Re: [PATCH] DMA: let filter functions of of_dma_simple_xlate possible check of_node

Santosh Shilimkar
2013-08-02T12:06:19Z

On Thursday 01 August 2013 10:00 PM, Richard Zhao wrote:
> pass of_phandle_args dma_spec to dma_request_channel in of_dma_simple_xlate,
> so the filter function could access of_node in of_phandle_args.
>
Am just curious the reasoning behind doing so. Can you please expand
above bit more with why you need to change it.

> It also remove restriction of #dma-cells has to be one.
>
> Signed-off-by: Richard Zhao <rizhao@nvidia.com>
> ---
> drivers/dma/edma.c | 7 +++++--
> drivers/dma/of-dma.c | 10 ++++------
> drivers/dma/omap-dma.c | 6 ++++--
> 3 files changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/dma/edma.c b/drivers/dma/edma.c
> index 4f6d87b..54582fd 100644
> --- a/drivers/dma/edma.c
> +++ b/drivers/dma/edma.c
> @@ -23,6 +23,7 @@
> #include <linux/platform_device.h>
> #include <linux/slab.h>
> #include <linux/spinlock.h>
> +#include <linux/of_dma.h>
>
> #include <linux/platform_data/edma.h>
>
> @@ -604,9 +605,11 @@ static struct platform_driver edma_driver = {
>
> bool edma_filter_fn(struct dma_chan *chan, void *param)
> {
> - if (chan->device->dev->driver == &edma_driver.driver) {
> + struct of_phandle_args *dma_spec = param;
> + if (chan->device->dev->driver == &edma_driver.driver &&
> + dma_spec->np == chan->device->dev->of_node) {
> struct edma_chan *echan = to_edma_chan(chan);
> - unsigned ch_req = *(unsigned *)param;
> + unsigned ch_req = dma_spec->args[0];
> return ch_req == echan->ch_num;
> }
> return false;
> diff --git a/drivers/dma/of-dma.c b/drivers/dma/of-dma.c
> index 75334bd..e1c4d3b 100644
> --- a/drivers/dma/of-dma.c
> +++ b/drivers/dma/of-dma.c
> @@ -192,11 +192,9 @@ struct dma_chan *of_dma_request_slave_channel(struct device_node *np,
> * @dma_spec: pointer to DMA specifier as found in the device tree
> * @of_dma: pointer to DMA controller data
> *
> - * A simple translation function for devices that use a 32-bit value for the
> + * A simple translation function for devices that use dma_spec for the
> * filter_param when calling the DMA engine dma_request_channel() function.
> - * Note that this translation function requires that #dma-cells is equal to 1
> - * and the argument of the dma specifier is the 32-bit filter_param. Returns
> - * pointer to appropriate dma channel on success or NULL on error.
> + * Returns pointer to appropriate dma channel on success or NULL on error.
> */
> struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
> struct of_dma *ofdma)
> @@ -207,10 +205,10 @@ struct dma_chan *of_dma_simple_xlate(struct of_phandle_args *dma_spec,
> if (!info || !info->filter_fn)
> return NULL;
>
> - if (count != 1)
> + if (count < 1)
> return NULL;
>
> return dma_request_channel(info->dma_cap, info->filter_fn,
> - &dma_spec->args[0]);
> + dma_spec);
> }
> EXPORT_SYMBOL_GPL(of_dma_simple_xlate);
> diff --git a/drivers/dma/omap-dma.c b/drivers/dma/omap-dma.c
> index ec3fc4f..32547ec 100644
> --- a/drivers/dma/omap-dma.c
> +++ b/drivers/dma/omap-dma.c
> @@ -693,9 +693,11 @@ static struct platform_driver omap_dma_driver = {
>
> bool omap_dma_filter_fn(struct dma_chan *chan, void *param)
> {
> - if (chan->device->dev->driver == &omap_dma_driver.driver) {
> + struct of_phandle_args *dma_spec = param;
> + if (chan->device->dev->driver == &omap_dma_driver.driver &&
> + dma_spec->np == chan->device->dev->of_node) {
> struct omap_chan *c = to_omap_dma_chan(chan);
> - unsigned req = *(unsigned *)param;
> + unsigned req = dma_spec->args[0];
>
> return req == c->dma_sig;
> }
>