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NAND: AMD Au1550 driver reads write-only register

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During the last cleanup of the AMD Au1550 NAND driver the old buglet was
reintroduced: as the MEM_STNDCTL register is write-only and seem to always
read as 0x31, read-modify-write to it done in au1xxx_nand_init() will have the
side effect of enabling -RCS0/1 pin override (via bits 4/5 of this reg.), thus
possibly causing a contention on the static bus when the NOR flash (using
-RCS0) or board control status registers (using -RCS2) are read. Luckily, this
goes away with a first NAND access, since au1550_hwcontrol() doesn't try to
read this register before writing anymore.

Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
This commit is contained in:
Sergei Shtylyov 2006-05-16 20:16:41 +04:00 committed by David Woodhouse
parent c41ff6e5f3
commit 155285c477
1 changed files with 2 additions and 4 deletions
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6
drivers/mtd/nand/au1550nd.c
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@ -347,11 +347,9 @@ static int __init au1xxx_nand_init(void)
au1550_mtd->priv = this;
au1550_mtd->owner = THIS_MODULE;
/* disable interrupts */
au_writel(au_readl(MEM_STNDCTL) & ~(1 << 8), MEM_STNDCTL);
/* disable NAND boot */
au_writel(au_readl(MEM_STNDCTL) & ~(1 << 0), MEM_STNDCTL);
/* MEM_STNDCTL: disable ints, disable nand boot */
au_writel(0, MEM_STNDCTL);
#ifdef CONFIG_MIPS_PB1550
/* set gpio206 high */