mtd: rawnand: marvell: Fix read logic for layouts with ->nchunks > 2

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=90d617633368ab97a2c7571c6e66dad54f39228d
Commit:     90d617633368ab97a2c7571c6e66dad54f39228d
Parent:     ea739a287f4f16d6250bea779a1026ead79695f2
Author:     Boris Brezillon <boris.brezillon at bootlin.com>
AuthorDate: Wed May 9 09:13:58 2018 +0200
Committer:  Boris Brezillon <boris.brezillon at bootlin.com>
CommitDate: Mon May 14 14:46:20 2018 +0200

    mtd: rawnand: marvell: Fix read logic for layouts with ->nchunks > 2
    
    The code is doing monolithic reads for all chunks except the last one
    which is wrong since a monolithic read will issue the
    READ0+ADDRS+READ_START sequence. It not only takes longer because it
    forces the NAND chip to reload the page content into its internal
    cache, but by doing that we also reset the column pointer to 0, which
    means we'll always read the first chunk instead of moving to the next
    one.
    
    Rework the code to do a monolithic read only for the first chunk,
    then switch to naked reads for all intermediate chunks and finally
    issue a last naked read for the last chunk.
    
    Fixes: 02f26ecf8c77 mtd: nand: add reworked Marvell NAND controller driver
    Cc: stable at vger.kernel.org
    Reported-by: Chris Packham <chris.packham at alliedtelesis.co.nz>
    Signed-off-by: Boris Brezillon <boris.brezillon at bootlin.com>
    Tested-by: Chris Packham <chris.packham at alliedtelesis.co.nz>
    Acked-by: Miquel Raynal <miquel.raynal at bootlin.com>
---
 drivers/mtd/nand/raw/marvell_nand.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/mtd/nand/raw/marvell_nand.c b/drivers/mtd/nand/raw/marvell_nand.c
index db5ec4e8bde9..ebb1d141b900 100644
--- a/drivers/mtd/nand/raw/marvell_nand.c
+++ b/drivers/mtd/nand/raw/marvell_nand.c
@@ -1194,11 +1194,13 @@ static void marvell_nfc_hw_ecc_bch_read_chunk(struct nand_chip *chip, int chunk,
 				  NDCB0_CMD2(NAND_CMD_READSTART);
 
 	/*
-	 * Trigger the naked read operation only on the last chunk.
-	 * Otherwise, use monolithic read.
+	 * Trigger the monolithic read on the first chunk, then naked read on
+	 * intermediate chunks and finally a last naked read on the last chunk.
 	 */
-	if (lt->nchunks == 1 || (chunk < lt->nchunks - 1))
+	if (chunk == 0)
 		nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_MONOLITHIC_RW);
+	else if (chunk < lt->nchunks - 1)
+		nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_NAKED_RW);
 	else
 		nfc_op.ndcb[0] |= NDCB0_CMD_XTYPE(XTYPE_LAST_NAKED_RW);