On 04/22/2013 03:33 AM, Lars-Peter Clausen wrote:
> Both of_dma_nbcells field of the of_dma_controller and the args_count field of
> the dma_spec are initialized by parsing the #dma-cells attribute of their
> device
> tree node. So if the device tree nodes of a DMA controller and the dma_spec
> match this means that of_dma_nbcells and args_count will also match. So the
> second test in the of_dma_find_controller loop is redundant because given the
> first test yields true the second test will also yield true. So we can safely
> remove the test whether of_dma_nbcells matches args_count. Since this was the
> last user of the of_dma_nbcells field we can remove it altogether.
This assumes that someone has correctly added the dma information to the
dma slave binding. I could see systems where different dma controllers
have different of_dma_nbcells and so someone could put the enter wrong
number of cells for a dma slave binding. Its really to catch user error.
> Signed-off-by: Lars-Peter Clausen <l...@metafoo.de>
> ---
> drivers/dma/of-dma.c | 14 +-------------
> include/linux/of_dma.h | 1 -
> 2 files changed, 1 insertion(+), 14 deletions(-)
>
> diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
> index 268cc8a..75334bd 100644
> --- a/drivers/dma/of-dma.c
> +++ b/drivers/dma/of-dma.c
> @@ -35,8 +35,7 @@ static struct of_dma *of_dma_find_controller(struct
> of_phandle_args *dma_spec)
> struct of_dma *ofdma;
>
> list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers)
> - if ((ofdma->of_node == dma_spec->np) &&
> - (ofdma->of_dma_nbcells == dma_spec->args_count))
> + if (ofdma->of_node == dma_spec->np)
> return ofdma;
Other device-tree functions perform similar tests to this such as ...
static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
{
struct gg_data *gg_data = data;
int ret;
if ((gc->of_node != gg_data->gpiospec.np) ||
(gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
(!gc->of_xlate))
return false;
...
Cheers
Jon
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