Hi Michael,
On Wed, May 28, 2014 at 2:18 AM, Michael Schmitz <schmitzmic@xxxxxxxxx> wrote:
When deciding whether a ST-RAM DMA buffer needs to be allocated, the
Atari SCSI driver checks whether there's more than a single chunk of
RAM (there's always ST-RAM, so the second one indicates FastRAM).
That's no longer a good test now with the kernel capable of running
from FastRAM (and the ST-RAM chunk being dropped in MM init).
Maybe we need another variable to hold the number of memory chunks
before adjustment. Or look at size or physical base address of the
first chunk...
That's why DMA masks have been invented. The one in atari_scsi.c seems
to have the bits inverted, compared to all other places in the kernel.
But indeed, that doesn't help for the initial check:
if (MACH_IS_ATARI && ATARIHW_PRESENT(ST_SCSI) &&
!ATARIHW_PRESENT(EXTD_DMA) && m68k_num_memory > 1) {
atari_dma_buffer = atari_stram_alloc(STRAM_BUFFER_SIZE, "SCSI");
if (!atari_dma_buffer) {
printk(KERN_ERR "atari_scsi_detect: can't
allocate ST-RAM "
"double buffer\n");
return 0;
}
atari_dma_phys_buffer = virt_to_phys(atari_dma_buffer);
atari_dma_orig_addr = 0;
}
You can loop over m68k_memory[], and check if any chunk lies outside
the first 16 MiB?
If everything fails, you can allocate it unconditionally (it's just
one 4 KiB page).
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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