[U-Boot] [PATCH 2/2] ehci-hcd.c, musb_core, usb.h: Add USB_DMA_MINALIGN define for cache alignment

Ilya Yanok ilya.yanok at cogentembedded.com
Mon Jul 9 20:37:14 CEST 2012


Hi Marek,

On Sun, Jul 8, 2012 at 7:08 AM, Marek Vasut <marex at denx.de> wrote:

> -       /* Invalidate the memory area occupied by buffer */
> -       invalidate_dcache_range(((uint32_t)buffer & ~31),
> -               ((uint32_t)buffer & ~31) + roundup(length, 32));
> +       /*
> +        * Invalidate the memory area occupied by buffer
> +        * Don't try to fix the buffer alignment, if it isn't properly
> +        * aligned it's upper layer's fault so let
> invalidate_dcache_range()
> +        * vow about it. But we have to fix the length as it's actual
> +        * transfer length and can be unaligned. This is potentially
> +        * dangerous operation, it's responsibility of the calling
> +        * code to make sure enough space is reserved.
> +        */
> +       invalidate_dcache_range((uint32_t)buffer,
> +               ALIGN_END_ADDR(u8, buffer, length));
>

We shouldn't use ALIGN_END_ADDR here. This can lead to strange results on
systems with ARCH_DMA_MINALIGN < 32.

Regards, Ilya.


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