DPAA fman dma addresses

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DPAA fman dma addresses

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sedat_altun
Contributor III

I am trying to use SDK 1.9 DPAA on T4240 . I need how the physical addresses (that FMAN puts the etherent packets via DMA) are allocated for use of FMAN DMA.

My problem is about alignment. I need dword aligned skb->data  addresses after receiving packets from FMAN, but in dpa_rx routine after skb_pull  of ethernet header(14 bytes) I have skb->data addresses which are not dword aligned, but my hardware DMA requires dword aligned addresses so I need to change the skb->data address without loss of packet fields.

Any help will be appreciated.

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Pavel
NXP TechSupport
NXP TechSupport

It looks like that code should be changed for assigning alignment data buffer.

Usually the following code is used for data alignment:

#define MASK_ALIGNMENT_4BYTES  (0x03) /*FEC needs 4bytes alignment*/

#define MASK_ALIGNMENT_8BYTES  (0x07)          /*FEC needs 64bytes alignment*/             

#define MASK_ALIGNMENT_32BYTES (0x1F)          /*FEC needs 32bytes alignment*/           

#define ADDR_ALIGNMENT(x) ((unsigned char *)(((unsigned long )(x) + (MASK_ALIGNMENT)) & (~MASK_ALIGNMENT)))

Length of array should be the following:

L - is real length of array

LL=L+MASK_ALIGNMENT - requried size of memory


Have a great day,
Pavel

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