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Commit 155285c4 authored by Sergei Shtylyov's avatar Sergei Shtylyov Committed by David Woodhouse
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NAND: AMD Au1550 driver reads write-only register 



     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: default avatarSergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent c41ff6e5

drivers/mtd/nand/au1550nd.c

+2 −4
Original line number Diff line number Diff line
@@ -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 */