On 2018-10-09 13:49, Vinod wrote:
> On 24-09-18, 16:00, Peter Ujfalusi wrote:
>> dma_get_any_slave_channel() would skip using the filter function, which
>> in some cases needed to be executed before the alloc_chan_resources
>> callback to make sure that all parameters are provided for the slave
>> channel.
>
> Another request API, i though you had solved that last time around :(
Yes, I thought so, but this time it is different.
I want to drop this patch myself also, but I need to figure out a way to
do what the dmadev_get_slave_channel() allows me to do.
In path 4, udma_of_xlate() and the udma_dma_filter_fn()
It might be possible that I look up a free udma_chan, do the setup via
the filter_fn() and finally call the dma_get_slave_channel().
Might work fine, but I wanted to avoid to implement my own find free
channel code when we have it already in DMAengine core.
>>
>> Signed-off-by: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
>> ---
>> drivers/dma/dmaengine.c | 20 ++++++++++++++++++++
>> include/linux/dmaengine.h | 2 ++
>> 2 files changed, 22 insertions(+)
>>
>> diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c
>> index 27b6d7c2d8a0..b80f1bdd8813 100644
>> --- a/drivers/dma/dmaengine.c
>> +++ b/drivers/dma/dmaengine.c
>> @@ -634,6 +634,26 @@ struct dma_chan *dma_get_any_slave_channel(struct dma_device *device)
>> }
>> EXPORT_SYMBOL_GPL(dma_get_any_slave_channel);
>>
>> +struct dma_chan *dmadev_get_slave_channel(struct dma_device *device,
>> + dma_filter_fn fn, void *fn_param)
>> +{
>> + dma_cap_mask_t mask;
>> + struct dma_chan *chan;
>> +
>> + dma_cap_zero(mask);
>> + dma_cap_set(DMA_SLAVE, mask);
>> +
>> + /* lock against __dma_request_channel */
>> + mutex_lock(&dma_list_mutex);
>> +
>> + chan = find_candidate(device, &mask, fn, fn_param);
>> +
>> + mutex_unlock(&dma_list_mutex);
>> +
>> + return IS_ERR(chan) ? NULL : chan;
>> +}
>> +EXPORT_SYMBOL_GPL(dmadev_get_slave_channel);
>> +
>> /**
>> * __dma_request_channel - try to allocate an exclusive channel
>> * @mask: capabilities that the channel must satisfy
>> diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
>> index 16c9d021988a..32010c6ae13a 100644
>> --- a/include/linux/dmaengine.h
>> +++ b/include/linux/dmaengine.h
>> @@ -1542,6 +1542,8 @@ void dma_async_device_unregister(struct dma_device *device);
>> void dma_run_dependencies(struct dma_async_tx_descriptor *tx);
>> struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
>> struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);
>> +struct dma_chan *dmadev_get_slave_channel(struct dma_device *device,
>> + dma_filter_fn fn, void *fn_param);
>> #define dma_request_channel(mask, x, y) __dma_request_channel(&(mask), x, y)
>> #define dma_request_slave_channel_compat(mask, x, y, dev, name) \
>> __dma_request_slave_channel_compat(&(mask), x, y, dev, name)
>> --
>> Peter
>>
>> Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
>> Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
>
- Péter
Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki.
Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki
