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SubjectRe: [PATCH 1/2] dw_dmac: backlink to dw_dma in dw_dma_chan is superfluous
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On 10 December 2012 17:06, Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> The same information could be exctracted from the struct dma_chan.
>
> The patch introduces two helpers dwc_get_src_data_width() and
> dwc_get_dst_data_width() as well.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> drivers/dma/dw_dmac.c | 27 ++++++++++++++++++++-------
> drivers/dma/dw_dmac_regs.h | 3 ---
> 2 files changed, 20 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
> index fdae96f..a9e9a07 100644
> --- a/drivers/dma/dw_dmac.c
> +++ b/drivers/dma/dw_dmac.c
> @@ -73,6 +73,22 @@ static inline unsigned int dwc_get_sms(struct dw_dma_slave *slave)
> */
> #define NR_DESCS_PER_CHANNEL 64
>
> +static inline unsigned int dwc_get_src_data_width(struct dma_chan *chan)
> +{
> + struct dw_dma *dw = to_dw_dma(chan->device);
> + struct dw_dma_slave *dws = chan->private;

I never liked the tabs used before the variable names in this driver.
Though have kept them while fixing existing routines.

So, i would like you to use spaces for new functions.

> +
> + return dw->data_width[dwc_get_sms(dws)];
> +}
> +
> +static inline unsigned int dwc_get_dst_data_width(struct dma_chan *chan)
> +{
> + struct dw_dma *dw = to_dw_dma(chan->device);
> + struct dw_dma_slave *dws = chan->private;
> +
> + return dw->data_width[dwc_get_dms(dws)];
> +}

Can you try merging these routines into a single routine, by adding a
single param?

> /*----------------------------------------------------------------------*/
>
> /*
> @@ -703,7 +719,6 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
> size_t len, unsigned long flags)
> {
> struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
> - struct dw_dma_slave *dws = chan->private;
> struct dw_desc *desc;
> struct dw_desc *first;
> struct dw_desc *prev;
> @@ -726,8 +741,8 @@ dwc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
>
> dwc->direction = DMA_MEM_TO_MEM;
>
> - data_width = min_t(unsigned int, dwc->dw->data_width[dwc_get_sms(dws)],
> - dwc->dw->data_width[dwc_get_dms(dws)]);
> + data_width = min(dwc_get_src_data_width(chan),
> + dwc_get_dst_data_width(chan));

min_t() is more efficient then min(), that's why it was used.

> src_width = dst_width = min_t(unsigned int, data_width,
> dwc_fast_fls(src | dest | len));
> @@ -792,7 +807,6 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> unsigned long flags, void *context)
> {
> struct dw_dma_chan *dwc = to_dw_dma_chan(chan);
> - struct dw_dma_slave *dws = chan->private;
> struct dma_slave_config *sconfig = &dwc->dma_sconfig;
> struct dw_desc *prev;
> struct dw_desc *first;
> @@ -826,7 +840,7 @@ dwc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
> ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_M2P) :
> DWC_CTLL_FC(DW_DMA_FC_D_M2P);
>
> - data_width = dwc->dw->data_width[dwc_get_sms(dws)];
> + data_width = dwc_get_src_data_width(chan);
>
> for_each_sg(sgl, sg, sg_len, i) {
> struct dw_desc *desc;
> @@ -889,7 +903,7 @@ slave_sg_todev_fill_desc:
> ctllo |= sconfig->device_fc ? DWC_CTLL_FC(DW_DMA_FC_P_P2M) :
> DWC_CTLL_FC(DW_DMA_FC_D_P2M);
>
> - data_width = dwc->dw->data_width[dwc_get_dms(dws)];
> + data_width = dwc_get_dst_data_width(chan);
>
> for_each_sg(sgl, sg, sg_len, i) {
> struct dw_desc *desc;
> @@ -1720,7 +1734,6 @@ static int dw_probe(struct platform_device *pdev)
>
> channel_clear_bit(dw, CH_EN, dwc->mask);
>
> - dwc->dw = dw;
> dwc->direction = DMA_TRANS_NONE;
>
> /* hardware configuration */
> diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
> index f9532c2..577f2dd 100644
> --- a/drivers/dma/dw_dmac_regs.h
> +++ b/drivers/dma/dw_dmac_regs.h
> @@ -214,9 +214,6 @@ struct dw_dma_chan {
>
> /* configuration passed via DMA_SLAVE_CONFIG */
> struct dma_slave_config dma_sconfig;
> -
> - /* backlink to dw_dma */
> - struct dw_dma *dw;
> };
>
> static inline struct dw_dma_chan_regs __iomem *
> --
> 1.7.10.4
>


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