On Fri, Oct 12, 2012 at 02:55:18AM +0200, vj wrote: > > Ups, missed that. That's really a huge speed gain. I wonder why this > > happens. Maybe the overhead of request/release sdram region is > > significant with MMU disabled. Could you play with the BUFSIZ parameter > > to see if there's a good compromise between speeding up your transfer > > and still sensible buffer sizes? > > Here are the results: > 13133*PAGE_SIZE: Transferred 53789775 bytes in 3.326747 seconds at > 15.419848 MBps > 64*PAGE_SIZE: Transferred 53789775 bytes in 3.478078 seconds at > 14.748928 MBps > 32*PAGE_SIZE: Transferred 53789775 bytes in 3.655790 seconds at > 14.031968 MBps > 16*PAGE_SIZE: Transferred 53789775 bytes in 3.987313 seconds at > 12.865286 MBps > 8*PAGE_SIZE: Transferred 53789775 bytes in 4.540697 seconds at > 11.297368 MBps > 4*PAGE_SIZE: Transferred 53789775 bytes in 5.876598 seconds at > 8.729188 MBps > 2*PAGE_SIZE: Transferred 53789775 bytes in 8.249404 seconds at > 6.218380 MBps > Note: 13133 is reading the file at once. So 32 * PAGE_SIZE could be a good compromise. That is still a fine enough granularity for requesting SDRAM regions. > > > > > BTW I wonder if it would be possible to use the MMU in your setup. We > > have a 1:1 flat mapping which should be no problem for the ROM code. > > You probably would have to use dma_alloc_coherent to allocate the > > buffers which are used for USB transfers. > > Tested with MMU enabled having the buffers on local stack: fail > with buffers allocated with xzalloc: fail > with dma_alloc_coherent: fail > all of them freezes when calling the ROM function > omap4_usbboot_pdata.io->write(...) > also tried this initcalls, all with same result: > core_initcall(omap4_usbboot_init); > postmmu_initcall(omap4_usbboot_init); > > Why it doesn't work? I don't know. But if anybody wants to investigate attached > is the ROM code. At the top of the file are the entry points used by > barebox, which > surely are wrong because aren't dword aligned! I have no idea. That's probably the point where a jtag debugger could help. Sascha -- Pengutronix e.K. | | Industrial Linux Solutions | http://www.pengutronix.de/ | Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | Amtsgericht Hildesheim, HRA 2686 | Fax: +49-5121-206917-5555 | _______________________________________________ barebox mailing list barebox@xxxxxxxxxxxxxxxxxxx http://lists.infradead.org/mailman/listinfo/barebox
