Re: [PATCH] dmaengine: fsl-edma: fixup reg offset and hw S/G support in big-endian model

From: Jingchang Lu
Date: Tue Sep 23 2014 - 13:54:20 EST


_______________________________________
From: Russell King - ARM Linux <linux@xxxxxxxxxxxxxxxx>
Sent: Tuesday, September 23, 2014 6:37 PM
To: Lu Jingchang-B35083
Cc: vinod.koul@xxxxxxxxx; dmaengine@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [PATCH] dmaengine: fsl-edma: fixup reg offset and hw S/G support in big-endian model

On Tue, Sep 23, 2014 at 05:15:19PM +0800, Jingchang Lu wrote:
> static u16 edma_readw(struct fsl_edma_engine *edma, void __iomem *addr)
> {
> - if (edma->big_endian)
> - return ioread16be(addr);
> - else
> + u32 dst;

This should be unsigned long, if it needs to exist.

> + /* swap the reg offset for these in big-endian mode */
> + if (edma->big_endian) {
> + dst = ((u32)addr & ~0x3) | (((u32)addr & 0x3) ^ 0x2);

This can be simplified to:

addr = (void __iomem *)((unsigned long)addr ^ 2);

Ditto for all the other cases.

I will do that, Thanks.

Best Regards,
Jingchang

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