Re: [ECOS] bugs in AT91 Ethernet driver

[Andrew Lunn <andrew at lunn dot ch>]

> About a TX driver.
> At91sam9260 errata says, TX buffer and buffer descriptors must be 
> allocated in fast memory, e.g. internal SRAM.
> So, eCos scheme with TX buffers which dinamically allocated from the heap 
> (heap is in external SDRAM at 9260EK)
> is do not work in interrupt mode.

This will be because of the history of the driver. It was developed on
the AT91SAM7X which does not have an external bus. Everything is in
SRAM.

However, you are wrong about the TX buffers being on the heap. The
buffer is inside the at91_eth_priv_t structure. This is allocated at
the end of if_at91.c. It will be placed in the data segment. 

What is needed is some compiler/linker magic to put it into a
different segment which is placed in sram. This has been talked about
a few times on the mailling list.

  Andrew

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