On 07/21/2017 12:32 PM, Pierre Yves MORDRET wrote:
>
>
> On 07/21/2017 11:54 AM, Vinod Koul wrote:
>> On Fri, Jul 21, 2017 at 09:30:00AM +0000, Pierre Yves MORDRET wrote:
>>>>> +static enum dma_slave_buswidth stm32_mdma_get_max_width(u32 buf_len, u32
tlen)
>>>>> +{
>>>>> + enum dma_slave_buswidth max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
>>>>> +
>>>>> + while (((buf_len % max_width) || (tlen < max_width)) &&
>>>>> + (max_width > DMA_SLAVE_BUSWIDTH_1_BYTE))
>>>>> + max_width = max_width >> 1;
>>>>
>>>> ok, this is a bit hard to read...
>>>
>>> This code snippet has already been reworked and optimized. Would you mind to
>>> provide me a example with your expectation ? Thanks
>>
>> Code is optimized yes, but readable no
>>
>> I would like readability to be improved upon...
>>
>
> gotcha
>
Doest he code snippet below has a better looking for you ?
for (max_width = DMA_SLAVE_BUSWIDTH_8_BYTES;
max_width > DMA_SLAVE_BUSWIDTH_1_BYTE; max_width >>= 1)
if (((buf_len % max_width) == 0) && (tlen >= max_width))
break;
On 07/21/2017 07:17 PM, Vinod Koul wrote:
> On Fri, Jul 21, 2017 at 10:32:49AM +0000, Pierre Yves MORDRET wrote:
>>>>>> +static int stm32_mdma_set_xfer_param(struct stm32_mdma_chan *chan,
>>>>>> + enum dma_transfer_direction direction,
>>>>>> + u32 *mdma_ccr, u32 *mdma_ctcr,
>>>>>> + u32 *mdma_ctbr, u32 buf_len)
>>>>>> +{
>>>>>> + struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);
>>>>>> + struct stm32_mdma_chan_config *chan_config = &chan->chan_config;
>>>>>> + enum dma_slave_buswidth src_addr_width, dst_addr_width;
>>>>>> + phys_addr_t src_addr, dst_addr;
>>>>>> + int src_bus_width, dst_bus_width;
>>>>>> + u32 src_maxburst, dst_maxburst, src_best_burst, dst_best_burst;
>>>>>> + u32 ccr, ctcr, ctbr, tlen;
>>>>>> +
>>>>>> + src_addr_width = chan->dma_config.src_addr_width;
>>>>>> + dst_addr_width = chan->dma_config.dst_addr_width;
>>>>>> + src_maxburst = chan->dma_config.src_maxburst;
>>>>>> + dst_maxburst = chan->dma_config.dst_maxburst;
>>>>>> + src_addr = chan->dma_config.src_addr;
>>>>>> + dst_addr = chan->dma_config.dst_addr;
>>>>>
>>>>> this doesn't seem right to me, only the periphral address would come from
>>>>> slave_config, the memory address is passed as an arg to transfer..
>>>>>
>>>>> ...
>>>>>
>>>>
>>>> Correct. But these locals are managed in the case statement below. if direction
>>>> is Mem2Dev only dst_addr(Peripheral) is considered. In the other way around with
>>>> Dev2Mem direction only src_addr(Peripheral) is considered.
>>>> However to disambiguate I can move src_addr & dst_addr affectation in the
>>>> corresponding case statement if you'd like.
>>>
>>> But below you are over writing both, so in effect this is wasted cycles..
>>> anyway latter one is more clear, so lets remove from here.
>>>
>>
>> Sorry I don't follow ... or miss something
>> For instance if direction is Mem2Dev ..._xfer_param is going to configure
>> Destination Bus width and Addr given by slave_config. ..._setup_xfer in its turn
>> will configure source given as parameter.
>> Don't the see the over-writing
>
> ah re-looking at it, yes you are right.
>
> The above two assignments threw me off, I should have read it properly.
>
> But I think calculating for src and dstn always might not be optimal as you
> would use one only, so should these be moved to respective case where they
> are used...
>
Agree. This is my planned btw
Thanks
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