net: mvneta: 64bit platform support

Hi all,

Obviously, current mvneta driver can't work on 64bit platforms. For one thing the BM feature should be explicitly disabled, I just sent out one patch for this purpose.

What's more, the buf_cookie in mvneta_rx_desc need to be carefully considered. The driver use the buf_cookie(u32 type) to store the buffer virtual address, obviously it can't store the virtual address on 64bit platforms. I have two solutions:

solution A: let one reserved type in current mvneta_rx_desc, e.g reserved5 to store the high 32bit virt address, and hack code as the following:
#ifdef CONFIG_64BIT
rx_desc->reserved5 = high32(data);
#endif

solution B: add one member void **buf_virt_ptrs in mvneta_rx_queue, and point all buf_cookie usage to the according buf_virt_ptrs[i]

Is there any elegant solutions?

Thanks,
Jisheng

oh, missing some code:
#ifdef CONFIG_64BIT
data = ((u64)rx_desc->reserved5 << 32) | rx_desc->buf_cookie; #else
data = (void*)rx_desc->buf_cookie;
#endif

Please use the upper_32_bits() and lower_32_bits() macros to split up the pointer into two halves, and use the 64-bit version of the code above unconditionally, that should both work on all architectures without introducing any overhead.

Arnd