[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>

1 files changed, 14 insertions, 1 deletions

diff --git a/drivers/mtd/onenand/onenand_base.c b/drivers/mtd/onenand/onenand_base.c
index 2ea07f5723d1..2da6bb26353e 100644
--- 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);