RE: [RFC PATCH v3 05/16] ARM: edma: add AM33XX crossbar eventsupport

From: Hebbar, Gururaja
Date: Fri Oct 26 2012 - 08:54:27 EST


On Thu, Oct 18, 2012 at 18:56:44, Porter, Matt wrote:
> Adds support for the per-EDMA channel event mux. This is required
> for any peripherals using DMA crossbar mapped events.
>
> Signed-off-by: Matt Porter <mporter@xxxxxx>
> ---
> arch/arm/common/edma.c | 63 +++++++++++++++++++++++++++++++++++-
> include/linux/platform_data/edma.h | 1 +
> 2 files changed, 63 insertions(+), 1 deletion(-)
>

..snip..
..snip..

> +
> + for (i = 0; xbar_chans[i][0] != -1; i++) {
> + shift = (xbar_chans[i][1] % 4) * 8;
> + offset = xbar_chans[i][1] >> 2;
> + offset <<= 2;
> + mux = __raw_readl((void *)((u32)xbar + offset));
> + mux &= (~(0xff << shift));
> + mux |= (xbar_chans[i][0] << shift);
> + __raw_writel(mux, (void *)((u32)xbar + offset));

This method of calculating Xbar Channel offset has a bug that
the code breaks with unaligned access trap error when requested
channel to be mapped is odd.

This was fixed in Arago tree [1]. Kindly verify


> + }
> +
> + pdata->xbar_chans = xbar_chans;
> +
> + return 0;
> +}
> +

..snip..
..snip..

[1]
http://arago-project.org/git/projects/?p=linux-am33x.git;a=commitdiff;
h=c08d3cb557adf71c79aeefb38888395455824e83

Regards,
Gururaja
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