[MTD] OneNAND: Handle DDP chip boundary during read-while-load

The read-while-load method of reading from OneNAND needs to allow
for the change of bufferRAM address at the boundary between the
two chips in a double density (DDP) device.

Signed-off-by: Adrian Hunter <ext-adrian.hunter@nokia.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>

diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index 2ea07f5723d171b52ed10c614a60072bc975670b..2da6bb26353e22c6966c0835cf596cb227ac1883 100644 (file)
--- a/drivers/mtd/onenand/onenand_base.c
+++ b/drivers/mtd/onenand/onenand_base.c
@@ -710,7 +710,7 @@ static int onenand_read(struct mtd_info *mtd, loff_t from, size_t len,
        struct mtd_ecc_stats stats;
        int read = 0, column;
        int thislen;
-       int ret = 0;
+       int ret = 0, boundary = 0;
 
        DEBUG(MTD_DEBUG_LEVEL3, "onenand_read: from = 0x%08x, len = %i\n", (unsigned int) from, (int) len);
 
@@ -749,6 +749,17 @@ static int onenand_read(struct mtd_info *mtd, loff_t from, size_t len,
                from += thislen;
                if (read + thislen < len) {
                        this->command(mtd, ONENAND_CMD_READ, from, mtd->writesize);
+                       /*
+                        * Chip boundary handling in DDP
+                        * Now we issued chip 1 read and pointed chip 1
+                        * bufferam so we have to point chip 0 bufferam.
+                        */
+                       if (this->device_id & ONENAND_DEVICE_IS_DDP &&
+                                       unlikely(from == (this->chipsize >> 1))) {
+                               this->write_word(0, this->base + ONENAND_REG_START_ADDRESS2);
+                               boundary = 1;
+                       } else
+                               boundary = 0;
                        ONENAND_SET_PREV_BUFFERRAM(this);
                }
                /* While load is going, read from last bufferRAM */
@@ -758,6 +769,8 @@ static int onenand_read(struct mtd_info *mtd, loff_t from, size_t len,
                if (read == len)
                        break;
                /* Set up for next read from bufferRAM */
+               if (unlikely(boundary))
+                       this->write_word(0x8000, this->base + ONENAND_REG_START_ADDRESS2);
                ONENAND_SET_NEXT_BUFFERRAM(this);
                buf += thislen;
                thislen = min_t(int, mtd->writesize, len - read);