[PATCH 7/8 resend] dw_dmac.c: Pass Channel Allocation Order from platform_data

viresh kumar viresh.kumar at st.com
Wed Mar 2 22:48:49 EST 2011


On 03/03/2011 12:07 AM, Koul, Vinod wrote:
> On Mon, 2011-02-28 at 16:11 +0530, Viresh Kumar wrote:
>> In SPEAr Platform channels 4-7 have more Fifo depth. So we must get better
>> channel first. This patch introduces concept of channel allocation order in
>> dw_dmac. If user doesn't paas anything or 0, than normal (ascending) channel
> pass?

Oops!!

>> allocation will follow, else channels will be allocated in descending order.
>>
>> Signed-off-by: Viresh Kumar <viresh.kumar at st.com>
>> ---
>>  drivers/dma/dw_dmac.c   |    6 +++++-
>>  include/linux/dw_dmac.h |    3 +++
>>  2 files changed, 8 insertions(+), 1 deletions(-)
>>
>> diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
>> index 01f783d..37ffd2c 100644
>> --- a/drivers/dma/dw_dmac.c
>> +++ b/drivers/dma/dw_dmac.c
>> @@ -1314,7 +1314,11 @@ static int __init dw_probe(struct platform_device *pdev)
>>  		dwc->chan.device = &dw->dma;
>>  		dwc->chan.cookie = dwc->completed = 1;
>>  		dwc->chan.chan_id = i;
>> -		list_add_tail(&dwc->chan.device_node, &dw->dma.channels);
>> +		if (pdata->chan_allocation_order == CHAN_ALLOCATION_ASCENDING)
>> +			list_add_tail(&dwc->chan.device_node,
>> +					&dw->dma.channels);
>> +		else
>> +			list_add(&dwc->chan.device_node, &dw->dma.channels);
>>  
>>  		dwc->ch_regs = &__dw_regs(dw)->CHAN[i];
>>  		spin_lock_init(&dwc->lock);
>> diff --git a/include/linux/dw_dmac.h b/include/linux/dw_dmac.h
>> index c8aad71..057e883 100644
>> --- a/include/linux/dw_dmac.h
>> +++ b/include/linux/dw_dmac.h
>> @@ -19,6 +19,9 @@
>>   */
>>  struct dw_dma_platform_data {
>>  	unsigned int	nr_channels;
>> +#define CHAN_ALLOCATION_ASCENDING	0	/* zero to seven */
>> +#define CHAN_ALLOCATION_DESCENDING	1	/* seven to zero */
> Can you add these defines outside of this struct?

I did this deliberately. I feel this is probably the better way as it
tells us _clearly_ the place where this macro is going to be used.
So i would insist on keeping it as it is, if you agree??

>> +	unsigned int	chan_allocation_order;

-- 
viresh



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