Re: [RFC, EXPERIMENTAL] MIPS: add initial cache support

From: Sascha Hauer <s.hauer@pengutronix.de>
To: Antony Pavlov <antonynpavlov@gmail.com>
Cc: barebox@lists.infradead.org
Subject: Re: [RFC, EXPERIMENTAL] MIPS: add initial cache support
Date: Tue, 28 May 2013 08:15:06 +0200	[thread overview]
Message-ID: <20130528061506.GR32299@pengutronix.de> (raw)
In-Reply-To: <1369392445-30230-1-git-send-email-antonynpavlov@gmail.com>

Hi Antony,

On Fri, May 24, 2013 at 02:47:25PM +0400, Antony Pavlov wrote:
> Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
> ---
>  arch/mips/include/asm/cache.h    |    8 +
>  arch/mips/include/asm/cacheops.h |   78 +++++++
>  arch/mips/include/asm/cpu-info.h |    1 +
>  arch/mips/include/asm/io.h       |   66 ++++++
>  arch/mips/include/asm/r4kcache.h |  443 ++++++++++++++++++++++++++++++++++++++
>  arch/mips/lib/Makefile           |    1 +
>  arch/mips/lib/c-r4k.c            |   97 +++++++++
>  arch/mips/lib/dma.c              |   27 +++
>  include/linux/const.h            |   24 +++
>  9 files changed, 745 insertions(+)
>  create mode 100644 arch/mips/include/asm/cache.h
>  create mode 100644 arch/mips/include/asm/cacheops.h
>  create mode 100644 arch/mips/include/asm/r4kcache.h
>  create mode 100644 arch/mips/lib/dma.c
>  create mode 100644 include/linux/const.h
> 
> diff --git a/arch/mips/lib/dma.c b/arch/mips/lib/dma.c
> new file mode 100644
> index 0000000..0ca53f1
> --- /dev/null
> +++ b/arch/mips/lib/dma.c
> @@ -0,0 +1,27 @@
> +#include <common.h>
> +#include <asm/io.h>
> +#include <asm/mipsregs.h>
> +#include <malloc.h>
> +
> +static inline void __iomem *ioremap_nocache(phys_t offset, unsigned long size)
> +{
> +	return (void __iomem *) (unsigned long)CKSEG1ADDR(offset);
> +}
> +
> +void *dma_alloc_coherent(size_t size)
> +{
> +	void *ret;
> +
> +	ret = xmemalign(4096, size);
> +
> +	dma_inv_range((unsigned long)ret, (unsigned long)ret + size);

Is this needed? I mean you return the corresponding CKSEG1ADDR anyway
which should be coherent memory.

> +
> +	ret = ioremap_nocache((phys_t)ret, size);
> +
> +	return ret;
> +}
> +
> +void dma_free_coherent(void *mem, size_t size)
> +{
> +	free(mem);
> +}

I would expect to invalidate the cache here instead.

Sascha

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