[PATCH 05/11] ARM: add generic PrimeCell interface to COH 901 318 v5
Dan Williams
dan.j.williams at intel.com
Wed Apr 14 18:40:02 EDT 2010
Hi Linus,
On Wed, Apr 7, 2010 at 4:12 PM, Linus Walleij
<linus.walleij at stericsson.com> wrote:
> This extends the DMA engine driver for the COH 901 318 used in the
> U300 platform with the generic PrimeCell interface.
>
> Signed-off-by: Linus Walleij <linus.walleij at stericsson.com>
> ---
> drivers/dma/coh901318.c | 146 +++++++++++++++++++++++++++++++++++++++++++
> drivers/dma/coh901318_lli.c | 78 ++++++++++++++++++++++-
> 2 files changed, 221 insertions(+), 3 deletions(-)
>
[..]
> diff --git a/drivers/dma/coh901318_lli.c b/drivers/dma/coh901318_lli.c
> index 9f7e0e6..f37db49 100644
> --- a/drivers/dma/coh901318_lli.c
> +++ b/drivers/dma/coh901318_lli.c
> @@ -153,6 +153,39 @@ coh901318_lli_fill_memcpy(struct coh901318_pool *pool,
> lli->src_addr = src;
> lli->dst_addr = dst;
>
> + /*
> + * The DMA hardware will increase its pointer by 1,
> + * 2 or 4 bytes at a time depending on configuration.
> + * If using som oddly-aligned buffer this will cause
s/som/some/
> + * performance problems.
> + */
> +#if 0
> + ctrl_chained &= ~COH901318_CX_CTRL_SRC_BUS_SIZE_MASK;
> + ctrl_eom &= ~COH901318_CX_CTRL_SRC_BUS_SIZE_MASK;
> + ctrl_chained &= ~COH901318_CX_CTRL_DST_BUS_SIZE_MASK;
> + ctrl_eom &= ~COH901318_CX_CTRL_DST_BUS_SIZE_MASK;
> + if (src & 0x01) {
> + ctrl_chained |= COH901318_CX_CTRL_SRC_BUS_SIZE_8_BITS;
> + ctrl_eom |= COH901318_CX_CTRL_SRC_BUS_SIZE_8_BITS;
> + } else if (src & 0x02) {
> + ctrl_chained |= COH901318_CX_CTRL_SRC_BUS_SIZE_16_BITS;
> + ctrl_eom |= COH901318_CX_CTRL_SRC_BUS_SIZE_16_BITS;
> + } else {
> + ctrl_chained |= COH901318_CX_CTRL_SRC_BUS_SIZE_32_BITS;
> + ctrl_eom |= COH901318_CX_CTRL_SRC_BUS_SIZE_32_BITS;
> + }
> + if (dst & 0x01) {
> + ctrl_chained |= COH901318_CX_CTRL_DST_BUS_SIZE_8_BITS;
> + ctrl_eom |= COH901318_CX_CTRL_SRC_DST_SIZE_8_BITS;
> + } else if (dst & 0x02) {
> + ctrl_chained |= COH901318_CX_CTRL_DST_BUS_SIZE_16_BITS;
> + ctrl_eom |= COH901318_CX_CTRL_DST_BUS_SIZE_16_BITS;
> + } else {
> + ctrl_chained |= COH901318_CX_CTRL_DST_BUS_SIZE_32_BITS;
> + ctrl_eom |= COH901318_CX_CTRL_DST_BUS_SIZE_32_BITS;
> + }
> +#endif
It looks like this bit twiddling code is duplicated three times. Can
it be moved to a static inline in a header file and hide the #if 0
there as well. I assume you want it for documentation purposes in
case someone in the future has an unaligned usage model?
--
Dan
More information about the linux-arm-kernel
mailing list