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From: Dan Williams on 25 Mar 2010 21:00
On Thu, Mar 25, 2010 at 11:44 AM, Richard R�jfors
<richard.rojfors(a)pelagicore.com> wrote:
> Adds the support for the DMA engine withing the timberdale FPGA.
>
> The DMA channels are strict device to host, or host to device
> and can not be used for generic memcpy.
>
> Signed-off-by: Richard R�jfors <richard.rojfors(a)pelagicore.com>
[..]
> +struct timb_dma_chan {
> + � � � struct dma_chan � � � � chan;
> + � � � void __iomem � � � � � �*membase;
> + � � � spinlock_t � � � � � � �lock; /* Used for mutual exclusion */

Please add some value to this comment. I can assume it protects all
list manipulations, anything non-obvious worth noting?

[..]
> +
> +static int td_fill_desc(struct timb_dma_chan *td_chan, u8 *dma_desc,
> + � � � struct scatterlist *sg, bool last)
> +{
> + � � � if (sg_dma_len(sg) > USHORT_MAX) {
> + � � � � � � � dev_err(chan2dev(&td_chan->chan), "Too big sg element\n");
> + � � � � � � � return -EINVAL;
> + � � � }
> +
> + � � � /* length must be word aligned */
> + � � � if (sg_dma_len(sg) % sizeof(u32)) {
> + � � � � � � � dev_err(chan2dev(&td_chan->chan), "Incorrect length: %d\n",
> + � � � � � � � � � � � sg_dma_len(sg));
> + � � � � � � � return -EINVAL;
> + � � � }
> +
> + � � � dev_dbg(chan2dev(&td_chan->chan), "desc: %p, addr: %p\n",
> + � � � � � � � dma_desc, (void *)(int)sg_dma_address(sg));

That (int) cast is not needed, causes a compiler warning, and can be dropped.

Nice simple driver. You can just send a follow up patch to fix up
those minor issues. I've pushed it out to my 'next' branch [1].

--
Dan

git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx.git next
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