Re: [PATCH v2] OMAP: DMA: Add API for setting channel dest addr

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Manjunath,

On Tue, Mar 2, 2010 at 7:06 PM, Manjunatha GK <manjugk@xxxxxx> wrote:
> The new API - omap_set_dma_dst_pos(int lch, int value) is added
> for setting channel destination address in CPC/CDAC register
>
> Cc: Tony Lindgren <tony@xxxxxxxxxxx>
> Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> Cc: S, Venkatraman <svenkatr@xxxxxx>
> Signed-off-by: Manjunatha GK <manjugk@xxxxxx>
> Signed-off-by: Govindraj R <govindraj.raja@xxxxxx>
> ---
>  arch/arm/plat-omap/dma.c              |   17 +++++++++++++++++
>  arch/arm/plat-omap/include/plat/dma.h |    1 +
>  2 files changed, 18 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c
> index 2ab224c..c73f11a 100644
> --- a/arch/arm/plat-omap/dma.c
> +++ b/arch/arm/plat-omap/dma.c
> @@ -1109,6 +1109,23 @@ dma_addr_t omap_get_dma_dst_pos(int lch)
>  }
>  EXPORT_SYMBOL(omap_get_dma_dst_pos);
>
> +/**
> + * omap_set_dma_dst_pos() - Set DMA channel destination address
> + * @arg1:  lch      DMA logical channel number
> + * @arg2:  value    Value to write into CDAC register
> + *
> + * Writes "value" into the register CPC/CDAC
> + */
> +void omap_set_dma_dst_pos(int lch, int value)
> +{
> +       if (cpu_is_omap15xx())
> +               dma_write(value, CPC(lch));
> +       else
> +               dma_write(value, CDAC(lch));
> +
> +}
> +EXPORT_SYMBOL(omap_set_dma_dst_pos);
> +
>  int omap_get_dma_active_status(int lch)
>  {
>        return (dma_read(CCR(lch)) & OMAP_DMA_CCR_EN) != 0;
> diff --git a/arch/arm/plat-omap/include/plat/dma.h b/arch/arm/plat-omap/include/plat/dma.h
> index 02232ca..3b6e43e 100644
> --- a/arch/arm/plat-omap/include/plat/dma.h
> +++ b/arch/arm/plat-omap/include/plat/dma.h
> @@ -509,6 +509,7 @@ extern int omap_set_dma_callback(int lch,
>                        void *data);
>  extern dma_addr_t omap_get_dma_src_pos(int lch);
>  extern dma_addr_t omap_get_dma_dst_pos(int lch);
> +extern void omap_set_dma_dst_pos(int lch, int value);
>  extern void omap_clear_dma(int lch);
>  extern int omap_get_dma_active_status(int lch);
>  extern int omap_dma_running(void);
> --
 CDAC is not the destination address, as the API seems to suggest.
CDSA (Channel Destination Start Address) is.

CDAC is a running counter of the current transfer.
I propose to update the omap_start_dma to reset CDAC to 0 always.

Best regards,
Venkat.
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