Re: [PATCH 16/17] unicore32: add (void __iomem *) to io_p2v macro

From: Arnd Bergmann
Date: Mon Feb 28 2011 - 10:36:14 EST

On Sunday 27 February 2011, Guan Xuetao wrote:
> -#define PKUNITY_AC97_CONR __REG(PKUNITY_AC97_BASE + 0x0000)
> -#define PKUNITY_AC97_OCR __REG(PKUNITY_AC97_BASE + 0x0004)
> -#define PKUNITY_AC97_ICR __REG(PKUNITY_AC97_BASE + 0x0008)
> -#define PKUNITY_AC97_CRAC __REG(PKUNITY_AC97_BASE + 0x000C)
> -#define PKUNITY_AC97_INTR __REG(PKUNITY_AC97_BASE + 0x0010)
> -#define PKUNITY_AC97_INTRSTAT __REG(PKUNITY_AC97_BASE + 0x0014)
> -#define PKUNITY_AC97_ENABLE __REG(PKUNITY_AC97_BASE + 0x001C)
> -#define PKUNITY_AC97_OUT_FIFO __REG(PKUNITY_AC97_BASE + 0x0020)
> -#define PKUNITY_AC97_IN_FIFO __REG(PKUNITY_AC97_BASE + 0x0030)
> +#define PKUNITY_AC97_CONR io_p2v(PKUNITY_AC97_BASE + 0x0000)
> +#define PKUNITY_AC97_OCR io_p2v(PKUNITY_AC97_BASE + 0x0004)
> +#define PKUNITY_AC97_ICR io_p2v(PKUNITY_AC97_BASE + 0x0008)
> +#define PKUNITY_AC97_CRAC io_p2v(PKUNITY_AC97_BASE + 0x000C)
> +#define PKUNITY_AC97_INTR io_p2v(PKUNITY_AC97_BASE + 0x0010)

One more comment on the types here (applies to the entire patch):

It would be more straightforward to the define the underlying base
addresses using io_p2v, and then do a simple addition, instead of
another macro that adds a type cast:

#define PKUNITY_SYSTEM_AHB io_p2v(0xC0000000)
#define PKUNITY_PERIPHERAL_AHB io_p2v(0xEE000000)


#define PKUNITY_AC97_CONR (PKUNITY_AC97_BASE + 0x0000)
#define PKUNITY_AC97_OCR (PKUNITY_AC97_BASE + 0x0004)

It would be nice if you could do that for the entire set of hardware

In the long run, I would recommend moving away from hardcoded I/O addresses
entirely, but you can do that at the same time as moving to a flattened
device tree. When you do that, every driver will do an individual ioremap
to get the virtual address for a physical location, rather than doing it
once at boot time for all hardware. This makes the code more flexible when
dealing with multiple SoC implemetations, but it's not something that
you need to worry about too much for the initial merge.

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