Re: [PATCH 4/8] dmaengine: ste_dma40: Do not configure channelsduring an channel allocation

From: Rabin Vincent
Date: Fri Apr 12 2013 - 09:55:21 EST


2013/4/9 Lee Jones <lee.jones@xxxxxxxxxx>:
> diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
> index 2a0a9d4..9e423ad 100644
> --- a/drivers/dma/ste_dma40.c
> +++ b/drivers/dma/ste_dma40.c
> @@ -2463,16 +2463,10 @@ static int d40_alloc_chan_resources(struct dma_chan *chan)
> }
>
> pm_runtime_get_sync(d40c->base->dev);
> - /* Fill in basic CFG register values */
> - d40_phy_cfg(&d40c->dma_cfg, &d40c->src_def_cfg,
> - &d40c->dst_def_cfg, chan_is_logical(d40c));
>
> d40_set_prio_realtime(d40c);
>
> if (chan_is_logical(d40c)) {
> - d40_log_cfg(&d40c->dma_cfg,
> - &d40c->log_def.lcsp1, &d40c->log_def.lcsp3);
> -
> if (d40c->dma_cfg.dir == STEDMA40_PERIPH_TO_MEM)
> d40c->lcpa = d40c->base->lcpa_base +
> d40c->dma_cfg.src_dev_type * D40_LCPA_CHAN_SIZE;
> @@ -2487,14 +2481,6 @@ static int d40_alloc_chan_resources(struct dma_chan *chan)
> d40c->phy_chan->num,
> d40c->dma_cfg.use_fixed_channel ? ", fixed" : "");
>
> -
> - /*
> - * Only write channel configuration to the DMA if the physical
> - * resource is free. In case of multiple logical channels
> - * on the same physical resource, only the first write is necessary.
> - */
> - if (is_free_phy)
> - d40_config_write(d40c);

This function does basic initial configuration which is linked to
whether the channel is pysical or logical -- something that is not being
allowed to be runtime configured, so the place to call this function is
here. Furthermore, it clears the SSLNK/SDLNK which has to be done here,
when the phy channel is first allocated.
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