29 Jan
2008
29 Jan
'08
10:49 a.m.
On Tue, 29 Jan 2008 08:35:50 +0100 "Ulf Samuelsson" ulf.samuelsson@atmel.com wrote:
Your code does not support DMA transfers, while the current dataflash code runs DMA up to 50 Mbps.
so ? the point of u-boot is to do everything in PIO mode.
==> This is not how the dataflash support is implemented in U-Boot today. Current implementation is using DMA.
Current implementation is also AT91-only, which is a design flaw that is much worse than anything in Mike's approach.
That said, I think the low-level SPI API should make it possible for a low-level driver to do DMA. The proposed byte-at-a-time API does not allow this, while the existing spi_xfer() interface in include/spi.h does, assuming the buffers are properly aligned.
Haavard