANDHAM_FLEX_DATAREAD_CONFIG);
+
+ readsl(nandi->base + NANDHAM_FLEX_DATA, buf, aligned >> 2);
+
+ buf += aligned;
+ len -= aligned;
+
+ writel(FLEX_DATA_CFG_BEATS_1 | FLEX_DATA_CFG_CSN,
+ nandi->base + NANDHAM_FLEX_DATAREAD_CONFIG);
+ }
+
+ /* Mop up remaining bytes */
+ while (len > 0) {
+ *buf++ = (uint8_t)(readl(nandi->base + NANDHAM_FLEX_DATA)
+ & 0xff);
+ len--;
+ }
+}
+
+static void flex_write_buf(struct mtd_info *mtd, const uint8_t *buf, int len)
+{
+ struct nand_chip *chip = mtd->priv;
+ struct nandi_controller *nandi = chip->priv;
+ int aligned;
+
+ /* Write bytes until buf is 4-byte aligned */
+ while (len && ((unsigned int)buf & 0x3)) {
+ writel(*buf++, nandi->base + NANDHAM_FLEX_DATA);
+ len--;
+ };
+
+ /* USE 'BEATS_4/writesl */
+ if (len > 8) {
+ aligned = len & ~0x3;
+ writel(FLEX_DATA_CFG_BEATS_4 | FLEX_DATA_CFG_CSN,
+ nandi->base + NANDHAM_FLEX_DATAWRITE_CONFIG);
+ writesl(nandi->base + NANDHAM_FLEX_DATA, buf, aligned >> 2);
+ buf += aligned;
+ len -= aligned;
+ writel(FLEX_DATA_CFG_BEATS_1 | FLEX_DATA_CFG_CSN,
+ nandi->base + NANDHAM_FLEX_DATAWRITE_CONFIG);
+ }
+
+ /* Mop up remaining bytes */
+ while (len > 0) {
+ writel(*buf++, nandi->base + NANDHAM_FLEX_DATA);
+ len--;
+ }
+}
+
/*
* Hamming-FLEX operations (optimised replacements for nand_base.c versions)
*/
@@ -1743,6 +1812,9 @@ static void nandi_set_mtd_defaults(struct nandi_controller *nandi,
chip->priv = nandi;
chip->ecc.layout = &info->ecclayout;

+ chip->read_buf = flex_read_buf;
+ chip->write_buf = flex_write_buf;
+
chip->bbt_options |= NAND_BBT_USE_FLASH;

/* mtd_info */
--
1.8.3.2