pci_alloc_consistent doubt

[Dhananjay Maske]

Hi Everyone,
  Can some one please help me with pci_alloc_consistent and how to use the
buffer allocated by it ?.


Thank you in Advance.
Djay


On Thu, Mar 28, 2013 at 10:08 AM, Dhananjay Maske <
dhananjay.maske87 at gmail.com> wrote:

>
>
>
> On Thu, Mar 28, 2013 at 1:14 AM, Dhananjay Maske <
> dhananjay.maske87 at gmail.com> wrote:
>
>> Hi All,
>>      I am fairly New to Linux kernel Programming and i have few questions
>> with respect to pci_alloc_consistent .
>>
>> 1) as we know pci_alloc_consistent allocates dma buffers which is visible
>> to DMA controller as well as CPU.
>>     virt_add = pci_alloc_consistent(pdev, size, dma_addr_t bus_adrr);
>>
>> here it will allocate a buffer and return its virtual address and
>> corresponding bus address.
>>
>> My question is do these two address ultimately point to similar location
>> but from different perspectives ?.
>>
>> 2) After allocating these address, how do we proceed given that i have a
>> ASIC register which has the dma_rx_desc_start address ?
>>
>> 3) Also does all the HW's which support dma have the descriptor data
>> structures by provided by Vender or is there any specific format that dev
>> has to be aware of for designing such descriptor for that particular driver
>> ?
>>
>
>
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