Re: [PATCH 4/7] dw_dmac: autoconfigure block_size or use platform data

viresh kumar
2012-09-18T06:57:34Z

On Mon, Sep 17, 2012 at 1:09 PM, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> @@ -1380,6 +1370,7 @@ static int __devinit dw_probe(struct platform_device *pdev)
> bool autocfg;
> unsigned int dw_params;
> unsigned int nr_channels;
> + unsigned int max_blk_size;
> int irq;
> int err;
> int i;
> @@ -1420,6 +1411,9 @@ static int __devinit dw_probe(struct platform_device *pdev)
>
> dw->regs = regs;
>
> + /* get hardware configuration parameters */
> + max_blk_size = dma_readl(dw, MAX_BLK_SIZE);
> +

Do this only for autocfg case.

> /* Calculate all channel mask before DMA setup */
> dw->all_chan_mask = (1 << nr_channels) - 1;
>
> @@ -1465,6 +1459,14 @@ static int __devinit dw_probe(struct platform_device *pdev)
> INIT_LIST_HEAD(&dwc->free_list);
>
> channel_clear_bit(dw, CH_EN, dwc->mask);
> +
> + /* hardware configuration */
> + if (autocfg) {
> + dwc->block_size =
> + (4 << ((max_blk_size >> 4 * i) & 0xf)) - 1;

Put a comment on what are you doing here.

> + } else {
> + dwc->block_size = pdata->block_size;
> + }

Don't need {} for single line statements.

> }
>
> /* Clear all interrupts on all channels. */
> diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
> index 0f96965..233f5e5 100644
> --- a/drivers/dma/dw_dmac_regs.h
> +++ b/drivers/dma/dw_dmac_regs.h
> @@ -186,6 +186,9 @@ struct dw_dma_chan {
>
> unsigned int descs_allocated;
>
> + /* hardware configuration */
> + unsigned short block_size;
> +

You actually don't save any memory here with short and actually makes access
to block_size more complex. keeping it int would be better i believe.

viresh