[PATCH v2 6/8] MTD: xway: fix nand locking

[Hauke Mehrtens]

From: John Crispin <john at phrozen.org>

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>
---
 drivers/mtd/nand/xway_nand.c | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/drivers/mtd/nand/xway_nand.c b/drivers/mtd/nand/xway_nand.c
index 1511bdb..064ee41 100644
--- a/drivers/mtd/nand/xway_nand.c
+++ b/drivers/mtd/nand/xway_nand.c
@@ -94,13 +94,16 @@ static void xway_reset_chip(struct nand_chip *chip)
 
 static void xway_select_chip(struct mtd_info *mtd, int chip)
 {
+	static unsigned long csflags;
 
 	switch (chip) {
 	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, csflags);
 		break;
 	case 0:
+		spin_lock_irqsave(&ebu_lock, csflags);
 		ltq_ebu_w32_mask(0, NAND_CON_NANDM, EBU_NAND_CON);
 		ltq_ebu_w32_mask(0, NAND_CON_CE, EBU_NAND_CON);
 		break;
@@ -114,7 +117,6 @@ static void xway_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 	struct nand_chip *chip = mtd_to_nand(mtd);
 	struct xway_nand_data *data = nand_get_controller_data(chip);
 	unsigned long nandaddr = (unsigned long) chip->IO_ADDR_W;
-	unsigned long flags;
 
 	if (ctrl & NAND_CTRL_CHANGE) {
 		if (ctrl & NAND_CLE)
@@ -124,11 +126,9 @@ static void xway_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl)
 	}
 
 	if (cmd != NAND_CMD_NONE) {
-		spin_lock_irqsave(&ebu_lock, flags);
 		writeb(cmd, (void __iomem *) (nandaddr | data->xway_latchcmd));
 		while ((ltq_ebu_r32(EBU_NAND_WAIT) & NAND_WAIT_WR_C) == 0)
 			;
-		spin_unlock_irqrestore(&ebu_lock, flags);
 	}
 }
 
@@ -141,14 +141,8 @@ 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));
 }
 
 
@@ -156,26 +150,20 @@ static void xway_read_buf(struct mtd_info *mtd, u_char *buf, int len)
 {
 	struct nand_chip *this = mtd_to_nand(mtd);
 	unsigned long nandaddr = (unsigned long) this->IO_ADDR_R;
-	unsigned long flags;
 	int i;
 
-	spin_lock_irqsave(&ebu_lock, flags);
 	for (i = 0; i < len; i++)
 		buf[i] = ltq_r8((void __iomem *)(nandaddr | NAND_READ_DATA));
-	spin_unlock_irqrestore(&ebu_lock, flags);
 }
 
 static void xway_write_buf(struct mtd_info *mtd, const u_char *buf, int len)
 {
 	struct nand_chip *this = mtd_to_nand(mtd);
 	unsigned long nandaddr = (unsigned long) this->IO_ADDR_W;
-	unsigned long flags;
 	int i;
 
-	spin_lock_irqsave(&ebu_lock, flags);
 	for (i = 0; i < len; i++)
 		ltq_w8(buf[i], (void __iomem *)(nandaddr | NAND_WRITE_DATA));
-	spin_unlock_irqrestore(&ebu_lock, flags);
 }
 
 /*
-- 
2.8.1