mtd: nand: xway: fix nand locking

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Gitweb:     http://git.infradead.org/?p=mtd-2.6.git;a=commit;h=e7e1f7be335458139e0a112bd0aae40d33dfe3a8
Commit:     e7e1f7be335458139e0a112bd0aae40d33dfe3a8
Parent:     44772fa5ec4162ef133f1294299d1e1ada7d2d11
Author:     John Crispin <john at phrozen.org>
AuthorDate: Mon Jun 20 23:32:11 2016 +0200
Committer:  Boris Brezillon <boris.brezillon at free-electrons.com>
CommitDate: Mon Jul 11 08:40:15 2016 +0200

    mtd: nand: xway: fix nand locking
    
    The external Bus Unit (EBU) can control different flash devices, but
    these NAND flash commands have to be atomic and should not be
    interrupted in between. Lock the EBU from the beginning of the command
    till the end by moving the lock to the chip select.
    
    Signed-off-by: John Crispin <john at phrozen.org>
    Signed-off-by: Hauke Mehrtens <hauke at hauke-m.de>
    Signed-off-by: Boris Brezillon <boris.brezillon at free-electrons.com>
---
 drivers/mtd/nand/xway_nand.c | 20 ++++++++------------
 1 file changed, 8 insertions(+), 12 deletions(-)

diff --git a/drivers/mtd/nand/xway_nand.c b/drivers/mtd/nand/xway_nand.c
index ab93b35..08f796e 100644
--- a/drivers/mtd/nand/xway_nand.c
+++ b/drivers/mtd/nand/xway_nand.c
@@ -65,17 +65,22 @@
 
 struct xway_nand_data {
 	struct nand_chip	chip;
+	unsigned long		csflags;
 };
 
-static void xway_select_chip(struct mtd_info *mtd, int chip)
+static void xway_select_chip(struct mtd_info *mtd, int select)
 {
+	struct nand_chip *chip = mtd_to_nand(mtd);
+	struct xway_nand_data *data = nand_get_controller_data(chip);
 
-	switch (chip) {
+	switch (select) {
 	case -1:
 		ltq_ebu_w32_mask(NAND_CON_CE, 0, EBU_NAND_CON);
 		ltq_ebu_w32_mask(NAND_CON_NANDM, 0, EBU_NAND_CON);
+		spin_unlock_irqrestore(&ebu_lock, data->csflags);
 		break;
 	case 0:
+		spin_lock_irqsave(&ebu_lock, data->csflags);
 		ltq_ebu_w32_mask(0, NAND_CON_NANDM, EBU_NAND_CON);
 		ltq_ebu_w32_mask(0, NAND_CON_CE, EBU_NAND_CON);
 		break;
@@ -88,12 +93,10 @@ static void xway_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 {
 	struct nand_chip *this = mtd_to_nand(mtd);
 	unsigned long nandaddr = (unsigned long) this->IO_ADDR_W;
-	unsigned long flags;
 
 	if (cmd == NAND_CMD_NONE)
 		return;
 
-	spin_lock_irqsave(&ebu_lock, flags);
 	if (ctrl & NAND_CLE)
 		writeb(cmd, (void __iomem *) (nandaddr | NAND_WRITE_CMD));
 	else if (ctrl & NAND_ALE)
@@ -101,7 +104,6 @@ static void xway_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 
 	while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
 		;
-	spin_unlock_irqrestore(&ebu_lock, flags);
 }
 
 static int xway_dev_ready(struct mtd_info *mtd)
@@ -113,14 +115,8 @@ static unsigned char xway_read_byte(struct mtd_info *mtd)
 {
 	struct nand_chip *this = mtd_to_nand(mtd);
 	unsigned long nandaddr = (unsigned long) this->IO_ADDR_R;
-	unsigned long flags;
-	int ret;
 
-	spin_lock_irqsave(&ebu_lock, flags);
-	ret = ltq_r8((void __iomem *)(nandaddr + NAND_READ_DATA));
-	spin_unlock_irqrestore(&ebu_lock, flags);
-
-	return ret;
+	return ltq_r8((void __iomem *)(nandaddr + NAND_READ_DATA));
 }
 
 /*